H+

A1

2

7

V

CC

A2

1

8

AL

LD

3

6

H–

GND

4

5

Logic

Regulator

+

–

+

–

Lock Detect/

Auto Restart

+

–

Hall

Amp

TMP821

SLDS152A – JANUARY 2008 – REVISED MAY 2015

www.ti.com

7 Detailed Description

7.1 Overview

The TMP821 device is a two phase half wave motor predriver suited for small fan applications. The two switches

are controlled from the logic generated from differential hall sensors connected to the device. The drive logic

operates in push-pull configuration. The TMP821 device is a very small package with minimum external

components required, making the design very simple and easy. Speed information is available on a pin. The lock

detect feature is also part of the features provided by the device whose timing is configured by connecting an

external capacitor.

7.2 Functional Block Diagram

6

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