www.fairchildsemi.com
FAN1581
5A Adjustable/Fixed Ultra Low Dropout
Linear Regulator
Features
Description
• Ultra Low dropout voltage, 0.4V typical at 5A
• Remote sense operation
• Fast transient response
• Load regulation: 0.05% typical
• 0.5% initial accuracy
• On-chip thermal limiting
The FAN1581, FAN1581-1.5, and FAN1581-2.5 are ultra-low
dropout regulators with 5A 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 FAN1581 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 FAN1581-1.5 offers fixed 1.5V with
5A current capabilities for GTL+ bus VTT termination. The
FAN1581-2.5 offers fixed 2.5V with 5A current capability
for logic IC operation and processors while minimizing the
overall power dissipation.
• 5-Pin SPAK and TO-263 packages
Applications
• Pentium® Processors
• PowerPC™, AMD K5 and K6 processors
• Pentium support of GTL+ bus supply
• Low voltage logic supply
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.
• Embedded Processor supplies
• Split plane regulator
• New 2.5V and 1.8V Logic Families
The FAN1581 series regulators are available in the 5-Pin
SPAK and TO-263 power packages.
Typical Applications
VIN = 3.3V
10µF
VIN
VSENSE
+
+
FAN1581–2.5
VOUT
2.5V at 5A
VIN = 3.3V
VCNTL = 5V
1µF
VCNTL
VIN
VSENSE
+
+
22µF
GND
10µF
FAN1581
VOUT
2.1V at 5A
VCNTL = 5V
VCNTL
+
22µF
Adj
124Ω
VIN = 5.75V
10µF
VIN
VSENSE
+
86.6Ω
FAN1581
VOUT
5V at 5A
VCNTL = 12V
VCNTL
+
22µF
Adj
124Ω
374Ω
Pentium is a registered trademark of Intel Corporation. PowerPC is a trademark of IBM Corporation.
REV. 1.1.3 2/20/02