RT9176
1.5A Fixed and Adjustable Low Dropout Positive Voltage
Regulators
General Description
The RT9176 series of high performance positive voltage
regulators is designed for applications requiring low dropout
performance at fully rated current. Additionally, the RT9176
series provides excellent regulation over variations in line
and load. Outstanding features include low dropout
performance at rated current, fast transient response,
internal current-limiting, and thermal-shutdown protection
of the output device. The RT9176 series of three terminal
regulators offers fixed and adjustable voltage options
available in space-saving SOT-223, TO-252, and TO-263
packages.
Features
Low Dropout Performance, 1.5V Max.
Full Current Rating Over Line and Temperature
Fast Transient Response
±
2% Output Voltage Accuracy
1.5V, 1.8V, 2.5V, 2.85V, 3.3V, and 3.5V Fixed and
Adjustable Output Voltage
SOT-223, TO-252, and TO-263 Packages
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Active SCSI Termination
Low Voltage Microcontrollers
Switching Power Supply Post-Regulator
Ordering Information
RT9176-
Package Type
G : SOT-223
L: TO-252
M : TO-263
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Output Voltage
Default : Adjustable
15 : 1.5V
18 : 1.8V
25 : 2.5V
28 : 2.85V
33 : 3.3V
35 : 3.5V
Pin ConFigurations
(TOP VIEW)
3
2
1
VIN
VOUT (TAB)
ADJ/GND
SOT-223
3
2
1
VIN
VOUT (TAB)
ADJ/GND
Note :
RichTek Pb-free and Green products are :
RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
Suitable for use in SnPb or Pb-free soldering processes.
100%matte tin (Sn) plating.
3
2
1
TO-252
VIN
VOUT (TAB)
ADJ/GND
TO-263
DS9176-11 March 2007
www.richtek.com
1
RT9176
Typical Application Circuit
RT9176
V
IN
= 5V
+
C1
10uF
VIN
ADJ
VOUT
V
REF
I
ADJ
R1
133
1%
R2
232
1%
+
V
OUT
= 3.45V
C2
10uF
Tantalum
V OUT = V REF (1+
(1) C1 needed if device is far from filter capacitors.
(2) C2 required for stability.
R2
R1
) + I ADJ R 2
Figure 1. Adjustable Voltage Regulator
V
IN
= 5V
+
GND
+
RT9176-33
VIN
VOUT
GND
+
C1
10uF
I
Q
V
OUT
3.3V
C2
10uF
Tantalum
(1) C1 needed if device is far from filter capacitors.
(2) C2 required for stability.
Figure 2. Active SCSI Bus Terminator
RT9176-28
VIN
VOUT
18 - 27 Lines
+
10uF
I
Q
22uF
Figure 3. Fixed Voltage Regulator
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2
DS9176-11 March 2007
RT9176
Function Block Diagram
VIN
S.O.A.
Current
Limiting
Amplifier
LIMIT
VOUT
SENSE
Thermal Overload
Voltage
Regulation
Amplifer
V
REF
ADJ/GND
Functional Pin Description
Pin Name
ADJ/GND
VOUT
VIN
Pin Function
Adjust Output Voltage or GND
Output Voltage
Power Input
DS9176-11 March 2007
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3
RT9176
Absolute Maximum Ratings
(Note 1)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 15V
Power Dissipation, P
D
@ T
A
= 25°C
SOT-223 ----------------------------------------------------------------------------------------------------------------- 0.740W
TO-252 -------------------------------------------------------------------------------------------------------------------
1.471W
TO-263 ------------------------------------------------------------------------------------------------------------------- 2.222W
Package Thermal Resistance (Note 6)
SOT-223,
θ
JA
------------------------------------------------------------------------------------------------------------ 135°C/W
SOT-223,
θ
JC
----------------------------------------------------------------------------------------------------------- 19°C/W
TO-252,
θ
JA
------------------------------------------------------------------------------------------------------------- 68° C/W
TO-252,
θ
JC
------------------------------------------------------------------------------------------------------------- 7.5° C/W
TO-263,
θ
JA
------------------------------------------------------------------------------------------------------------- 45° C/W
TO-263,
θ
JC
------------------------------------------------------------------------------------------------------------- 7.8° C/W
Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260° C
Junction Temperature ------------------------------------------------------------------------------------------------- 150°C
Storage Temperature Range ----------------------------------------------------------------------------------------
−
65°C to 150°C
ESD Susceptibility (Note 2)
HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 8kV
MM (Machine Mode) -------------------------------------------------------------------------------------------------- 750V
Recommended Operating Conditions
(Note 3)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 3V to 12V
Junction Temperature Range ----------------------------------------------------------------------------------------
−
40°C to 125°C
Electrical Characteristics
(T
A
= 25° C, unless otherwise specified)
Parameter
Symbol
Test Conditions
I
OUT
= 10mA, (V
IN
−V
OUT
) = 2V,
Min
Typ
Max
Units
V
V
Reference Voltage
(Note 4)
RT9176
V
REF
T
A
= 25°C
10mA
<
I
OUT
<
1.5A,
1.5V
<
V
IN
-V
OUT
<
10V
I
OUT
= 10mA, V
IN
= 3.3V, T
J
= 25°C
0
<
I
OUT
<
1.5A, 3.3V
<
V
IN
<
10V
I
OUT
= 10mA, V
IN
= 3.3V, T
J
= 25°C
0
<
I
OUT
<
1.5A, 3.3V
<
V
IN
<
10V
I
OUT
= 10mA, V
IN
= 4.0V, T
J
= 25°C
0
<
I
OUT
<
1.5A, 4.0V
<
V
IN
<
10V
I
OUT
= 10mA, V
IN
= 4.25V, T
J
= 25°C
0
<
I
OUT
<
1.5A, 4.25V
<
V
IN
<
10V
0
<
I
OUT
<
1.5A, 4.75V
<
V
IN
<
10V
I
OUT
= 10mA, V
IN
= 5V, T
J
= 25°C
0
<
I
OUT
<
1.5A, 5.0V
<
V
IN
<
10V
1.243 1.256 1.281
1.231 1.256 1.294
1.485
1.470
1.5
1.5
1.53
1.55
1.85
1.87
RT9176-15
RT9176-18
RT9176-25
Output Voltage
(Note 4)
RT9176-28
RT9176-33
RT9176-35
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4
1.797 1.815
1.779 1.815
2.460 2.500 2.544
2.450 2.500 2.550
2.822 2.850 2.910
2.793 2.850 2.936
3.234 3.300 3.400
3.465 3.500 3.570
3.430 3.500 3.605
DS9176-11 March 2007
V
OUT
V
I
OUT
= 10mA, V
IN
= 4.75V, T
J
= 25°C 3.267 3.300 3.365
RT9176
Parameter
RT9176
RT9176-15
Line Regulation
(Note 4)
RT9176-18
RT9176-25
RT9176-28
RT9176-33
RT9176-35
RT9176
RT9176-15
Load Regulation
(Note 4)
RT9176-18
RT9176-25
RT9176-28
RT9176-33
RT9176-35
Dropout Voltage
Current Limit
Minimum Load Current RT9176
Quiescent Current
Ripple Rejection
Adjust Pin Current
Adjust Pin Current Change
RT9176-XX
I
Q
PSRR
I
ADJ
ΔI
ADJ
10mA
≤
I
OUT
≤
1.5A, V
IN
= 5V
(Note 5)
V
DROP
I
LIM
ΔV
LOAD
ΔV
LINE
Symbol
Test Conditions
I
OUT
= 10mA,
1.5V
≤
V
IN
−V
OUT
≤
10V
I
OUT
= 0mA, 3.3V
≤
V
IN
≤
15V
I
OUT
= 0mA, 3.3V
≤
V
IN
≤
15V
I
OUT
= 0mA, 4.0V
≤
V
IN
≤
15V
I
OUT
= 0mA, 4.25V
≤
V
IN
≤
15V
I
OUT
= 0mA, 4.75V
≤
V
IN
≤
15V
I
OUT
= 0mA, 5.0V
≤
V
IN
≤
15V
(V
IN
−V
OUT
) = 3V, 0mA
≤
I
OUT
≤
1.5A
V
IN
= 3.3V, 0
≤
I
OUT
≤
1.5A
V
IN
= 3.3V, 0
≤
I
OUT
≤
1.5A
V
IN
= 4.0V, 0
≤
I
OUT
≤
1.5A
V
IN
= 4.25V, 0
≤
I
OUT
≤
1.5A
V
IN
= 4.75V, 0
≤
I
OUT
≤
1.5A
V
IN
= 5.0V, 0
≤
I
OUT
≤
1.5A
I
OUT
= 500mA
I
OUT
= 1.5A
V
IN
= 5V
(V
IN
−V
OUT
) = 2V
V
IN
= 5V
f
RIPPLE
= 120Hz ,
(V
IN
−
V
OUT
) = 2V, V
RIPPLE
= 1V
P-P
Min Typ Max Units
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
--
1.5
--
--
--
--
--
0.1
1
1
1
1
1
1
0.2
1
1
1
1
1
1
1.3
1.75
5
5
72
65
0.2
0.3
6
6
6
6
6
6
0.4
10
10
10
10
12
15
1.5
--
10
10
--
120
5
%
mV
mV
mV
mV
mV
mV
%
mV
mV
mV
mV
mV
mV
V
V
A
mA
mA
dB
μA
μA
1.15 1.25
Note 1.
Stresses listed as the above
“Absolute
Maximum Ratings” may cause permanent damage to the device. These are for
stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the
operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended
periods may remain possibility to affect device reliability.
Note 2.
Devices are ESD sensitive. Handling precaution recommended.
Note 3.
The device is not guaranteed to function outside its operating conditions.
Note 4.
Low duty cycle pulse testing with Kelvin connections.
Note 5.
The dropout voltage is defined as V
IN
-V
OUT
, which is measured when V
OUT
is V
OUT(NORMAL)
−
100mV.
Note 6.
θ
JA
is measured in the natural convection at T
A
= 25°C on a low effective thermal conductivity test board of
JEDEC 51-3 thermal measurement standard. The pad size is 6mm
2
on SOT-223 packages, 100mm
2
on TO-252
packages, 125mm
2
on TO-263 packages.
DS9176-11 March 2007
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