AME, Inc. PWM Control 3A Buck Converter AME5107 n General Description n Applications l PC Motherboard AME5107provides 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. l LCD Monitor l Graphic Card l DVD-Video Player l Telecom Equipment l ADSL Modem l Printer and other Peripheral Equipment l Microprocessor core supply l Networking power supply 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-8L mini-package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 18V, it is also suitable for the operation via an AC adapter. n Features l Input voltage: 3.6V to 18V. l Output voltage: 0.8V to VCC. l Duty ratio: 0% to 100% PWM control C l Oscillation frequency: 350KHz typ. l Soft-start, Current limit, Enable function l Thermal Shutdown function l Built-in internal SW P-channel MOS l SOP-8 Package l All AME’ s Lead Free Products Meet RoHS Standards Rev.A.01 S 1 AME, Inc. PWM Control 3A Buck Converter AME5107 n Typical Application Note: VOUT = V FB x (1+RA/RB) RB=0.7K~ 5K Ω VIN =12V,IMAX=3A VOUT 2.5V 3.3V 5V L1 Value 22uH 27uH 33uH n Function Block Diagram SW Oscillation Circuit Reference Voltage Source with Soft Start IN PWM-Switched Control Circuit + - FB Thermal Shutdown VEN 100µA GND EN 2 OCSET Rev.A.01 AME, Inc. PWM Control 3A Buck Converter AME5107 n Pin Configuration SOP-8 Top View 8 7 6 AME5107 5 1. FB 2. EN 3. OCSET AME5107 4. IN 5. SW 6. SW 1 2 3 4 7. GND 8. GND * Die Attach: Conductive Epoxy n Pin Description Pin Number Pin Name Pin Description Output voltage Feedback input. Set the outputCvoltage by selecting values for Ra and Rb using: 1 FB Ra + Rb V OUT = 0 .8V Rb Connect the ground of the feedback network to an AGND (Analog Ground) plane which should be tied directly to the GND pin. Rev.A.01 Enable Control Input, active high. The enable pin is an active high control. Tie this pin above 2V to enable the device. Tie this pin below 0.8V to shut down the device. In shutdown, all function are disabled. Do not leave EN pin floating. 2 EN 3 OCSET 4 IN 5,6 SW Switch Node Connection to Inductor. 7,8 GND Ground. Tie directly to ground plane. Add an external resistor to set max output current. Input Supply Voltage Pin. Bypass this pin with a capacitor. The capacitor shall be placed as close to the device as possible. 3 AME, Inc. PWM Control 3A Buck Converter AME5107 n Ordering Information AME5107 x x x x xxx x Special Feature Output Voltage Number of Pins Package Type Operating Ambient Temperature Range Pin Configuration Pin Configuration A (SOP-8) Operating Ambient Package Type Temperature Range 1. FB 2. EN 3. OCSET 4. IN 5. SW 6. SW 7. GND 8. GND I: -20OC to 85OC H: SOP Number of Pins Output Voltage Special Feature A: 8 ADJ: Adjustable Z: Lead free n Ordering Information Part Number Marking* Output Voltage Package Operating Ambient Temperature Range AME5107AIHAADJZ 5107 AADJ yyww ADJ SOP-8 -20OC to 85OC Note: ww represents the date code. * A line on top of the first letter represents lead free plating such as 5107 AADJ yyww. Please consult AME sales office or authorized Rep./Distributor for the availability of package type. 4 Rev.A.01 AME, Inc. PWM Control 3A Buck Converter AME5107 n Absolute Maximum Ratings Parameter Symbol Maximum Input Supply Voltage IN -0.3V to 22V EN,SW Pin Voltages VEN , VSW -0.3V to 0.3V VFB -0.3V to VIN FB Pin Voltage Unit V TBD* ESD Classification Caution: Stree above the listed absolute maximum rating may cause permanent damage to the device. *HBM B: 2000~3999V n Recommended Operating Conditions Parameter Symbol Rating Unit Ambient Temperature Range TA -20 to 85 o C Junction Temperature Range TJ -20 to 125 o C Storage Temperature Range TSTG -40 to 150 o C C n Thermal Information Parameter Package Thermal Resistance* (Junction to Case) SOP-8 Die Attach Symbol Maximum θJC 60 Unit o Thermal Resistance (Junction to Ambient) SOP-8 Internal Power Dissipation SOP-8 Conductive Epoxy Solder Iron (10 Sec)** θJA 150 PD 810 350 C/W mW o C * Measure θJC on center of molding compound if IC has no tab. ** MIL-STD-202G-210F Rev.A.01 5 AME, Inc. PWM Control 3A Buck Converter AME5107 n Electrical Specifications VIN = 12V, TA = 25oC,Unless otherwise specified. Parameter Test Condition Input Voltage VIN Feedback Voltage VFB IOUT=0.1A FB Pin Bias Current IFB IOUT=0.1A Switch Current ISW Current Consumption During Power Off ISSS Min Typ 3.6 0.782 Max Units 18 V 0.8 0.818 V 0.1 0.5 µA 3.5 A VEN =0V 10 µA Output Voltage Line Regulation REGLINE VIN =5V to 18V 2 4 % Output Voltage Load Regulation REGLOAD IOUT=0.1A to 3A 0.2 0.5 % 350 400 KHz Oscillator Frequency fOSC Frequency of Current Limit or Short Circuit Protect fOSC1 Enable High (enabled) VIH_EN Measure wave form at SW pin Measure wave form at SW pin Evaluate oscillation at SW pin Evaluate oscillation stop at SW pin 300 10 KHz 2.0 V Enable Low (shutdown) VIL_EN EN High Input Current IIH_EN 20 µA EN Low Input Current IIL_EN -10 µA OCSET Pin Bias Current IOCSET 75 90 105 µA t SS 0.3 2 5 mS VIN =5V 110 150 VIN =12V 70 100 Soft Start Time Internal MOSFET RDSON 6 Symbol RDSON VFB=0V 0.8 mΩ Rev.A.01 AME, Inc. PWM Control 3A Buck Converter AME5107 n Detailed Description PWM Control The AME5107 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of the AME5107, 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 AME5107 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 x RDS(ON) =IOCSET x ROCSET See above formula for setting the current limit value. C Rev.A.01 7 AME, Inc. PWM Control 3A Buck Converter AME5107 n Characterization Curve(For reference only) Vin vs. FB Line Regulation 0.84 3.40 0.83 3.35 0.82 0.81 V OUT(V) VFB(V) 3.30 0.80 0.79 0.78 3.25 3.20 0.77 VIN =12V 0.76 VOUT=3.3V 0.75 V OUT =3.3V 3.15 I OUT =0.2A 0.74 0 2 4 6 8 10 12 14 16 IOUT =0.2A 3.10 18 0 2 4 6 8 10 12 VIN(V) VI N (V) Load Regulation VIN v.s Frequency 5.1 14 16 18 380 5.0 375 4.9 370 Fosc (KHZ) VOUT ( V ) 4.8 4.7 4.6 4.5 365 360 355 4.4 350 4.3 4.1 0 340 0.5 1 1.5 2 2.5 V OUT=3.3V 345 VIN =12V 4.2 3 IOUT =0.2A 0 2 4 6 8 10 IOUT ( A ) V IN (V) Efficiency Vout Ripple 12 14 16 18 100 90 Efficiency (% ) 80 VOUT=5V 70 VOUT =3.3V V SW 5V /div VOUT 20 mV/div 60 50 40 30 VIN = 12V V OUT= 3.3V I OUT=0.1A 20 10 0 8 0.5 1 1.5 IOUT ( A ) 2 2.5 3 Rev.A.01 AME, Inc. PWM Control 3A Buck Converter AME5107 n Characterization Curve(For reference only) Vout Ripple Frequency of short current protect VSW 5V/div VSW VOUT 5V/div 20mV/div VIN =12V VOUT=3.3V I OUT=3A Soft start time VOUT VIN =12V 2 V/div VO U T=5V ILOAD=3A V SW 5 V/div EN 5 V/div C Rev.A.01 9 AME, Inc. PWM Control 3A Buck Converter AME5107 n Tape and Reel Dimension SOP-8 P PIN 1 W AME AME Carrier Tape, Number of Components Per Reel and Reel Size 10 Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size SOP-8 12.0±0.1 mm 4.0±0.1 mm 2500pcs 330±1 mm Rev.A.01 AME, Inc. PWM Control 3A Buck Converter AME5107 n Package Dimension SOP-8 Side View Top View C SYMBOLS MAX MIN MAX A 1.35 1.75 0.05315 0.0689 A1 0.10 0.30 0.00394 0.01181 A2 L D θ INCHES MIN E H MILLIMETERS 1.473 REF 0.05799 REF B 0.33 0.51 0.01299 0.02008 0.19 0.25 0.00748 0.00984 D 4.80 5.33 0.18898 0.20984 7o(4X) E 3.80 4.00 0.14961 0.15748 e 1.27 BSC A e A1 A2 C Front View B 0.05000 BSC L 0.40 1.27 0.01575 0.05000 H 5.80 6.30 0.22835 0.24803 y - 0.10 θ 0 o 8 o 0 o 0.00394 8 o C Rev.A.01 11 www.ame.com.tw E-Mail: [email protected] Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. AME, Inc. , December 2007 Document: ORT6513-DS5107-A.01 Corporate Headquarter U.S.A. (Subsidiary) AME, Inc. Analog Microelectronics, Inc. 2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan. Tel: 886 2 2627-8687 Fax: 886 2 2659-2989 3100 De La Cruz Blvd., Suite 201 Santa Clara, CA. 95054-2438 Tel : (408) 988-2388 Fax: (408) 988-2489