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
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 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 system has reset,
the TL7700A then initiates an internal time count
that delays the return of the reset outputs to their inactive states. Since the time delay for most microcomputers and microprocessors is in the order of
several machine cycles, the device internal time delay is determined by an external capacitor connected to the CT input (pin 3).
tpo = 1.3 x 104 x CT
Where : CT is in farads (F) and tpo 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 external 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 – 25oC to 85oC ; the TL7700AC series is characterized from 0oC to 70oC.
July 2000
D
SO8
ORDERING NUMBERS
Temperature Range
o
Minidip
S08
0 to 70 C
TL77XXACP
TL77XXACD
-25 to 85oC
TL77XXAIP
TL77XXAID
PIN CONNECTION (top view)
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