ADM1178-1ARMZ-R7(RevPrD) 查看數據表（PDF） - Analog Devices

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ADM1178-1ARMZ-R7
(Rev.:RevPrD)

Hot Swap Controller and Digital Power Monitor with AlertB Output

Analog Devices 

Preliminary Technical Data

Hot Swap Controller and

Digital Power Monitor with AlertB Output

ADM1178

FEATURES

Allows Safe Board Insertion and Removal from a Live

Backplane

Controls Supply Voltages from 3.15 V to14 V

Precision Current Sense Amplifier

Precision Voltage Input

12-Bit ADC for Current and Voltage Readback

Charge Pumped Gate Drive for External N-FET Switch

Adjustable Analog Current Limit with Circuit Breaker

Fast Response Limits Peak Fault Current

Automatic Retry or Latch-Off On Current Fault

Programmable hot swap timing via TIMER pin

Active-high ON pin

AlertB pin for overcurrent interrupt

I2C Fast Mode compliant interface (400 KHz max)

10-lead MSOP package

APPLICATIONS

Power Monitoring/Power Budgeting

Central office Equipment

Telecommunication and Datacommunication Equipment

PC/Servers

GENERAL DESCRIPTION

The ADM1178 is an integrated hotswap controller and current

sense amplifier that offers digital current and voltage

monitoring via an on-chip 12-bit ADC, communicated through

an I2C interface.

An internal current sense amplifier senses voltage across the

sense resistor in the power path via the VCC and SENSE pins.

The ADM1178 limits the current through this resistor by

controlling the gate voltage of an external N-channel FET in the

power path, via the GATE pin. The sense voltage (and hence the

inrush current) is kept below a preset maximum.

The ADM1178 protects the external FET by limiting the time

that it spends with the maximum current running in it. This

current limit period is set by the choice of capacitor attached to

the TIMER pin. Additionally, the device provides protection

from overcurrent events at times after the hot-swap event is

complete. In the case of a short-circuit event the current in the

sense resistor will exceed an overcurrent trip threshold, and the

FET will be switched off immediately by pulling down the

GATE pin.

FUNCTIONAL BLOCK DIAGRAM

VCC

SENSE

ADM1178

Mux

V

0

+

A

-

I

1

12-Bit

ADC

Current Sense

Amplifier

Alert

SDA

I2C

SCL

ADR

ALERTB

ON

+

1.3V -

UV Comparator

FET Drive

Controller

GND

TIMER

3.15V - 14V

Figure 1.

APPLICATIONS DIAGRAM

RSENSE

N-Channel FET

GATE

Vcc SENSE

GATE

ADM1178

ON

SDA

SCL

T IM E R

ALERTB

GND ADR

CONTROLLER

SDA

SCL P=VI

INT E RRU PT

Figure 2.

A 12-bit ADC can measure the current seen in the sense

resistor, and also the supply voltage on the VCC pin.

An industry standard I2C interface allows a controller to read

current and voltage data from the ADC. Measurements can be

initiated by an I2C command. Alternatively the ADC can run

continuously and the user can read the latest conversion data

whenever it is required. Up to 4 unique I2C addresses can be

created by the way the ADR pin is connected.

The ADM1178 is packaged in a 10-lead MSOP package.

Rev. PrD May 2006

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

© 2006 Analog Devices, Inc. All rights reserved.

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