Alliance Semiconductor ASM1233M Service Manual

查询ASM1233M供应商

October 2003

rev 1.0

General Description

The ASM1233M is a voltage supervisor with low-power, 5V µP

Reset, with an active LOW, open-drain output. Maximum supply

current over temperature is a low 20µA.

The ASM1233M generates an active LOW reset signal

whenever the monitored supply is out of tolerance. A precision

reference and comparator circuit monitor power supply (V

level. Tolerance level options are 5% ,and 10% for a 5V power

supply. The tolerance is 15% for the 3.3V, ASM1233M. When

an out-of-tolerance condition is detected, an internal power-fail

signal is generated which forces an active LOW reset signal.

After V

remains active for 350ms to allow the power supply and system

microprocessor to stabilize.

The ASM1233M is designed with a open-drain output stage and

operates over the extended industrial temperature range.

Devices are available in compact surface mount SO-8

packages and 3-lead TO-92 packages.

returns to an in-tolerance condition, the reset signal

CC

Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output

CC

Applications

• Set-top boxes

• Cellular phones

•PDAs

• Energy management systems

• Embedded control systems

• Printers

• Single board computers

)

Typical Operating Circuit

V

CC

ASM1233M

RESET

ASM1233M

Microprocessor

RESET

Other low power products in this family include the ASM1810/

11/12/15/16/17 and ASM1233D.

Key Features

• Low Supply Current

•20 µA maximum (5.5 V)

•15µA maximum (3.6 V)

• Automatically restarts a microprocessor after power failure

• 350ms reset delay after V

dition

• Active LOW power-up reset, 5kΩ internal pull-up

• Precision temperature-compensated voltage reference and

comparator

• Eliminates external components

• Low-cost TO-92 package

• Compact surface mount SO-8 package

• Operating temperature -40°C to +85°C

returns to an in-tolerance con-

CC

Alliance Semiconductor

2575 Augustine Drive . Santa Clara, CA 95054 . Tel: [phone] . Fax: [phone] . www.alsc.com

Notice: The information in this document is subject to change without notice

GND

Block Diagram

V

CC

2

ASM1233M

5.0kΩ

Supply

Tolerance

Bias

Delay

+

+

-

-

Reference

Delay

150ms

150ms

Typical

Typical

GND

4

1

RESET

October 2003

rev 1.0

Pin Configuration

ASM1233M

RESET

V

CC

NC

GND

Pin Description

Pin #

SO-8 TO-92

1 1 RESET Active LOW reset output

22

SO-8

1

2

3

4

8

NC

NC

7

NC

6

ASM1233M-X

NC

5

Pin Name Description

V

CC

Power supply input

TO-92*

ASM1233M-X

2

1

3

3, 5, 6, 7 and 8 - NC No Connection.

4 3 GND Ground.

* See Ordering Information

Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output

Notice: The information in this document is subject to change without notice

2 of 9

October 2003

rev 1.0

Application Information

Operation - Power Monitor

The ASM1233M detects out-of-tolerance power supply

conditions. It resets a processor during power-up, power-

down and generates a reset to the system processor when

the monitored power supply voltage is below the reset

threshold. When an out-of-tolerance V

the RESET signal is asserted. On power-up, RESET is kept

active (LOW) for approximatley 350ms after the power supply

voltage has reached the selected tolerance. This allows the

power supply and microprocessor to stablize before RESET

is released.

t

(MIN)

V

CCTP

voltage is detected,

CC

R

V

CCTP

V

CCTP

(MAX)

t

V

CCTP

F

t

RPD

V

OL

V

CC

V

(MAX)

CCTP

RESET

Figure 2: Timing Diagram: Power-Down

ASM1233M

V

(MIN)

CCTP

~

~

~

~

V

CC

~

RESET

Figure 1: Timing Diagram: Power-Up

~

t

RPU

V

OH

Low Power, 5V/3.0V, µP Reset, Active LOW, Open-Drain Output

Notice: The information in this document is subject to change without notice

3 of 9