WO2013044413A1

WO2013044413A1 - Providing analog tuning for a radio with a controllable number of pins

Info

Publication number: WO2013044413A1
Application number: PCT/CN2011/001656
Authority: WO
Inventors: Lawrence Der; Liguo JIANG; Gang Yuan
Original assignee: Silicon Laboratories Inc.
Priority date: 2011-09-30
Filing date: 2011-09-30
Publication date: 2013-04-04
Also published as: CN103959659A; CN103959659B

Abstract

According to one embodiment, the present invention includes a system that has a mechanical tuning mechanism to enable a user to select a radio channel, a variable resistance coupled to the mechanical tuning mechanism, and a radio receiver implemented on a die of a semiconductor package. The variable resistance has a first terminal to couple to a supply voltage and a second terminal to couple to a ground voltage, and a connection to provide a variable analog voltage responsive to the user selection. In turn, the receiver is coupled to receive the variable analog voltage via a first pin of the package, receive the supply voltage via a second pin of the package, and receive the ground voltage via a third pin of the package, in a single pin tuning mode. The receiver can downconvert a radio frequency (RF) signal to a second frequency signal with a mixing signal having a frequency based on the variable analog voltage.

Description

PROVIDING ANALOG TUNING FOR A

RADIO WITH A CONTROLLABLE NUMBER OF PINS

Background

[0001] Radios are pervasive in many different forms, including portable radios, mobile radios in cars, radios in cellular telephones, as well as radios for the home, such as clock radios, stereo receivers and so forth. Many of today's radios operate using digital tuning, in which a user can select a desired channel digitally, e.g., using control buttons to select a given digital representation of the channel. However, many radios still provide a mechanical analog control such as a tuning wheel, where a user rotates the wheel to a selected position that represents a given channel.

[0002] Many radios are now being produced via a single semiconductor package that, along with several external components, achieves a complete radio solution. However, to couple those off-chip components to the package, a large number of pins or connections to the package are needed. This raises costs, size and increases complexity. Analog tuned radios, conventionally require use of two to three dedicated pins to enable analog tuning with the required precision, which thus increases pin count and corresponding package and other costs.

Summary of the Invention

[0003] According to one aspect of the present invention, an integrated circuit (IC) formed of a semiconductor package includes a radio receiver formed on a single semiconductor die. This die couples to pads of the IC that in turn are connected to pins of the package. Specifically, a first pad of the IC is to couple to a supply voltage and a first pad of the die is couple to the first pad of the IC via a first bonding mechanism. A second pad of the IC is to couple to a variable resistance that is adjustable by a user to tune to a radio channel, and a second pad of the die is coupled to the second pad of the IC via a second bonding mechanism. A third pad of the IC is to couple to a reference potential and a third pad of the die is coupled to the third pad of the IC via a third bonding mechanism. In turn, a fourth pad of the IC is configurable to couple to the supply voltage or to be unconnected. And a fourth pad of the die is coupleable to the fourth pad of the IC when the fourth pad of the IC is configured to couple to the supply voltage, and otherwise the fourth pad of the die is decoupled from the fourth pad of the IC.

[0004] The radio can further include an analog-to-digital converter (ADC) to receive the supply voltage as a first reference voltage and to receive a tuning voltage from the second pad of the die to convert the tuning voltage to a digital value. In turn, a controller can be coupled to receive the digital value corresponding to a level of the variable resistance, and control a local oscillator coupled to a mixer responsive to the digital value. In some implementations, the radio can further include a filter coupled to receive the supply voltage and to output a filtered supply voltage to the ADC.

[0005] In some embodiments, the radio can be configured for a single pin tuning mode or a multiple pin tuning mode depending on the package in which the radio is incorporated. This configurability can be realized using switches both on the die and within the package. As an example, a first switch of the package can couple the supply voltage to a first terminal of the variable resistance in the single pin tuning mode and to couple the supply voltage to the first terminal from the fourth pad of the IC in a non-single pin tuning mode. Further, a second switch of the die can controllably couple the supply voltage or a regulated voltage to the ADC.

[0006] Another aspect of the present invention is directed to a system that includes a mechanical tuning mechanism to enable a user to select a radio channel, a variable resistance coupled to the mechanical tuning mechanism, and a radio receiver implemented on a die of a semiconductor package. The variable resistance has a first terminal to couple to a supply voltage and a second terminal to couple to a ground voltage, and a connection to provide a variable analog voltage responsive to the user selection. In turn, the receiver is coupled to receive the variable analog voltage via a first pin of the package, receive the supply voltage via a second pin of the package, and receive the ground voltage via a third pin of the package. The receiver can downconvert a radio frequency (RF) signal to a baseband signal using a mixing signal having a frequency controlled based on the variable analog voltage. Brief Description of the Drawings

[0007] FIG. 1 is a schematic diagram of a single pin tuning solution in accordance with an embodiment of the present invention.

[0008] FIG. 2 is a schematic diagram of a hybrid tuning solution in accordance with another embodiment of the present mention.

[0009] FIG. 3 is a block diagram of a radio receiver in accordance with one embodiment of the present invention.

[0010] FIG. 4 is a block diagram of a system in accordance with an embodiment of the present invention.

Detailed Description

[0011] In various embodiments, a semiconductor-based radio may provide for different modes of analog tuning by coupling of an off-chip variable impedance that can be controlled by a user to tune to a desired channel. This off-chip impedance can be a resistor in many implementations and can be configured to be controllable based on a given control. This control may be by a user's manual adjusting of a tuning wheel or selection of a radio channel digitally that in turn causes an off-chip controller such as a microcontroller unit (MCU) to generate an analog signal to control the variable resistance.

[0012] As will be described, different modes of operation can be provided to enable coupling of this off-chip resistor to an on-chip analog-to-digital converter (ADC) that converts an incoming analog signal to a digital value. This digital value in turn can be provided to an internal controller such as an MCU to enable tuning to the desired channel.

[0013] In a first mode, a so-called single pin solution can be provided. That is, a variable resistor, also referred to herein as a potentiometer, can be coupled to a single semiconductor die radio incorporated in a semiconductor package by way of a single pin, thus reducing the number of package pins used to enable analog tuning. Although described as a single pin solution, understand that additional pins may be used in connection with the analog tuning. Namely, a supply voltage pin and a reference voltage (e.g., ground) pin, which may be present in any semiconductor package to provide power and reference can also be used. A second mode is a hybrid mode in which a circuit can be controlled to use more than one pin, and which is described further below.

[0014] Referring now to FIG. 1 , shown is a schematic diagram of a single pin tuning solution in accordance with an embodiment of the present invention. As shown in FIG. 1 , system 10, which is a portion of a radio, shows a division between on-chip components 50 and off-chip components 5. With regard to the off-chip components, a first signal line may provide a battery voltage (V_Bat) which can be received from a power supply such as a battery source (which may generally be located outside the package and coupled to this signal line via a package pin). As seen, this battery voltage may be provided to a first pad P1A, which can be an off- chip pad present within the package itself, but off-chip. However in other implementations, such pad can be present on a circuit board to which the semiconductor package including chip 50 is coupled. As further seen, this battery voltage can further be coupled to a first terminal of a potentiometer variable resistor (PVR) or potentiometer R1 , which is further coupled to a reference voltage GND by a second terminal of the potentiometer. As seen, a tuning signal can be provided via a signal line coupled between potentiometer R1 and a second pad P2A. And the reference voltage can be provided via a signal line coupled to a third pad P3A. Both pads P2A and P3A may be off-chip pads as with pad P1A. Each of the pads couple to a pin of the semiconductor package (not shown for ease of illustration in FIG. 1 ). But the pins for the supply voltage and reference voltage are needed in any externally supplied IC, and as such only a single dedicated package pin is used for analog tuning. That is, pads P1 B and P3B are the only pads of the package that provide supply and reference voltages to the chip, and thus the need for dedicated pads and pins of the package for analog tuning is avoided here.

[0015] In general, the tuning signal can thus provide a voltage that is representative of the desired channel, e.g., as controlled by a user's adjustment of a tuning wheel. In other implementations, rather than an analog tuning wheel, a radio can be provided with a digital control such that a user can request a desired channel by way of input of a digital frequency selection, which in turn can be provided to an off-chip controller to provide a command to a radio, e.g., via a serial bus, or the off-chip controller can convert this value into a voltage to be provided to the variable resistance. By controlling the potentiometer, a variable voltage is thus provided that can be used to determine a ratio of the total available resistance (and thus voltage) which is used to represent a desired radio channel. Generally, this potentiometer can be thought of as a resistor divider having resistances Rx and Ry. Based on control of the variable resistance, a tuning voltage corresponding to a ratio, e.g., (Ry/Rx+Ry) x Veat can thus be obtained. In various implementations, the input voltage range of the tuning voltage can be set to approximately half of the supply voltage to maintain immunity to interruption currents. To enable interconnection between these off-chip pads and corresponding on-chip pads P1 B - P3B, a plurality of bonding mechanisms B1-B3 can be provided. As will be discussed further below, in certain implementations these bonding mechanisms and pads may be provided with certain capabilities to reduce resistance and improve sensitivity to interference.

[0016] With reference now to on-chip components 50, note that the battery voltage can be coupled to an impedance Z, which generally corresponds to the various circuitry of the semiconductor radio that is powered by the battery voltage. Because of varying amounts of current consumption in different modes of operation and so forth, this impedance is not at a steady-state and accordingly, variable currents can occur, which in turn can cause interference with the tuning voltage provided by off-chip potentiometer R1.

[0017] As further seen, the battery voltage received at pad P1 B can be provided to a low pass filter (LPF) 20. Similarly, the tuning voltage received at pad P2B can further be coupled to LPF 20 and in addition, the reference voltage received at pad P3B also can be coupled to LPF 20. Although shown as a single filter for ease of illustration, understand that different filters may be provided for each of these signals, and in some implementations different corner frequencies can be provided for the different filters. By using LPF 20, the signals can be filtered of interference caused, e.g., by interfering currents due to varying current consumption of the semiconductor radio. This filter is also anti-alias filter for a converter, namely an auxiliary ADC 30. This bandwidth of the filter is less than half of sample rate of ADC 30. In various embodiments, LPF 20 can be set with a relatively low bandwidth, to obtain the low frequency or DC value of the signal.

[0018] As further seen in FIG. 1 , the battery voltage can be provided as a positive reference voltage to a first input terminal of a converter, namely an auxiliary ADC 30. Auxiliary ADC 30 may be controllable to receive a variety of analog inputs and can be controlled, e.g., by a controller to generate digital values each corresponding to one of the analog inputs as indicated by the controller. In turn, the tuning voltage can be provided to a second input terminal of ADC 30. As a result, ADC 30 may generate an N-bit output representative of the tuning voltage. This digital output may thus correspond to a digital tuning signal that can be provided to a MCU (not shown in FIG. 1) that in turn can generate one or more control signals to control various front end analog circuitry of the semiconductor radio to cause tuning to a desired channel.

[0019] Although the implementation of FIG. 1 may provide for a smallest number of package connections (namely one dedicated pin in addition to conventional supply and reference voltage pins) in some designs this single pin solution may be insufficient from power supply or design accuracy requirements. Accordingly, other embodiments can provide a hybrid approach in which a semiconductor-based radio is provided with controllable features such that a single semiconductor die solution can be implemented into different packages having different numbers of available pin connections. Thus this hybrid implementation enables the single pin solution of FIG. 1 and furthermore provides for additional modes that use additional pins of a semiconductor package.

[0020] Referring now to FIG. 2, shown is a schematic diagram of a hybrid pin solution in accordance with another embodiment of the present mention. As seen in FIG. 2, circuit 100 includes both off-chip components 105 and on-chip components 150. In addition to a LPF 120 and an ADC 130, which can be configured similarly to these components discussed with regard to FIG. 1 , a low dropout (LDO) regulator 140 may further be present on-chip. As will be described further below, LDO regulator 140 can be configured to receive the supply voltage via a bonding mechanism B4, e.g., a battery voltage, and generate one or more regulated voltage outputs that can be provided to various circuitry of the semiconductor radio (not shown for ease of illustration in FIG. 2).

[0021] To effect different modes of operation, switches can be provided, both on-chip and off-chip. As seen, an off-chip switch S1 may be provided and further an on-chip switch S2 also may be provided.

[0022] To enable a single pin solution as discussed above with regard to FIG. 1 , both of switches S1 and S2 can be switched to the left. Thus switch S1 may be controlled to provide the supply voltage Veat to potentiometer R1. And furthermore, switch S2 may be controlled to provide the supply voltage V_Bat directly to node N1 via pad P4B. Accordingly, per this control, bonding mechanism B1 is not present and thus a single pin tuning solution is realized. In this single pin mode of circuit 100, the remaining connections may be as above in FIG. 1.

[0023] In other implementations, bonding mechanism B1 can be provided and the positive reference voltage provided to ADC 130 may be received on-chip via pad P4B and then through LDO 140. In this configuration, both of switches S1 and S2 may be switched to the right. Thus note that switch S1 may be controlled to provide a regulated supply voltage to potentiometer R1 from the signal line coupled to pad P1A. And switch S2 may be configured to provide a regulated voltage to node N1. In other respects, this mode of circuit 100 of FIG. 2 can operate as discussed above with regard to the first mode.

[0024] As mentioned above, certain design configurations with regard to the pads and bonding mechanism can be made to enable reduced resistance and greater noise immunity. As examples, instead of a single bond wire to couple the on-chip pad with the off-chip pad, the bonding mechanism can be realized with multiple separate bond wires provided for connection between each pad pair, reducing resistance as compared to a single wire solution. In some embodiments, at least two bond wires may be provided per pad pair to provide for a low noise connection. Furthermore in many implementations, these bond wires can be formed of gold, copper, aluminum or alloys thereof, to reduce resistance. Furthermore, the pads themselves can be configured as star connections, both on and off chip to reduce resistance and provide a low noise path. As examples, the pads can be fabricated as Kelvin pads to reduce resistance. At the very least, such multiple bond wire connections and Kelvin pads can be implemented for the supply voltage and reference voltage signal paths.

[0025] Referring now to FIG. 3, shown is a block diagram of a radio receiver in accordance with one embodiment of the present invention. As shown in FIG. 3, receiver 200, which may be a fully integrated complementary metal oxide semiconductor (CMOS) integrated circuit (i.e., a single die IC), includes circuitry to receive incoming radio frequency (RF) signals, downconvert them to baseband frequency, perform demodulation and provide audio signals therefrom. As shown, incoming signals, which may be received from an AM or FM antenna, are provided to an analog front end that includes low noise amplifiers (LNAs) 220_a and 220b, respectively, each of which may be controlled in turn by automatic gain control (AGC) circuits 225_a and 225_b. The amplified incoming signals are provided to respective mixers 230_a and 230_b, which perform a mixing operation to downconvert the RF signals to a lower frequency, e.g., an intermediate frequency (IF), such as a 10.7 megahertz (MHz) IF for FM and a 455 kilohertz (kHz) IF for AM, a low intermediate frequency (low-IF), zero-IF or baseband frequency.

[0026] As shown in FIG. 3, the RF signals are mixed with a local oscillator (LO) signal output from a LO 240. The frequency of LO 240 may be controlled using an automatic frequency control circuit 245 or a PLL, which may receive an incoming clock signal such as may be generated by an off-chip crystal oscillator. Still further, fine tuning of LO 240 may be under control of a microcontroller unit (MCU) 290, details of which will be discussed further below.

[0027] Still referring to FIG. 3, the downmixed signals are provided to an analog-to-digital converter (ADC) 250 that in turn provides digitized signals to a digital signal processor (DSP) 260, which may perform various signal processing and demodulation operations to obtain the message content in the incoming signals. In turn, digitized message information may be provided to a digital-to-analog converter (DAC) 270, which provides output audio signals corresponding to the message content.

[0028] As further shown in FIG. 3, potentiometer R1 is coupled to IC 200. As seen, this potentiometer is coupled between a battery voltage and a ground potential. The potentiometer may be controlled by a tuning mechanism of a radio incorporating IC 200. For example, a clock radio, mobile radio, boom box or so forth may have a manual tuning wheel to enable mechanical tuning, rather than by using a digitally controlled tuning mechanism or, as described above in other embodiments, the potentiometer can be controlled by an analog voltage generated by an off-chip controller responsive to controlling of a digital tuning mechanism that in turn is converted by the controller into the analog voltage. Accordingly, based on this control, a variable voltage is provided via an LPF 285 to an ADC 280, which converts this voltage into a digital representation, e.g., a digital control signal that in turn is provided to MCU 290. MCU 290 may control the fine tuning of LO 240 based on this control signal to thus enable the radio to tune to the desired channel. Depending on the mode of operation MCU 290 may further control front end tuning mechanisms.

[0029] Referring to FIG. 4, in accordance with some embodiments of the invention, an AM/FM/WB receiver 10 (such as an implementation of that shown in the embodiment of FIG. 3) may be part of a multimedia device 400. As examples, the device 400 may be a clock radio, a portable device such as a dedicated MP3 player, a cellular telephone or PDA with audio capabilities, or other such devices.

[0030] Among its other functions, the device 400 may store digital content on a storage 430, which may be a flash memory or hard disk drive, as a few examples. The device 400 generally includes an application subsystem 460 that may, for example, receive input from a touchpad 462 of the wireless device 400 and display information on a display 470. Furthermore, the application subsystem 460 may generally control the retrieval and storage of content from the storage 430 and the communication of, e.g., audio with the AM/FM receiver 10. As shown, AM/FM receiver 10 may be directly connected to speakers 440 and 450 for output of audio data. As depicted in FIG. 4, the AM/FM receiver 10 may be coupled by a matching network 432 to an FM receiver antenna 482 and may be coupled by a matching network 434 to an AM receiver antenna 484, which can be tunable or programmable, e.g., via application subsystem 460 that provides control information to control a pre-selection capacitance and/or inductance of matching network 434.

[0031] As further shown in FIG. 4, application subsystem 460 may further be coupled to a variable impedance 455 that is mechanically controlled by a user, e.g., via a tuning wheel 415. Information regarding the variable impedance is provided to application subsystem 460, which may in turn control both an LO of receiver 10 and/or matching network 434 to enable tuning to a desired channel.

[0032] In accordance with some embodiments of the invention, device 400 may have the ability to communicate over a communications network, such as a cellular network. For these embodiments, the device 400 may include a baseband subsystem 475 that is coupled to the application subsystem 460 for purposes of encoding and decoding baseband signals for this wireless network. Baseband subsystem 475 may be coupled to a transceiver 476 that is connected to corresponding transmit and receive antennas 477 and 478. While the scope of the present invention is not limited in this regard, at least some implementations may be incorporated in a computer-readable storage medium such as instructions present in a non-volatile storage within or accessible by application subsystem 460 to enable the subsystem to control frequency selection based on a measure of variable impedance 415.

[0033] Thus one embodiment enables use of only one dedicated pin which connects the output of a potentiometer voltage to the input of the ADC. The supply and ground voltages of the PVR can be shared with supply and ground voltages provided to the chip. By way of the layout, filtering, and bondwire mechanisms, interference can be suppressed while still enabling accurate ADC conversion with only one dedicated pin for analog tuning. In addition, via use of a potentiometer for analog tuning, the need for an external varactor or factory alignment can be avoided, reducing a bill of material, manufacturing costs and size consumed for a given design. [0034] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.

Claims

What is claimed is:

1. An integrated circuit (IC) comprising:

a radio receiver formed on a single semiconductor die including an analog front end having an amplifier to receive a radio frequency (RF) signal and a mixer to downconvert the RF signal to a second frequency signal;

a demodulator to receive the second frequency signal and obtain an audio signal therefrom;

a first pad of the IC to couple to a supply voltage;

a first pad of the single semiconductor die to couple to the first pad of the IC via a first bonding mechanism;

a second pad of the IC to couple to a variable resistance, wherein the variable resistance is adjustable by a user to tune to a radio channel;

a second pad of the single semiconductor die coupled to the second pad of the IC via a second bonding mechanism;

a third pad of the IC to couple to a reference potential;

a third pad of the single semiconductor die coupled to the third pad of the IC via a third bonding mechanism;

a fourth pad of the IC configurable to couple to the supply voltage or to be unconnected;

a fourth pad of the single semiconductor die couplable to the fourth pad of the IC when the fourth pad of the IC is configured to couple to the supply voltage, and otherwise the fourth pad of the single semiconductor die is decoupled from the fourth pad of the IC.

2. The IC of claim 1 , further comprising an analog-to-digital converter (ADC) to receive the supply voltage as a first reference voltage and to receive a tuning voltage from the second pad of the single semiconductor die and to convert the tuning voltage to a digital value.

3. The IC of claim 2, further comprising a controller to receive the digital value corresponding to a level of the variable resistance, the controller to control a local oscillator coupled to the mixer responsive to the digital value.

4. The IC of claim 2, further comprising a first filter coupled to receive the supply voltage and to output a filtered supply voltage to the ADC.

5. The IC of claim 4, further comprising a low dropout (LDO) regulator coupled to the first pad of the single semiconductor die to receive the supply voltage and to provide a regulated voltage to the first filter.

6. The IC of claim 5, further comprising a second switch to controllably couple the supply voltage to the first filter or to provide the regulated voltage to the first filter.

7. The IC of claim 4, further comprising a second filter coupled to receive the tuning voltage and to output a filtered tuning voltage to the ADC.

8. The IC of claim 2, wherein the IC is configured as an N-pin package, wherein the fourth pads are decoupled and not coupled to a pin of the N-pin package, the IC configured for a single pin tuning mode.

9. The IC of claim 8, further comprising a first switch to couple the supply voltage to a first terminal of the variable resistance in the single pin tuning mode and to couple a regulated voltage to the first terminal from the fourth pad of the IC in a non-single pin tuning mode.

10. The IC of claim 1 , wherein the first bonding mechanism comprises a plurality of bond wires.

11. An apparatus comprising:

a radio receiver configured within a semiconductor package and formed on a single semiconductor die including an analog front end having an amplifier to receive a radio frequency (RF) signal and a mixer to downconvert the RF signal to a second frequency signal; a demodulator to receive the second frequency signal and obtain an audio signal therefrom;

a first pad of the semiconductor package to couple to a supply voltage;

a first pad of the single semiconductor die to couple to the first pad of the semiconductor package via a first bonding mechanism;

a second pad of the semiconductor package to couple to a variable resistance, wherein the variable resistance is adjustable by a user to tune to a radio channel; a second pad of the single semiconductor die coupled to the second pad of the semiconductor package via a second bonding mechanism;

a third pad of the semiconductor package to couple to a reference potential; a third pad of the single semiconductor die coupled to the third pad of the semiconductor package via a third bonding mechanism;

a low dropout (LDO) regulator coupled to the first pad of the single

semiconductor die to receive the supply voltage and to provide a regulated voltage; and

a first filter to receive the regulated voltage and to output a filtered regulated voltage.

12. The apparatus of claim 11 , further comprising a fourth pad of the semiconductor package configurable to couple to the regulated voltage or to be unconnected, a fourth pad of the single semiconductor die couplable to the fourth pad of the semiconductor package when the fourth pad of the semiconductor package is configured to couple to the regulated voltage, and otherwise the fourth pad of the single semiconductor die is decoupled from the fourth pad of the

semiconductor package.

13. The apparatus of claim 12, wherein the semiconductor package is an N-pin package, wherein the fourth pads are decoupled and not coupled to a pin of the N-pin package.

14. The apparatus of claim 12, further comprising:

a first switch controllable to couple the supply voltage to a first terminal of the variable resistance in a first mode and to couple the regulated voltage to the first terminal from the fourth pad of the semiconductor package in a second mode; and a second switch controllable to couple the supply voltage or the regulated voltage to the first filter.

15. A system comprising:

a mechanical tuning mechanism to enable a user to select a radio channel; a variable resistance coupled to the mechanical tuning mechanism and having a first terminal to couple to a supply voltage and a second terminal to couple to a ground voltage, and a connection to provide a variable analog voltage

responsive to the user selection; and

a radio receiver implemented on a semiconductor die of a semiconductor package coupled to receive the variable analog voltage via a first pin of the semiconductor package, coupled to receive the supply voltage via a second pin of the semiconductor package, and coupled to receive the ground voltage via a third pin of the semiconductor package, the radio receiver having an analog portion to downconvert a radio frequency (RF) signal to a baseband signal, a digital portion to receive the baseband signal and demodulate the baseband signal, and a

microcontroller to receive an indication of the variable analog voltage and to control a frequency of the downconversion responsive thereto.

16. The system of claim 15, wherein the variable resistance is to enable the user selection of the radio channel without a factory aligned external varactor in the system.

17. The system of claim 15, further comprising an analog-to-digital converter (ADC) of the semiconductor die to receive the variable analog voltage and to provide a digitized representation of the variable analog voltage to the

microcontroller.

18. The system of claim 17, further comprising a filter coupled to the supply voltage and to output a filtered supply voltage to the ADC.

19. The system of claim 18, further comprising a low dropout (LDO) regulator to receive the supply voltage and to provide a regulated voltage to the filter.

20. The system of claim 15, wherein the semiconductor package is configured as an N-pin package, wherein the supply voltage and the reference voltage obtained via the second and third pins of the semiconductor package are the only supply and reference sources for the radio receiver, and are further usable to perform tuning to the radio channel in connection with the variable analog voltage.