RT9164A
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DS9164A-15 April 2011 www.richtek.com
(TOP VIEW)
1A Fixed and Adjustable Low Dropout Positive Voltage
Regulators
General Description
The RT9164A series of high performance positive voltage
regulators is designed for applications requiring low dropout
performance at fully rated current. Additionally, the RT9164A
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 RT9164A series of three terminal
regulators offers fixed and adjustable voltage options
available in space-saving SOT-223, TO-252, and TO-263
packages.
Ordering Information
Features
zz
zz
zLow Dropout Performance, 1.4V Max
zz
zz
zFull Current Rating Over Line and Temperature
zz
zz
zFa st Transient Re sponse
zz
zz
z±2% Output V oltage Accura cy
zz
zz
z1.5V, 1.8V, 2.5V, 2.85V, 3.0V, 3.3V, and 3.5V Fixed
Adjustable Output Voltage
zz
zz
zSOT -223, T O-252, and T O-263 Pack ages
zz
zz
zRoHS Compliant and 100% Lead (Pb)-Free
TO-252 (R-Type)
SOT-223
TO-263
ADJ/GND
VOUT (TAB)
VIN
1
2
3
1
2
3
ADJ/GND
VOUT (TAB)
VIN
1
2
3
ADJ/GND (TAB)
VOUT
VIN
1
2
3
ADJ/GND
VOUT (TAB)
VIN
TO-252
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.
Applications
zActive SCSI Termination
zLow Voltage Microcontrollers
zSwitching Power Supply Post-Regulator
Pin ConFigurations
RT9164A-
Package Type
G : SOT-223
L: TO-252
LR : TO-252 (R-Type)
M : TO-263
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Output Voltage
Default : Adjustable
15 : 1.5V
18 : 1.8V
25 : 2.5V
28 : 2.85V
30 : 3.0V
33 : 3.3V
35 : 3.5V
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
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Figure 3. Active SCSI Bus Terminator
Figure 2. Fixed Voltage Regulator
Typical Application Circuit
Figure 1. Adjustable Voltage Regulator
VIN VOUT
ADJ
RT9164A
R1
133
R2
232
+
+
CIN
10uF
COUT
10uF
Tantalum
1%
1%
IADJ
VREF
VIN = 5V VOUT = 3.45V
VOUT = VREF(1+ )+IADJ R2
R1
R2
(1) CIN needed if device is far from filter capacitors.
(2) COUT required for stability.
VIN VOUT
GND
RT9164A-33
+
+
10uF 10uF
Tantalum
VIN = 5V VOUT
3.3V
CIN COUT
(1) CIN needed if device is far from filter capacitors.
(2) COUT required for stability.
IQ
VIN VOUT
GND
RT9164A-28
+
+
10uF
IQ
22uF
18 - 27 Lines
CIN COUT
VIN = 5V
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Function Block Diagram
Functional Pin Description
Pi n Name Pi n Functio n
ADJ/GND Adjust Output or Ground.
VOUT Output Voltage.
VIN Power Input.
Current
Limiting
Amplifier
Thermal Overload
Voltage
Regulation
Amplifer VREF
S.O.A.
VIN
VOUT
ADJ/GND
LIMIT
SENSE
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Absolute Maximum Ratings (Note 1)
zSupply Input Voltage ------------------------------------------------------------------------------------------------------ 15V
zPower Dissipation, PD @ TA = 25°C
SOT-223 --------------------------------------------------------------------------------------------------------------------- 0.740W
TO-252 ----------------------------------------------------------------------------------------------------------------------- 1.471W
TO-263 ----------------------------------------------------------------------------------------------------------------------- 2.222W°C
zPackage Thermal Resistance (Note 2)
SOT-223, θJA ---------------------------------------------------------------------------------------------------------------- 135°C/W
SOT-223, θJC --------------------------------------------------------------------------------------------------------------- 19°C/W
TO-252, θJA ------------------------------------------------------------------------------------------------------------------ 68°C/W
TO-252, θJC ----------------------------------------------------------------------------------------------------------------- 7.5°C/W
TO-263, θJA ------------------------------------------------------------------------------------------------------------------ 45°C/W
TO-263, θJC ----------------------------------------------------------------------------------------------------------------- 7.8°C/W
zLead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------- 260°C
zJunction Temperature ----------------------------------------------------------------------------------------------------- 150°C
zStorage Temperature Range --------------------------------------------------------------------------------------------- −65°C to 150°C
zESD Susceptibility (Note 3)
HBM (Human Body Mode) ----------------------------------------------------------------------------------------------- 8 kV
MM (Machine Mode) ------------------------------------------------------------------------------------------------------ 750V
Electrical Characteristics
(TA = 25°C, unless otherwise specified)
Recommended Operating Conditions (Note 4)
zSupply Input Voltage ------------------------------------------------------------------------------------------------------ 3V to 14V
zJunction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C
To be continued
Parameter Symbol Test Conditions Min Typ Max Unit
IOUT = 10mA, (VIN − VOUT) = 2V,
TA = 25°C 1.243 1.256 1.281 V
Reference Voltage
(Note 5) RT9164A VREF 10mA < IOUT < 1.0A,
1.5V < VIN − VOUT < 10V 1.231 1.256 1.294 V
IOUT = 10mA, VIN = 3.3V, TJ = 25°C 1.485 1.5 1.53
RT9164A -15
10mA < IOUT < 1.0A, 3.3V < VIN < 10V 1.470 1.5 1.55
IOUT = 10mA, VIN = 3.3V, TJ = 25°C 1.797 1.815 1.85
RT9164A -18
10mA < IOUT < 1.0A, 3.3V < VIN < 10V 1.779 1.815 1.87
IOUT = 10mA, VIN = 4.0V, TJ = 25°C 2.475 2.500 2.550
RT9164A -25
10mA < IOUT < 1.0A, 4.0V < VIN < 10V 2.450 2.500 2.575
IOUT= 10mA, VIN= 4.25V, TJ = 25°C 2.822 2.850 2.910
RT9164A -28 10mA < IOUT < 1.0A, 4.25V < VIN < 10V 2.793 2.850 2.936
IOUT = 10mA, VIN= 4.5V, TJ = 25°C 2.970 3.000 3.060
Output Voltage
(Note 5)
RT9164A -30
VOUT
10mA < IOUT < 1.0A, 4.5V < VIN < 10V 2.940 3.000 3.090
V
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Parameter Symbol Test Conditions Min Typ Max Unit
IOUT = 10mA, VIN = 4.75V, TJ = 25°C 3.267 3.300 3.365
RT9164A -33 10mA < IOUT< 1.0A, 4.75V < V IN < 10V 3.234 3.300 3.400
IOUT = 10mA, VIN= 5V, TJ = 25°C 3.465 3.500 3.570
Output Voltage
(Note 5) RT9164A -35
VOU T
10mA < IOUT < 1.0A, 5.0V < VIN < 10V 3.430 3.500 3.605
V
RT9164A IOUT = 10mA,
1.5V ≤ VIN − V OUT ≤ 10V -- 0.1 0.3 %
RT9164A -15 IOUT = 10mA, 3.3V ≤ VIN ≤ 15V -- 1 6
RT9164A -18 IOUT = 10mA, 3.3V ≤ VIN ≤ 15V -- 1 6
RT9164A -25 IOUT = 10mA, 4.0V ≤ VIN ≤ 15V -- 1 6
RT9164A -28 IOUT = 10mA, 4.25V ≤ VIN ≤ 15V -- 1 6
RT9164A -30 IOUT = 10mA, 4.5V ≤ VIN ≤ 15V -- 1 6
RT9164A -33 IOUT = 10mA, 4.75V ≤ VIN ≤ 15V -- 1 6
Line Regulation
(Note 5)
RT9164A -35
ΔVLINE
IOUT = 10mA, 5.0V ≤ VIN ≤ 15V -- 1 6
mV
RT9164A (VIN − VOUT) = 3V, 10mA ≤ I OUT ≤ 1.0A -- 0.2 0.4 %
RT9164A -15 VIN = 3.3V, 10mA ≤ I OUT ≤ 1.0A -- 1 10
RT9164A -18 VIN = 3.3V, 10mA ≤ I OUT ≤ 1.0A -- 1 10
RT9164A -25 VIN = 4.0V, 10mA ≤ I OUT ≤ 1.0A -- 1 10
RT9164A -28 VIN = 4.25V, 10mA ≤ I OUT ≤ 1.0A -- 1 10
RT9164A -30 VIN = 4.5V, 10mA ≤ I OUT ≤ 1.0A -- 1 12
RT9164A -33 VIN = 4.75V, 10mA ≤ I OUT ≤ 1.0A -- 1 12
Load Regulation
(Note 5)
RT9164A -35
ΔVLOAD
VIN = 5.0V, 10mA ≤ I OUT ≤ 1.0A -- 1 15
mV
IOUT = 500mA -- 1.15 1.25
Dropout Voltage (Note 6) VDROP IOUT = 1.0A -- 1.3 1.4 V
Current Limit ILIM V
IN = 5V 1.0 1.8 -- A
Minimum Load Current RT9164A (VIN − VOU T) = 2V -- 5 10
Quiescent Current RT9164A -XX IQ V
IN = 5V -- 5 10 mA
Ripple Rejection PSRR fRIPPLE = 120Hz ,
(VIN − VOU T) = 2V, VRIPPLE = 1VP-P -- 72 -- dB
Adjust Pin Current IADJ -- 65 120 μA
Adjust Pin Current Change ΔIAD J 10mA ≤ IOUT ≤ 1.0A, VIN = 5V -- 0.2 5 μA
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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. θJA is measured in the natural convection at TA = 25°C on a low effective thermal conductivity test board of
JEDEC 51-3 thermal measurement standard. The case point of θJC is on the center of the exposed pad. The pad size
is 6mm2 on SOT-223 packages, 100mm2 on TO-252 packages, 125mm2 on TO-263 packages.
Note 3. Devices are ESD sensitive. Handling precaution recommended.
Note 4. The device is not guaranteed to function outside its operating conditions.
Note 5. Low duty cycle pulse testing with Kelvin connections.
Note 6. The dropout voltage is defined as VIN − VOUT, which is measured when VOUT is VOUT(NORMAL) − 100mV.
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Typical Operating Characteristics
Current Limit vs. Temperature
1.5
1.6
1.7
1.8
1.9
2
-50 -25 0 25 50 75 100 125
Temperature
Current Limit (A)1
(°C)
VIN = 5V
CIN = 10uF Electrolytic
CO = 10uF Tantalum
VOUT = 2.5V, RL = 1Ω
ADJ Pin Current vs. Temperature
40
50
60
70
80
-50 -25 0 25 50 75 100 125
Temperature
ADJ Pin Current (uA
)
(°C)
VIN = 5V
CIN = 10uF Electrolytic
CO = 10uF Tantalum
R1 = R2 = 100Ω
RL = ∞
Output Voltage vs. Temperature
1.4
1.8
2.2
2.6
3
3.4
-50 -25 0 25 50 75 100 125
Temperature
Output Voltage (V)
(°C)
VIN = 5V
CIN = 10uF Electrolytic
CO = 10uF Tantalum
RL = ∞
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.5V
Current Limit vs. Input Voltage
0
0.5
1
1.5
2
2.5
3
2 4 6 8 10 12 14
Input Voltage (V)
Current Limit (A)
CIN = 10uF Electrolytic
CO = 10uF Tantalum
VOUT = 2.5V, RL = 1Ω
Quiescent Current vs. Temperature
0
1
2
3
4
5
6
7
-50-25 0 255075100125
Temperature
Quiescent Current (mA)
(°C)
VIN = 5V
CIN = 10uF Electrolytic
CO = 10uF Tantalum
RL = ∞
VOUT = 2.5V
Reference Voltage vs. Temperature
1.23
1.24
1.25
1.26
1.27
-50 -25 0 25 50 75 100 125
Temperature
Reference Voltage
(°C)
VIN = 5V
CIN = 10uF Electrolytic
CO = 10uF Tantalum
R1 = R2 = 100Ω
RL = ∞
(V)
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Dropout Volta ge vs. Io
0.8
0.9
1.0
1.1
1.2
1.3
0 0.3 0.6 0.9 1.2 1.5
Load Current (A)
Dropout Voltage (V)1
CIN = 10uF Electrolytic
CO = 10uF Tantalum
VOUT = 2.5V
-40°C
25°C
125°CVIN = 5V, VOUT = 2.5V
CIN = 10uF Electrolytic
CO = 10uF Tantalum
RL = 1Ω
Current Limit
Time (2.5ms/Div)
Current Limit (A)
0.5
0
1
3.5
3
2.5
2
1.5
VOUT = 2.5V
CO = 10uF Tantalum
ILOAD = 100mA
Line Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
6
5
7
30
20
0
Input Voltage
Deviation (V)
40
-20
VOUT = 1.5V
CO = 10uF Tantalum
ILOAD = 100mA
Line Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
6
5
7
30
20
10
0
Input Voltage
Deviation (V)
-10
VOUT = 3.3V
CO = 10uF Tantalum
ILOAD = 100mA
Line Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
6
5
7
30
20
0
Input Voltage
Deviation (V)
40
-20
VIN = 3.3V, VOUT = 1.5V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Load Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
0.5
0
1
200
100
0
Load Current (A)
300
-100
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VIN = 5V, VOUT = 3.3V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Load Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
1
0
2
200
100
0
Load Current (A)
300
-100
VIN = 5V, VOUT = 2.5V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Load Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
1
0
2
200
100
0
Load Current (A)
300
-100
VIN = 5V, VOUT = 3.3V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Load Transient Response
Time (10us/Div)
200
100
0
300
-100
VIN = 5V, VOUT = 3.3V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Output Voltage
Deviation (mV)
Load Current (A)
0
0.5
1
VIN = 5V, VOUT = 2.5V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Load Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
0
200
100
0
Load Current (A)
300
0.5
1
-100
VIN = 3.3V, VOUT = 1.5V
CIN = CO = 10uF Tantalum
Preload = 0.1A
Load Transient Response
Time (10us/Div)
Output Voltage
Deviation (mV)
1
0
2
200
100
0
Load Current (A)
300
-100
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Application Information
Output voltage adjustment
Like most regulators, the RT9164A regulates the output
by comparing the output voltage to an internally generated
reference voltage. On the adjustable version as shown in
Figure 4, the VREF is available externally as 1.25V between
VOUT and ADJ. The voltage ratio formed by R1 and R2
should be set to conduct 10mA (minimum output load).
The output voltage is given by the following equation :
VOUT = VREF (1 +
1
2
R
R ) + IADJ R2
On fixed versions of RT9164A, the voltage divider is provided
internally.
Figure 4. Basic Adjustable Regulator
Input Bypa ss Ca pacitor
An input capacitor is recommended. A 10μF tantalum on
the input is a suitable input bypassing for almost all
applications.
Adjust T erminal Bypa ss Ca pacitor
The adjust terminal can be bypassed to ground with a
bypass capacitor (CADJ) to improve ripple rejection. This
bypass capacitor prevents ripple from being amplified as
the output voltage is increased. At any ripple frequency,
the impedance of the CADJ should be less than R1 to prevent
the ripple from being amplified :
(2π x fRIPPLE x CADJ) < R1
The R1 is the resistor between the output and the adjust
pin. Its value is normally in the range of 100-200Ω. For
example, with R1 = 124Ω and fRIPPLE = 120Hz, the CADJ
should be > 11μF.
Output Ca pacitor
RT9164A requires a capacitor from VOUT to GND to provide
compensation feedback to the internal gain stage. This is
to ensure stability at the output terminal. Typically, 10μF
tantalum or 50μF aluminum electrolytic with 30mΩ to 2Ω
range capacitor is sufficient.
The output capacitor does not have a theoretical upper
limit and increasing its value will increase stability.
COUT = 100μF or more is typical for high current regulator
design.
VIN VOUT
ADJ
RT9164A
R1
R2
+
+
10uF 10uF
IADJ
VREF
VIN VOUT
65uF
+
CADJ
CIN COUT
Load Regulation
When the adjustable regulator is used (Figure 6), the best
load regulation is accomplished when the top of the resistor
divider (R1) is connected directly to the output pin of the
RT9164A. When so connected, RP is not multiplied by
the divider ratio. For Fixed output version, the top of R1 is
internally connected to the output and ground pins can be
connected to low side of the load.
Figure 5
Region of Stable COUT ESR vs. Load Current
0.01
0.1
1
10
0 0.2 0.4 0.6 0.8 1
Load Current (A)
COUT ESR (Ω)
COUT = 100uF
COUT = 10uF
Instable
Instable
Stable
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PD = (VIN − VOUT) x IOUT
TJUNCTION = TAMBIENT + (PD x θJA)
Note: TJUNCTION must not exceed 125°C
Current Limit Protection
RT9164A is protected against overload conditions. Current
protection is triggered at typically 1.8A.
Thermal Consideration
The RT9164A series contain thermal limiting circuitry
designed to protect itself from over-temperature conditions.
Even for normal load conditions, maximum junction
temperature ratings must not be exceeded. As mention in
thermal protection section, we need to consider all sources
of thermal resistance between junction and ambient. It
includes junction-to-case, case-to-heat-sink interface, and
heat sink thermal resistance itself.
Junction-to-case thermal resistance is specified from the
IC junction to the bottom of the case directly below the
die. Proper mounting is required to ensure the best possible
thermal flow from this area of the package to the heat
sink. The case of all devices in this series is electrically
connected to the output. Therefore, if the case of the device
must be electrically isolated, a thermally conductive spacer
is recommended.
VIN VOUT
ADJ
RT9164A
R1
R2
VIN
Connect R2 to load
(Connect R1 to VOUT
or case)
RL
RP Parasitic
Line Resistance
Figure 6. Best Load Regulation Using Adjustable
Output Regulator
Thermal Protection
RT9164A has thermal protection which limits junction
temperature to 150°C. However, device functionality is only
guaranteed to a maximum junction temperature of 125°C.
The power dissipation and junction temperature for RT9164A
are given by
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Outline Dimension
Dimension s In Millimeter s Dimension s 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
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Dim e nsion s In M i ll imete rs Dime nsio ns In I nche s
Symbol Min Max Min Max
A 2.184 2.388
0.086 0.094
B 0.889 2.032 0.035 0.080
b 0.508 0.889 0.020 0.035
b1 1.016 Ref. 0.040 Ref.
b2 0.457 0.584 0.018 0.023
C 0.457 0.584
0.018 0.023
D 6.350 6.731
0.250 0.265
D1 5.207 5.461
0.205 0.215
E 5.334 6.223
0.210 0.245
e 2.108 2.438 0.083 0.096
L1 9.398 10.414
0.370 0.410
L2 0.508 Ref. 0.020 Ref.
L3 0.635 1.016
0.025 0.040
U 3.810 Ref. 0.150 Ref.
V 3.048 Ref. 0.120 Ref.
R 0.200 0.850 0.008 0.033
S 2.500 3.400 0.098 0.134
T 0.500 0.850 0.020 0.033
3-Lead TO-252 Surface Mount Package
A
C
b2
b
b1
D
B
E
L3
e
L1
L2
V
U
D1
S
T
R
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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
Dimension s In Millimeters Dimension s In Inches
Symbol Min Max Min Max
A 4.064 4.826 0.160 0.190
B 1.143 1.676 0.045 0.066
b 0.660 0.914 0.026 0.036
b1 1.143 1.397 0.045 0.055
b2 0.305 0.584 0.012 0.023
C 1.143 1.397 0.045 0.055
D 9.652 10.668 0.380 0.420
E 8.128 9.652 0.320 0.380
e 2.286 2.794 0.090 0.110
L1 14.605 15.875 0.575 0.625
L2 2.286 2.794 0.090 0.110
U 6.223 Ref. 0.245 Ref.
V 7.620 Ref. 0.300 Ref.
3-Lead TO- 263 Surface Mount Package
C
b2
A
L1
B
E
e
L2
V
U
D
b
b1
