RT9201 RICHTEK | Alldatasheet

Document overview

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Technical content

Features

l +2.5V to +5.5V Input Range l Adjustable Output From 0.85V to VIN l 600mA Output Current l 95% Efficiency l No Schottky Diode Required l 85mA Quiescent Current l 100% Duty Cycle in Low-Dropout Mode l 800kHz Fixed-Frequency PWM Operation l Pulse-skipping Mode Operation During Light Ioad l RoHS Compliant and 100% Lead (Pb)-Free

Applications

l Personal Information Appliances l Portable Instruments l Distributed Power Systems l Battery-Powered Equipment (1 Li-Ion or 3 NiMH/NiCd) (TOP VIEW) VDFN-10L 3x3 General Description The RT9201 is a high-efficiency pulse-width-modulated (PWM) step-down DC-DC converter. Capable of delivering 600mA output current over a wide input voltage range from 2.5 to 5.5V, the RT9201 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and handy-terminals. Four operational modes are available: PWM, PSM, Low- Dropout and shut-down modes. Internal synchronous rectifier with low RDS(ON) dramatically reduces conduction loss at PWM mode. No external Schottky diode is required in practical application. The RT9201 auto- matically turns off the synchronous rectifier while the inductor current is low and enters discontinuous PWM mode. This can increase efficiency at light load condition. The RT9201 enters PSM (pulse-skipping mode) at extremely light load condition. The equivalent switching frequency is reduced to increase the efficiency in PSM. The RT9201 enters Low-Dropout mode when normal PWM cannot provide regulated output voltage by continuously turning on the upper P-MOSFET. RT9201 enters shut-down mode and consumes less than 0.1µA when EN pin is pulled low. The switching ripple is easily smoothed-out by small package filtering elements due to a fixed operation frequency of 800kHz. This along with small VDFN package provides small PCB area application. Other features include soft start, 0.8V internal reference voltage with 1% accuracy, over temperature protection, and over current protection. 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. Note : Richtek Pb-free and Green 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. }100% matte tin (Sn) plating. RT9201 Package Type QV : VDFN-10L 3x3 (V-Type) Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commer- cial Standard) NC VDD PVDD PGND LX EN SS FB GND NC GND

DS9201-12 August 2007www.richtek.com Typical Application Circuit Recommended using lower ESR capacitor F2F1 OUT R RR0.8V +×= VOUT (V) VIN (V) RF1 (W) CF1 (pF) RF2 (W) CF2 (pF) LX (mH) CSS (pF) CIN (uF) COUT (uF) 0.85 2.5 to 4.0 24k 330 390k 10 4.7 330 10 22 or (10 x 2) 1.375 2.5 to 5.0 280k 33 390k 10 4.7 330 10 22 or (10 x 2) 1.5 2.5 to 5.5 343k 22 390k 10 6.8 470 10 22 or (10 x 2) 1.8 2.5 to 5.5 487k 15 390k 10 6.8 470 10 22 or (10 x 2) 2.5 3.5 to 5.5 820k 10 390k 10 10 680 10 22 or (10 x 2) Recommended component selection for typical application circuit. Component Supplier Series Inductance ( µH) ESR (mW) Current Rating (mA) Dimensions (mm) SH4018 4.7 6.8 100 150 1500 1150 1000 4.8x4.8x1.8 ABC SR0302 4.7 6.8 150 180 250 1200 1000 800 3x2.8x2.5 TDK SLF6028 4.7 6.8 1600 1500 1300 6x6x2.8 Coilcraft DO1606 4.7 6.8 150 200 300 1100 1000 900 6.5x5.23x2 Suggested Inductors PVDD VDD GND LX FB SS PGND RT9201 8 7 65, Exposed Pad (11) VOUT RF1 RF2 1 EN CF1 CF2 CSS LX CIN COUT VIN GPIO

DS9201-12 August 2007www.richtek.com Function Block Diagram Functional Pin Description Pin No. Pin Name Pin Function 1 EN Tie this pin to 1.4V or higher to enable the device. Tie below 0.4V to shut-down. 2 SS Soft Start, connect a capacitor from this pin to GND. 3 FB Feedback Input pin. Connect a resistive voltage divider from the output voltage to FB to GND. 4, 10 NC No Connection. 5 GND Analog Ground. 6 PGND Power Ground. 7 LX Switch node. Drains of the internal P-Channel and N-Channel MOSFET switches. Connect an inductor to LX pins together as close as possible. 8 PVDD Main Power Supply Pin. 9 VDD Device Input Power Pin. Exposed Pad (11) GND The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. OSC & Shutdown Control Current Sense Control Logic Zero Detector Driver Slope Compensation VREF LX ENPVDD PGND FB SS VDD GND PWM Comparator0.8V Error Amplifier 300kΩ Component Supplier Part No. Capacitance (uF) Case Size C2012X5R0J106M 10 0805 TDK C3225X5R0J226M 22 1210 ECJ2FB0J106M 10 0805 Panasonic ECJHVB0J226M 22 1206 JMK212BJ106M 10 0805 JMK212BJ226MG 22 0805 TAIYO YUDEN JMK316BJ226ML 22 1206 Suggested Capacitors For CIN and COUT

DS9201-12 August 2007www.richtek.com

Electrical Characteristics

(VIN = 3.6V, VOUT = 2.5V, EN = VIN, LX = 10µH, CIN = 10µF, COUT = 22µF, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Units Input Voltage Range VIN 2.5 -- 5.5 V Adjustable Output Range VOUT (Note 4) 0.85 -- VIN V Reference Voltage VREF I L = 300mA -- 0.8 -- V Cross Regulation ΔVCROSS VIN = 2.5V to 5.5V, IL = 600mA to 0mA −3 -- +3 % FB Input Current IFB V FB = VIN −50 -- 50 nA PMOSFET RON PRDS(ON) ILX = 200mA 0.2 0.37 0.43 Ω NMOSFET RON NRDS(ON) ILX = 200mA 0.2 0.3 0.35 Ω Quiescent Current IQ I LX = 0mA, VFB = VREF + 0.15 40 85 140 µA Shutdown Current IQ(SD) EN = 0V, V IN = 5.5V 0.01 2 7 µA Oscillator Frequency fOSC I OUT = 100mA 600 800 1k kHz EN Input High Threshold VIH V IN = 2.5V to 5.5V 1.5 -- -- V EN Input Low Threshold VIL V IN = 2.5V to 5.5V -- -- 0.4 V Thermal Shutdown Temperature TSD 125 150 -- °C Maximum Duty Cycle VIN = VOUT 100 -- -- % Minimum On Time No Load 0.1 0.2 0.3 µs LX Leakage Current EN = 0V,VIN = 5.5V, VLX = 0V or VLX = 5.5V −20 1 20 µA Recommended Operating Conditions (Note 3) Absolute Maximum Ratings (Note 1) l Power Dissipation, PD @ TA = 25°C l Package Thermal Resistance l ESD Susceptibility (Note 2)

DS9201-12 August 2007www.richtek.com 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. Guarantee the VOUT range from 0.85V to V IN base on VOUT>0.3VIN.

DS9201-12 August 2007www.richtek.com Typical Operating Characteristics Frequency vs. Temperature 730 740 750 760 770 780 790 800 810 820 -50-250255075100125150 Temperature Frequency (kHz) (°C) VIN = 3.3V VOUT = 1.8V IOUT = 400mA Output Voltage vs. Temperature 1.790 1.792 1.794 1.796 1.798 1.800 1.802 1.804 1.806 -50-250255075100125150 Temperature Output Voltage (V) (°C) VIN = 3.3V VOUT = 1.8V IOUT = 200mA Frequency vs. Input Voltage 790 795 800 805 810 815 820 825 830 22.533.544.555.56 Input Voltage (V) Frequency (kHz) VOUT = 1.8V IOUT = 400mA VFB vs. Temperature 0.803 0.804 0.805 0.806 0.807 0.808 0.809 0.810 -50-250255075100125150 Temperature VFB (V) (°C) Efficiency vs. Output Current 100 1101001000 Output Current (mA) Efficiency (%) VIN = 3.3V VOUT = 1.8V VIN = 5V VOUT = 3.3V Efficiency vs. Temperature 100 -50-250255075100125150 Temperature Efficiency (%) (°C) VIN = 3.3V VOUT = 1.8V IOUT = 200mA

DS9201-12 August 2007www.richtek.com Current Limit vs. Input Voltage 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 1.12 1.14 22.533.544.555.56 Input Voltage (V) Current Limit (A) Output Voltage vs. Output Current 1.80 1.82 1.84 1.86 1.88 1.90 0100200300400500600700800 Output Current (mA) Output Voltage (V) VIN = 3.3V VOUT = 1.8V Output Voltage vs. Output Current 3.25 3.28 3.30 3.33 3.35 3.38 3.40 3.43 3.45 0100200300400500600700800 Output Current (mA) Output Voltage (V) VIN = 5V VOUT = 3.3V Minimum On-Time vs. Input Voltage 100 150 200 250 300 2.533.544.555.56 Input Voltage (V) Minimum On-Time (ns) VOUT = 1.8V VOUT = 1.3V Minimum On-Time vs. Temperature 100 150 200 250 300 -50-250255075100125150 Temperature Minimum On-Time (ns) (°C) VIN = 3.3V VOUT = 1.8V IOUT = 0A Time (500 µs/Div) VIN = 3.3V, V OUT = 1.8V IOUT = 0A to 600mA 100 -100 500 VOUT (mV) IOUT (mA) Load Transient Response

DS9201-12 August 2007www.richtek.com Load Transient Response Time (500 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 0 to 600mA 100 -100 500 VOUT (mV) IOUT (mA) Load Transient Response Time (500 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 300 to 600mA 100 -100 500 VOUT (mV) IOUT (mA) Load Transient Response Time (500 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 300 to 0mA 100 -100 500 VOUT (mV) IOUT (mA) Load Transient Response Time (500 µs/Div) VIN = 3.3V, V OUT = 1.8V IOUT = 300 to 600mA 100 -100 500 VOUT (mV) IOUT (mA) Load Transient Response Time (500 µs/Div) 300 to 0mA VIN = 3.3V, V OUT = 1.8V IOUT = 300 to 0mA 100 -100 500 VOUT (mV) IOUT (mA) Ripple & Noise Time (500ns/Div) VIN = 3.3V, V OUT = 1.8V IOUT = 600mA LX (V) IOUT (mA) VOUT (mV) 500

DS9201-12 August 2007www.richtek.com Soft Start Time (200 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 0A, CSS = 330pF 500 VEN (V) VOUT (V) IIN (mA) Soft Start Time (200 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 0A, CSS = 1000pF 500 VEN (V) VOUT (V) IIN (mA) Soft Start Time (500 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 600mA, CSS = 1000pF 500 VEN (V) VOUT (V) IIN (mA) Soft Start Time (200 µs/Div) VIN = 5V, V OUT = 3.3V IOUT = 600mA, CSS = 330pF 500 VEN (V) VOUT (V) IIN (mA)

DS9201-12 August 2007www.richtek.com

Application Information

RT9201 is a high-efficiency pulse-width-modulated (PWM) step-down DC-DC converter. Capable of delivering 600mA output current over a wide input voltage range from 2.5V to 5.5V, the RT9201 is ideally suited for portable electronic devices that are powered from 1-cell Li-ion battery or from other power sources within the range such as cellular phones, PDAs and handy-terminals. Chip Enable/Disable and Soft Start Four operational modes are available: PWM, PSM, Low- Drop-Out and shut-down modes. Pulling EN pin lower than 0.4V shuts down the RT9201 and reduces its quiescent current to 0.1µA. Pulling EN pin higher than 1.4V enables the RT9201 and initiates the softstart cycle. A softstart capacitor connected to SS pin along with the internal 300k Ω resistor determines V REF ramp-up speed and the softstart behavior. A softstart capacitor between 330pF to 1000pF is recommended for smooth start-up of RT9201. PWM Operation During normal operation, the RT9201 regulates output voltage by switching at a constant frequency and then transferring the power to the load in each cycle by PWM. The RT9201 uses a slope-compensated, current-mode PWM controller capable of achieving 100% duty cycle. At each rising edge of the internal oscillator, the Control Logic cell sends a PWM ON signal to the Driver cell to turn on internal PMOSFET. This allows current to ramp up through the inductor to the load, and stores energy in a magnetic field. The switch remains on until either the current-limit is tripped or the PWM comparator signals for the output in regulation. After the switch is turned off, the inductor releases the magnetic energy and forces current through the NMOSFET synchronous rectifier to the output-filter capacitor and load. The output-filter capacitor stores charge when the inductor current is above the average output current and releases charge when the inductor current is below the average current to smooth the output voltage across the load. A Zero Detector monitors inductor current by sensing voltage drop across the NMOSFET synchronous rectifier when it turns on. The NMOSFET turns off and allows the converter entering discontinuous conduction mode when the inductor current decreases to zero. The zero current defection on threshold is about 50mA.This reduces conduction loss and increase power conversion efficiency at light load condition. PSM Operation The minimum on-time of RT9201 is approximately 200ns. Consequently, the converter will enter pulse-skipping- mode (PSM) during extreme light load condition or when modulation index (VOUT/VIN) is extreme low. This could reduce switching loss and further increase power conversion efficiency. For example : VIN = 3.8V, VOUT = 2.5V & ILOAD = 4mA Low Dropout Mode Operation The maximum on-time can exceed one oscillator cycle, which permits operation up to 100% duty cycle. As the input voltage drops, the duty cycle increases until the PMOSFET is held on continuously. Dropout voltage in 100% duty cycle is the output current multiplied by the on-resistance of the internal switch and inductor, around 300mV (IOUT = 600mA). When the converter operates around the boundary of Low-Dropout-Mode and PWM, sub-harmonic oscillation and large ripple may occur at output voltage as shown in Figure 1. Figure 2 illustrates the boundary of stable PWM

DS9201-12 August 2007www.richtek.com 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 Outline Dimension Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.800 1.000 0.031 0.039 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.180 0.300 0.007 0.012 D 2.950 3.050 0.116 0.120 D2 2.300 2.650 0.091 0.104 E 2.950 3.050 0.116 0.120 E2 1.500 1.750 0.059 0.069 e 0.500 0.020 L 0.350 0.450 0.014 0.018 V-Type 10L DFN 3x3 Package 11 22 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. DETAIL A Pin #1 ID and Tie Bar Mark Options D E A L be SEE DETAIL A