ADM1051A 查看數據表（PDF） - Analog Devices

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ADM1051A

Precision Dual Voltage Regulator Controllers

Analog Devices 

a

Precision Dual Voltage

Regulator Controllers

ADM1051/ADM1051A

FEATURES

Two Independent Controllers on One Chip

1.515 V and 1.818 V Outputs

Shutdown Inputs to Control Each Channel

Compatible with PC Motherboard TYPEDET Signal

؎2.5% Accuracy Over, Line, Load, and Temperature

Low Quiescent Current

Low Shutdown Current

Works with External N-Channel MOSFETs for Low Cost

“Hiccup Mode” Fault Protection

No External Voltage or Current Setting Resistors

1.8 V/3.3 V ICH Sequenced Power-Up on ADM1051A

Small, 8-Lead SOIC Package

APPLICATIONS

Desktop Computers

Servers

Workstations

GENERAL DESCRIPTION

The ADM1051/ADM1051A are dual, precision, voltage regula-

tor controllers intended for power rail generation and active bus

termination on personal computer motherboards. They contain a

precision 1.2 V bandgap reference and two channels consisting of

control amplifiers driving external power devices. Each channel

has a shutdown input to turn off amplifier output and Hiccup

Mode protection circuitry for the external power device. The

shutdown input on the 1.5 V channel can also be used with the

TYPEDET signal on a PC motherboard to select the output voltage.

The ADM1051/ADM1051A operate from a 12 V supply, which

gives sufficient headroom for the amplifiers to drive external

N-channel MOSFETs, operating as source-followers, as the

external series pass devices. This has the advantage that N-

channel devices are cheaper than P-channel devices of similar

performance, and the circuit is easier to stabilize than one using

P-channel devices in a common-source configuration.

SHDN1

SHDN2

FUNCTIONAL BLOCK DIAGRAM

VCC

ADM1051/ADM1051A

BANDGAP

REFERENCE

CONTROL

AMPLIFIER

FORCE 1

VCC

SENSE 1

50␮A

SHUTDOWN

CONTROL

HICCUP

COMPARATOR

VCC

50␮A

VCC

POWER-ON

RESET

NO CONNECTION

ON ADM1051A

CONTROL

AMPLIFIER

FORCE 2

SENSE 2

SHUTDOWN

CONTROL

HICCUP

COMPARATOR

CLK/DELAY

GENERATOR

CLOCK

OSCILLATOR

VIN

3.3V

100␮F

VOUT1

2؋100␮F

VIN

3.3V

100␮F

VOUT2

2؋100␮F

GND

REV. 0

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

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

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

Tel: 781/329-4700 World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 2000

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