RT9161/A
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DS9161/A-35 April 2011 www.richtek.com
Pin Configurations
300/500mA Low Dropout Linear Voltage Regulator
Ordering Information
(TOP VIEW)
General Description
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.
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.
Applications
zVoltage Regulator for LAN Card, CD-ROM, and DVD
zWireless Communication Systems
zBattery Powered Systems
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
Features
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zLow Dropout Voltage of 200mV at Output Current
100mA, 450mV at Output Current 300mA, and
750mV at 500mA Output Current
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zGuaranteed 300/500mA Output Current
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zInternal 1.5ΩΩ
ΩΩ
Ω P-MOSFET Draws No Ba se Current
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zLow Ground Current 1 10μμ
μμ
μA
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z2% Accuracy Output V oltage
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zInput Voltage Range up to 12V
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zExtremely Tight Load Regulation
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zFa st Tran sient Response
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zCurrent-limiting and Thermal-limiting
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zRoHS Compliant and 100% Lead (Pb)-Free
Note :
Richtek 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. SOT-89
SOT-23-3
SOT-223
GND VOUT
VIN
2
3
GND VIN
(TAB)
VOUT
123
GND VIN
(TAB)
VOUT
123
Output Voltage
15 : 1.5V
16 : 1.6V
:
49 : 4.9V
50 : 5.0V
RT9161/A-
Package Type
V : SOT-23-3
X : SOT-89
G : SOT-223
ZL : TO-92 (L-Type)
ZT : TO-92 (T-Type)
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
500mA Output Current
300mA Output Current
RT9161/A
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Function Block Diagram
Typical Application Circuit
Pi n Name Pi n F unction
VOUT Output Voltage.
GND Ground.
VIN Power Input.
Functional Pin Description
Current
Limiting
Sensor
Thermal
Shutdown
+
-
Error Amp
1.2V
Reference
VIN
GND
VOUT
VIN
GND
VOUT
RT9161/A
+
+
COUT
Electrolytic
10uF
CIN
1uF
VIN VOUT
2
3
1VIN
GND
VOUT
TO-92 (L-Type)
2
3
1GND
VIN
VOUT
TO-92 (T-Type)
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Absolute Maximum Ratings
zInput Voltage ---------------------------------------------------------------------------------------------------------------- −0.3 to 14V
zOperating Junction Temperature Range ------------------------------------------------------------------------------- −40°C to 125°C
zStorage Temperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C
zPower Dissipation, PD @ TA = 25°C
SOT-23-3 --------------------------------------------------------------------------------------------------------------------- 0.4W
SOT-89 ----------------------------------------------------------------------------------------------------------------------- 0.571W
SOT-223 --------------------------------------------------------------------------------------------------------------------- 0.741W
TO-92 ------------------------------------------------------------------------------------------------------------------------- 0.625W
zPackage 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, C OUT = 10μF, unless otherwise specified.)
Parameter Symbol Test Conditions Min Typ Max Unit
Output Voltage Accuracy ΔVOUT I
L = 1mA, VIN = 5V −2 -- 2 %
Output Voltage Temperature
Coefficient -- 50 150
PPM/°C
Line Regulation ΔVLINE I
L = 1mA, VIN= 4.5 to 12V -- 2 3
%VOUT
Load Regulation (Note 2) ΔVLOAD I
L = 1mA to 300/500mA, VIN = 5V -- 1 30/50 mV
RT9161 350 580 --
Current Limit
(Note 3) RT9161A ILIM V
IN = 5V, VOUT = 0V 500 900 -- mA
Dropout Voltage (Note 4) VDROP I
L = 300/500mA -- 450/750 600/1000 mV
Standby Current ISTANDBY I
L = 0, VIN = 12V -- 110 180 μA
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.
RT9161/A
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Quiescient Current vs. Temperature
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
-30 0 30 60 90 120
Temperature
Quiescient Current (mA)
Typical Operating Characteristics
Temperature Stability
2.4
2.6
2.8
3
3.2
3.4
-50-250 255075100125
Temperature
Output Voltage (V)
VOUT = 3.3V
VOUT = 2.5V
(°C)
VIN = 5V
(°C)
Dropout Voltage (VIN-VOUT)
0
0.2
0.4
0.6
0.8
1
0 100 200 300 400 500
ILoad (mA)
Dropout Voltage (V)
VOUT = 3.3V
125°C
25°C
Short Circuit Current
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0246810
Input/Output Differential (V)
Short Circuit Current (A)
125°C
25°C
T
T
T
1
>
2
>
≈
≈
100
0
-100
-200
7
6
5
4
Line Transient Response
Time
(
100
μ
S/Div
)
Output Voltage
Deviation (mV)
Input Voltage
Deviation
(
V
)
C
OUT
= 10μF Electrolytic
I
OUT
= 0.1A
V
OUT
= 3.3V
T
A
= 25°C
Time (100μs/Div)
T
T
T
1
>
2
>
≈
≈
100
0
-100
-200
7
6
5
4
Line Transient Response
Time
(
100
μ
S/Div
)
Output Voltage
Deviation (mV)
Input Voltage
Deviation
(
V
)
COUT = 10μF Electrolytic
IOUT = 0.1A
VOUT = 2.5V
TA = 25°C
Time (100μs/Div)
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T
T
1
>
2
>
Time (100
μ
S/Div)
≈
Load Transient Response
C
IN
= 1μF
C
OUT
= 10μF
Load Current
(
mA
)
100
50
1
-50
60
40
20
0
-20
Output Voltage
Deviation (mV)
≈
V
IN
= 5V
V
OUT
= 3.3V
T
A
= 25°C
Time (100μs/Div)
T
T
1 >
2 >
Time (100
μ
S/Div)
≈
Load Transient Response
CIN = 1μF
COUT = 10μF
Load Current
(
mA
)
200
100
10
-100
150
100
50
0
-50
Output Voltage
Deviation (mV)
≈
VIN = 5V
VOUT = 3.3V
T
A
= 25°C
Time (100μs/Div)
T
T
T
1 >
2 >
Time (100
μ
S/Div)
≈
Load Transient Response
C
IN
= 1μF
C
OUT
= 10μF
Load Current
(
mA
)
200
100
10
-100
150
100
50
0
-50
Output Voltage
Deviation (mV)
≈
V
IN
= 5V
V
OUT
= 2.5V
T
A
= 25°C
Time (100μs/Div)
PSRR
-60
-50
-40
-30
-20
-10
0
10 100 1000 10000 100000 1000000
Frequency (Hz)
PSRR (dB)
CIN = 1uF
COUT = 10uF Tantalum
VIN = 5V
VOUT = 3.3V
TA = 25°C
10mA
100mA
1M100K10K1K
PSRR
-60
-50
-40
-30
-20
-10
0
10 100 1000 10000 100000 1000000
Frequency (Hz)
PSRR (dB)
CIN = 1uF
COUT = 10uF Tantalum
VIN = 5V
VOUT = 2.5V
TA = 25°C
10mA
100mA
1M100K10K1K
T
T
T
1 >
2 >
Time (100
μ
S/Div)
≈
Load Transient Response
C
IN
= 1μF
C
OUT
= 10μF
Load Current
(
mA
)
100
50
1
-50
60
40
20
0
-20
Output Voltage
Deviation (mV)
≈
V
IN
= 5V
V
OUT
= 2.5V
T
A
= 25°C
Time (100μs/Div)
RT9161/A
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DS9161/A-35 April 2011www.richtek.com
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.
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 :
PD(MAX) = ( TJ(MAX) − TA ) / θJA
Where TJ(MAX) is the maximum operation junction
temperature 125°C, TA is the ambient temperature and the
θJA is the junction to ambient thermal resistance.
For recommended operating conditions specification of
RT9161/A, where TJ(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
SOT-23-3 packages
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
SOT-223 packages
PD(MAX) = ( 125°C − 25°C ) / 160 = 0.625 W for
TO-92 packages
The maximum power dissipation depends on operating
ambient temperature for fixed TJ(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.
Region of Stable COUT ESR vs. Load Current
0.01
0.1
1
10
100
0 100 200 300 400 500
Load Current (mA)
COUT ESR (Ω)
VIN = 3.3V
CIN = 1uF
COUT = 10uF
Instable
Stable
Figure 2. Derating Curves
0
100
200
300
400
500
600
700
800
0 153045607590105120
Ambient Temperature
Maximum Power Dissipation (mW)
(°C)
SOT-223 package
TO-29 package
SOT-89 package
SOT-23-3 package
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DS9161/A-35 April 2011 www.richtek.com
Outline Dimension
3-Lead TO-92 Plastic Package
A1
L
b
e
D1
E
D
C
A
Dim e nsions In Mill imet e rs Dime nsions In I nc hes
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
RT9161/A
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A
bA1
B
D
C
e
H
L
SOT-23-3 Surface Mount Pack age
Dim e nsions In Mill imet e rs Dime nsions In I nc hes
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
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DS9161/A-35 April 2011 www.richtek.com
C1
B
b
b1
b
A
C
ee
D
D1
H
A
3-Lead SOT-89 Surface Mount Package
Dim e nsions In Millimet e rs Dime nsions In I nc he s
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
RT9161/A
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DS9161/A-35 April 2011www.richtek.com
Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit
design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be
guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek.
Richtek Technology Corporation
Headquarter
5F, No. 20, Taiyuen Street, Chupei City
Hsinchu, Taiwan, R.O.C.
Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing)
5F, No. 95, Minchiuan Road, Hsintien City
Taipei County, Taiwan, R.O.C.
Tel: (8862)86672399 Fax: (8862)86672377
Email: marketing@richtek.com
Dimen sion s In Millimeters Dimen sions In Inch es
Symbol 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