4

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©

1999 IMP, Inc.

IMP705/6/7/8, 8

3L

Pin Descriptions

Feature Summary

Pin Number

IMP705/706

IMP707/708

IMP813L

DIP/SO MicroSO DIP/SO MicroSO DIP/SO MicroSO Name

Function

Manual RESET input. The active LOW input triggers a reset

1

3

1

3

1

3

MR

pulse. A 250

µA pull-up current allows the pin to be driven

by TTL / CMOS logic or shorted to ground with a switch.

2

424

2

4

+5V power supply input.

3

5

3

5

3

5

GND

Ground reference for all signals.

Power-fail voltage monitor input. With PFI less than

4

6

4

6

4

6

PFI

when not used.

5

7

5

7

5

7

PFO

Power-fail output. The output is active LOW and sinks

current when PFI is less than 1.25V.

Watchdog input. WDI controls the internal watchdog

timer. A HIGH or LOW signal for 1.6sec at WDI

allows the internal timer to run-out, setting WDO LOW.

68

——

6

8

WDI

The watchdog function is disabled by floating WDI or

by connecting WDI to a high-impedance three-state

buffer. The internal watchdog timer clears when:

RESET is asserted; WDI is three-stated; or WDI sees

a rising or falling edge.

——

6

——

—

NC

Not connected.

Active-LOW reset output. Pulses LOW for 200ms

the reset threshold (IMP705: 4.65V, IMP705J: 4.00V,

7

171

——

RESET

IMP706: 4.40V). RESET remains LOW for 200ms

goes from LOW to HIGH. A watchdog timeout will not

trigger RESET unless WDO is connected to MR.

Watchdog output. WDO pulls LOW when the 1.6 sec

internal watchdog timer times-out and does not go

HIGH until the watchdog is cleared. In addition, when

82

——

8

2

WDO

Unlike RESET, WDO does not have a minimum pulse

threshold, WDO goes HIGH with no delay.

——

8

2

7

1

RESET

Active-HIGH reset output

. RESET is the inverse of

RESET. The IMP813L has only a RESET output.

IMP705

IMP706

IMP707

IMP708

IMP813L

Power-fail detector

I

I

III

Brownout detection

I

I

III

Manual RESET input

I

I

III

Power-up/down RESET

I

I

III

Watchdog timer

II

I

Active-HIGH RESET output

III

Active-LOW RESET output

II

I

I

RESET threshold

4.65V/4.00V

4.40V

4.65V

4.40V

4.65V