ANALOG DEVICES ADM1052 Service Manual

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Precision Dual Voltage

a

FEATURES
Two Independent Controllers on One Chip
Two 2.525 V Outputs
Shutdown Inputs to Control Each Channel
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
Small, 8-Lead SO Package

APPLICATIONS
Desktop Computers
Servers
Workstations

FUNCTIONAL BLOCK DIAGRAM

V

ADM1052

V

CC

50A

BANDGAP

REFERENCE

Regulator Controller

ADM1052

GENERAL DESCRIPTION

The ADM1052 is a dual, precision, voltage regulator controller
intended for power rail generation and active bus termination
on personal computer motherboards. It contains 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 ADM1052 operates from a 12 V supply. This 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.

3.3V

CC

CONTROL

AMPLIFIER

FORCE 1

SENSE 1

100F

V

OUT1

2  100F

SHDN1

SHDN2

V

CC

50A

V

CC

POWER-ON

RESET

SHUTDOWN

CONTROL

SHUTDOWN

CONTROL

CLK/DELAY

GENERATOR

GND

COMPARATOR

COMPARATOR

REV. A

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.

HICCUP

CONTROL

AMPLIFIER

FORCE 2

SENSE 2

HICCUP

CLOCK

OSCILLATOR

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 2001

3.3V

100F

V

OUT2

2  100F

(VCC = 12 V  6%, VIN = 3.3 V, TA = 0C to 70C, both channels, unless otherwise

ADM1052–SPECIFICATIONS

Parameter Min Typ Max Unit Test Conditions/Comments

OUTPUT VOLTAGE

Channel 1, Channel 2 2.525 V SHDN1, SHDN2 Floating

OUTPUT VOLTAGE ACCURACY –2.5 +2.5 % V

Load Regulation –5 +5 mV V
Line Regulation –5 +5 mV V

CONTROL AMPLIFIER

Control Amplifier Open-Loop Gain 100 dB
Control Amplifier Slew Rate 3 V/µs
Closed-Loop Settling Time 5 µsI
Turn-On Time 5 µs To 90% of Force High Output Level (C
Sense Input Impedance
Force Output Voltage Swing, V
Force Output Voltage Swing, VF (Low) 2 V RL = 10 kΩ to V

HICCUP MODE

Hiccup Mode Hold-Off Time 30 60 90 ms Figure 2
Hiccup Mode Threshold 0.8 × V
Hiccup Comparator Glitch Immunity 100 µs
Hiccup Mode On-Time 0.5 1.0 1.5 ms
Hiccup Mode Off-Time 20 40 60 ms
Power-On Reset Threshold 6 9 V

SHUTDOWN, SHDN1, SHDN2

Shutdown Input Low Voltage, V
Shutdown Input High Voltage, V
Supply Current, Normal Operation 2.4 4.0 mA Shutdown Inputs Floating
Supply Current, Shutdown Mode 600 1000 µA Both Channels Shut Dow

NOTES

1

Guaranteed by design.

Specifications subject to change without notice.

1

(High) 10 V RL = 10 kΩ to GND

F

IL

IH

2.0 V

noted. See Test Circuit.)

50 kΩ

V

OUT

0.8 V

= 3.0 V to 3.6 V, I

IN

= 3.3 V, I

IN

= 3.0 V to 3.6 V, I

IN

= 10 mA to 2 A

O

OUT

CC

= 10 mA to 1 A

OUT

= 10 mA to 1 A

OUT

= 1 A

1

n

1

= 470 pF)

L

–2–

REV. A

ADM1052

TOP VIEW

(Not to Scale)

8

7

6

5

1

2

3

4

FORCE 2

SENSE 2

SHDN2

GND

V

CC

FORCE 1

SENSE 1

SHDN1

ADM1052

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS*

(TA = 25°C unless otherwise noted)

VCC to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 V

SHDN1, SHDN2 to GND . . . . . . . . –0.3 V to (V

+ 0.3 V)

CC

SENSE1, SENSE2 to GND . . . . . . . . . . . . –0.3 V to +5.5 V

FORCE1, FORCE2 . . . . . . . . Short-Circuit to GND or V

CC

Continuous Power Dissipation (TA = 70°C) . . . . . . . 650 mW

°

8-Lead SOIC . . . . . . . . . . . . (Derate 8.3 mW/

C above 70°C)

Operating Temperature Range

Commercial (J Version) . . . . . . . . . . . . . . . . . . 0°C to 70°C

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . 300°C

*This is a stress rating only and functional operation of the device at these or any

other conditions above those indicated in the operation sections of this specifica­tion is not implied. Exposure to absolute maximum rating conditions for extended
periods of time may affect reliability.

THERMAL CHARACTERISTICS

8-Lead Small Outline Package: ␪JA = 150°C/W

ORDERING GUIDE

Temperature Package Package

Model Range Description Option

ADM1052JR 0°C to 70°C 8-Lead SOIC SO-8

PIN FUNCTION DESCRIPTIONS

Pin
No. Mnemonic Function

1 FORCE 2 Output of Channel 2 control amplifier to

gate of external N-channel MOSFET.

2 SENSE 2 Input from source of external MOSFET to

inverting input of Channel 2 control
amplifier, via output voltage-setting feed­back resistor network.

3 SHDN2 Digital Input. Active-low shutdown control

with 50 µA internal pull-up. The output
of Channel 2 control amplifier goes to
ground when SHDN2 is taken low.

4 GND Device Ground Pin.
5 SHDN1 Digital Input. Active-low shutdown control

with 50 µA internal pull-up. The output
of Channel 1 control amplifier goes to
ground when SHDN1 is taken low.

6 SENSE 1 Input from source of external MOSFET

to inverting input of Channel 1 control
amplifier, via output voltage-setting
feedback resistor network.

7 FORCE 1 Output of Channel 2 control amplifier to

gate of external N-channel MOSFET.

8V

CC

12 V Supply.

LEAVE OPEN OR

CONNECT TO

LOGIC SIGNALS

IF SHUTDOWN

REQUIRED

SHDN1

SHDN2

12V

V

CC

ADM1052

GND

1F

FORCE 2

SENSE 2

PHD55N03LT

FORCE 1

SENSE 1

MTD3055VL

3.3V

3.3V

100F

V

OUT1

2  100F

100F

V

OUT2

2  100F

PIN CONFIGURATION

Figure 1. Test Circuit

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the ADM1052 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.

REV. A

–3–