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RT9172
3A Fixed Output Voltage LDO Regulator
General Description
The RT9172 series of low-dropout linear regulators operate from a +2.25V to +6.0V input supply. A wide range of preset output voltage options is available. These low dropout linear regulators respond very fast to step changes in load, which are suitable for low voltage microprocessor applications. The RT9172 uses an internal PMOS as the pass device, which does not cause extra GND current in heavy load and dropout condition. The shutdown mode of low operation current makes the IC suitable for power-saving systems. The other features include current limiting and over temperature protection.
Features
Low Dropout Voltage Low Ground Pin Current Load Regulation of 0.4% at 3A 0.5mA Quiescent Current in Shutdown Mode Guaranteed Output Current of 3A DC Available in TO-263 and TO-220 Packages Output Voltage Accuracy 1.5% Error Flag Indicates Output Status Sense Option Improves Better Load Regulation Extremely Low Output Capacitor Requirements Over-Temperature/Over- Current Protection RoHS Compliant and 100% Lead (Pb)-Free
Ordering Information
RT9172
-
Applications
Microprocessor Power Supplies GTL, GTL+, BTL, and SSTL Bus Terminators Power Supplies for DSPs SCSI Terminator Post Regulators High Efficiency Linear Regulators Battery Chargers Other Battery Powered Applications
Package Type T5 : TO-220-5 M5 : TO-263-5 T : TO-220 M : TO-263 G : SOT-223 S : SOP-8 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) Output Voltage 15 : 1.5V 16 : 1.6V : 32 : 3.2V 33 : 3.3V S : Pin Out Exchange N : Pin 5 bond SENSE F : Pin 5 bond FLG
Pin Configurations
(TOP VIEW)
VIN GND VOUT (TAB)
2
3
1
2
3
Note : RichTek Pb-free and Green products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. 100%matte tin (Sn) plating.
1 2
TO-220
1
VIN GND VOUT (TAB)
TO-263
3
VOUT SENSE GND NC
2 3 4
8 7 6 5
VIN GND GND EN
VIN GND VOUT (TAB)
SOP-8
SOT-223
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RT9172
5 4 3 2 1 SENSE/FLG VOUT GND (TAB) VIN EN
5 4 3 2 1
SENSE/FLG VOUT GND (TAB) VIN EN
TO-220-5 RT9172NCT5 RT9172FCT5
TO-263-5 RT9172NCM5 RT9172FCM5
5 4 3 2 1
VOUT SENSE GND (TAB) EN VIN
5 4 3 2 1
VOUT SENSE GND (TAB) EN VIN
TO-220-5 RT9172SCT5
TO-263-5 RT9172SCM5
Functional Pin Description
Pin No. RT9172RT9172F RT9172N RT9172S RT9172RT91721 2 3 4 5 -1 2 3 4 -5 2 1 3 5 -4 -1 2 3 --CT CM CG EN VIN GND VOUT FLG SENSE Chip Enable (Active Hight) Power Input Voltage Ground Output Voltage ERROR Flag Remote Sense Pin Name Pin Function
Typical Application Circuit
RT9172-25 VIN = 3.3V CIN 10uF VIN VOUT GND VOUT 2.5V, 3A
+ +
COUT
Figure 1
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RT9172
RT9172N-25 VIN = 3.3V CIN 10uF VIN 10K EN SENSE GND VOUT ILOAD L O A D
+ +
Trace resistance = Rt
VLOAD = 2.5V
COUT
Figure 2
RT9172F-25 VIN = 3.3V CIN 10uF VIN 10K EN GND FLG VOUT
+
Trace resistance = Rt VOUT = 2.5V
VLOAD = 2.5V -ILOADRt ILOAD L O A D
+
10K
COUT
Figure 3 Recommend COUT: Please note that the part must be paralleled with the least a 100F electrolytic capacitor when using a 10F (or greater) ceramic type as the output capacitor to prevent the output oscillating.
Function Block Diagram
RT9172F
VIN
VOUT
Buffer Amlifier
Thermal
Current Limiting Sensor VREF GND EN
+
+
FLG
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RT9172
RT9172N/RT9172S
VIN VOUT
Buffer Amlifier
Thermal
SENSE
Current Limiting Sensor VREF EN
+
GND
RT9172
VIN VOUT
Buffer Amlifier
Thermal
Current Limiting Sensor
VREF
+
GND
Absolute Maximum Ratings
Input Voltage ------------------------------------------------------------------------------------------------------------ 6V Power Dissipation, PD @ TA = 25C SOT-223 ----------------------------------------------------------------------------------------------------------------- 0.741W SOP-8 -------------------------------------------------------------------------------------------------------------------- 0.625W TO-263 ------------------------------------------------------------------------------------------------------------------- 2.222W TO-220 ------------------------------------------------------------------------------------------------------------------- 1.820W Package Thermal Resistance (Note 4) SOT-223, JC ----------------------------------------------------------------------------------------------------------- 23C/W SOT-223, JA ------------------------------------------------------------------------------------------------------------ 135C/W SOP-8, JC -------------------------------------------------------------------------------------------------------------- 45C/W SOP-8, JA -------------------------------------------------------------------------------------------------------------- 160C/W TO-263, JC ------------------------------------------------------------------------------------------------------------- 7.8C/W TO-263, JA ------------------------------------------------------------------------------------------------------------- 45C/W TO-220, JC ------------------------------------------------------------------------------------------------------------- 15C/W TO-220, JA ------------------------------------------------------------------------------------------------------------- 55C/W ESD Rating ------------------------------------------------------------------------------------------------------------- 3 kV Storage Temperature Range ---------------------------------------------------------------------------------------- -65C to 150C Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260C Junction Temperature Range ---------------------------------------------------------------------------------------- -40C to +125C
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RT9172
Electrical Characteristics
(Limits in standard typeface are for TA = 25C, unless otherwise specified: VIN = VO(NOM) + 1.0V, IL = 10mA, COUT = 10F(Electrolytic), VEN = VIN)
Parameter Output Voltage Tolerance Input Voltage Range Line Regulation Load Regulation
Symbol
Test Conditions
Min -1.5
Typ 0 -0.35 0.4 0.1 0.1 400 1.2 0.5 5 5 170 10 VIN 0 0.1 1 --
Max +1.5 5.5 1 1 0.4 0.4 700 3 5 -----0.4 ----
Units % V % %
VIN VLINE VLOAD VDROP IQ IGSD IO(PEAK) ILIMIT TSD Guaranteed by design Guaranteed by design Output = High Output = Low VEN = VIN ILEAKAGE VFLG = 0.5V VEN = 0V VOUT + 0.4V < VIN < 5.5V Note 1 Note 2 Note 3
2.25 -------3.5 3.5 --1.2 ---2
Dropout Voltage Quiescent Current Shutdown Supply Current Peak Output Current Short Circuit Protection Current Limit Over Temperature Protection Shutdown Threshold Thermal Shutdown Hysteresis Shutdown Function EN Pin Shutdown Threshold EN Input Current FLG Pin Leakage Current FLG Pin Sink Current
IL = 3A
mV mA A A
A C C
VEN
V nA nA mA
Note 1. RT9172-CX, RT9172F-XXCX5, 10mA < IL < 3A Note 2. RT9172S-XXCX5, RT9172N-XXCX5, 10mA < IL < 3A Note 3. RT9172CS, 10mA < IL < 1.5A Note 4. JA is measured in the natural convection at T A = 25C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. The case point of JC is on the center of the exposed pad. The pad size is 125mm2 on TO-263 packages.
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RT9172
Typical Operating Characteristics
Temperature Stability
2.60
1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0
Quiescent Current vs. Load Current
2.56
2.52
2.48
2.44
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) VIN = VO + 1.0V ILOAD = 10mA
-35 -15 5 25 45 65 85 105 125
Quiescent Current (mA)
Output Voltage (V)
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) VIN = VO + 1.0V
0.0 0.5 1.0 1.5 2.0 2.5 3.0
2.40
Temperature (C)
Load Current (A)
Quiescent Current vs. Temperature
1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -35 -15 5 25 45 65 85 105 125
Quiescent Current vs. Supply Voltage
1.5
Quiescent Current (mA)
Quiescent Current (mA)
1.2
0.9
0.6
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) VIN = VO + 1.0V ILOAD = 10mA
0.3
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) VIN = 2V to 6V ILOAD = 10mA
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
0.0
Temperature (C)
Supply Voltage (V)
Dropout Voltage (VIN - VOUT)
0.7 0.6
Current Limit vs. Temperature
6.0
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum)
5.2
Dropout Voltage (V)
0.5 0.4
Current Limit (A)
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) VIN = VOUT + 1.0V
4.4
TJ = 125C
0.3 0.2
3.6
TJ = 25C
0.1 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0
2.8
2.0 -35 -15 5 25 45 65 85 105 125
Load Current (A)
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Temperature (C)
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RT9172
PSRR
-15 -20 -25
Load Regulation Deviation
0.00
ILOAD = 100mA ILOAD = 10mA
Output Voltage Deviation (%) A
VOUT = 2.5V COUT = 10uF (Electrolytic)
-0.03
PSRR (dB)
-30 -35 -40 -45 -50 -55
-0.06
-0.09
-0.12
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) ILOAD = 10mA
-35 -15 5 25 45 65 85 105 125
-0.15
10
100
1K
10K
100K
1M
Frequency (Hz)
Temperature (C)
EN Pin Shutdown Response
100
Range of Stable ESR Values
Output Capacitor ESR( ).
Output Voltage (V)
2 1 0 VOUT = 1.8V CIN = 1uF (Ceramic) COUT = 10uF (Tantalum) ILOAD = 100mA TA = 25C
10
CIN = 1uF (MLCC) COUT = 10uF (MLCC)
Shutdown Voltage (V)
2 1 0
1
Stable Region
0.1
Reqion of Instability
0.01
0
1
2
3
4
5
6
7
8
9
10
0
0.5
1
1.5
2
2.5
3
Time (ms)
Output Current (A)
Line Transient Response
Output Voltage Deviation(mV)
40 20 0
Line Transient Response
Output Voltage Deviation(mV)
40 20 0 CIN = 1uF (Ceramic) VOUT = 2.5V TA = 25C COUT = 10uF (Tantalum) ILOAD = 100mA
CIN = 1uF (Ceramic) VOUT = 2.5V TA = 25C
COUT = 10uF (Electrolytic) ILOAD = 100mA
Input Voltage Deviation (V)
5.5 4.5 3.5
Input Voltage Deviation (V)
5.5 4.5 3.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Time (ms) DS9172-14 March 2007
Time (ms) www.richtek.com 7
RT9172
Load Transient Response
Output Voltage Deviation(mV) Output Voltage Deviation(mV)
200 100 0 CIN = 1uF (Ceramic) VOUT = 2.5V TA = 25C COUT = 100uF (Electrolytic) ILOAD :100mA 3A
Load Transient Response
200 100 0 CIN = 1uF (Ceramic) VOUT = 2.5V TA = 25C COUT = 10uF (Tantalum) ILOAD : 100mA 3A
Load Current Deviation (A)
6 3 0
Load Current Deviation (A)
6 3 0
0
0.1
0.2 0.3 0.4 0.5 0.6 0.7
0.8
0.9
10
0
0.1
0.2 0.3 0.4 0.5 0.6 0.7
0.8
0.9
10
Time (ms)
Time (ms)
Noise Signal
1.5 CIN = 1uF (Ceramic) VOUT = 2.5V TA = 25C COUT = 10uF (Tantalum) ILOAD :10mA 1.5
Noise Signal
CIN = 1uF (Ceramic) VOUT = 2.5V TA = 25C COUT = 10uF (Tantalum) ILOAD :100mA
Output Voltage (mV)
0.5 0 -0.5 -1.0 -1.5 0 1 2 3 4 5 6 7 8 9 10
Output Voltage (mV)
1.0
1.0 0.5 0 -0.5 -1.0 -1.5 0 1 2 3 4 5 6 7 8 9 10
Time (ms)
Time (ms)
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RT9172
Application Information
Capacitor Selection An output capacitor as part of the device frequency compensation to maintain stability and improve transient response. Proper capacitor selection is important to ensure proper operation. When the output capacitor is 10F or greater, the output capacitor should have an ESR less than 2. This will improve transient response as well as promote stability. Ultra-low-ESR capacitor (<100m), such as ceramic chip capacitors, may promote instability. These very low ESR levels may cause an oscillation and/or underdamped transient response. A low-ESR solid tantalum capacitor works extremely well and provides good transient response and stability over temperature. Aluminum electrolytics can also be used, as long as the ESR of the capacitor is <2. The value of the output capacitor can be increased without limit. Higher capacitor values help to improve transient response and ripple rejection and reduce output noise. The RT9172 requires a minimum input capacitance of 1F between the input and ground pins to prevent any impedance interactions with the supply. The RT9172 requires a minimum of 10F (tantalum, or electrolytic) capacitance between the output and ground pins for proper operation. Please note that the part must be paralleled with the least a 100F electrolytic capacitor when using a 10F (or greater) ceramic type as the output capacitor to prevent the output oscillating. Error Operation (FLG) The RT9172 produces a logic low signal at the FLG pin when the output drops out of regulation due to low input voltage, current limiting, or thermal limiting. The internal error FLG comparator has an open drain output stage. Hence, the FLG pin should be pulled high through a pull up resistor. Sense Pin In applications where the regulator output is not very close to the load, RT9172 can provide better remote load regulation using the SENSE pin. Figure 2. and Figure 3. depict the advantage of the SENSE option. RT9172 regulates the voltage at the output pin. Hence, the voltage at the remote load will be the regulator output voltage minus the drop across the trace resistance. For example, in the case of a 3.3V output, if the trace resistance is 100m, the voltage at the remote load will be 3V with 3A of load current, ILOAD. The RT9172 regulates the voltage at the sense pin. Connecting the sense pin to the remote load will provide regulation at the remote load, as shown in Figure 2. and Figure 3. Chip Enable Operation A CMOS logic level signal at the chip enable (EN) pin will turn-off the regulator. Pin EN must be actively terminated through a 10k pull-up resistor for a proper operation. If this pin is driven from a source that actively pulls high and low (such as a CMOS rail to rail comparator), the pull-up resistor is not required. This pin must be tied to VIN if not used. Dropout Voltage The dropout voltage of a regulator is defined as the minimum input-to-output differential required to stay within 2% of the output voltage. The RT9172 uses an internal MOSFET with an RDS(ON) 160m. For CMOS LDOs, the dropout voltage is the product of the load current and the RDS(ON) of the internal MOSFET. Maximum Output Current Capability RT9172 can deliver a continuous current of 1.5 A over the full operating temperature range. A heatsink may be required depending on the maximum power dissipation and maximum ambient temperature of the application. Under all possible conditions, the junction temperature must be within the range specified under operating conditions. The total power dissipation of the device is given by : PD = (VIN - VOUT) IOUT+ (VIN) IGND where IGND is the operating ground current of the device (specified under Electrical Characteristics).
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RT9172
Outline Dimension
D F M C
E1 L1 E
b1
A1
L2
e
b
b2
A
Symbol A A1 b b1 b2 C D E e E1 F L1 L2 M
Dimensions In Millimeters Min 4.064 2.032 0.635 1.143 0.305 1.143 9.779 7.620 2.286 11.176 2.616 17.526 7.544 3.708 Max 4.826 2.921 1.016 1.524 0.559 1.397 10.668 9.398 2.794 12.954 2.870 18.542 8.636 3.962
Dimensions In Inches Min 0.160 0.080 0.025 0.045 0.012 0.045 0.385 0.300 0.090 0.440 0.103 0.690 0.297 0.146 Max 0.190 0.115 0.040 0.060 0.022 0.055 0.420 0.370 0.110 0.510 0.113 0.730 0.340 0.156
3-Lead TO- 220 Plastic Package
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RT9172
D B C U
V E L1
b1 L2 e b b2
A
Symbol A B b b1 b2 C D E e L1 L2 U V
Dimensions In Millimeters Min 4.064 1.143 0.660 1.143 0.305 1.143 9.652 8.128 2.286 14.605 2.286 Max 4.826 1.676 0.914 1.397 0.584 1.397 10.668 9.652 2.794 15.875 2.794
Dimensions In Inches Min 0.160 0.045 0.026 0.045 0.012 0.045 0.380 0.320 0.090 0.575 0.090 Max 0.190 0.066 0.036 0.055 0.023 0.055 0.420 0.380 0.110 0.625 0.110
6.223 Ref. 7.620 Ref.
0.245 Ref. 0.300 Ref.
3-Lead TO- 263 Surface Mount
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RT9172
D D1
H
C
B
L e e
L1
A b
A1
Symbol A A1 b B C D D1 e H L L1
Dimensions In Millimeters Min 1.450 0.020 0.610 3.302 6.706 6.299 2.896 2.261 0.229 1.550 0.800 Max 1.803 0.100 0.787 3.708 7.290 6.706 3.150 2.362 0.330 1.950 1.100
Dimensions In Inches Min 0.057 0.0008 0.024 0.130 0.264 0.248 0.114 0.089 0.009 0.061 0.009 Max 0.071 0.0047 0.031 0.146 0.287 0.264 0.124 0.093 0.013 0.077 0.013
3-Lead SOT-223 Surface Mount Package
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RT9172
D C
M F E1 E
P A1
e
b
b2
A
Symbol A A1 b b2 C e D E E1 F M P
Dimensions In Millimeters Min 4.064 2.032 0.635 0.305 1.143 1.524 9.779 7.620 11.176 14.224 3.708 24.689 Max 4.826 2.921 1.016 0.559 1.397 1.829 10.668 9.398 12.954 15.113 3.962 26.416
Dimensions In Inches Min 0.160 0.080 0.025 0.012 0.045 0.060 0.385 0.300 0.440 0.560 0.146 0.972 Max 0.190 0.115 0.040 0.022 0.055 0.072 0.420 0.370 0.510 0.595 0.156 1.040
5-Lead TO-220 Plastic Package
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RT9172
D B
C
U
V E L1
L2 e b b2
A
Symbol A B b b2 C D E e L1 L2 U V
Dimensions In Millimeters Min 4.064 1.143 0.660 0.305 1.143 9.652 8.128 1.524 14.605 2.286 Max 4.826 1.676 0.914 0.584 1.397 10.668 9.652 1.829 15.875 2.794
Dimensions In Inches Min 0.160 0.045 0.026 0.012 0.045 0.380 0.320 0.060 0.575 0.090 Max 0.190 0.066 0.036 0.023 0.055 0.420 0.380 0.072 0.625 0.110
6.223 Ref. 7.620 Ref.
0.245 Ref. 0.300 Ref.
5-Lead TO-263 Plastic Surface Mount Package
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RT9172
A
H M
J
B
F
C I D
Dimensions In Millimeters Symbol Min A B C D F H I J M 4.801 3.810 1.346 0.330 1.194 0.170 0.050 5.791 0.400 Max 5.004 3.988 1.753 0.508 1.346 0.254 0.254 6.200 1.270
Dimensions In Inches Min 0.189 0.150 0.053 0.013 0.047 0.007 0.002 0.228 0.016 Max 0.197 0.157 0.069 0.020 0.053 0.010 0.010 0.244 0.050
8-Lead SOP Plastic Package
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) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
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