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Fairchild Semiconductor |
www.fairchildsemi.com
FAN1582
3A Adjustable/Fixed Ultra Low Dropout
Linear Regulator
Features
• Ultra Low dropout voltage, 0.4V typical at 3A
• Remote sense operation
• Fast transient response
• Load regulation: 0.05% typical
• 0.5% initial accuracy
• On-chip thermal limiting
• 5-Pin SPAK, TO-252 DPAK, and TO-263 packages
Applications
• Pentium® Processors
• PowerPC™, AMD K5 and K6 processors
• Pentium support of GTL+ bus supply
• Low voltage logic supply
• Embedded Processor supplies
• Split plane regulator
• New 2.5V and 1.8V Logic Families
Description
The FAN1582, FAN1582-1.5, and FAN1582-2.5 are ultra-low
dropout regulators with 3A output current capability. These
devices have been optimized for low voltage applications
including VTT bus termination, where transient response and
minimum input voltage are critical. The FAN1582 is ideal
for low voltage microprocessor applications requiring a reg-
ulated output from 1.3V to 5.7V with a power input supply
of 1.75V to 6.5V. The FAN1582-1.5 offers fixed 1.5V with
3A current capabilities for GTL+ bus VTT termination. The
FAN1582-2.5 offers fixed 2.5V with 3A current capability
for logic IC operation and processors while minimizing the
overall power dissipation.
Current limit ensures controlled short-circuit current. On-chip
thermal limiting provides protection against any combination
of overload and ambient temperature that would create exces-
sive junction temperatures.
The FAN1582 series regulators are available in the 5-Pin
SPAK, TO-252 DPAK, and TO-263 power packages.
Typical Applications
VIN = 3.3V
10µF
+
VCNTL = 5V
VIN VSENSE
FAN1582
VCNTL
VOUT
Adj
VIN = 3.3V
10µF
+
124Ω
2.1V at 3A
+
22µF
86.6Ω
VCNTL = 5V
1µF
+
VIN = 5.75V
10µF
+
VCNTL = 12V
VIN VSENSE
FAN1582–2.5
VCNTL
VOUT
GND
VIN VSENSE
FAN1582
VCNTL
VOUT
Adj
2.5V at 3A
+
22µF
124Ω
5V at 3A
+
22µF
374Ω
Pentium is a registered trademark of Intel Corporation. PowerPC is a trademark of IBM Corporation.
REV. 1.1.2 2/26/03
FAN1582
Pin Assignments
FAN1582M-1.5, -2.5
FRONT VIEW
FAN1582M
FRONT VIEW
PRODUCT SPECIFICATION
FAN1582P
FRONT VIEW
FAN1582P-1.5, -2.5
FRONT VIEW
FAN1582D
FRONT VIEW
FAN1582D-1.5, -2.5
FRONT VIEW
1 2 3 45
1 2 3 45
12 3 45
12 3 45
1 2 3 45
1 2 3 45
5-Lead Plastic TO-263
ΘJC=3°C/W*
Tab is out.
5-Lead Plastic SPAK
ΘJC=2°C/W*
Tab is out.
5-Lead Plastic TO-252 DPAK
ΘJC=3°C/W*
Tab is out.
*With package soldered to 0.5 square inch copper area over backside ground plane or internal
power plane, θJA can vary from 30 °C/W to more than 40 °C/W. Other mounting techniques
can provide a thermal resistance lower than 30 °C/W.
Pin Definitions
Pin Number
1
Pin Name
VSense
2 ADJ/GND
3 VOUT
4 VCNTL
5 VIN
Pin Function Descrition
Remote Voltage Sense. Connect this pin to the load to permit true
remote sensing and avoid trace drops.
Adjust or Ground. On the FAN1582, this pin forms the feedback to
determine the output voltage. On the FAN1582-1.5 and -2.5, connect this
pin to ground.
Output Voltage. This pin and the tab are output.
Control Voltage. This pin draws small-signal power to control the
FAN1582 circuitry. Connect to a voltage higher than VIN, as shown in the
applications circuits.
Input Voltage.
Internal Block Diagram
4
VCNTL, Control
Thermal
Shutdown
Current
Limit
Vref Voltage Loop
Amplifier
5 Vin, Power
3 Output
1 Sense
2 Adj
2 REV. 1.1.2 2/26/03
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