IMP705 Datasheet, PDF (4/9 Pages) IMP, Inc – LOW-POWER μP SUPERVISOR CIRCUITS

IMP705/6/7/8, 813L
Pin Descriptions
Pin Number
IMP705/706
IMP707/708
IMP813L
DIP/SO MicroSO DIP/SO MicroSO DIP/SO MicroSO Name
1
3
1
3
1
3
MR
2
4
2
4
2
4
V_CC
3
5
3
5
3
5
GND
4
6
4
6
4
6
PFI
5
7
5
7
5
7
PFO
6
8
—
—
6
8
WDI
—
—
6
—
—
—
NC
7
1
7
1
—
—
RESET
8
2
—
—
8
2
WDO
—
—
8
2
7
1
RESET
Function
Manual RESET input. The active LOW input triggers a reset
pulse. A 250µA pull-up current allows the pin to be driven
by TTL / CMOS logic or shorted to ground with a switch.
+5V power supply input.
Ground reference for all signals.
Power-fail voltage monitor input. With PFI less than
1.25V, PFO goes low. Connect PFI to ground or V_CC
when not used.
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.
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.
Not connected.
Active-LOW reset output. Pulses LOW for 200ms
when triggered, and stays low whenever V_CC is below
the reset threshold (IMP705: 4.65V, IMP705J: 4.00V,
IMP706: 4.40V). RESET remains LOW for 200ms
after V_CC rises above the RESET threshold or MR
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
V_CC is below the reset threshold, WDO remains low.
Unlike RESET, WDO does not have a minimum pulse
width and as soon as V_CC exceeds the reset
threshold, WDO goes HIGH with no delay.
Active-HIGH reset output. RESET is the inverse of
RESET. The IMP813L has only a RESET output.
Feature Summary
Power-fail detector
Brownout detection
Manual RESET input
Power-up/down RESET
Watchdog timer
Active-HIGH RESET output
Active-LOW RESET output
RESET threshold
4
IMP705
I
I
I
I
I
I
4.65V/4.00V
IMP706
I
I
I
I
I
I
4.40V
IMP707
I
I
I
I
I
I
4.65V
408-432-9100/www.impweb.com
IMP708
I
I
I
I
I
I
4.40V
IMP813L
I
I
I
I
I
I
4.65V
© 1999 IMP, Inc.