CN110896300A - Broadband low-noise amplifier - Google Patents

Broadband low-noise amplifier Download PDF

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Publication number
CN110896300A
CN110896300A CN201811059541.6A CN201811059541A CN110896300A CN 110896300 A CN110896300 A CN 110896300A CN 201811059541 A CN201811059541 A CN 201811059541A CN 110896300 A CN110896300 A CN 110896300A
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transistor
stage circuit
gain
resistor
noise amplifier
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黄冲
逯召静
刘览琦
张科峰
胡昂
石琴琴
杨阳
谭珍
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Wuhan Syntek Ltd
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Wuhan Syntek Ltd
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/56—Modifications of input or output impedances, not otherwise provided for
    • H03F1/565—Modifications of input or output impedances, not otherwise provided for using inductive elements
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/45179—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using MOSFET transistors as the active amplifying circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2200/00—Indexing scheme relating to amplifiers
    • H03F2200/294—Indexing scheme relating to amplifiers the amplifier being a low noise amplifier [LNA]
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45032—Indexing scheme relating to differential amplifiers the differential amplifier amplifying transistors are multiple paralleled transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
    • H03F2203/45—Indexing scheme relating to differential amplifiers
    • H03F2203/45148—At least one reactive element being added at the input of a dif amp

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Abstract

The invention discloses a broadband low-noise amplifier, which belongs to the field of integrated circuits and comprises a matching amplifier stage circuit, a first gain boost stage circuit and a second gain boost stage circuit. The matching amplification stage circuit adopts a common-gate input matching and noise elimination structure to realize the broadband matching, the single-end to differential conversion and the extremely low noise performance of the broadband low noise amplifier; in addition, the matching amplifier stage circuit comprises a grid inductor and a feedback capacitor, and the high-frequency gain of the broadband low-noise amplifier is compensated through the parallel connection of the grid inductor and the feedback capacitor; the first gain boost stage circuit is used for compensating the gain of the intermediate frequency band of the broadband low noise amplifier; the second gain boost stage circuit is used for compensating the low-frequency band gain of the broadband low noise amplifier; and the three-stage circuit of the broadband low-noise amplifier compensates the full-band gain. The invention realizes the functions of broadband input matching and high-frequency gain compensation.

Description

Broadband low-noise amplifier
Technical Field
The invention relates to the field of integrated circuits, in particular to a broadband low-noise amplifier.
Background
With the development of the technology, the integrated wireless communication chip is widely applied to a plurality of industries such as a combat system, a large-scale emergency communication system, navigation positioning, an internet of things, a sensor network, digital television broadcasting, public safety, intelligent building home, a radio station, a mobile terminal, toy electronics and the like, and accordingly various communication protocol standards are derived. In order to meet the market demand, the most popular research in the wireless communication field is to design a transceiver chip compatible with multiple protocols to meet the increasing demands of users for voice, video, data browsing, etc., which requires that the first-stage amplifier (low-noise amplifier) used as the signal processing of the wireless communication transceiver needs to have characteristics of broadband, high gain, high linearity, low noise, impedance matching, etc. Meanwhile, for better signal processing, a low noise amplifier is required to output a differential signal.
The broadband low-noise amplifier is a very important module in a communication link, is positioned at the foremost end of the whole receiving link circuit, directly amplifies signals received by an antenna and plays a vital role in signal quality. In this process, the useful signal in the communication band is amplified by the wideband low noise amplifier, while the noise generated by the wireless spatial channel is suppressed by the gain of the amplifier, while the noise added by the amplifier itself is so small that the useful signal is amplified without affecting its quality. Various types of interference transmitted by the wireless space channel generate signal intermodulation quantity, and the interference is suppressed by the good linear performance of the amplifier. Wideband low noise amplifier modules are typically required to have wideband input matching, in-band noise low, in-band gain flat, etc. requirements. In general, the design of a low noise amplifier is mostly narrow-band input, low noise and high gain requirements for specific application environments; however, the amplifier for broadband input and low noise often has disadvantages in various aspects, such as difficulty in matching broadband input, large noise coefficient, high-frequency gain attenuation, and the like.
In the prior art, a wide-band low noise amplifier usually adopts a common gate-common source (CG-CS) amplifier, and the transconductance g is adjustedmLoad RloadChanging the gain to achieve the gain target; in addition, the differential output realizes the Noise cancellation of the channel Noise of the common-gate transistor in the amplifier, and reduces the Noise coefficient (Noise Figure, abbreviated as NF in English); the single-ended input and differential balun (English abbreviated as balun) output are realized on the whole, and the impedance matching requirement is met. However, the technology has the defects that: such CG-CS amplifiers achieve partial noise cancellation, but due to the presence of parasitic capacitances at the input, the input matching will deteriorate as the input frequency increases; output side parasitics cause the output impedance to decrease with increasing frequency, resulting in overall gain to decrease with increasing frequency.
Disclosure of Invention
The invention aims to solve the technical problems that input matching of a broadband low-noise amplifier is large along with frequency change and high-frequency gain is attenuated along with frequency in the background technology, and provides the broadband low-noise amplifier.
The technical scheme adopted by the invention for solving the technical problems is as follows: constructing a wideband low noise amplifier comprising: the matching amplifier stage circuit, the first gain boost stage circuit and the second gain boost stage circuit;
the input end of the matching amplification stage circuit is the input end of the broadband low-noise amplifier and is used for inputting a single-ended input signal; the differential output end of the matching amplifier stage circuit is connected with the differential input end of the first gain boost stage circuit; the differential output end of the first gain boost stage circuit is connected with the differential input end of the second gain boost stage circuit; the differential output end of the second gain boost stage circuit is the differential output end of the broadband low noise amplifier;
the matching amplifier stage circuit comprises a grid inductor and a feedback capacitor, and high-frequency gain of the broadband low-noise amplifier is compensated and high-frequency matching degree is increased through parallel connection of the grid inductor and the feedback capacitor; the first gain boost stage circuit is used for compensating the gain of the intermediate frequency band of the broadband low noise amplifier; the second gain boost stage circuit is used for compensating the low-frequency band gain of the broadband low noise amplifier; and compensating the full-band gain through a three-stage circuit of the broadband low-noise amplifier.
Preferably, the matching amplifier stage circuit further comprises an input capacitor, an off-chip inductor, a first transistor, a second transistor, a third transistor, a fourth transistor, a first load resistor, a second load resistor, a first output parasitic coupling capacitor and a second output parasitic coupling capacitor;
the source electrode of the first transistor is respectively connected with one end of the input capacitor and one end of the off-chip inductor; the other end of the input capacitor is connected with the grid electrode of the second transistor; the other end of the off-chip inductor is connected with a source electrode of the second transistor; the drain electrode of the first transistor is connected with the source electrode of the third transistor; the drain electrode of the second transistor is connected with the source electrode of the fourth transistor; the feedback capacitor is arranged between the grid electrode of the first transistor and the drain electrode of the second transistor; the gate inductor is arranged between the gate of the third transistor and the gate of the fourth transistor; one end of the first output parasitic coupling capacitor is connected with the drain electrode of the third transistor and one end of the first load resistor respectively, and the other end of the first output parasitic coupling capacitor is connected with one differential output end of the matching amplification stage circuit; one end of the second output parasitic coupling capacitor is connected with the drain electrode of the fourth transistor and one end of the second load resistor respectively, and the other end of the second output parasitic coupling capacitor is connected with the other differential output end of the matching amplifier stage circuit; the other end of the first load resistor is connected with the other end of the second load resistor.
Preferably, the first transistor is an input common-gate transistor, the second transistor is an input common-source transistor, the third transistor is an output common-gate transistor, and the fourth transistor is an output common-gate transistor.
Preferably, the first transistor is used for converting the noise current input from the input end into a first voltage at one differential output end of the matching amplification stage circuit; the second transistor is used for converting the noise current input by the input end into a second voltage at the other differential output end of the matching amplification stage circuit; cancelling noise of the first transistor by summing the second noise voltage with the first noise voltage.
Preferably, the first gain boost stage circuit includes a fifth transistor, a sixth transistor, a seventh transistor, an eighth transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a first inductor, a second inductor, a third output parasitic coupling capacitor, and a fourth output parasitic coupling capacitor;
the grid electrode of the fifth transistor is respectively connected with one differential output end of the matching amplifier stage circuit and one end of the first resistor, and the drain electrode of the fifth transistor is connected with the source electrode of the seventh transistor; the grid electrode of the sixth transistor is respectively connected with the other differential output end of the matching amplifier stage circuit and one end of the second resistor, and the drain electrode of the sixth transistor is connected with the source electrode of the eighth transistor; the other end of the first resistor is connected with the other end of the second resistor; a source electrode of the fifth transistor is connected with a source electrode of the sixth transistor; a gate of the seventh transistor is connected to a gate of the eighth transistor; one end of the third output parasitic coupling capacitor is connected with one end of the third resistor and the drain electrode of the seventh transistor respectively, and the other end of the third output parasitic coupling capacitor is connected with one differential output end of the first gain boost stage circuit; the other end of the third resistor is connected with one end of the first inductor; one end of the fourth output parasitic coupling capacitor is connected with one end of the fourth resistor and the drain electrode of the eighth transistor respectively, and the other end of the fourth output parasitic coupling capacitor is connected with the other differential output end of the first gain boost stage circuit; the other end of the fourth resistor is connected with one end of the second inductor; the other end of the first inductor is connected with the other end of the second inductor.
Preferably, the fifth transistor and the sixth transistor are transistors with variable transconductance; the seventh transistor and the eighth transistor are common gate transistors.
Preferably, the first resistor and the second resistor have the same resistance value.
Preferably, the circuit structures of the first gain boost stage circuit and the second gain boost stage circuit are identical.
The broadband low-noise amplifier disclosed above has the following beneficial effects: the invention adopts negative feedback and gain compensation modes to complete the functions of broadband input matching and high-frequency gain compensation, has the advantages of simple circuit matching, controllable gain flatness, high three-stage isolation degree and the like, and overcomes the defects of difficult input matching and high-frequency gain attenuation of the common broadband low-noise amplifier.
Drawings
Fig. 1 is a block diagram of a wideband low noise amplifier according to the present invention;
FIG. 2 is a schematic circuit diagram of a matching amplifier stage circuit in a wideband low noise amplifier according to the present invention;
FIG. 3(a) is a comparison graph of the simulation results of the noise coefficients of the circuit with or without the feedback capacitor of the broadband low noise amplifier according to the present invention;
FIG. 3(b) is a comparison graph of simulation results of circuit gain and matching degree when the broadband low noise amplifier provided by the invention has or does not have a feedback capacitor;
FIG. 4 is a schematic circuit diagram of a first gain boost stage circuit in a wideband low noise amplifier according to the present invention;
FIG. 5 is a small signal equivalent diagram of a first gain boost stage circuit in a wideband low noise amplifier according to the present invention;
fig. 6 is a schematic circuit diagram of a second gain boost stage circuit in a wideband low noise amplifier according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a wideband low noise amplifier provided in the present invention, where the wideband low noise amplifier includes: the gain control circuit comprises a matching amplifier stage circuit 1, a first gain boost stage circuit 2 and a second gain boost stage circuit 3;
the input end of the matched amplifier stage circuit 1 is the input end In1 of the broadband low noise amplifier, and is used for inputting a single-ended input signal SIn(ii) a The differential output ends OUT1+ and OUT 1-of the matching amplification stage circuit 1 are connected with the differential input ends of the first gain boost stage circuit 2; the differential output ends OUT2+ and OUT 2-of the first gain boost stage circuit 2 are connected with the differential input ends of the second gain boost stage circuit 3; the differential output end of the second gain boost stage circuit 3 is the differential output end OUT3+ or OUT 3-of the broadband low noise amplifier;
the matching amplifier stage circuit 1 adopts a common-gate input matching and noise elimination structure and is used for realizing the broadband matching, the single-end-to-differential conversion and the extremely low noise performance of the broadband low noise amplifier; in addition, the matching amplifier stage circuit 1 further includes a gate inductor LgAnd a feedback capacitor CfbThrough gate inductance LgAnd a feedback capacitor CfbTo compensate the gain at high frequency of the broadband low noise amplifier and to increase the high frequency matching; the first gain boost stage circuit 2 is used for compensating the intermediate frequency band gain of the broadband low noise amplifier; the second gain boost stage circuit 3 is used for compensating the low-frequency band gain of the broadband low noise amplifier; and compensating the full-band gain together through the three-stage circuit of the broadband low-noise amplifier.
First, match amplifier stage circuit 1
Referring to fig. 2, a schematic circuit diagram of a matching amplifier stage circuit in a wideband low noise amplifier according to the present invention is shown, where the matching amplifier stage circuit 1 includes an input capacitor CfinOff-chip inductance LoffA first transistor M1, a second transistor M2, a third transistor M3, a fourth transistor M4, and a first load resistor RCGA second load resistor RCSA first output parasitic coupling capacitor C1 and a second output parasitic coupling capacitor C2; first crystalThe sources of the transistors M1 are connected with input capacitors CfinAnd off-chip inductance LoffOne end of (a); input capacitance CfinThe other end of the first transistor M2 is connected to the gate of the second transistor M2; off-chip inductance LoffThe other end of the first transistor M2 is connected to the source of the second transistor M2; the drain of the first transistor M1 is connected to the source of the third transistor M3; the drain of the second transistor M2 is connected to the source of the fourth transistor M4; feedback capacitance CfbIs arranged between the gate of the first transistor M1 and the drain of the second transistor M2; grid inductance LgIs arranged between the gate of the third transistor M3 and the gate of the fourth transistor M4; one end of the first output parasitic coupling capacitor C1 is connected to the drain of the third transistor M3 and the first load resistor RCGAnd the other end of the first input terminal is connected to a differential output terminal OUT1+ of the matching amplifier stage circuit 1; one end of the second output parasitic coupling capacitor C2 is connected to the drain of the fourth transistor M4 and the second load resistor RCSAnd the other end of the same is connected with the other differential output end OUT 1-of the matching amplifier stage circuit 1; a first load resistor RCGAnd the other end of the second load resistor RCSAnd the other end of the two are connected. The first transistor M1 is an input common-gate transistor, the second transistor M2 is an input common-source transistor, the third transistor M3 is an output common-gate transistor, and the fourth transistor M4 is an output common-gate transistor.
The parameters in the matched amplifier stage circuit 1 are as follows:
iin: from the antenna signal SInEquivalent input small signal current;
Vin: from the antenna signal SInAn equivalent input small signal voltage;
gm,CG: the transconductance of the input common-gate transistor M1;
gm,CS: the transconductance of the input common-source transistor M2;
Vn,in: the equivalence of the noise voltage generated by M1 at its source;
Vn,CG: m1 equivalent noise voltage at the output (drain);
Vn,CS: m2 equivalent noise voltage at the output (drain);
Av,CG: the amplification gain of M1 on the signal;
Av,CS: the amplification gain of M2 on the signal;
Vout,CG: m1 equivalent noise voltage at the output (source).
The matching amplifier stage circuit 1 is formed by combining an input common-gate transistor M1 and an input common-source transistor M2. The matching principle is that the transconductance g of M1 is utilizedm,CG. The gate inductance L of the output common-gate transistor M3 can be ignored when considering low frequency input matching and gain and noisegAnd a feedback capacitor CfbHigh order effects of (a). Calculating the input impedance R of the input common-gate transistor M1inCan be regarded as the reciprocal of its transconductance, i.e. 1/gm,CGApparent antenna impedance is RSThe two are only required to be equal, and impedance matching can be realized in a relatively wide frequency range, namely
Figure BDA0001796689920000061
The principle of converting the single-ended signal into the differential signal of the matching amplifier stage circuit 1 is as follows: first, for the slave antenna impedance RsThe signal input to the source of M1 can be considered as a small signal current iinThe small signal current will pass through M1, load R at M1CGThe up-flow, according to kirchhoff's current law, is calculated for the input small signal current as:
Figure BDA0001796689920000071
this means that the input impedance R of the input common-gate transistor M1inCan be expressed as:
Figure BDA0001796689920000072
from equation (3), the gain A provided by M1v,CGIs Av,CG＝gm,CG·RCG. And for M2, it is a standard input common source amplifying crystalThe gain of the tube, therefore, is equal to the multiplication of the transconductance by the load, while the phase of the signal is inverted, i.e. Av,CS＝-gm,CS·RCS. In combination, there are:
Av,CG＝-Av,CS＝gm,CG·RCG＝gm,CS·RCS(4)
as can be seen from equation (4), for the same antenna signal, the amplification gains of M1 and M2 are the same, but the polarities are opposite, so that differential signals with the same amplitude and 180 ° phase difference are formed at the drain outputs of M1 and M2, and the conversion process from single-ended signals to differential signals is completed.
The low noise principle of the matched amplifier stage circuit 1 is that the input common source transistor M2 is used for amplifying the noise Vn at the source of M1 to generate the noise Vn at the drain of M1, namely RCGThe noise of the same phase and the same amplitude is processed, so that the noise can be mutually cancelled in the output differential signal, and the noise generated by the M1 is eliminated from the whole. Since M1 is a transistor in the first stage of the wideband low noise amplifier, which has an amplifying effect on the signal, the elimination of this noise will greatly benefit the low noise design of the wideband low noise amplifier. This process requires that certain conditions be met, first, the noise current generated by M1 is derived from RCGR flowing to antenna endSThis noise current will generate a noise voltage at the source and drain of M1, respectively:
Figure BDA0001796689920000073
Figure BDA0001796689920000074
at the same time, Vn,inAmplified via the gate of M2, this noise voltage is amplified according to equation (4) as:
Vn,CS＝Vn,in·Av,CS＝α·in·RS·(-gm,CS·RCS) (7)
from equations (4), (5), equation (7) can be converted into:
Vn,CS＝-α·in·RCG＝Vn,CG(8)
it can be seen that the noise voltage generated by M1 is in phase and uniform in amplitude at the drains of M1 and M2. Since the differential signal is obtained by subtracting the two-end signals, in the differential signal transmission, this noise is cancelled out due to the consistent phase amplitude in the subtraction process, so that the noise of M1 is completely eliminated. It is noted that since M1 and M2 are the amplifying transistors of the first stage circuit in the wideband low noise amplifier, their noise has the largest influence on the wideband low noise amplifier, and the cancellation of the noise of M1 will greatly optimize the noise performance of the wideband low noise amplifier.
On the other hand, the noise of M2 cannot be eliminated by this structure, but since the work of impedance matching is mainly completed by M1, the size of M2 does not necessarily need to maintain a specific transconductance, so that the noise of M2 can be suppressed by increasing the size of M2 (i.e., increasing the transconductance). To satisfy equation (4), it is necessary to reduce the load resistance R of M2 accordinglyCSThis creates an imbalance in the output impedance of the matched amplifier stage, which is not a problem for the high impedance formed by the gate input of the subsequent stage.
In the matched amplifier stage 1, although M2 can change the size-raised transconductance to suppress noise, its gain is still limited by M1 because it is consistent with M1. And M1 needs to be satisfied in order to realize impedance matching
Figure BDA0001796689920000081
The transconductance g is limitedm,CGAnd thus there is a large limit to the gain. If it is too high by raising its load resistance RCGSeeking for gain increase, the output dynamic range is decreased due to the limitation of the power supply voltage, and even the M1 is difficult to work normally due to insufficient drain voltage. Therefore, it is difficult to achieve high gain performance in the matched amplifier stage. The gate inductance L is increased in the matching amplifier stage circuit 1gAnd a feedback capacitor Cfb. Drain of M2 through feedback capacitor CfbThe gate terminal of M1 is connected to match the input impedance closer to the source impedance to meet the input matching and gain boost requirements. In order to verify the gate inductance Lg and the feedback capacitance CfbThe influence on the circuit performance is realized by verifying the actual situation through the simulation of a spectrum simulator, and the simulation result is shown in fig. 3(a) and 3 (b). As shown in fig. 3(a), the simulation shows that the wideband low noise amplifier provided by the present invention has feedback capacitor C or not under the same size, bias, current, resistance and processfbThe noise coefficient of the circuit compares the situation: in the presence of a feedback capacitor CfbThe noise figure of the circuit is higher than that of the circuit without feedback capacitor CfbThe time is short. As shown in fig. 3(b), the simulation shows that the wideband low noise amplifier provided by the present invention has feedback capacitor C or not under the same size, bias, current, resistance and processfbAnd then, the gain and matching contrast conditions of the circuit are as follows: in the presence of a feedback capacitor CfbThe gain of the circuit is higher than that of the capacitor C without feedbackfbThe time is short; in the presence of a feedback capacitor CfbThe circuit matching degree is higher than that of the capacitor C without feedbackfbIt is good. (Note: NF in the simulation of FIG. 3(a) represents the noise figure; S21 in the simulation of FIG. 3(b) represents the gain, S11 represents the degree of matching.)
Second, first gain boost stage circuit 2
Referring to fig. 4, the first gain boost stage circuit 2 of the wideband low noise amplifier according to the present invention includes a fifth transistor M5, a sixth transistor M6, a seventh transistor M7, an eighth transistor M8, and a first resistor RF1A second resistor RF2A third resistor RL2LA fourth resistor RL2RA first inductor L2LA second inductor L2RA third output parasitic coupling capacitor C3 and a fourth output parasitic coupling capacitor C4; the gates of the fifth transistor M5 are respectively connected to a differential output terminal OUT1+ of the matched amplifier stage circuit 1 and the first resistor RF1Its drain is connected to the source of the seventh transistor M7; the gates of the sixth transistors M6 are connected to the other differential output O of the matched amplifier stage circuit 1UT 1-and a second resistor RF2A drain thereof is connected to the source of the eighth transistor M8; a first resistor RF1And the other end of the second resistor RF2The other ends of the two are connected; a source of the fifth transistor M5 is connected to a source of the sixth transistor M6; the gate of the seventh transistor M7 is connected to the gate of the eighth transistor M8; one end of the third output parasitic coupling capacitor C3 is connected with the third resistor R respectivelyL2LAnd the drain of the seventh transistor M7, the other end of which is connected to a differential output terminal OUT2+ of the first gain stage circuit 2; third resistor RL2LIs connected with a first inductor L2LOne end of (a); one end of the fourth output parasitic coupling capacitor C4 is connected with the fourth resistor R respectivelyL2RAnd the drain of the eighth transistor M8, the other end of which is connected to the other differential output terminal OUT 2-of the first gain boost stage circuit 2; a fourth resistor RL2RIs connected with a second inductor L2ROne end of (a); first inductance L2LAnd the other end of the second inductor L2RAnd the other end of the two are connected. The fifth transistor M5 and the sixth transistor M6 are transistors with variable transconductance; the seventh transistor M7 and the eighth transistor M8 are common gate transistors; a first resistor RF1And a second resistor RF2Are equal.
The parameters in the first gain boost stage circuit 2 are as follows:
BLNAHLNA high gain bits;
BLNAMLNA low gain bits;
m5, M6: gm variable cell;
m7, M8 is a common gate amplifier;
gm: a transconductance of the transistor;
g″m: second derivative of the transistor transconductance.
As the gain-up stage 2 shown in fig. 4, M5 and M6 are amplifying transistors operating in the saturation region. The small-signal equivalent diagram of fig. 4 is shown in fig. 5, and the transconductances of the common-gate amplifier M7 and the common-source amplifier M5 are equivalent to one transconductance cell Gm by the switching signal BLNAHAnd BLNAMControlling the additional load tube. Load inductance L2LAnd a load inductanceL2REquivalent to L in FIG. 5load(ii) a Load resistance R2LLoad resistance R2REquivalent to R in FIG. 5load(ii) a The third output parasitic coupling capacitor C3 and the fourth output parasitic coupling capacitor C4 are equivalent to C in FIG. 5loadEquivalent impedance is ZTConsidering the output impedance of the Gm transconductance cell to be reduced to resistor R0And finally the equivalent load R of the small-signal circuitLIs an equivalent load ZTAnd R0In parallel, as shown in equation (9), where s represents a signal transformation parameter:
Figure BDA0001796689920000101
input impedance Z of small signal circuitinAs shown in equation (10):
Figure BDA0001796689920000102
the gain of the small-signal circuit is shown as (11):
Av＝(1/Zin-sCgs-Gm)RL(11)
expressions (9) to (11) represent impedance and gain in a small-signal circuit
To simplify the calculation, R can be madeload0 due to R0The effective impedance R of the small signal circuit can be obtained in a simplified way if the output impedance is mainly LC impedanceLAnd a gain Av：
Figure BDA0001796689920000111
Av＝GmRL(13)
According to different LloadCloadDifferent resonance frequency points and impedance sizes can be selected, and different gains Gm R can be obtained by controlling different GmsL. Finally, the gain of the gain boost stage circuit 2 is: a. thev＝GmRLThe gain of the intermediate frequency can be compensated.
Third and second gain boost stage circuit 3
Referring to fig. 6, the circuit schematic diagram of the second gain boost stage circuit in the wideband low noise amplifier provided by the present invention, the circuit structure of the second gain boost stage circuit 3 is completely the same as the circuit structure of the first gain boost stage circuit 2. So that the gain A of the second gain boost stage circuit 3 can be obtainedv3＝GmRL' the gain of the low intermediate frequency can be compensated.
In summary, the present invention provides a circuit composed of three stages for overcoming the disadvantages of difficult input matching and high frequency gain attenuation of a wideband low noise amplifier: the matching amplifier stage circuit, the first gain boost stage circuit and the second gain boost stage circuit; the matching amplification stage circuit adopts a common-gate input matching and noise elimination structure, and realizes the broadband matching, single-end to differential conversion and extremely low noise performance of the broadband low noise amplifier; in addition, the matching amplifier stage circuit further comprises a grid inductor and a feedback capacitor, and the grid inductor and the feedback capacitor are connected in parallel to compensate the gain of the broadband low-noise amplifier at the high frequency; the first gain boost stage circuit is used for compensating the gain of the intermediate frequency band of the broadband low noise amplifier; the second gain boost stage circuit is used for compensating the low-frequency band gain of the broadband low noise amplifier; the three stages of the broadband low noise amplifier together compensate the full band gain. The invention realizes the functions of broadband input matching and high-frequency gain compensation, and has the advantages of simple circuit matching, controllable gain flatness, high three-level isolation and the like.
Various operations of embodiments are provided herein. In one embodiment, the one or more operations may constitute computer readable instructions stored on one or more computer readable media, which when executed by an electronic device, will cause the computing device to perform the operations. The order in which some or all of the operations are described should not be construed as to imply that these operations are necessarily order dependent. Those skilled in the art will appreciate alternative orderings having the benefit of this description. Moreover, it should be understood that not all operations are necessarily present in each embodiment provided herein.
Also, as used herein, the word "preferred" is intended to serve as an example, instance, or illustration. Any aspect or design described herein as "preferred" is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word "preferred" is intended to present concepts in a concrete fashion. The term "or" as used in this application is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless specified otherwise or clear from context, "X employs A or B" is intended to include either of the permutations as a matter of course. That is, if X employs A; b is used as X; or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing examples.
Also, although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The present disclosure includes all such modifications and alterations, and is limited only by the scope of the appended claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary implementations of the disclosure. In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for a given or particular application. Furthermore, to the extent that the terms "includes," has, "" contains, "or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term" comprising.
Each functional unit in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium. The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Each apparatus or system described above may perform the method in the corresponding method embodiment.
In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.

Claims (8)

1. A wideband low noise amplifier, comprising: the circuit comprises a matching amplifier stage circuit (1), a first gain boost stage circuit (2) and a second gain boost stage circuit (3);
the input end of the matching amplification stage circuit (1) is the input end (In1) of the broadband low noise amplifier, and is used for inputting a single-ended input signal (S)In) (ii) a The differential output end (OUT1+, OUT1-) of the matching amplification stage circuit (1) is connected with the differential input end of the first gain boost stage circuit (2); the differential output end (OUT2+, OUT2-) of the first gain boost stage circuit (2) is connected with the differential input end of the second gain boost stage circuit (3); the differential output end of the second gain boost stage circuit (3) is the differential output end (OUT3+, OUT3-) of the broadband low noise amplifier;
the matching amplifier stage circuit (1) comprises a gate inductance (L)g) And a feedback capacitance (C)fb) Through the gate inductance (L)g) And the feedback capacitance (C)fb) The parallel connection of (1) and (2) is used for compensating the high-frequency gain of the broadband low-noise amplifier and increasing the high-frequency matching degree; the first gain boost stage circuit (2) is used for compensating the intermediate frequency band gain of the broadband low noise amplifier; the second gain boost stage circuit (3) is used for compensating the low-frequency band gain of the broadband low noise amplifier; and compensating the full-band gain through a three-stage circuit of the broadband low-noise amplifier.
2. A wideband low noise amplifier according to claim 1, characterized in that the matched amplifier stage circuit (1) further comprises an input capacitance (C)fin) Off-chip inductance (L)off) The load circuit comprises a first transistor (M1), a second transistor (M2), a third transistor (M3), a fourth transistor (M4), and a first load resistor (R)CG) A second load resistor (R)CS) A first output parasitic coupling capacitor (C1) and a second output parasitic coupling capacitor (C2);
the sources of the first transistors (M1) are respectively connected with the input capacitors (C)fin) And the off-chip inductor (L)off) One end of (a); the input capacitance (C)fin) Is connected to the gate of the second transistor (M2); the off-chip inductor (L)off) Is connected to the source of the second transistor (M2); the drain of the first transistor (M1) is connected to the source of the third transistor (M3); the drain of the second transistor (M2) is connected to the source of the fourth transistor (M4); the feedback capacitance (C)fb) Disposed between the gate of the first transistor (M1) and the drain of the second transistor (M2); the gate inductance (L)g) Is disposed between the gate of the third transistor (M3) and the gate of the fourth transistor (M4); one end of the first output parasitic coupling capacitor (C1) is connected to the drain of the third transistor (M3) and the first load resistor (R)CG) And the other end of the first terminal is connected to a differential output (OUT1+) of the matching amplifier stage (1); one end of the second output parasitic coupling capacitor (C2) is connected to the drain of the fourth transistor (M4) and the second load resistor (R)CS) And the other end of the differential amplifier is connected with the other differential output end (OUT1-) of the matching amplifier stage circuit (1); the first load resistance (R)CG) And the other end of the second load resistor (R) and the second load resistor (R)CS) And the other end of the two are connected.
3. The wideband low noise amplifier according to claim 2, wherein the first transistor (M1) is an input common-gate transistor, the second transistor (M2) is an input common-source transistor, the third transistor (M3) is an output common-gate transistor, and the fourth transistor (M4) is an output common-gate transistor.
4. The wideband low noise amplifier according to claim 2, wherein the first transistor (M1) is configured to convert a noise current inputted from the input terminal (In1) into a first voltage at one differential output terminal (OUT1+) of the matched amplifier stage circuit (1); the second transistor (M2) is used for converting the noise current input by the input end (In1) into a second voltage at the other differential output end (OUT1-) of the matching amplification stage circuit (1); cancelling noise of the first transistor (M1) by summing the second noise voltage with the first noise voltage.
5. The wideband low noise amplifier according to claim 1, wherein the first gain-boosting stage circuit (2) comprises a fifth transistor (M5), a sixth transistor (M6), a seventh transistor (M7), an eighth transistor (M8), a first resistor (R8)F1) A second resistor (R)F2) A third resistor (R)L2L) A fourth resistor (R)L2R) A first inductor (L)2L) A second inductor (L)2R) A third output parasitic coupling capacitor (C3) and a fourth output parasitic coupling capacitor (C4);
the gate of the fifth transistor (M5) is respectively connected with one differential output end (OUT1+) of the matching amplifier stage circuit (1) and the first resistor (R)F1) A drain thereof is connected to the source of the seventh transistor (M7); the grid electrode of the sixth transistor (M6) is respectively connected with the other differential output end (OUT1-) of the matching amplification stage circuit (1) and the second resistor (R)F2) A drain thereof is connected to the source of the eighth transistor (M8); the first resistor (R)F1) And the other end of the second resistor (R) and the second resistor (R)F2) The other ends of the two are connected; a source of the fifth transistor (M5) and a source of the sixth transistor (M6) are connected; a gate of the seventh transistor (M7) and a gate of the eighth transistor (M8) are connected; one end of the third output parasitic coupling capacitor (C3) is connected with the third output parasitic coupling capacitorResistance (R)L2L) And the drain of said seventh transistor (M7), the other terminal being connected to a differential output terminal (OUT2+) of said first gain stage circuit (2); the third resistor (R)L2L) Is connected to the first inductance (L)2L) One end of (a); one end of the fourth output parasitic coupling capacitor (C4) is respectively connected with the fourth resistor (R)L2R) And the drain of the eighth transistor (M8), the other terminal being connected to the other differential output terminal (OUT2-) of the first gain stage circuit (2); the fourth resistor (R)L2R) Is connected with a second inductor (L)2R) One end of (a); the first inductance (L)2L) And said second inductance (L)2R) And the other end of the two are connected.
6. The wideband low noise amplifier according to claim 5, wherein the fifth transistor (M5) and the sixth transistor (M6) are transistors with variable transconductance; the seventh transistor (M7) and the eighth transistor (M8) are common gate transistors.
7. Broadband low noise amplifier according to claim 5, characterized in that said first resistance (R)F1) And said second resistance (R)F2) Are equal.
8. A wideband low noise amplifier according to claim 1, characterized in that the circuit structure of the first gain stage circuit (2) and the second gain stage circuit (3) are identical.
CN201811059541.6A 2018-09-12 2018-09-12 Broadband low-noise amplifier Pending CN110896300A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111478671A (en) * 2020-04-13 2020-07-31 电子科技大学 Novel low-noise amplifier applied to Sub-GHz frequency band
CN112653397A (en) * 2020-12-11 2021-04-13 电子科技大学 Broadband transconductance enhanced low-noise amplifier
CN113325710A (en) * 2021-05-26 2021-08-31 广东电网有限责任公司 Automatic tracking system and method for high-frequency noise amplitude gain
CN113467320A (en) * 2021-07-21 2021-10-01 西安龙飞电气技术有限公司 Weak signal detection algorithm based on gain compensation
CN114520008A (en) * 2020-11-20 2022-05-20 西部数据技术公司 Data storage device employing amplifier feedback for impedance matching
CN117674738A (en) * 2024-02-02 2024-03-08 深圳飞骧科技股份有限公司 Broadband differential low-noise amplifier and radio frequency chip

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111478671A (en) * 2020-04-13 2020-07-31 电子科技大学 Novel low-noise amplifier applied to Sub-GHz frequency band
CN114520008A (en) * 2020-11-20 2022-05-20 西部数据技术公司 Data storage device employing amplifier feedback for impedance matching
CN114520008B (en) * 2020-11-20 2024-04-19 西部数据技术公司 Data storage device employing amplifier feedback for impedance matching
CN112653397A (en) * 2020-12-11 2021-04-13 电子科技大学 Broadband transconductance enhanced low-noise amplifier
CN113325710A (en) * 2021-05-26 2021-08-31 广东电网有限责任公司 Automatic tracking system and method for high-frequency noise amplitude gain
CN113467320A (en) * 2021-07-21 2021-10-01 西安龙飞电气技术有限公司 Weak signal detection algorithm based on gain compensation
CN117674738A (en) * 2024-02-02 2024-03-08 深圳飞骧科技股份有限公司 Broadband differential low-noise amplifier and radio frequency chip
CN117674738B (en) * 2024-02-02 2024-04-05 深圳飞骧科技股份有限公司 Broadband differential low-noise amplifier and radio frequency chip

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