I2C Register

Interface With

Undervoltage

Lockout

Interrupt

Generator

32-kHz

Oscillator

VCORE

Registers

Automatic

Backup

Switch

V

CC

4.7

NŸ

4.7

NŸ

4.7

NŸ

V

CC

V

CC

IRQ

SCL

SDA

GND

OSCO

OSCI

V

BACK

1 µF

.22 F

Place supply-decoupling

capacitor near supply pin

Use only

super-capacitor

or battery, not

both

Copyright © 2016, Texas Instruments Incorporated

7

BQ32002

www.ti.com

SLUSA96B – AUGUST 2010 – REVISED APRIL 2016

Product Folder Links: BQ32002

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Copyright © 2010–2016, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The BQ32002 is a real-time clock that features an automatic backup supply with integrated oscillator-fail

detection.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1

IRQ Function

The IRQ pin of the BQ32002 functions as a general-purpose output or a frequency test output. The function of

IRQ is configurable in the device register space by setting the FT, FTF, and OUT bits. On initial power cycles,

the OUT bit is set to one, and the FTF and FT bits are set to zero. On subsequent power-ups, with backup

supply present, the OUT bit remains unchanged, and the FTF and FT bits are set to zero. When operating on

when operating on backup supply. The effect of the calibration logic is not normally observable when IRQ is

configured to output 1 Hz. The calibration logic functions by periodically adjusting the width of the 1-Hz clock.

The calibration effect is observable only every eight or sixteen minutes, depending on the sign of the calibration.