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RT9170
300mA, 15A Quiescent Current CMOS LDO Regulator
General Description
The RT9170 is CMOS ultra low quiescent current and low dropout (ULDO) regulators. The devices are capable of supplying 300mA of output current continuously. The RT9170's performance is optimized for batterypowered systems to deliver 15A ultra low quiescent current and extremely low dropout voltage. Regulator ground current increases only slightly in dropout, further prolonging the battery life. The other features include ultra low dropout voltage, high output accuracy, current limiting protection, and high ripple rejection ratio. The devices are available in fixed output voltages range of 1.2V to 3.3V with 0.1V per step. The RT9170 regulators are available in SOT-23-3, SOT-23-5 and 3-lead SOT-89 packages.
Features
Ultra-Low Quiescent Current (Typically 15A) Guaranteed 300mA Output Current Low Dropout : 240mV at 300mA Wide Operating Voltage Ranges : 2V to 5.5V Fast Transient Response Tight Load and Line Regulation TTL-Logic-Controlled Enable Input Current Limiting & Thermal Protection Only 1F Output Capacitor Required for Stability High Power Supply Rejection Ratio Custom Voltage Available RoHS Compliant and 100% Lead (Pb)-Free
Applications
Cellular Phones and Pagers Battery-Powered Equipment Laptop, Palmtops, Notebook Computers Hand-Held Instruments PCMCIA Cards
Ordering Information
RT9170Package Type V: SOT-23-3 B: SOT-23-5 X : SOT-89 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) Output Voltage 12 : 1.2V 13 : 1.3V : 32 : 3.2V 33 : 3.3V
Pin Configurations
(TOP VIEW)
VIN 3 1 GND 2
EN 5 1
VOUT
NC 4 2 3
GND
VIN VOUT
SOT-23-3 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 3
SOT-23-5
Marking Information
For marking information, contact our sales representative directly or through a RichTek distributor located in your area, otherwise visit our website for detail.
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GND
VIN VOUT (TAB)
SOT-89
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RT9170
Typical Application Circuit
VIN VIN RT9170EN GND VOUT CB VOUT
CIN 1uF
COUT 1uF
Chip Enable
Functional Pin Description
Pin No. RT91703 2 1 CV RT91702 3 1 5 4 CB RT91702 3 1 CX VIN VOUT GND EN NC Power Input Voltage Output Voltage Ground Chip Enable (Active Low) No Connection Pin Name Pin Function
Function Block Diagram
VIN Current Limit & Thermal Shutdown VOUT
+ EN
GND
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Absolute Maximum Ratings
(Note 1) Supply Input Voltage -------------------------------------------------------------------------------------------------- 7V Power Dissipation, PD @ TA = 25C SOT-23-3 ---------------------------------------------------------------------------------------------------------------- 0.4W SOT-23-5 ---------------------------------------------------------------------------------------------------------------- 0.4W SOT-89 ------------------------------------------------------------------------------------------------------------------- 0.571W Package Thermal Resistance (Note 7) SOT-23-3, JA ---------------------------------------------------------------------------------------------------------- 250C/W SOT-23-5, JA ---------------------------------------------------------------------------------------------------------- 250C/W SOT-89, JA ------------------------------------------------------------------------------------------------------------- 175C/W Junction Temperature ------------------------------------------------------------------------------------------------- 150C Storage Temperature Range ---------------------------------------------------------------------------------------- -65C to 150C ESD Susceptibility (Note 2) HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 3)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 2V to 5.5V Enable Input Voltage -------------------------------------------------------------------------------------------------- 0V to 5.5V Junction Temperature Range ---------------------------------------------------------------------------------------- -40C to 125C
Electrical Characteristics
(VIN = VOUT + 1V, CIN = COUT = 1F, TA = 25C, unless otherwise specified)
Parameter Output Voltage Accuracy Current Limit Quiescent Current Dropout Voltage Line Regulation Load Regulation Standby Current EN Threshold (Note 4) (Note 6) (Note 5)
Symbol VOUT ILIM IQ VDROP VLINE VLOAD ISTBY
Test Conditions IOUT = 1mA RLOAD = 1 VEN 0.6V, IOUT = 0mA IOUT = 300mA VIN = (VOUT + 0.3V) to 5.5V, IOUT = 1mA 1mA < IOUT < 300mA VEN 2V (Shutdown), VIN = 5.5V VIN = 2V to 5.5V, Enable VIN = 2V to 5.5V, Shutdown f = 1kHz, COUT = 1F
Min -2 300 ---0.3 ---2 ---
Typ --15 240 0.018 0.01 0.1 ---40 150
Max +2 ---+0.3 0.04 -0.6 ----
Units % mA A mV %/V %/mA A V dB C
Logic-Low Voltage VIL Logic-High Voltage VIH PSRR TSD
Power Supply Rejection Thermal Shutdown Temperature
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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. Devices are ESD sensitive. Handling precaution recommended. Note 3. The device is not guaranteed to function outside its operating conditions Note 4. Regulation is measured at constant junction temperature by using a 20ms current pulse. Devices are tested for load regulation in the load range from 1mA to 300mA. Note 5. Quiescent, or ground current, is the difference between input and output currents. It is defined by IQ = IIN - IOUT under no load condition (IOUT = 0mA). The total current drawn from the supply is the sum of the load current plus the ground pin current. Note 6. Standby current is the input current drawn by a regulator when the output voltage is disabled by a shutdown signal (VEN 2V). It is measured with VIN = 5.5V. Note 7. JA is measured in the natural convection at TA = 25C on a low effective thermal conductivity test board of 51-3 thermal measurement standard. JEDEC
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Typical Operating Characteristics
Temperature Stability
2.55 2.53
Quiescent Current vs. Load Current
18 17
No Load
Output Voltage (V)1
2.51 2.49
Quiescent Current (uA) 1
105 125
16 15 14 13 12 11 10
ILOAD = 250mA
2.47 2.45 2.43 2.41 2.39 2.37 2.35 -35 -15 5 25 45 65 85
VIN = 3.5V VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 1uF (Ceramic)
VIN = 3.5V VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 1uF (Ceramic)
0 0.05 0.1 0.15 0.2 0.25 0.3
Temperature (C)
Load Current (A)
Quiescent Current vs. Temperature
18 16
18
Quiescent Current vs. Supply Voltage
16
ILOAD = 200mA
Quiescent Current (uA) 1
Quiescent Current (uA) 1
14 12 10 8 6 4 2 0 -35 -15 5 25 45 65 85 105 125
14 12 10 8 6 4 2 0 2 2.5 3 3.5 4 4.5 5 5.5
No Load
No Load ILOAD = 200mA
VIN = 3.5V VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 1uF (Ceramic)
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 1uF (Ceramic)
Temperature (C)
Supply Voltage (V)
Dropout Voltage vs. Load Current
300
Output Voltage vs. Supply Voltage
2.55
VOUT = 3.3V
250
Dropout Voltage (mV)
200
Output Voltage (V)1
TJ = 125C TJ = 25C
150 100
2.53
2.51
2.49
TJ = -40C
50 0 0 0.05 0.1 0.15 0.2 0.25 0.3
2.47
VOUT = 2.5V CIN = 1uF (Ceramic) COUT = 1uF (Ceramic) ILOAD = 1mA
2.5 3 3.5 4 4.5 5 5.5
2.45
Load Current (A)
Supply Voltage (V)
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Load Regulation Deviation vs. Temperature
0
Current Limit vs. Temperature
1.60
Load Regulation Deviation (%/mA)
-0.0005 -0.001 -0.0015 -0.002 -0.0025 -0.003 -0.0035 -0.004
1.40
Current Limit (A)
1.20
1.00
0.80
VOUT = 2.5V
-0.0045 -35 -15 5 25 45 65 85 105 125
0.60
VIN = 5V VOUT = 3.3V RL = 1
-50 -25 0 25 50 75 100 125
Temperature (C)
Temperature (C)
PSRR
0 -10
Current Limit
3.0 CIN = 10uF (Ceramic) X5R COUT = 10uF (Ceramic) X5R VIN = 5V RL = 1
VIN = 3.5V VOUT = 2.5V COUT = 1uF (Ceramic) ILOAD = 10mA
ILOAD = 250mA
PSRR(dB)1
Current Limit (A)
10K 100K 1M
-20 -30 -40 -50 -60 -70
2.5 2.0 1.5 1.0 0.5 0
10
100
1K
Time (5ms/Div)
Frequency (Hz)
Enable Respone
Output Voltage (V)
6 4 2 0
Enable Respone
EN Voltage (V) Output Voltage (V)
3 2 1 0 2 1 0 VIN = 5V VOUT = 3.3V CIN = 1uF(Ceramic) COUT = 1uF(Ceramic) ILOAD = 300mA
VIN = 5V VOUT = 3.3V CIN = 1uF (Ceramic) COUT = 1uF (Ceramic) ILOAD = 300mA
EN Voltage (V)
2 0
Time (25ms/DIV)
Time (5ms/Div)
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Load Transient Response
Load Current (mA) Input Voltage Deviation (V)
VIN = 3.5V, VOUT = 2.5V TA = 25C 250 0 CIN = 1uF (Ceramic) COUT = 1uF (Ceramic) 6
Line Transient Response
VOUT = 2.5V 5 TA = 25C 4 3 COUT = 1uF (Ceramic) IOUT = 250mA
200 0 -200
Output Voltage Deviation (mV)
100 0
Output Voltage Deviation (mV)
-100
Time (0.5ms/Div)
Time (0.5ms/Div)
Noise
VIN = 3.5V, VOUT = 2.5V 300 IOUT = 250mA 200 CIN = 1uF (Ceramic) COUT = 1uF (Ceramic)
Noise(uV)
100 0 -100 -200 -300
Times (2.5ms/Div)
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Application Information
Like any low-dropout regulator, the RT9170 requires input and output decoupling capacitors. The device is specifically designed for portable applications requiring minimum board space and smallest components. These capacitors must be correctly selected for good performance (see Capacitor Characteristics Section). Please note that linear regulators with a low dropout voltage have high internal loop gains which require care in guarding against oscillation caused by insufficient decoupling capacitance. Input Capacitor An input capacitance of 1F is required between the device input pin and ground directly (the amount of the capacitance may be increased without limit). The input capacitor MUST be located less than 1 cm from the device to assure input stability (see PCB Layout Section). A lower ESR capacitor allows the use of less capacitance, while higher ESR type (like aluminum electrolytic) require more capacitance. Capacitor types (aluminum, ceramic and tantalum) can be mixed in parallel, but the total equivalent input capacitance/ ESR must be defined as above to stable operation. There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be 1F over the entire operating temperature range. Output Capacitor The RT9170 is designed specifically to work with very small ceramic output capacitors. A ceramic capacitor (temperature characteristics X7R, X5R, Z5U, or Y5V) in 1F to 10F with 5m to 50m range is suitable for the RT9170 application. The recommended minimum capacitance for the device is 1F, X5R or X7R dielectric ceramic, between VOUT and GND for stability, but it may be increased without limit. Higher capacitance values help to improve transient. The output capacitor's ESR is critical because it forms a zero to provide phase lead which is required for loop stability. No Load Stability The device will remain stable and in regulation with no external load. This is specially import in CMOS RAM keepalive applications. Input-Output (Dropout) Volatge A regulator's minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the device uses a PMOS, its dropout voltage is a function of drain-tosource on-resistance, RDS(ON), multiplied by the load current : VDROPOUT = VIN -VOUT = RDS(ON) x IOUT Current Limit The RT9170 monitors and controls the PMOS' gate voltage, limiting the output current to 0.3A (min). The output can be shorted to ground for an indefinite period of time without damaging the part. Short-Circuit Protection The device is short circuit protected and in the event of a peak over-current condition, the short-circuit control loop will rapidly drive the output PMOS pass element off. Once the power pass element shuts down, the control loop will rapidly cycle the output on and off until the average power dissipation causes the thermal shutdown circuit to respond to servo the on/off cycling to a lower frequency. Please refer to the section on thermal information for power dissipation calculations. Capacitor Characteristics It is important to note that capacitance tolerance and variation with temperature must be taken into consideration when selecting a capacitor so that the minimum required amount of capacitance is provided over the full operating temperature range. In general, a good tantalum capacitor will show very little capacitance variation with temperature, but a ceramic may not be as good (depending on dielectric type).
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Aluminum electrolytics also typically have large temperature variation of capacitance value. Equally important to consider is a capacitor's ESR change with temperature: this is not an issue with ceramics, as their ESR is extremely low. However, it is very important in Tantalum and aluminum electrolytic capacitors. Both show increasing ESR at colder temperatures, but the increase in aluminum electrolytic capacitors is so severe they may not be feasible for some applications. Ceramic : For values of capacitance in the 10F to 100F range, ceramics are usually larger and more costly than tantalums but give superior AC performance for bypassing high frequency noise because of very low ESR (typically less than 10m). However, some dielectric types do not have good capacitance characteristics as a function of voltage and temperature. Z5U and Y5V dielectric ceramics have capacitance that drops severely with applied voltage. A typical Z5U or Y5V capacitor can lose 60% of its rated capacitance with half of the rated voltage applied to it. The Z5U and Y5V also exhibit a severe temperature effect, losing more than 50% of nominal capacitance at high and low limits of the temperature range. X7R and X5R dielectric ceramic capacitors are strongly recommended if ceramics are used, as they typically maintain a capacitance range within 20% of nominal over full operating ratings of temperature and voltage. Of course, they are typically larger and more costly than Z5U/Y5U types for a given voltage and capacitance. Tantalum : Solid tantalum capacitors are recommended for use on the output because their typical ESR is very close to the ideal value required for loop compensation. They also work well as input capacitors if selected to meet the ESR requirements previously listed. Tantalums also have good temperature stability: a good quality tantalum will typically show a capacitance value that varies less than 10-15% across the full temperature range of 125C to -40C. ESR will vary only about 2X going from the high to low temperature limits. The increasing ESR at lower temperatures can cause oscillations when marginal quality capacitors are used (if the ESR of the capacitor is near the upper limit of the stability range at room temperature). Aluminum : This capacitor type offers the most capacitance for the money. The disadvantages are that they are larger in physical size, not widely available in surface mount, and have poor AC performance (especially at higher frequencies) due to higher ESR and ESL. Compared by size, the ESR of an aluminum electrolytic is higher than either Tantalum or ceramic, and it also varies greatly with temperature. A typical aluminum electrolytic can exhibit an ESR increase of as much as 50X when going from 25C down to -40C. It should also be noted that many aluminum electrolytics only specify impedance at a frequency of 120Hz, which indicates they have poor high frequency performance. Only aluminum electrolytics that have an impedance specified at a higher frequency (between 20kHz and 100kHz) should be used for the device. Derating must be applied to the manufacturer's ESR specification, since it is typically only valid at room temperature. Any applications using aluminum electrolytics should be thoroughly tested at the lowest ambient operating temperature where ESR is maximum. Thermal Considerations The RT9170 series can deliver a current of up to 300mA over the full operating junction temperature range. However, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 125C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Power dissipation can be calculated based on the output current and the voltage drop across regulator. PD = (VIN - VOUT) IOUT + VIN IGND
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RT9170
The final operating junction temperature for any set of conditions can be estimated by the following thermal equation : PD (MAX) = ( TJ (MAX) - TA ) / JA Where TJ (MAX) is the maximum junction temperature of the die (125 C) and T A is the maximum ambient temperature. The junction to ambient thermal resistance (JA) for SOT-23-3 and SOT-23-5 packages at recommended minimum footprint is 250 C/W, 175C/W for SOT-89 package (JA is layout dependent). Visit our website in which "Recommended Footprints for Soldering Surface Mount Packages" for detail. PCB Layout Good board layout practices must be used or instability can be induced because of ground loops and voltage drops. The input and output capacitors MUST be directly connected to the input, output, and ground pins of the device using traces which have no other currents flowing through them. The best way to do this is to layout CIN and COUT near the device with short traces to the VIN, VOUT, and ground pins. The regulator ground pin should be connected to the external circuit ground so that the regulator and its capacitors have a "single point ground". It should be noted that stability problems have been seen in applications where "vias" to an internal ground plane were used at the ground points of the device and the input and output capacitors. This was caused by varying ground potentials at these nodes resulting from current flowing through the ground plane. Using a single point ground technique for the regulator and it's capacitors fixed the problem. Since high current flows through the traces going into VIN and coming from VOUT, Kelvin connect the capacitor leads to these pins so there is no voltage drop in series with the input and output capacitors. Optimum performance can only be achieved when the device is mounted on a PC board according to the diagram below: SOT-23-5 Board Layout
EN NC
VOUT
GND
VIN
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Outline Dimension
D
H L
C
B
e
A A1 b
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 1.803 0.080 0.300 Max 1.295 0.152 1.803 0.508 2.997 3.099 2.007 0.254 0.610
Dimensions In Inches Min 0.035 0.000 0.055 0.014 0.102 0.106 0.071 0.003 0.012 Max 0.051 0.006 0.071 0.020 0.118 0.122 0.079 0.010 0.024
SOT-23-3 Surface Mount Package
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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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D D1
A
C
B
C1 e e H A b b
Dimensions In Inches Min 0.055 0.014 0.094 0.016 0.155 0.031 0.173 0.055 0.057 0.014 Max 0.063 0.019 0.102 0.021 0.167 0.047 0.181 0.069 0.061 0.017
b1
Symbol A b B b1 C C1 D D1 e H
Dimensions In Millimeters Min 1.397 0.356 2.388 0.406 3.937 0.787 4.394 1.397 1.448 0.356 Max 1.600 0.483 2.591 0.533 4.242 1.194 4.597 1.753 1.549 0.432
3-Lead SOT-89 Surface Mount 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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