Fairchild Semiconductor RC1117X25 Datasheet
www.fairchildsemi.com
REV. 1.3.1 11/18/02
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 industrystandard SOT-223, TO-263 (D2PAK), and TO-252 (DPAK)
power packages.
Typical Applications
V
IN
= 3.3V V
IN
V
OUT
ADJ
1.5V at 1A
RC1117
10µF22µF
R1
124Ω
R2
24.9Ω
V
IN
= 5V V
IN
V
OUT
GND
2.85V at 1A
RC1117-2.85
10µF
++
+
+
22µF
V
OUT
= V
REF
(1 + R2/R1) + I
Adj
• R2
RC1117
1A Adjustable/Fixed Low Dropout Linear Regulator
PRODUCT SPECIFICATION RC1117
2
REV. 1.3.1 11/18/02
Pin Assignments
*With package soldered to 0.5 square inch copper area over backside ground plane or internal power plane., Θ
JA
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 Min. Max. Unit
V
IN
7.5 V
Operating Junction Temperature Range 0 125
°
C
Storage Temperature Range -65 150
°
C
Lead Temperature (Soldering, 10 sec.) 300
°
C
Front View
4-Lead Plastic SOT-223
Θ
JC
= 15°C/W*
3-Lead Plastic TO-252
ΘJC = 3°C/W*
Tab is
V
OUT
Tab is
V
OUT
1
ADJ/
GND
IN
23
3-Lead Plastic TO-263
Θ
JC
= 3°C/W*
Tab is
V
OUT
1
ADJ/
GND
INOUT
2 3
3
2
1
IN
OUT
ADJ/GND
RC1117 PRODUCT SPECIFICATION
REV. 1.3.1 11/18/02
3
Electrical Characteristics
Operating Conditions: V
IN
≤
7V, T
J
= 25°C unless otherwise specified.
The • denotes specifications which apply over the specified operating temperature range.
Notes:
1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are
measured at a constant junction temperature by low duty cycle pulse testing.
2. Line and load regulation are guaranteed up to the maximum power dissipation (18W). Power dissipation is determined by
input/output differential and the output current. Guaranteed maximum output power will not be available over the full input/
output voltage range.
3. RC1117 only.
Parameter Conditions Min. Typ. Max. Units
Reference Voltage, V
REF
3
1.5V ≤ (V
IN
- V
OUT
) ≤
5.75V,
10mA ≤ I
OUT
≤ 1A •
1.225
(-2%)
1.250 1.275
(+2%)
V
Output Voltage 10mA ≤ I
OUT
≤
1A
RC1117-2.5, 4V ≤ V
IN
≤
7V
RC1117-2.85, 4.35V ≤ V
IN
≤
7V
RC1117-3.3, 4.8V ≤ V
IN
≤
7V
RC1117-5, 6.5V ≤ V
IN
≤
7V
•
•
•
•
2.450
2.793
3.234
4.900
2.5
2.85
3.3
5.0
2.550
2.907
3.366
5.100
V
V
V
V
Line Regulation
1,2
(V
OUT
+ 1.5V) ≤ V
IN
≤
7V, I
OUT
= 10mA •
0.005 0.2 %
Load Regulation
1,2
(V
IN
– V
OUT
) = 2V, 10mA ≤ I
OUT
≤ 1A •
0.05 0.5 %
Dropout Voltage
∆
V
REF
= 1%, I
OUT
= 1A
•
1.100 1.200 V
Current Limit (V
IN
– V
OUT
) = 2V
•
1.1 1.5 A
Adjust Pin Current, I
Adj
3
•
35 120
µ
A
Adjust Pin Current Change
3
1.5V ≤ (V
IN
– V
OUT
) ≤
5.75,
10mA ≤ I
OUT
≤ 1A •
0.2 5
µ
A
Minimum Load Current 1.5V ≤ (V
IN
– V
OUT
) ≤
5.75
•
10 mA
Quiescent Current V
IN
= V
OUT
+ 1.25V
•
413mA
Ripple Rejection f = 120Hz, C
OUT
= 22 µ F Tantalum,
(V
IN
– V
OUT
) = 3V, I
OUT
= 1A
60 72 dB
Thermal Regulation T
A
= 25 ° C, 30ms pulse 0.004 0.02 %/W
Temperature Stability
•
0.5 %
Long-Term Stability T
A
= 125 ° C, 1000hrs. 0.03 1.0 %
RMS Output Noise
(% of V
OUT
)
T
A
= 25 ° C, 10Hz ≤ f ≤ 10kHz 0.003 %
Thermal Resistance, Junction
to Case
SOT-223 15
°
C/W
TO-252, TO-263 3
°
C/W
Thermal Shutdown Junction Temperature 155
°
C
Thermal Shutdown
Hysteresis
10
°
C
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