Datasheet

Reference
Voltage
+
-
+
-
R
S
Q
+
-
V
s
= 500 mV Typ
RESET
GND
CT
SENSE
V
CC
I
CT
(A)
High:
On
I
S
(A)
TL7700
SLVS220F –JULY 1999–REVISED AUGUST 2011 www.ti.com
FUNCTIONAL BLOCK DIAGRAM
A. I
CT
= 15 μA (Typ), I
s
= 2.5 μA (Typ)
TERMINAL FUNCTIONS
TERMINAL
DESCRIPTION
NO.
NAME
P, PS, PW DGK
Timing capacitor connection. This terminal sets the RESET output pulse duration (t
po
). It is
connected internally to a 15-μA constant-current source. There is a limit on the switching speed of
internal elements; even if CT is set to 0, response speeds remain at approximately 5 to 10 μs. If CT
is open, the device can be used as an adjustable-threshold noninverting comparator. If CT is low, the
CT 1 3
internal output-stage comparator is active, and the RESET output transistor is on. An external
voltage must not be applied to this terminal due to the internal structure of the device. Therefore,
drive the device using an open-collector transistor, FET, or 3-state buffer (in the low-level or
high-impedance state).
GND 4 5 Ground. Keep this terminal as low impedance to reduce circuit noise.
NC 3, 6, 7 2, 6, 7 No internal connection
Reset output. This terminal can be connected directly to a system that resets in the active-low state.
A pullup resistor usually is required because the output is an npn open-collector transistor. An
RESET 8 1
additional transistor should be connected when the active-high reset or higher output current is
required.
Voltage sense. This terminal has a threshold level of 500 mV. The sense voltage and hysteresis can
be set at the same time when the two voltage-dividing resistors are connected. The reference
SENSE 2 4
voltage is temperature compensated to inhibit temperature drift in the threshold voltage within the
operating temperature range.
V
CC
5 8 Power supply. This terminal is used in an operating-voltage range of 1.8 V to 40 V.
2 Copyright © 1999–2011, Texas Instruments Incorporated