®
TL7700A Series
SUPPLY VOLTAGE SUPERVISORS
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POWER-ON RESET GENERATOR
AUTOMATIC RESET GENERATION AFTER
VOLTAGE DROP
WIDE SUPPLY VOLTAGE RANGE ... 3V TO
18V
PRECISION VOLTAGE SENSOR
TEMPERATURE-COMPENSATED VOLTAGE
REFERENCE
TRUE AND COMPLEMENT RESET OUTPUTS
EXTERNALLY ADJUSTABLE PULSE WIDTH
N
Min idip
DESCRIPTION
The TL7700Aseriesaremonolithicintegratedcircuit
supplyvoltagesupervisorsspecifically desi-gnedfor
use as reset controllers in microcomputer and mi-
croprocessor systems. During power-up the device
tests the supply voltage and keeps the RESET and
RESET outputs active (high and low, respectively)
as long as the supply voltage has not reached its
nominal voltage value. Taking RESIN low has the
same effect. To ensure that the microcomputer sys-
tem hasreset, the TL7700Athen initiates aninternal
time delay that delays the return of the reset outputs
to theirinactivestates. Since the timedelay for most
microcomputersand microprocessors is in the order
of several machine cycles, the device internal time
delay is determined by an external time delay is de-
termined by an external capacitor connected to the
C
T
input (pin 3).
t
d
= 1.3 x 10
4
x C
T
Where : C
T
is in farads (F) and t
d
in seconds (s). In
addition, when the supply voltage drops below the
nominal value, the outputs will be active until the
supply voltage returns to the nominal value. An ex-
ternalcapacitor(typically0.1
µF)
must be connected
to the REF output (pin 1) to reduce the influence of
fast transients in the supply voltage.
The TL7700AI series is characterized for operation
from – 25
o
C to 85
o
C ; the TL7700AC series is char-
acterized from 0
o
C to 70
o
C.
April 2000
D
SO 8
ORDERING NUMBERS
Temperature Range
0 to 70 C
-25 to 85 C
o
o
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TL77XXACP
TL77XXAIP
S08
TL77XXACD
TL77XXAID
PIN CONNECTION
(top view)
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