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Analog Devices |
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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
Precision Dual Voltage
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 con-
trol 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 suffi-
cient 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
ADM1052
VCC
50A
FUNCTIONAL BLOCK DIAGRAM
VCC
BANDGAP
REFERENCE
SHUTDOWN
CONTROL
HICCUP
COMPARATOR
3.3V
CONTROL
AMPLIFIER
FORCE 1
SENSE 1
100F
VOUT1
2 ؋ 100F
3.3V
SHDN2
VCC
50A
VCC
CONTROL
AMPLIFIER
FORCE 2
SENSE 2
SHUTDOWN
CONTROL
HICCUP
COMPARATOR
100F
VOUT2
2 ؋ 100F
POWER-ON
RESET
CLK/DELAY
GENERATOR
CLOCK
OSCILLATOR
GND
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.
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., 2001
ADM1052–SPECIFICATIONS (VCC = 12 V ؎ 6%, VIN = 3.3 V, TA = 0؇C to 70؇C, both channels, unless otherwise
noted. See Test Circuit.)
Parameter
Min Typ Max
Unit Test Conditions/Comments
OUTPUT VOLTAGE
Channel 1, Channel 2
2.525
V SHDN1, SHDN2 Floating
OUTPUT VOLTAGE ACCURACY
Load Regulation
Line Regulation
–2.5
–5
–5
CONTROL AMPLIFIER
Control Amplifier Open-Loop Gain
Control Amplifier Slew Rate
Closed-Loop Settling Time
Turn-On Time
Sense Input Impedance1
Force Output Voltage Swing, VF (High)
Force Output Voltage Swing, VF (Low)
100
3
5
50
10
2
+2.5
+5
+5
5
% VIN = 3.0 V to 3.6 V, IOUT = 10 mA to 1 A
mV VIN = 3.3 V, IOUT = 10 mA to 1 A1
mV VIN = 3.0 V to 3.6 V, IOUT = 1 A1
dB
V/µs
µs IO = 10 mA to 2 A
µs To 90% of Force High Output Level (CL = 470 pF)
kΩ
V RL = 10 kΩ to GND
V RL = 10 kΩ to VCC
HICCUP MODE
Hiccup Mode Hold-Off Time
Hiccup Mode Threshold
Hiccup Comparator Glitch Immunity
Hiccup Mode On-Time
Hiccup Mode Off-Time
Power-On Reset Threshold
30 60
90
ms Figure 2
0.8 × VOUT V
100 µs
0.5 1.0
1.5
ms
20 40
60
ms
6 9V
SHUTDOWN, SHDN1, SHDN2
Shutdown Input Low Voltage, VIL
Shutdown Input High Voltage, VIH
Supply Current, Normal Operation
Supply Current, Shutdown Mode
0.8
2.0
2.4 4.0
600 1000
V
V
mA Shutdown Inputs Floating
µA Both Channels Shut Down
NOTES
1Guaranteed by design.
Specifications subject to change without notice.
–2– REV. A
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