LP3470A

VCC

GND

RESET

Microcontroller

VCC

RESET

LDO

IN

OUT

SRT

VCC1

12

LP3470A

SNVSBF5C – JULY 2019 – REVISED MAY 2020

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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. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

The LP3470A is a micropower CMOS voltage supervisor that is ideal for use in battery-powered microprocessor

and other digital systems. It is small in size and provides voltage monitoring and supervisory functions with nano-

Iq and programmable delay, making it a good solution in a variety of applications. The LP3470A is available in

six standard reset threshold voltage options, and the reset time-out period is adjustable using an external

capacitor providing maximum flexibility in any application. This device can ensure system reliability and ensures

that a connected microprocessor will operate only when a minimum voltage supply is satisfied.

9.2 Typical Application

The LP3470A can be used as a simple supervisor circuit to monitor the input supply to a microprocessor as

shown in Figure 11.

Figure 11. Power-On Reset Circuit

9.2.1 Design Requirements

For this design example, use the parameters listed in Table 1 as the input parameters.

Table 1. Design Parameters

DESIGN PARAMETER

EXAMPLE VALUE

Input supply voltage

0.95 to 10 V

Reset threshold voltage

2.63 V, 2.75 V, 2.93 V, 3.08 V, 3.65 V, 4 V, 4.38 V, 4.63 V

External pullup resistor

0.68 to 68 k

Ω

External reset time-out period capacitor

CSRT = 1 nF

Reset time-out period

619 µs

9.2.2 Detailed Design Procedure

The minimum application circuit requires the LP3470A Power-On Reset Circuit IC and a pullup resistor

connecting the reset pin to VCC. The reset delay can be programmed with an additional capacitor connected

from the SRT pin to GND. See RESET Time-Out Period and Pull-up Resistor Selection for information on

choosing specific values for components.