IMP1

4/A/D

Application Information

©

1999 IMP, Inc.

408-432-9100/www.impweb.com

5

Manual Reset Operation

Pushbutton switch input, PBRST, allows the user to override the

internal trip point detection circuits and issue reset signals. The

pushbutton input is debounced and is pulled HIGH through a

40k

Ω, internal pull-up resistor.

When at least one of the reset outputs is not asserted, a pushbut-

ton initiated reset signal can be issued by holding PBRST LOW for

at least 2ms. When PBRST is held LOW, both resets become active

and remain active for approximately 350ms after PBRST returns

HIGH. See Figure 3 and Figure 4.

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Table 1. Threshold Selection

Figure 3. Pushbutton Reset

1834_04.eps

3.3V

1

5VRESET

2

3.3VRESET

5VTOL

IMP1834

3

4

3.3VTOL

GND

8

7

6

5

PBRST

5V

Figure 4. Timing Diagram: Pushbutton Reset

RESET

RESET

PBRST

1834_05.eps

(IMP1834D)