Page No. : 1/8 RS6514 PWM Control 4A Step-Down Converter RS6514 provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM control circuit is able to vary the duty ratio linearly from 0 up to 100%. This converter also contains an error amplifier circuit as well as a soft-start circuit that prevents overshoot at startup. An enable function, an over current protect function and a short circuit protect function are built inside, and when OCP or SCP happens, the operation frequency will be reduced from 350KHz to 30KHz. Also, an internal compensation block is built in to minimum external component count. With the addition of an internal P-Channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOP–8/EP (Exposed Pad) mini-package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 20V, it is also suitable for the operation via an AC adapter. Features Applications • Input voltage: 3.6V to 20V. • PC Motherboard • LCD Monitor • Graphic Card • DVD-Video Player • Telecom Equipment • ADSL Modem • Printer and other Peripheral Equipment • Microprocessor core supply • Output voltage: 0.8V to VCC. • Duty ratio: 0% to 100% PWM control • Oscillation frequency: 350KHz typ. • Soft-start, Current limit, Enable function • Thermal Shutdown function • Built-in internal SW P-channel MOS • SOP-8L Pb-Free Package. • Networking power supply . Pin Configurations Pin 1: Feedback pin. Pin 2: Power-off pin H: Normal operation (Step-down operation) L: Step-down operation stopped Pin 5: Output Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI Pin 6: Output Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI (All circuits deactivated) DS-RS6514-02 March, 2009 Pin 3: Add an external resistor to set max output current Pin 7, 8: GND Pin Pin 4: IC power supply pin Pin 9: Output Pin (Exposed Pad). Must be connected to bare copper ground plane. www.Orister.com Page No. : 2/8 Block Diagram Absolute Maximum Ratings Symbol Parameter Range Units VCC VCC Pin Voltage VSS-0.3 to VSS+22 V VFB VEN Feedback Pin Voltage EN Pin Voltage Switch Pin Voltage Power Dissipation Operating Temperature Range Storage Temperature Range VSS-0.3 to VCC VSS-0.3 to VIN+0.3 VSS-0.3 to VIN+0.3 Internally limited -20 to +125 -40 to +150 V V V mW o C o C VOUTPUT PD TOPR TSTG Electrical Characteristics (VIN = 12V, Ta=25°C, unless otherwise specified) Symbol VIN VFB IFB ISW ISSS ΔVOUT/VOUT ΔVOUT/VOUT FOSC FOSC1 VSH VSL ISH ISL IOCSET TSS Parameter Input Voltage Feedback Voltage Feedback Bias Current Switch Current Current Consumption During Power Off Line Regulation Load Regulation Oscillation Frequency Frequency of Current Limit or Short Circuit Protect EN Pin Input Voltage EN Pin Input Leakage Current OCSET Pin Bias Current Soft-Start Time RDSON Internal MOSFET RDSON EFFI Efficiency Thermal Resistance Junction-to-Ambient θJA DS-RS6514-02 March, 2009 Conditions IOUT=0.1A IOUT=0.1A - Min. 3.6 0.782 4.5 Typ. 0.8 0.1 - Max. 20 0.818 0.5 - Unit V V uA A VEN=0V - 10 - uA VIN=5V～18V IOUT=0.1 to 4A Measure waveform at SW pin 300 2 0.2 350 4 0.5 400 % % KHz Measure waveform at SW pin 10 - - KHz Evaluate oscillation at SW pin Evaluate oscillation stop at SW pin - 2.0 75 20 -10 90 0.8 105 uA uA uA ms - 0.3 2 5 VIN=5V，VFB=0V VIN=12V，VFB=0V VIN=12V，VOUT=5V，IOUT=4A - 110 70 90 150 100 - - - 65 - V mΩ % o C/W www.Orister.com Page No. : 3/8 Typical Application Circuit Note: VOUT = VFB x (1+RA/RB) RB=0.7K~5K ohm VIN=12V, IMAX = 4A VOUT L1 Value 2.5V 22uH 3.3V 27uH 5V 33uH Function Description PWM Control The RS6514 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of the RS6514, the pulse width varies in a range from 0 to 100%, according to the load current. The ripple voltage produced by the switching can easily be removed through a filter because the switching frequency remains constant. Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load current. Under Voltage Lockout The under voltage lockout circuit of the RS6514 assures that the high-side MOSFET driver outputs remain in the off state whenever the supply voltage drops below 3.3V. Normal operation resumes once VCC rises above 3.5V. RDS(ON) Current Limiting The current limit threshold is setting by the external resistor connecting from VCC supply to OCSET. The internal 100uA sink current crossing the resistor sets the voltage at the pin of OCSET. When the PWM voltage is less than the voltage at OCSET, an over-current condition is triggered. ILOAD × RDS(ON) =IOCSET × ROCSET See above formula for setting the current limit value. DS-RS6514-02 March, 2009 www.Orister.com Page No. : 4/8 Typical Performance Characteristics DS-RS6514-02 March, 2009 www.Orister.com Page No. : 5/8 Typical Performance Characteristics DS-RS6514-02 March, 2009 www.Orister.com Page No. : 6/8 SOP-8/EP (EXPOSED PAD) Dimension NOTE: 1) Control dimension is in inches. Dimension in bracket is millimeters. 2) Exposed Pad Option Only (N-Package) ; 2.55+/- 0.25mm x 3.38 +/- 0.44mm. Recommended Solder Board Area: 2.80mm x 3.82mm = 10.7mm2 (16.6mil2) Ordering Information PART NUMBER RS6514SE DS-RS6514-02 March, 2009 PACKAGE SOP-8/EP www.Orister.com Page No. : 7/8 Soldering Methods for Orister’s Products 1. Storage environment: Temperature=10oC~35oC Humidity=65%±15% 2. Reflow soldering of surface-mount devices Figure 1: Temperature profile tP Critical Zone TL to TP TP Ramp-up TL tL Temperature Tsmax Tsmin tS Preheat Ramp-down 25 t 25oC to Peak Time Profile Feature Sn-Pb Eutectic Assembly Pb-Free Assembly <3oC/sec <3oC/sec 100oC 150oC 60~120 sec 150oC 200oC 60~180 sec <3oC/sec <3oC/sec Time maintained above: - Temperature (TL) - Time (tL) 183oC 60~150 sec 217oC 60~150 sec Peak Temperature (TP) 240oC +0/-5oC 260oC +0/-5oC Time within 5oC of actual Peak Temperature (tP) 10~30 sec 20~40 sec Ramp-down Rate <6oC/sec <6oC/sec <6 minutes <8 minutes Peak temperature Dipping time 245 C ±5 C 5sec ±1sec Average ramp-up rate (TL to TP) Preheat - Temperature Min (Tsmin) - Temperature Max (Tsmax) - Time (min to max) (ts) Tsmax to TL - Ramp-up Rate Time 25oC to Peak Temperature 3. Flow (wave) soldering (solder dipping) Products o Pb devices. Pb-Free devices. DS-RS6514-02 March, 2009 o o o 260 C +0/-5 C 5sec ±1sec www.Orister.com Page No. : 8/8 Important Notice: • All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of Orister Corporation. • Orister Corporation reserves the right to make changes to its products without notice. • Orister Corporation products are not warranted to be suitable for use in Life-Support Applications, or systems. • Orister Corporation assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. DS-RS6514-02 March, 2009 www.Orister.com