TL7700_07 Datasheet, PDF (2/17 Pages) Texas Instruments – SUPPLY-VOLTAGE SUPERVISOR

TL7700
SUPPLYĆVOLTAGE SUPERVISOR
SLVS220C − JULY 1999 − REVISED NOVEMBER 2004
functional block diagram
VCC
Vs = 500 mV TYP
Reference
Voltage
RESET
SENSE
+
−
High:
On
+
+
−
−
ICT†
R
Q
S
IS†
†ICT _{= 15 µA TYP; Is = 2.5 µA TYP}
GND
CT
Terminal Functions
TERMINAL
NAME NO.
CT
1
GND
NC
4
3, 6, 7
RESET
8
SENSE
2
VCC
5
DESCRIPTION
Timing capacitor connection. This terminal sets the RESET output pulse duration (tpo). 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 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).
Ground. Keep this terminal as low impedance to reduce circuit noise.
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 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 voltage is temperature compensated to inhibit
temperature drift in the threshold voltage within the operating temperature range.
Power supply. This terminal is used in an operating-voltage range of 1.8 V to 40 V.
2
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