9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification, and TI

does not warrant its accuracy or completeness. TI’s customers are responsible for determining

suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

Figure 9-1 shows an application where the TL7705B device is being used to sense the voltage supply for a

microcontroller that is supplied with 5 V. If the voltage supply drops below the threshold voltage, the RESET pin

is pulled LOW, signaling the microcontroller to reset.

9.2 Typical Application

TL7705B

Copyright © 2016, Texas Instruments Incorporated

Figure 9-1. Reset Controller Schematic for a Microprocessor

9.2.1 Design Requirements

The external components required include the decoupling capacitor for the REF pin and the timing capacitor for

the CT pin. Additionally, because the RESET output is open collector, a pullup resistor is required to ensure the

correct HIGH level for the microcontroller RESET pin.

9.2.2 Detailed Design Procedure

TI recommends pullup and pulldown resistors of 10 kΩ.

To achieve a 2.6 ms time delay, use CT = 0.1 µF.

Both outputs of the TL770xB must be terminated with similar value resistors, even when only one is being used.

This prevents unwanted plateauing in either output waveform during switching, which may be interpreted as an

undefined state or delay system reset

TL7702B, TL7705B, TL7733B

SLVS037O – SEPTEMBER 1989 – REVISED DECEMBER 2020

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