®
RT9161/A
300/500mA Low Dropout Linear Voltage Regulator
General Description
Features
The RT9161/A is a 300/500mA fixed output voltage low
dropout linear regulator. Typical ground current is
approximately 110μA, from zero to maximum loading
conditions. Wide range of available output voltage fits most
of applications. Built-in output current-limiting most
thermal-limiting provide maximal protection against any
fault conditions.
Low Dropout Voltage of 200mV at Output Current
100mA, 450mV at Output Current 300mA, and
750mV at 500mA Output Current
Guaranteed 300/500mA Output Current
Internal 1.5Ω
Ω P-MOSFET Draws No Base Current
Low Ground Current 110μ
μA
For ease of application, the RT9161/A comes in the popular
3-pin SOT-23 (300mA), SOT-89 (300mA), SOT-223
(500mA), or TO-92 packages.
2% Accuracy Output Voltage
Input Voltage Range up to 12V
Extremely Tight Load Regulation
Fast Transient Response
Current-limiting and Thermal-limiting
RoHS Compliant and 100% Lead (Pb)-Free
Ordering Information
RT9161/A-
Applications
Package Type
V : SOT-23-3
X : SOT-89
G : SOT-223
ZL : TO-92 (L-Type)
ZT : TO-92 (T-Type)
Voltage Regulator for LAN Card, CD-ROM, and DVD
Wireless Communication Systems
Battery Powered Systems
Marking Information
For marking information, contact our sales representative
Lead Plating System
directly or through a Richtek distributor located in your
P : Pb Free
G : Green (Halogen Free and Pb Free) area.
Output Voltage
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
Pin Configurations
(TOP VIEW)
VIN
500mA Output Current
300mA Output Current
3
1
Richtek products are :
GND
3
VOUT
GND
SOT-23-3
RoHS compliant and compatible with the current
require-
VIN VOUT
(TAB)
SOT-89
ments of IPC/JEDEC J-STD-020.
2
2
Note :
Suitable for use in SnPb or Pb-free soldering
processes.
2
1
GND
3
VIN VOUT
(TAB)
SOT-223
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DS9161/A-36 September 2022
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1
RT9161/A
3
2
VOUT
3
VOUT
GND
1
VIN
2
1
VIN
GND
TO-92 (L-Type)
TO-92 (T-Type)
Typical Application Circuit
RT9161/A
VIN
VOUT
+
CIN
1uF
+
VIN
COUT
10uF
GND
VOUT
Electrolytic
Part Status
Part No
Status
RT9161A-XXPX
Lifebuy
Package
Lead Plating System
SOT-89
P : Pb Free
The part status values are defined as below :
Active : Device is in production and is recommended for new designs.
Lifebuy : The device will be discontinued, and a lifetime-buy period is in effect.
NRND : Not recommended for new designs.
Preview : Device has been announced but is not in production.
EOL: Richtek has discontinued the production of the device.
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DS9161/A-36 September 2022
RT9161/A
Functional Pin Description
Pin Name
Pin Function
VOUT
Output Voltage.
GND
Ground.
VIN
Power Input.
Functional Block Diagram
VIN
VOUT
Thermal
Shutdown
Error Amp
-
+
Current
Limiting
Sensor
1.2V
Reference
GND
Copyright © 2022 Richtek Technology Corporation. All rights reserved.
DS9161/A-36 September 2022
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RT9161/A
Absolute Maximum Ratings
Input Voltage ---------------------------------------------------------------------------------------------------------------- −0.3 to 14V
Operating Junction Temperature Range ------------------------------------------------------------------------------- −40°C to 125°C
Storage Temperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C
Power Dissipation, PD @ TA = 25°C
SOT-23-3 --------------------------------------------------------------------------------------------------------------------- 0.4W
SOT-89 ----------------------------------------------------------------------------------------------------------------------- 0.571W
SOT-223 --------------------------------------------------------------------------------------------------------------------- 0.741W
TO-92 ------------------------------------------------------------------------------------------------------------------------- 0.625W
Package Thermal Resistance (Note 1)
SOT-23-3, θJA --------------------------------------------------------------------------------------------------------------- 250°C/W
SOT-23-3, θJC --------------------------------------------------------------------------------------------------------------- 140°C/W
SOT-89, θJA ----------------------------------------------------------------------------------------------------------------- 175°C/W
SOT-89, θJC ----------------------------------------------------------------------------------------------------------------- 100°C/W
SOT-223, θJA ---------------------------------------------------------------------------------------------------------------- 135°C/W
SOT-223, θJC --------------------------------------------------------------------------------------------------------------- 15°C/W
TO-92, θJA ------------------------------------------------------------------------------------------------------------------- 160°C/W
TO-92, θJC ------------------------------------------------------------------------------------------------------------------- 125°C/W
Electrical Characteristics
(TA = 25° C, CIN = 1μF, COUT = 10μF, unless otherwise specified.)
Parameter
Symbol
Output Voltage Accuracy
VOUT
Test Conditions
IL = 1mA, VIN = 5V
Output Voltage Temperature
Coefficient
Line Regulation
Load Regulation
(Note 2)
Current Limit
(Note 3)
RT9161
Dropout Voltage
(Note 4)
Standby Current
RT9161A
Min
Typ
Max
Unit
2
--
2
%
--
50
150
PPM/C
VLINE
IL = 1mA, VIN= 4.5 to 12V
--
2
3
%VOUT
VLOAD
IL = 1mA to 300/500mA, VIN = 5V
--
1
30/50
mV
ILIM
VIN = 5V, VOUT = 0V
350
580
--
500
900
--
VDROP
IL = 300/500mA
ISTANDBY IL = 0, VIN = 12V
---
450/750 600/1000
110
180
mA
mV
A
Note 1. θJA is measured in the natural convection at TA = 25°C on a low effective single layer thermal conductivity test board of
JEDEC 51-3 thermal measurement standard.
Note 2. Regulation is measured at constant junction temperature, using pulsed ON time.
Note 3. Current Limit is measured at constant junction temperature, using pulsed ON time.
Note 4. The dropout voltage is defined as VIN − VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV.
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RT9161/A
Typical Operating Characteristics
Temperature Stability
Quiescient Current vs. Temperature
0.14
0.12
VOUT = 3.3V
3.2
Quiescient Current (mA)
Output Voltage (V)
3.4
3
2.8
2.6
VOUT = 2.5V
0.10
0.08
0.06
0.04
0.02
VIN = 5V
0.00
2.4
-50
-25
0
25
50
75
100
-30
125
0
Temperature (°C)
60
90
120
Temperature (°C)
Dropout Voltage (VIN-VOUT)
1
Short Circuit Current
1.4
125°C
0.8
Short Circuit Current (A)
Dropout Voltage (V)
30
25°C
0.6
0.4
0.2
1.2
125°C
1
25°C
0.8
0.6
0.4
0.2
VOUT = 3.3V
0
0
0
100
200
300
400
500
0
2
Line Transient Response
6
5
T
4
Output Voltage
Deviation (mV)
7
VOUT = 3.3V
TA = 25C
Input Voltage
Deviation (V)
COUT = 10F Electrolytic
IOUT = 0.1A
TT
100
0
-100
-200
Time(100μs/Div)
(100S/Div)
Time
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DS9161/A-36 September 2022
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8
10
Line Transient Response
COUT = 10F Electrolytic
IOUT = 0.1A
6
5
VOUT = 2.5V
TA = 25C
T
4
Output Voltage
Deviation (mV)
Input Voltage
Deviation (V)
7
4
Input/Output Differential (V)
I Load (mA)
100
TT
0
-100
-200
Time(100μs/Div)
(100S/Div)
Time
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RT9161/A
Load Transient Response
VIN = 5V
VOUT = 3.3V
CIN = 1F
40 COUT = 10F
20 TA = 25C
TT
0
-20
T
1
-50
50 TA = 25C
0
TT
100
T
10
-100
Time(100μs/Div)
(100S/Div)
Time
Load Transient Response
VIN = 5V
VOUT = 2.5V
CIN = 1F
40 COUT = 10F
TA = 25C
20
0
TT
-20
T
1
-50
PSRR
0
-50
T
-100
Time(100μs/Div)
(100S/Div)
Time
PSRR
CIN = 1uF
COUT = 10uF Tantalum
VIN = 5V
VOUT = 2.5V
TA = 25°C
-10
-40
10
100mA
-30
TT
100
0
PSRR (dB)
-20
TA = 25C
50
Time(100μs/Div)
(100S/Div)
Time
CIN = 1uF
COUT = 10uF Tantalum
VIN = 5V
VOUT = 3.3V
TA = 25°C
VIN = 5V
VOUT = 2.5V
CIN = 1F
100 COUT = 10F
200
Load Current
(mA)
Load Current
(mA)
50
150
-50
100
PSRR (dB)
Output Voltage
Deviation (mV)
Output Voltage
Deviation (mV)
Load Transient Response
-10
Time
Time(100μs/Div)
(100S/Div)
60
0
VIN = 5V
VOUT = 3.3V
CIN = 1F
100 COUT = 10F
200
Load Current
(mA)
50
150
-50
100
Load Current
(mA)
Output Voltage
Deviation (mV)
Output Voltage
Deviation (mV)
Load Transient Response
60
-20
100mA
-30
-40
-50
10mA
10mA
-60
-60
10
100
1000
1K
10000
10K
100000
100K
Frequency (Hz)
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1000000
1M
10
100
1K
1000
10K
10000
100K
100000
1M
1000000
Frequency (Hz)
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DS9161/A-36 September 2022
RT9161/A
Application Information
A 10uF capacitor with 200mΩ or higher ESR, connecting
between VOUT and GND pins, is recommended for
stability. A capacitor with ESR smaller than 200 mΩ may
cause VOUT oscillation as shown in Figure 1. Operating
temperature should be well considered to ensure that the
capacitance is no less than 10uF over the operating
temperature range. Please take the notice that Aluminum
electrolytic capacitors may cause VOUT oscillation when
operating below −25°C. The capacitance can be increased
without limit for better transient response.
A 1uF or higher capacitor should be placed between VIN
and GND to filter out input noise and ensure stable output
voltage.
Region of Stable COUT ESR vs. Load Current
100
For recommended operating conditions specification of
RT9161/A, where T J(MAX) is the maximum junction
temperature of the die (125°C) and TA is the maximum
ambient temperature. The junction to ambient thermal
resistance θJA is layout dependent. For SOT-223 packages,
the thermal resistance θJA is 135°C/W on the standard
JEDEC 51-3 single-layer 1S thermal test board. The
maximum power dissipation at TA = 25°C can be calculated
by following formula :
PD(MAX) = ( 125°C − 25°C ) / 250 = 0.400 W for
PD(MAX) = ( 125°C − 25°C ) / 175 = 0.571 W for
SOT-89 packages
PD(MAX) = ( 125°C − 25°C ) / 135 = 0.741 W for
1
SOT-223 packages
Stable
PD(MAX) = ( 125°C − 25°C ) / 160 = 0.625 W for
0.1
Instable
TO-92 packages
0.01
0
100
200
300
400
500
Load Current (mA)
Figure 1
Thermal protection limits power dissipation in RT9161/A.
When the operation junction temperature exceeds 165°C,
the OTP circuit starts the thermal shutdown function and
turns the pass element off. The pass element turn on again
after the junction temperature cools by 30°C.
For continuous operation, do not exceed absolute
maximum operation junction temperature 125°C. The
power dissipation definition in device is :
PD = (VIN − VOUT) x IOUT + VIN x IQ
The maximum power dissipation depends on the thermal
resistance of IC package, PCB layout, the rate of
surroundings airflow and temperature difference between
junction to ambient. The maximum power dissipation can
be calculated by following formula :
Copyright © 2022 Richtek Technology Corporation. All rights reserved.
DS9161/A-36 September 2022
The maximum power dissipation depends on operating
ambient temperature for fixed T J(MAX) and thermal
resistance θJA. For RT9161/A packages, the Figure 2 of
derating curves allows the designer to see the effect of
rising ambient temperature on the maximum power
allowed.
Maximum Power Dissipation (mW)
C OUT ESR (Ω)
Where T J(MAX) is the maximum operation junction
temperature 125°C, TA is the ambient temperature and the
θJA is the junction to ambient thermal resistance.
SOT-23-3 packages
VIN = 3.3V
CIN = 1uF
COUT = 10uF
10
PD(MAX) = ( TJ(MAX) − TA ) / θJA
800
SOT-223 package
700
TO-29 package
600
SOT-89 package
500
400
300
SOT-23-3 package
200
100
0
0
15
30
45
60
75
90
105
120
Ambient Temperature (°C)
Figure 2. Derating Curves
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RT9161/A
Outline Dimension
A
D
E
L
b
e
C
D1
A1
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
3.175
4.191
0.125
0.165
A1
1.143
1.372
0.045
0.054
b
0.406
0.533
0.016
0.021
C
0.406
0.533
0.016
0.021
D
4.445
5.207
0.175
0.205
D1
3.429
5.029
0.135
0.198
E
4.318
5.334
0.170
0.210
e
1.143
1.397
0.045
0.055
L
12.700
0.500
3-Lead TO-92 Plastic Package
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DS9161/A-36 September 2022
RT9161/A
H
D
L
C
B
e
A
A1
b
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
0.889
1.295
0.035
0.051
A1
0.000
0.152
0.000
0.006
B
1.397
1.803
0.055
0.071
b
0.356
0.508
0.014
0.020
C
2.591
2.997
0.102
0.118
D
2.692
3.099
0.106
0.122
e
1.803
2.007
0.071
0.079
H
0.080
0.254
0.003
0.010
L
0.300
0.610
0.012
0.024
SOT-23-3 Surface Mount Package
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RT9161/A
D
D1
A
B
C
C1
e
e
H
A
b
b1
b
Dimensions In Millimeters
Dimensions In Inches
Symbol
Min
Max
Min
Max
A
1.397
1.600
0.055
0.063
b
0.356
0.483
0.014
0.019
B
2.388
2.591
0.094
0.102
b1
0.406
0.533
0.016
0.021
C
3.937
4.242
0.155
0.167
C1
0.787
1.194
0.031
0.047
D
4.394
4.597
0.173
0.181
D1
1.397
1.753
0.055
0.069
e
1.448
1.549
0.057
0.061
H
0.356
0.432
0.014
0.017
3-Lead SOT-89 Surface Mount Package
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RT9161/A
Dimensions In Millimeters
Symbol
Dimensions In Inches
Min
Max
Min
Max
A
1.400
1.800
0.055
0.071
A1
0.020
0.100
0.001
0.004
b
0.600
0.840
0.024
0.033
B
3.300
3.700
0.130
0.146
C
6.700
7.300
0.264
0.287
D
6.300
6.700
0.248
0.264
b1
2.900
3.100
0.114
0.122
e
2.300
0.091
H
0.230
0.350
0.009
0.014
L
1.500
2.000
0.059
0.079
L1
0.800
1.100
0.031
0.043
3-Lead SOT-223 Surface Mount Package
Richtek Technology Corporation
14F, No. 8, Tai Yuen 1st Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789
Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should
obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot
assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be
accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries.
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