www.fairchildsemi.com
REV. 1.1.0 11/7/03
Features
• Low dropout voltage
• Load regulation: 0.05% typical
• Trimmed current limit
• On-chip thermal limiting
• Standard SOT-223, TO-220, and TO-252 packages
• Three-terminal adjustable or fixed 1.8V, 2.5V, 2.85V,
3.3V, 5V
Applications
• Active SCSI terminators
• High efficiency linear regulators
• Post regulators for switching supplies
• Battery chargers
• 12V to 5V linear regulators
• Motherboard clock supplies
Description
The FAN1117A and FAN1117A-1.8, -2.5, -2.85, -3.3 and -5
are low dropout three-terminal regulators with 1A output
current capability. These devices have been optimized for low
voltage where transient response and minimum input voltage
are critical. The 2.85V version is designed specifically to be
used in Active Terminators for SCSI bus.
Current limit is trimmed to ensure specified output current
and controlled short-circuit current. On-chip thermal limiting
provides protection against any combination of overload and
ambient temperatures that would create excessive junction
temperatures.
Unlike PNP type regulators where up to 10% of the output
current is wasted as quiescent current, the quiescent current
of the FAN1117A flows into the load, increasing efficiency.
The FAN1117A series regulators are available in the
industry-standard SOT-223, TO-220, and TO-252 (DPAK)
power packages.
Typical Applications
V
IN
= 12V V
IN
V
OUT
ADJ
9V at 1A
FAN1117A
10µF22µF
R1
124Ω
R2
768Ω
V
IN
= 12V V
IN
V
OUT
GND
5V at 1A
FAN1117A-5
10µF
++
+
+
22µF
V
OUT
= V
REF
(1 + R2/R1) + I
ADJ
• R2
FAN1117A
1A Adjustable/Fixed Low Dropout Linear Regulator