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Preliminary
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 0.5A 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
Ordering Information
RT9172 Package type T5 : TO-220-5 M5 : TO-263-5 T : TO-220 M : TO-263 G : SOT-223 Operating temperature range C: 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
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
Pin Configurations
Part Number RT9172CT Pin Configurations
TOP VIEW 1. VIN 2. GND (TAB) 3. VOUT
123
(Plastic TO-220)
RT9172-
CM
TOP VIEW 1. VIN 2. GND (TAB) 3. VOUT
1 2 3
(Plastic TO-263)
RT9172-
CG
1 2 3
TOP VIEW 1. VIN 2. GND (TAB) 3. VOUT
(Plastic SOT-223)
To be continued
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RT9172
Part Number RT9172NRT9172FCT5 CT5 Pin Configurations
Preliminary
Part Number RT9172SCT5 Pin Configurations
TOP VIEW 1. 2. 3. 4. 5. VIN EN GND (TAB) SENSE VOUT
TOP VIEW 1. 2. 3. 4. 5. EN VIN GND (TAB) VOUT SENSE/FLG
(Plastic TO-220-5)
(Plastic TO-220-5)
12 3 4 5
12 3 4 5
RT9172NRT9172F-
CM5 CM5
TOP VIEW 1. 2. 3. 4. 5. EN VIN GND (TAB) VOUT SENSE/FLG
RT9172S-
CM5
TOP VIEW 1. 2. 3. 4. 5. VIN EN GND (TAB) SENSE VOUT
(Plastic TO-263-5)
(Plastic TO-263-5)
12 34 5
12 34 5
Typical Application Circuit
VIN = 3.3V CIN 1F VIN RT9172-25 VOUT GND COUT VOUT 2.5V, 3A
Fig. 1
VIN = 3.3V CIN 10 F
RT9172N-25 VIN VOUT EN GND SENSE
Trace resistance = Rt VLOAD = 2.5V ILOAD COUT L O A D
Fig. 2
RT9172F-25 VIN = 3.3V 10K CIN 10F EN GND FLG VIN VOUT Trace resistance = Rt
V OUT = 2.5V
VLOAD = 2.5V-I LOADRt ILOAD COUT L O A D
10K
Fig. 3 Recommend COUT: (1) 10F (or larger) electrolytic or tantalum capacitance (2) 1F or 10F ceromic capacitor parrell with 100F electrolytic or tantalum capacitance
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Preliminary Function Block Diagram
RT9172F
VIN Buffer Amplifier Thermal Current Limiting Sensor VOUT
RT9172
EN
_+
Vref GND
RT9172N/RT9172S
VIN VOUT SENSE Buffer Amplifier Thermal Current Limiting Sensor _ +
EN
Vref GND
RT9172
VIN
Buffer Amplifier
Thermal Current Limiting Sensor
_
+
Vref GND
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+ _
FLG
VOUT
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RT9172
Absolute Maximum Ratings
Input Voltage Power Dissipation ESD Rating Storage Temperature Range Lead Temperature (Soldering, 5 sec.) Package Thermal Resistance TO-263, JC TO-263, JA TO-220, JC TO-220, JA SOT-223, JC SOT-223, JA Junction Temperature Range
Preliminary
6V Internally Limited 3 kV -65C to 150C 260C 8C/W 19.4C/W 8C/W 62C/W 15C/W 60C/W -40C to +125C
Electrical Characteristics
(Limits in standard typeface are for TA = 25C, unless otherwise specified: VIN = VO(NOM) + 1.0V, IL = 10mA, COUT = 10F (Ceramic), VEN = VIN) Parameter Output Voltage Tolerance Input Voltage Range Line Regulation Load Regulation 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 ILEAKAGE VFLG = 0.5V VEN Output = High Output = Low VEN = VIN 1.2 ---2 VIN 0 0.1 1 --0.4 ---V nA nA mA TSD Guaranteed by design Guaranteed by design --170 10 --C C ILIMIT 3.5 5 -A VIN VLINE VLOAD VDROP IQ IGSD IO(PEAK) VEN = 0V VOUT + 0.4V < VIN < 6.0V Note 1 Note 2 IL = 300mA IL = 3A Symbol Test Conditions Min -1.5 2.25 -------3.5 Typ 0 -0.35 0.4 0.1 50 400 1.2 0.5 5 Max +1.5 6 0.8 1 0.3 70 700 3 5 -Units % V % % mV mA A A
Note 1: RT9172-CX, RT9172F-XXCX5, 10mA < IL < 3A Note 2: RT9172S-XXCX5, RT9172N-XXCX5, 10mA < IL < 3A
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Preliminary Pin Description
Pin No. RT9172F 1 2 3 4 5 -RT9172N 1 2 3 4 -5 RT9172S 2 1 3 5 -4 RT9172 -1 2 3 --Pin Name EN VIN GND VOUT FLG SENSE Chip Enable Power Input Ground Output Voltage ERROR Flag Remote Sense Pin Function
RT9172
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RT9172
Typical Operating Charateristics
0 -10 -20
Preliminary
PSRR
CIN = 1nF COUT = 10F Electrolytic Capacitor VIN = 5V VOUT = 2.5V TA = 25C
0 -10 -20
PSRR
CIN = 1nF COUT = 68F Tantalum Capacitor VIN = 5V VOUT = 2.5V TA = 25C
PSRR (dB)
-30 -40 -50 -60 -70
PSRR (dB)
-30 -40 -50 -60
10mA 100mA
10mA
100mA 10 100 1K 10K 100K 1M
-70
10
100
1K
10K
100K
1M
Frequency (Hz)
Frequency (Hz)
Noise Signal & Spectrum Distribution
Time (mS) Noise Level (uV) Noise Signal (uV)
200 1500 160 500 120 -500 80 40 0 0 25 50 75 100 125
Noise Signal & Spectrum Distribution
Noise Signal (uV)
0 200 1000 160 0 2
0
2
4
6
8
10
Time (mS)
4
6
8
10
Noise Level (uV)
-1000 120 80 40 0
CIN = 1F COUT = 10F Tantalum Capacitor Load = 100mA Sampling Rate = 250KHz
CIN = 1F COUT = 10F Tantalum Capacitor Load = 10mA Sampling Rate = 250KHz
0
25
Frequency (KHz)
Frequency (KHz)
50
75
100
125
Noise Signal & Spectrum Distribution
Noise Signal (uV)
Noise Signal (uV)
0 200 1000 0 160 -1000 120 80 40 0 0 25 2
Noise Signal & Spectrum Distribution
0 200 1000 0 160 -1000 120 80 40 0 0 25 50 75 100 125 2
Time (mS)
4
6
8
10
Time (mS)
4
6
8
10
Noise Level (uV)
Frequency (KHz)
50
75
100
125
Noise Level (uV)
CIN = 1F COUT = 68F Tantalum Capacitor Load = 10mA Sampling Rate = 250KHz
CIN = 1F COUT = 68F Tantalum Capacitor Load = 100mA Sampling Rate = 250KHz
Frequency (KHz)
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Preliminary
RT9172
Load Transient Response
Load Transient Response
Output Voltage Deviation (V)
VIN = 3.5V
Output Voltage Deviation (V)
0.3
CIN = 10F Electrolytic
0.3
CIN = 68F Tantalum
VIN = 3.5V
0.2 COUT = 10F Tantalum 0.1 02 >
T T
0.2 COUT = 10F Tantalum 0.1 02 >
T T
-0.1 Load Current (A)
1
1 0.1 >
Load Current (A)
T
-0.1
T
1
1 0.1 >
0
10
20
30
40
50
60
70
80
90 100
0
10
20
30
40
50
60
70
80
90 100
Time (S)
Time (S)
Line Transient Response
Output Voltage (mV)
Line Transient Response
Output Voltage (mV) 150 100 50 02 > -50
150
COUT = 10F 100 VOUT = 2.5V Loading = 100mA
50
T T
COUT = 68F VOUT = 2.5V Loading = 100mA T
T
02 > -50
Input Voltage (V)
4.5 3.5
1
Input Voltage (V)
T
T
4.5
1>
3.5 0 10 20 30 40 50 60 70 80 90 100
0
10
20
30
40
50
60
70
80
90 100
Time (S)
Time (S)
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RT9172
Functional Description
Capacitor Selection
Preliminary
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 MOS-FET 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). The maximum allowable temperature rise (TRMAX) depends on the maximum ambient temperature (TAMAX) of the application, and the maximum allowable junction temperature (TJMAX): TRMAX = TJMAX - TAMAX The maximum allowable value for junction to ambient Thermal Resistance, JA = TRMAX - TAMAX The maximum allowable value for junction to ambient Thermal Resistance, JA, can be calculated using the formula: JA = TRMAX / PD RT9172 are available in TO-220, TO-263, and SOT223 packages. The thermal resistance depends in amount of copper area or heat sink, and on air flow. If the maximum allowable value of JA calculated above is 60 C/W for TO-220 package, 60 C/W for TO-263 package, and 140 can dissipate enough heat package, no heatsink is needed since the package to satisfy these requirements. If the value for allowable JA falls below these limits, a heat sink is required.
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, if used 10F ceromic please parrell with 100F tantalum or electrolytic. Larger capacitance provides better load dynamics and noise performance. 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. Fig.2 and Fig.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 Fig.2 and Fig.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.
C/W for SOT-223
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Preliminary
Heatsinking TO-220Packages The thermal resistance of a TO-220 package can be reduced by attaching it to a heat sink or a copper plane on a PC board. If a copper plane is to be used, the values of JA will be same as shown in next section for TO-263 package. Heatsinking TO-263 and SOT-223 Packages The TO-263 and SOT-223 packages use the copper plane on the PCB as a heatsink. The tab of these packages are soldered to the copper plane for heat sinking. Fig.4 shows a curve for JA of TO-263 package for different copper area sizes, using a typical PCB with 1 ounce copper and no solder mask over the copper area for heat sinking.
RT9172
1 square inch produces very little
As shown in the figure, increasing the copper area beyond improvement. The minimum value for JA for the TO263 package mounted to a PCB is 32C/W.
JA vs. Copper (1 Ounce) Area for TO-263
200 180 160
TRMAX = TJMAX - TAMAX
4W
140 120 100 80 60 40 20 0 0 0.5 1 1.5 2 2.5 3
2.5W
1W
Copper Foil Area (SQ. IN.)
Fig. 4
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RT9172
Package Information
Preliminary
D F
A
M
C
E1 MARK L1 A1 b1 E
b2 b L2
e
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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Preliminary
RT9172
A
D B
C
E
MARK L1
b1 L2 e b b2
U
V
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. 3-Lead TO- 263 Surface Mount
0.245 Ref. 0.300 Ref.
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RT9172
Preliminary
D D1
C
B
L e e
A b
A1
H
Symbol A A1 b B C D D1 e H L
Dimensions In Millimeters Min -0.020 0.610 3.302 6.706 6.299 2.896 2.261 0.229 0.914 Max 1.803 0.100 0.787 3.708 7.290 6.706 3.150 2.362 0.330 --
Dimensions In Inches Min -0.0008 0.024 0.130 0.264 0.248 0.114 0.089 0.009 0.036 Max 0.071 0.0047 0.031 0.146 0.287 0.264 0.124 0.093 0.013 --
3-Lead SOT-223 Plastic Surface Mount
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Preliminary
RT9172
D
A
M
C F
E1 MARK E
P
A1
b2
e
b
Symbol A A1 b b2 C c 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
Preliminary
D B MARK L1
A
C
E
L2 e
b
b2
U
V
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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Preliminary
RT9172
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RT9172
Preliminary
RICHTEK TECHNOLOGY CORP.
Headquarter
6F, No. 35, Hsintai Road, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5510047 Fax: (8863)5537749
RICHTEK TECHNOLOGY CORP.
Taipei Office (Marketing)
8F-1, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek-ic.com.tw
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