JPH0490620A - Semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and more particularly to the configuration of an output driver that outputs information in a semiconductor device to the outside.

[Conventional technology]

Figure 3 shows the output driver of the conventional device.
0MO5 consisting of a first drive circuit P-channel transistor 1° connected to the first power supply line VDD' and a second drive circuit N-channel transistor 2o connected to the second power supply line GND'. configuring the inverter of the configuration.

As a countermeasure against characteristic deterioration due to hot electrons, the P-channel transistor 1o and the N-channel transistor 20 have a long channel length (generally 5 μm or more).
used numerically.

Generally speaking, an equivalent circuit including a back cage for sealing a semiconductor device is as shown in FIG.

RVD and LVD are the parasitic resistance and parasitic inductance of the lead of the VDD terminal, respectively. RVS.

LVS are the parasitic resistance and parasitic inductance of the leads of the VSS terminal, respectively. Rr, Lr beams.

These are the parasitic resistance and parasitic inductance of the UT terminal. The parasitic inductance typically has a value of 20 to 30 nH.

The capacitance OL is connected to the external output terminal DOU of the semiconductor device.
This is an external additional capacitor connected to T, and usually a capacitance of several tens of pF (picofarad) to 10Qpr is connected.

Signals GP and GN are input signals of the output driver, and are connected to the gates of P-channel transistor 1D and N-channel transistor 20, respectively. VDD'
, VSS' are power supply lines within the semiconductor device.

The operation of the output driver of the conventional device configured as described above is shown in FIG. 5, for example. - Numerical In order to prevent a through current between the KP channel transistor 10 and the N channel transistor 20, a phase difference is provided to each gate input so that both transistors are not turned on at the same time.
In the figure, after the P-channel transistor 10 starts to turn off at tl, the N-channel transistor 2o starts to turn on at t2. Also t5. The same holds true for t4.

The external output terminal DOUT changes from High level to LOW due to the conduction of the N-channel transistor 20 after t2, and then changes from High level to Low due to the conduction of the P-channel transistor 10 after t4.

Further, the external output terminal DOUT has reflected waveforms such as oversheet or undershoot and ringing due to parasitic resistance, parasitic inductance, and parasitic capacitance.

[Problem to be solved by the invention]

Since the conventional semiconductor devices described above are configured as described above, the channel width of the drive circuit is generally increased to provide a margin in the access time of the semiconductor device, which has the following problems. , it is possible to obtain a large drive current, but the amount of current a I that changes over a certain period of time
/ a t becomes thick (and parasitic inductance causes overshoot or undershoot and reflected waveforms such as ringing to occur in the output waveform.Especially when multiple terminals change to the same level at the same time. This has caused a serious problem in that a very large reflected waveform is generated, causing malfunctions in external circuits, or the power supply of the semiconductor device itself is fluctuated, causing the semiconductor device to malfunction.

In the body, the output driver includes at least a first transistor connected directly to an external output terminal, and a second transistor connected to the external output terminal via a resistor and connected in parallel with the first transistor; a first drive circuit connected in series between the first and second transistors and a first power supply line; a third transistor connected directly to the external output terminal; and a resistor connected to the external output terminal. a fourth transistor connected in parallel with the third transistor; and a second drive circuit connected in series between the third and fourth transistors and a second power supply line. It is characterized by being composed of.

2) The semiconductor device of the present invention is the first and second semiconductor device described above.

A feature is that the third and fourth transistors can be selectively set to 0N10FF.

[Means for Solving the Problems] [Operations] 1) The semiconductor device of the present invention provides information within the semiconductor device. -It is possible to programmably change the driving method of the drive circuit of the cow guide, which is equipped with an output driver that outputs the signal to the outside.It is possible to select the driving force according to the intended use, and it is possible to prevent overshoot of the external output terminal. To reduce potential fluctuations such as ρ・
I can do it.

〔Example〕

FIG. 1 is a diagram showing an embodiment of an output driver according to the present invention. In FIG. 1, a P-channel transistor 12 is a transistor whose drain electrode is connected to an external output terminal DOUT and whose gate is connected to a selection signal SP1. The P-channel transistor 15 is a transistor whose drain electrode is connected to the external output terminal DOUT via the damping resistor R11, and whose gate is connected to the selection signal SP2. P-channel transistor 14 is another transistor whose drain electrode is connected to external output terminal DoUT via damping resistor R12. The drain electrode of the N-channel transistor 16 is an external output terminal.

It is a transistor connected to UT and whose gate is connected to selection signal SN1.

The N-channel transistor 17 is a transistor whose drain electrode is connected to the external output terminal DOUT via the damping resistor R21, and whose gate is connected to the selection signal SN2. The N-channel transistor 18 is another transistor whose drain electrode is connected to the external output terminal DOUT via the damping resistor R22, and whose gate is connected to the selection signal SNS.

The first drive circuit is connected to VDD', which is the first power supply line, and is connected in series to the P-channel transistors 12, 13, and 14, and the gate electrode is connected to the masonry GP by input/output signals of the output driver. The second drive circuit is connected to the second power supply line SS', and is connected to the P-channel transistors 11, 16, 17, .
It is composed of an N-channel transistor 15 connected in series to 18 N-channel transistors, and whose gate electrode is connected to 1GN, which is the input signal of the output driver.

As a specific example, the transistor size of the conventional device is Pch W=800 μ7W/L=3.6 μ
7WN Ch W”6 0 0 μ771/
Applying the present invention to an output driver with L: 3.0 11m, the size of each transistor is Pch W=8°001”'/I,=1.8pm
NCh w=6oopm/L=15pmR1i R
=20Ω R12R=40 0 R21R==200 R22R=400. At this time, the sum of the channel lengths of P-channel transistors 11, 12, 15.14 and N-channel transistors 15, 16, 17.18 is the same as that of the conventional device, so the hot electron resistance characteristics are the same as that of the conventional device. . In addition, the load capacity of the input signals of the output driver, GP and GN, is 1/1 of that of the conventional device.
It becomes 2.

FIG. 2 shows operating waveforms of an embodiment of the present invention.

When the external load capacitance is small, the selection signals sp1 to SP
5. It is possible to select a driving force sufficient to drive the external load capacitance by SNi to SN5, and prevent unnecessary overshoot or undershoot and ringing from occurring in the output signal. In addition, when a large driving force is required, it can be obtained by selecting a transistor with a low damping resistor that can provide a driving force, or a transistor without a damping resistor. [Effects of the Invention] As described above, According to the present invention, it is possible to programmably select the driving force of the output driver of a semiconductor device according to the load, and it is possible to prevent unnecessary overflow soot or undercut and ringing. Malfunctions can be prevented when installed.

Further, according to the present invention, it is possible to select a semiconductor device mounted on a board and an output driver with a driving force suitable for the board mounted.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a semiconductor device showing one embodiment of the present invention, and FIG. 2 is a diagram showing operating waveforms of the above embodiment. 3 is a circuit diagram of a conventional semiconductor device, FIG. 4 is an equivalent circuit diagram of the device of FIG. 5, and FIG.
It is a figure which shows the operation waveform of the apparatus of a figure. Note that the same reference numerals in the figures indicate the same or equivalent parts.・・・・・・・・・・・・・・・・・・First drive circuit・・・・・・・・・・・・・・・・・・Second Drive circuit・・・・・・・・・・・・・・・・・・
...P-channel transistor, 14...
...P-channel transistor...
・・・・・・・・・・・・N-channel transistor,
18... N-channel transistor 1, R12... Resistor 1, R22... Resistor or more Applicant Seiko Epson Corporation Agent Patent attorney Lead Sueki Sanbe (1 other person) s5 ss

Claims (2)

[Claims] (1) In a semiconductor device that includes an output driver that outputs information in the semiconductor device to the outside, the output driver includes at least a first transistor that is directly connected to an external output terminal, and a first transistor that is connected to the external output terminal via a resistor. a second transistor connected in parallel with the first transistor; a first drive circuit connected in series between the first and second transistors and a first power supply line; and an external output. a third transistor directly connected to the terminal; a fourth transistor connected to the external output terminal via a resistor and connected in parallel with the third transistor; and the third and fourth transistors and the second transistor. and a second drive circuit connected in series between the power supply line and the second drive circuit. (2) The semiconductor device according to claim 1, wherein the first, second, third, and fourth transistors can be selectively turned on and off.