TLC7701-Q1_16 Datasheet, PDF (1/18 Pages) Texas Instruments – MICROPOWER SUPPLY VOLTAGE SUPERVISORS

TLC7701-Q1, TLC7705-Q1, TLC7733-Q1
MICROPOWER SUPPLY VOLTAGE SUPERVISORS
D Qualified for Automotive Applications
D Power-On Reset Generator
D Automatic Reset Generation After
Voltage Drop
D Precision Voltage Sensor
D Temperature-Compensated Voltage
Reference
D Programmable Delay Time by External
Capacitor
D Supply Voltage Range . . . 2 V to 6 V
D Defined RESET Output from V_DD ≥ 1 V
D Power-Down Control Support for Static
RAM With Battery Backup
D Maximum Supply Current of 16 μA
D Power Saving Totem-Pole Outputs
SGLS208A − OCTOBER 2003 − REVISED MAY 2008
PW PACKAGE
(TOP VIEW)
CONTROL 1
RESIN 2
CT 3
GND 4
8 V_DD
7 SENSE
6 RESET
5 RESET
description
The TLC77xx family of micropower supply voltage supervisors provide reset control, primarily in microcomputer
and microprocessor systems.
During power-on, RESET is asserted when V_DD reaches 1 V. After minimum V_DD (≥ 2 V) is established, the
circuit monitors SENSE voltage and keeps the reset outputs active as long as SENSE voltage (V_I(SENSE))
remains below the threshold voltage. An internal timer delays return of the output to the inactive state to ensure
proper system reset. The delay time, t_d, is determined by an external capacitor:
t_d = 2.1 × 10⁴ × C_T
Where
C_T is in farads
t_d is in seconds
Except for the TLC7701, which can be customized with two external resistors, each supervisor has a fixed
SENSE threshold voltage set by an internal voltage divider. When SENSE voltage drops below the threshold
voltage, the outputs become active and stay in that state until SENSE voltage returns above threshold voltage
and the delay time, t_d, has expired.
In addition to the power-on-reset and undervoltage-supervisor function, the TLC77xx adds power-down control
support for static RAM. When CONTROL is tied to GND, RESET will act as active high. The voltage monitor
contains additional logic intended for control of static memories with battery backup during power failure. By
driving the chip select (CS) of the memory circuit with the RESET output of the TLC77xx and with the CONTROL
driven by the memory bank select signal (CSH1) of the microprocessor (see Figure 10), the memory circuit is
automatically disabled during a power loss. (In this application the TLC77xx power has to be supplied by the
battery.)
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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