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RT9167/A
Low-Noise, Fixed Output Voltage,300mA/500mA LDO Regulator
General Description
The RT9167/A is a 300mA/500mA low dropout and low noise micropower regulator suitable for portable applications. The output voltages range from 1.5V to 5.0V in 100mV increments and 2% accuracy. The RT9167/A is designed for use with very low ESR capacitors. The output remains stable even with 1F ceramic output capacitor. The RT9167/A uses an internal PMOS as the pass device, which does not cause extra GND current in heavy load and dropout conditions. The shutdown mode of nearly zero operation current makes the IC suitable for battery-powered devices. Other features include a reference bypass pin to improve low noise performance, current limiting, and over temperature protection.
Features
Stable with Low-ESR Output Capacitor Low Dropout Voltage (350mV @ 300mA) Low Operation Current -80A Typical Shutdown Function Low Noise Output Low Temperature Coefficient Current and Thermal Limiting Custom Voltage Available SOT-23-5 and SOP-8 Packages RoHS Compliant and 100% Lead (Pb)-Free
Applications
Cellular Telephones Laptop, Notebook, and Palmtop Computers Battery-powered Equipment Hand-held Equipment
Ordering Information
RT9167/A-
Package Type Marking Information B : SOT-23-5 For marking information, contact our sales representative BR : SOT-23-5 (R-Type) S : SOP-8 directly or through a RichTek distributor located in your Operating Temperature Range area, otherwise visit our website for detail. P : Pb Free with Commercial Standard G : Green (Halogen Free with CommerPin Configurations cial Standard) Output Voltage 15 : 1.5V 16 : 1.6V : 49 : 4.9V 50 : 5.0V 2H : 2.85V 500mA Output Current 300mA Output Current
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. SOP-8
EN VIN VOUT BP 2 3 4 8 7 6 5 GND GND GND GND
(TOP VIEW)
VIN GND EN
1 2 3
5
VOUT
VOUT GND
1 2 3
5
BP
4
BP
VIN
4
EN
SOT-23-5
SOT-23-5 (R-Type)
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RT9167/A
Functional Pin Description
Pin Name VIN GND EN BP VOUT Pin Function Power Input Voltage Ground Chip Enable (Active High) Reference Noise Bypass Output Voltage
Function Block Diagram
Shutdown and Logic Control VREF BP
+ Error Amplifier
EN
VIN
MOS Driver Current-Limit and Thermal Protection VOUT R1 R2
GND
Typical Application Circuit
RT9167/A VIN CIN 1uF IN GND EN BP OUT V COUT OUT 1uF
+ +
Chip Enable
CBP 10nF
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RT9167/A
Absolute Maximum Ratings
Input Voltage ------------------------------------------------------------------------------------------------------------ 8V Power Dissipation, PD @ TA = 25C SOT-23-5 ---------------------------------------------------------------------------------------------------------------- 0.4W SOP-8 -------------------------------------------------------------------------------------------------------------------- 0.625W Package Thermal Resistance (Note1) SOT-23-5, JA ----------------------------------------------------------------------------------------------------------- 250C/W SOT-23-5, JC ---------------------------------------------------------------------------------------------------------- 130C/W SOP-8, JA -------------------------------------------------------------------------------------------------------------- 160C/W SOP-8, JC -------------------------------------------------------------------------------------------------------------- 60C/W Operating Junction Temperature Range -------------------------------------------------------------------------- -40C to 125C Storage Temperature Range ---------------------------------------------------------------------------------------- -65C to 150C Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260C
Electrical Characteristics
(VIN = 5.0V, CIN = 1F, COUT = 1F, TA = 25C, unless otherwise specified)
Parameter Input Voltage Range Output Voltage Accuracy Maximum Output Current Current Limit RT9167 RT9167A RT9167 RT9167A RT9167/A Quiescent Current
Symbol VIN VOUT
Test Conditions
Min 2.9
Typ ------700 80 90 90 1.1 55 350 600 ------0.01 155
Max 7 7 +2 ----150 150 150 5 100 450 750 6 30 35 -0.4 100 1 --
Units V % mA mA
IL = 50mA IL = 1mA
2.7 -2 300 500 400 500 ----------1.6 -----
IMAX
ILIM RLOAD = 1 No Load IOUT = 300mA IOUT = 500mA IOUT = 1mA VDROP IOUT = 50mA IOUT = 300mA IOUT = 500mA VLINE VIN= (VOUT+0.15) to 7V, IOUT =1mA IOUT = 0mA to 300mA IOUT = 0mA to 500mA VIN= 3V to 5.5V VIN = 3V to 5.5V VOUT = 0V
RT9167/A IG RT9167A RT9167/A RT9167/A RT9167/A RT9167A
A
Dropout Voltage (VOUT(Normal) = 3.0V Version) Line Regulation Load Regulation
(2)
mV
mV/V mV V V nA A C
RT9167/A RT9167A
VLOAD VIH VIL ISD
EN Input High Threshold EN Input Low Threshold EN Bias Current Shutdown Supply Current Thermal Shutdown Temperature
IGSD
TSD
To be continued
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RT9167/A
Parameter Output Noise Ripple Rejection Symbol eNO PSRR Test Conditions CBP = 10nF, COUT = 10F F = 100Hz, CBP = 10nF, COUT = 10F Min --Typ 350 58 Max --Units nV Hz dB
Note 1. 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. Pin 1 of SOP-8 and pin4 of SOT-23-5 packages are the case position for JA measurement. Note 2. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) - 100mV.
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Typical Operating Characteristics
Output Voltage vs. Temperature
3.33 3.32
120 105
Quiescent Current vs. Temperature
Quiescent Current (uA) 1
Output Voltage (V)
3.31 3.30 3.29 3.28 3.27 3.26
90 75 60 45 30 15
VOUT = 3.3V
3.25 -50 -25 0 25 50 75 100 125 150
VOUT = 3.3V
0 -50 -25 0 25 50 75 100 125 150
Temperature (C)
Temperature (C)
Dropout Voltage vs. Load Current
250
Dropout Voltage vs. Load Current
600
125C
Dropout Voltage (mV)
200
Dropout Voltage (mV)
125C 25C
150
500
25C
400 300 200 100 0
100
-40C
-40C
50
RT9167 VOUT = 5.0V
RT9167A VOUT = 3.3V
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
0 0 0.05 0.1 0.15 0.2 0.25 0.3
Load Current (A)
Load Current (A)
Current Limit vs. Temperature
700 650
900 800
Current Limit vs. Temperature
Current Limit (mA)
Current Limit (mA)
RT9167 VOUT = 5.0V
600 550 500 450 400 350 300 -50 -25 0 25 50 75 100 125
700 600 500 400 300 200 -50 -25 0 25 50 75 100 125
RT9167A VOUT = 3.3V
Temperature (C)
Temperature (C)
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RT9167/A
Load Transient Response
60
Load Transient Response
60
Output Voltage Deviation (mV)
40 20 0 -20
Output Voltage Deviation (mV)
CIN = 10uF COUT = 1uF CBP = 10nF
VIN = 4V VOUT = 3.0V
40 20 0 -20
CIN = 10uF COUT = 4.7uF CBP = 10nF
VIN = 4V VOUT = 3.0V
Load Current (mA)
50 1 -50
Load Current (mA)
50 1 -50
Time (50us/Div)
Time (50us/Div)
Line Transient Response
150
Line Transient Response
150
Output Voltage Deviation (mV)
100 50 0 -50
Output Voltage Deviation (mV)
VOUT = 3.0V COUT = 1uF CBP = 10nF
Loading = 1mA
100 50 0 -50
VOUT = 3.0V COUT = 1uF CBP = 10nF
Loading = 50mA
Input Voltage Deviation (V)
5 4
Input Voltage Deviation (V)
5 4
Time (1ms/Div)
Time (1ms/Div)
Line Transient Response
150
Line Transient Response
60
Output Voltage Deviation (mV)
100 50 0 -50
Output Voltage Deviation (mV)
VOUT = 3.0V COUT = 4.7uF CBP = 10nF
Loading = 1mA
40 20 0 -20
VOUT = 3.0V COUT = 4.7uF CBP = 10nF
Loading = 50mA
Input Voltage Deviation (V)
5 4
Input Voltage Deviation (V)
5 4
Time (500us/Div)
Time (500us/Div)
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RT9167/A
70 60 50
PSRR
PSRR (dB)
40 30 20 10 0
VOUT = 3.3V, ILOAD = 1mA COUT = 4.7uF, CBP = 10nF 10 10 100 100 1K 1000 10K 10000 100K 100000 1M 1000000
Frequency (kHz)
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RT9167/A
Application Information
Capacitor Selection and Regulator Stability Like any low-dropout regulator, the external capacitors used with the RT9167/A must be carefully selected for regulator stability and performance. Using a capacitor whose value is > 1F on the RT9167/A input and the amount of capacitance can be increased without limit. The input capacitor must be located a distance of not more than 0.5" from the input pin of the IC and returned to a clean analog ground. Any good quality ceramic or tantalum can be used for this capacitor. The capacitor with larger value and lower ESR (equivalent series resistance) provides better PSRR and line-transient response. The output capacitor must meet both requirements for minimum amount of capacitance and ESR in all LDOs application. The RT9167/A is designed specifically to work with low ESR ceramic output capacitor in space-saving and performance consideration. Using a ceramic capacitor whose value is at least 1F with ESR is > 5m on the RT9167/A output ensures stability. The RT9167/A still works well with output capacitor of other types due to the wide stable ESR range. Figure 1. shows the curves of allowable ESR range as a function of load current for various output voltages and capacitor values. Output capacitor of larger capacitance can reduce noise and improve loadtransient response, stability, and PSRR. The output capacitor should be located not more than 0.5" from the VOUT pin of the RT9167/A and returned to a clean analog ground. Note that some ceramic dielectrics exhibit large capacitance and ESR variation with temperature. It may be necessary to use 2.2F or more to ensure stability at temperatures below -10C in this case. Also, tantalum capacitors, 2.2F or more may be needed to maintain capacitance and ESR in the stable region for strict application environment. Tantalum capacitors maybe suffer failure due to surge current when it is connected to a low-impedance source of power (like a battery or very large capacitor). If a tantalum capacitor is used at the input, it must be guaranteed to have a surge current rating sufficient for the application by the manufacture. Use a 10nF bypass capacitor at BP for low output voltage noise. The capacitor, in conjunction with an internal 200k resistor, which connects bypass pin and the band-gap reference, creates an 80Hz low-pass filter for noise reduction. Increasing the capacitance will slightly decrease the output noise, but increase the start-up time. The capacitor connected to the bypass pin for noise reduction must have very low leakage. This capacitor leakage current causes the output voltage to decline by a proportional amount to the current due to the voltage drop on the internal 200k resistor. Figure 2 shows the power on response.
Region of Stable COUT ESR vs. Load Current
100.00 100
Unstable Region
10.00 10
COUT = 1uF
CBP == 1nF CBP 10nF
Stable Region
Voltage (0.5V/Div) Voltage (0.5V / DIV)
COUT ESR ()
CBP == 10nF BP 10nF
1.001
0.1 0.10 Unstable Region
0.01 0.01
0.001 0.00
0 50 100 150 200 250 300
VOUT ==3.0V VOUT 3.0V 0 0
Load Current (mA)
5.0
10.0
15.0 15.0
Figure 1
Time (ms) Time (ms)
Figure 2
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RT9167/A
Load-Transient Considerations The RT9167/A load-transient response graphs (see Typical Operating Characteristics) show two components of the output response: a DC shift from the output impedance due to the load current change, and the transient response. The DC shift is quite small due to the excellent load regulation of the IC. Typical output voltage transient spike for a step change in the load current from 0mA to 50mA is tens mV, depending on the ESR of the output capacitor. Increasing the output capacitor's value and decreasing the ESR attenuates the overshoot. Shutdown Input Operation The RT9167/A is shutdown by pulling the EN input low, and turned on by driving the input high. If this feature is not to be used, the EN input should be tied to VIN to keep the regulator on at all times (the EN input must not be left floating). To ensure proper operation, the signal source used to drive the EN input must be able to swing above and below the specified turn-on/turn-off voltage thresholds which guarantee an ON or OFF state (see Electrical Characteristics). The ON/OFF signal may come from either CMOS output, or an open-collector output with pullup resistor to the RT9167/A input voltage or another logic supply. The high-level voltage may exceed the RT9167/A input voltage, but must remain within the absolute maximum ratings for the EN pin. Internal P-Channel Pass Transistor The RT9167/A features a typical 1.1 P-Channel MOSFET pass transistor. It provides several advantages over similar designs using PNP pass transistors, including longer battery life. The P-channel MOSFET requires no base drive, which reduces quiescent current considerably. PNPbased regulators waste considerable current in dropout when the pass transistor saturates. They also use high base-drive currents under large loads. The RT9167/A does not suffer from these problems and consume only 80A of quiescent current whether in dropout, light-load, or heavyload applications. Figure 3 Input-Output (Dropout) Voltage A regulator's minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this will determine the useful end-of-life battery voltage. Because the RT9167/ A uses a P-Channel MOSFET pass transistor, the dropout voltage is a function of drain-to-source on-resistance [RDS(ON)] multiplied by the load current. Reverse Current Path The power transistor used in the RT9167/A has an inherent diode connected between the regulator input and output (see Figure 3). If the output is forced above the input by more than a diode-drop, this diode will become forward biased and current will flow from the VOUT terminal to VIN. This diode will also be turned on by abruptly stepping the input voltage to a value below the output voltage. To prevent regulator mis-operation, a Schottky diode should be used in any applications where input/output voltage conditions can cause the internal diode to be turned on (see Figure4). As shown, the Schottky diode is connected in parallel with the internal parasitic diode and prevents it from being turned on by limiting the voltage drop across it to about 0.3V. < 100mA to prevent damage to the part.
VIN
VOUT
VIN
VOUT
Figure 4
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RT9167/A
Operating Region and Power Dissipation The maximum power dissipation of RT9167/A depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. The power dissipation across the device is P = IOUT (VIN - VOUT). The maximum power dissipation is: PMAX = (TJ - TA) /JA where TJ - TA is the temperature difference between the RT9167/A die junction and the surrounding environment, JA is the thermal resistance from the junction to the surrounding environment. The GND pin of the RT9167/A performs the dual function of providing an electrical connection to ground and channeling heat away. Connect the GND pin to ground using a large pad or ground plane. Current Limit and Thermal Protection T9167 includes a current limit which monitors and controls the pass transistor's gate voltage limiting the output current to 350mA Typ. (700mA Typ. for RT9167A). Thermaloverload protection limits total power dissipation in the RT9167/A. When the junction temperature exceeds TJ = +155C, the thermal sensor signals the shutdown logic turning off the pass transistor and allowing the IC to cool. The thermal sensor will turn the pass transistor on again after the IC's junction temperature cools by 10C, resulting in a pulsed output during continuous thermaloverload conditions. Thermal-overloaded protection is designed to protect the RT9167/A in the event of fault conditions. Do not exceed the absolute maximum junctiontemperature rating of TJ = +150C for continuous operation. The output can be shorted to ground for an indefinite amount of time without damaging the part by cooperation of current limit and thermal protection. Thermal Considerations Thermal protection limits power dissipation in RT9167/A. When the operation junction temperature exceeds 165C, 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 30C. For continuous operation, do not exceed absolute maximum operation junction temperature 125C. The power dissipation definition in device is: PD = (VIN - VOUT) x IOUT + VIN x IQ
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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 ) / JA Where T J(MAX) is the maximum operation junction temperature 125C, TA is the ambient temperature and the JA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9167/A, where T J(MAX) is the maximum junction temperature of the die (125C) and TA is the operated ambient temperature. The junction to ambient thermal resistance JA is layout dependent. For SOT-23-5 package, the thermal resistance JA is 250C/W on the standard JEDEC 51-3 single-layer thermal test board. The maximum power dissipation at TA = 25C can be calculated by following formula : PD(MAX) = (125C - 25C) / 250 = 0.4W for SOT-23-5 package PD(MAX) = (125C - 25C) / 160 = 0.625W for SOP-8 package The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance JA. For RT9167/A packages, the Figure 5 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed.
Maximum Power Dissipation (mW)1
700 600 500 400 300 200 100 0 0 20 40 60 80 100 120 140
SOP-8
SOT-23-5
Ambient Temperature
Figure 5. Derating Curves for RT9167/A Packages
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RT9167/A
The value of junction to case thermal resistance JC is popular for users. This thermal parameter is convenient for users to estimate the internal junction operated temperature of packages while IC operating. It' s independent of PCB layout, the surroundings airflow effects and temperature difference between junction to ambient. The operated junction temperature can be calculated by following formula : TJ = TC + PD x JC Where TC is the package case temperature measured by thermal sensor, PD is the power dissipation defined by user' s function and the JC is the junction to case thermal resistance provided by IC manufacturer. Therefore it' s easy to estimate the junction temperature by any condition. For example, how to calculate the junction temperature of RT9167A-28CB SOT-23-5 package? If we use input voltage VIN = 3.3V at an output current IO = 500mA and the case temperature (pin 4 of SOT-23-5 package) TC = 70C measured by thermal couple while operating, then our power dissipation is as follows: PD = (3.3V - 2.8V) x 500mA + 3.3V x 90A 250mW And the junction temperature TJ could be calculated as following : TJ = TC + PD x JC TJ = 70C + 0.25W x 130C/W = 70C + 32.5C = 102.5C < TJ(MAX) =125C For this operation application, TJ is lower than absolute maximum operation junction temperature 125C and it's safe to use.
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RT9167/A
Outline Dimension
H D L C B
b A A1 e
Symbol A A1 B b C D e H L
Dimensions In Millimeters Min 0.889 0.000 1.397 0.356 2.591 2.692 0.838 0.080 0.300 Max 1.295 0.152 1.803 0.559 2.997 3.099 1.041 0.254 0.610
Dimensions In Inches Min 0.035 0.000 0.055 0.014 0.102 0.106 0.033 0.003 0.012 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024
SOT-23-5 Surface Mount Package
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RT9167/A
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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