TL7700A Series
July 2000
SUPPLY VOLTAGE SUPERVISORS
®
.
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
Minidip
DESCRIPTION
The TL7700A series are monolithic supply voltage
supervisor IC’s specifically designed for use as reset
controllers in microcomputer and microprocessor
systems. During power-up the device tests the sup-
ply voltage and keeps the RESET and
RESET out-
puts active (high and low, respectively) as long as
the supply voltage has not reached its nominal volt-
age value. Taking
RESIN low has the same effect.
To ensure that the microcomputer system has reset,
the TL7700A then initiates an internal time count
that delays the return of the reset outputs to their in-
active states. Since the time delay for most micro-
computers and microprocessors is in the order of
several machine cycles, the device internal time de-
lay is determined by an external capacitor con-
nected to the C
T
input (pin 3).
t
po = 1.3 x 10
4
x C
T
Where : C
T
is in farads (F) and t
po
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-
ternal capacitor (typically 0.1 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.
D
SO8
ORDERING NUMBERS
Temperature Range Minidip S08
0 to 70
o
C TL77XXACP TL77XXACD
-25 to 85
o
C TL77XXAIP TL77XXAID
PIN CONNECTION
(top view)
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