8.3 Feature Description

8.3.1 Wide Supply-Voltage Range

The TL77xxB family operates using a wide supply voltage from 3.6 V to 18 V.

8.3.2 Adjustable Pulse Duration

The CT pin enables the ability to set a user-defined time delay in order to ensure that the fault condition is

recognized. The external capacitor charges based on an internal current source until the voltage at the CT pin

exceeds that of the internal reference voltage.

The time delay is determined by the value of the external capacitor CT : td ≈ 2.6 × 104 × CT , where CT is in

farads (F) and td is in seconds (s).

The current source to charge the timing capacitor varies ±15%. Reference Voltage 2 is approximately 1.8 V and

varies approximately ±5%. Once the timing capacitor charges, it discharges to about 0.6 V, not completely to 0 V.

8.4 Device Functional Modes

Figure 8-1 displays how the RESET and RESET output pins respond to the change in the the SENSE and

RESIN input pins. When the RESIN pin is high, the RESET outputs are able to respond to a drop in the supply

voltage at the SENSE pin. When the RESIN pin is low, the RESET and RESET pins are set HIGH and LOW

respectively.

10%

VIT+

VIT±

VIT+

0 V

VIH

VIL

2 V

0.8 V

tPLH

50%

50%

10%

10%

90%

10%

t d

SENSE

Undefined

RESET

Voltage

Fault

t f

t r

90%

t f

t d

t r

t d

t PHL

10%

90%

90%

VOH

VOL

RESIN

RESET

Copyright © 2016, Texas Instruments Incorporated

Figure 8-1. TL77xxB RESET and RESET Response and Timing

www.ti.com

TL7702B, TL7705B, TL7733B

SLVS037O – SEPTEMBER 1989 – REVISED DECEMBER 2020

Copyright © 2020 Texas Instruments Incorporated

Submit Document Feedback

11