JPH01147655A - Piggyback type microcomputer device - Google Patents

Abstract

PURPOSE:To realize the switch of options via the wire bonding switch by adding an option deciding pad to a piggyback type microcomputer. CONSTITUTION:An option deciding pad 8 is set near a VDD or VSS pad 9. The option switch can be executed by a fact whether the wire bonding is secured or not between the pad 8 and an inner lead 10 wire-bonded to VDD or VSS. When the pad 8 is connected to the VSS, the input of an inverter 3 is set at a low level with a control signal 6 set at a high level. Thus, a P-type MOSFET 4 does not serve as a pull-up resistance. In case the pad 8 has no connection at all, the input of a high level is supplied to the inverter 3 via a pull-up transistor 7. Then the signal 6 is set at a low level and the MOSFET 4 functions as the pull-up resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to piggyback type microcomputers having an option switching function.

[Conventional technology]

A conventional example will be explained using a pull-up resistor. Figure 3 shows a circuit diagram of a pull-up resistor whose presence or absence is determined by depression implantation.

(2) is a second N-type MO8FET whose drain is connected to the drain and gate of the first N-type MO8FET (1), and whose source and gate are connected to the ground terminal, (3)
) is an inverter whose input is the terminal connected to the drain and gate of the first N-type MO3FET (1) and the drain of the second N-type MO8FET (2), and (4) is an inverter whose gate is an inverter (3) This is a P-type MO8FET whose source is connected to the power supply terminal and whose drain is connected to the output terminal (5) and serves as a pull-up resistor.

Next, the operation will be explained. If depression is implanted only into the first N-type MO8FET (1) during the wafer process, the N-type MO5FET (13) becomes a depression type transistor, so the inverter (
3) input is at %Ha level, P type MO9FET
(Since the gate of 41 is at "L# level," the P-type MO8
FET (4) becomes conductive and becomes a pull-up resistor.

Also, if depression is injected into only the second N-type MO5FET (2), then the N-type MO8FET (
Since 2) becomes a depletion type transistor, the input of the inverter (3) becomes “L” level, and the P-type MO6
Since the gate of FET (4) is 1H level, it is P type M
O3FET (4) is in a non-conducting state and does not act as a pull-up resistor.

[Problem that the invention seeks to solve]

The conventional model was configured as described above, so the option switching state could only be determined by the wafer process, and once the wafer process was completed, it could not be changed, and multiple masks had to be prepared to switch the option state. There was a problem that it had to be done.

This invention was made to solve the above-mentioned problems, and aims to provide a piggyback type microcomputer device that does not depend on the wafer process and allows option switching even after the wafer process is completed. .

[Means for solving problems]

In the piggyback type microcomputer device according to the present invention, a pad for determining an option is arranged near a vDD or VSS pad, and the pad for determining an option is wire-bonded or not to an inner lead wire-bonded to VDD or VSS. This makes it possible to switch options.

[Effect]

The piggyback type microcombuque device according to the present invention allows option switching by switching the wire bonding of the option determining pad.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (3) is an inverter that outputs a control signal (6) that determines the state of the pull-up transistor (4);
(7) is a P-type MO8FET whose drain is connected to the input of the inverter (3), whose gate is connected to VSS, and whose source is a pull-up resistor connected to the power supply. +8) is the input of the inverter (3) and the P-type MO8FET This is a determining pad connected to the drain of MO8FET (7). It is assumed that the deciding pad (8) is placed near the VSS pad (91).

FIG. 2 is an explanatory diagram showing a state in which a chip circuit incorporating the circuit shown in FIG. 1 is assembled.

In the figure, (8) is a determining pad, (9) is a VSS pad, and αQ is an inner lead to which the VSS pad (9) is connected by wire bonding. Note that for convenience of explanation of the present invention, other pads and other wire bonds are not shown.

The operation of the piggyback type microcomputer device of the present invention constructed as described above will now be described.

When the determining pad (8) is wire-bonded to the inner lead (LO) connected to the VSS pad (9) (the state shown in Figure 2), the input of the inverter (3) is ・L
Since the control signal (6) becomes a ``HH level'' level, the P-type MO8FET (4) does not act as a pull-up resistor.At this time, a current flows between the power supply and VSS through the pull-up transistor (7), but In the case of the piggyback type, several tens of mA constantly flows through the installed EPROM, so
This will not be a problem if the resistance value of the pull-up transistor (7) is adjusted.

Next, when the deciding pad (8) is not connected to anything and left open, the input of the inverter (3) becomes %H level, and the control signal (5) becomes "L" level, so P The type MO8FET (4) serves as a pull-up resistor.

In the above embodiment, the presence or absence of a pull-up resistor has been described as an example of option switching, but other functions may be used. In addition, instead of the inner lead wire connected to the VSS pad (9) in Figure 2, if the die pad is at the VSS level, the die pad and the determining pad may be wire-bonded. Up transistor (7)
By using a pull-down transistor instead of VSS in Figure 1,
A power pad may be used instead of the pad (9), and the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the deciding pad vss
It is installed near the hat, and options can be switched depending on the presence or absence of wire bonds.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the option switching operation of a piggyback computer according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of the structure of a chip equipped with the circuit of Fig. 1, and Fig. 3 is a conventional option switching operation. FIG. 3 is a circuit diagram showing the operation. In the figure, (3)...inverter, (4)...P-type MO8FET that serves as a pull-up resistor, (5)...
・Output terminal, (6)...Control signal, (7)...Pull-up transistor, (8)...Decision pad, (9
)...VSS Pat, αQ...VSS Pat (9)
Inner lead connected to 0... chip of piggyback microcomputer device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A pad that determines the state of the option, a circuit that controls an option switching signal based on the voltage level of the determining pad, and a circuit that controls the determining pad to either a "H" level or a "L" level.
``A piggyback type microcomputer device characterized by being able to switch options by wire-bonding to the level or not wire-bonding anywhere.''