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Fairchild Semiconductor |
www.fairchildsemi.com
RC1117
1A Adjustable/Fixed Low Dropout Linear Regulator
Features
• Low dropout voltage
• Load regulation: 0.05% typical
• Trimmed current limit
• On-chip thermal limiting
• Standard SOT-223, TO-263, and TO-252 packages
• Three-terminal adjustable or fixed 2.5V, 2.85V, 3.3V, 5V
Applications
• Active SCSI terminators
• High efficiency linear regulators
• Post regulators for switching supplies
• Battery chargers
• 5V to 3.3V linear regulators
• Motherboard clock supplies
Description
The RC1117 and RC1117-2.5, -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 RC1117 flows into the load, increasing efficiency.
The RC1117 series regulators are available in the industry-
standard SOT-223, TO-263 (D2PAK), and TO-252 (DPAK)
power packages.
Typical Applications
VIN = 3.3V
10µF
+
RC1117
VIN VOUT
ADJ
R1
124Ω
+ 1.5V at 1A
22µF
VOUT = VREF(1 + R2/R1) + IAdj • R2
VIN = 5V
10µF
+
RC1117-2.85
VIN VOUT
GND
R2
24.9Ω
+ 2.85V at 1A
22µF
REV. 1.3.1 11/18/02
PRODUCT SPECIFICATION
RC1117
Pin Assignments
Tab is
VOUT
Front View
3
2
1
IN
OUT
ADJ/GND
4-Lead Plastic SOT-223
ΘJC = 15°C/W*
Tab is
VOUT
123
ADJ/
GND
IN
3-Lead Plastic TO-252
ΘJC = 3°C/W*
Tab is
VOUT
1 23
ADJ/ OUT
GND
IN
3-Lead Plastic TO-263
ΘJC = 3°C/W*
*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 50°C/W. Other mounting techniques may provide better thermal resistance than 30°C/W.
Absolute Maximum Ratings
Parameter
VIN
Operating Junction Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec.)
Min.
0
-65
Max.
7.5
125
150
300
Unit
V
°C
°C
°C
2 REV. 1.3.1 11/18/02
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