TLC7701, TLC7725, TLC7703, TLC7733, TLC7705 MICROPOWER SUPPLY VOLTAGE SUPERVISORS

SLVS087I - DECEMBER 1994 - REVISED AUGUST 1997

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features

Power-On Reset Generator
Automatic Reset Generation After Voltage Drop
Precision Voltage Sensor
Temperature-Compensated Voltage Reference
Programmable Delay Time by External Capacitor
Supply Voltage Range...2 V to 6 V
Defined RESET\ Output from V_DD >=1 V
Power-Down Control Support for Static RAM With Battery Backup
Maximum Supply Current of 16 uA
Power Saving Totem-Pole Outputs
Temperature Range...-40°C to 125°C

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.)

The TLC77xxQ is characterized for operation over a temperature range of -40°C to 125°C, and the TLC77xxI is characterized for operation over a temperature range of -40°C to 85°C.

Title: MICROPOWER SUPPLY VOLTAGE SUPERVISORS
Product Family: SUPPLY VOLTAGE SUPERVISORS
Device Functionality: SUPPLY VOLTAGE SUPERVISOR
Orderable Devices: TLC7701ID, TLC7701IDR, TLC7701IPWLE, TLC7701QD, TLC7701QDR, TLC7703ID, TLC7703IDR, TLC7703IPWLE, TLC7703QD, TLC7703QDR, TLC7705ID, TLC7705IDR, TLC7705IP, TLC7705IPWLE, TLC7705MFKB, TLC7705MJGB, TLC7705QD, TLC7705QDR, TLC7705QP, TLC7705QPWLE, TLC7725ID, TLC7725IDR, TLC7725IP, TLC7725IPWLE, TLC7725QD, TLC7725QDR, TLC7725QPWLE, TLC7733ID, TLC7733IDR, TLC7733IP, TLC7733IPWLE, TLC7733MFKB, TLC7733MJGB, TLC7733QD, TLC7733QDR, TLC7733QP

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View more information about generic part numbers:TLC7701, TLC7703, TLC7705, TLC7725, TLC7733

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