ACE722A Technology 2A PWM BUCK DC-DC Converter Description ACE722A is a 420kHz fixed frequency PWM buck (step-down) DC-DC converter, capable of driving a 2A load with high efficiency, low ripple and excellent line and load regulation. The device includes a voltage reference, an oscillation circuit, an error amplifier, an internal PMOS and etc. The PWM control circuit is able to adjust the duty ratio linearly from 0 to 100%. The enable function, over current protection function, short circuit protection function and soft-start function are built inside. When OCP or SCP happens, the operation frequency will be reduced from 420kHz to 40kHz. An internal compensation block is employed to minimize external components. The ACE722A serves as an ideal power supply unit for portable devices, especially for chip set power in portable systems. It’s widely used for PDVD, LCD monitor and DPF chip set powers. Features • • • • • • • • • • 2A Constant Output Current 130mΩ RDSON Internal Power MOSFET Switch Up to 94% Efficiency Fixed 420kHz Frequency Wide 4.75V to 25V Input Voltage Range Output Voltage Adjustable from 0.8V to 21V Built in Thermal Shutdown Function Built-in Current Limit Function Built-in Soft-Start Function Support Ceramic or Electrolytic Capacitors Application • • • • • Portable DVE LCD Monitor/LCD TV Digital Photo Frame ADSL Set-up Box Absolute Maximum Ratings Parameter Symbol Max Unit Input Voltage FB Pin Voltage VIN VFB -0.3 to 30 -0.3 to 6 V V EN Pin Voltage VEN -0.3 to VIN V COMP Pin Voltage VCOMP -0.3 to 6 V SW Pin Voltage VSW -0.3 to VIN V Power Dissipation PD Internally Limited mW O Thermal Resistance (Junction to Ambient, No Heat Sink, Free AIR) θJA 100 C/W O Operating Junction Temperature TJ 150 C O Storage Temperature TSTG -65 to 150 C O Lead Temperature (Soldering, 10sec) TLEAD 260 C ESD (Human Body Model) ESD 2000 V VER 1.2 1 ACE722A Technology 2A PWM BUCK DC-DC Converter Note 1: Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability. Packaging Type SOP-8 1 8 2 7 3 6 4 5 Pin SOP-8 1 NC 2 VIN 3 4 SW GND Function Not Connected Supply Voltage Input Pin. ACE722A operates from a 4.75V to 25V DC voltage. Bypass VIN to GND with a suitable large capacitor to eliminate noise on the input. Power Switch Output Pin. SW is the switch node that supplies power to the output. Ground Pin Feedback Pin. Through an external resistor divider network, FB senses the output voltage 5 FB and regulates it. To prevent current limit run away in a short circuit fault condition, the frequency feedback comparator lowers the oscillator frequency to 40kHz when the FB voltage is below 0.52V. The feedback threshold voltage is 0.8V. 6 COMP 7 EN 8 NC Compensation Pin. This pin is the output of the error amplifier. Frequency compensation is done at this pin by connecting a series RC to ground (parallel a C if necessary) Enable Pin. Drive EN pin high to turn on the device, drive it low to turn off. Default of this pin is high level. Not Connected VER 1.2 2 ACE722A Technology 2A PWM BUCK DC-DC Converter Ordering information Selection Guide ACE722A XX + H Halogen - free Pb - free FM : SOP-8 Block Diagram Recommended Operating Conditions Parameter Symbol Min Max Unit Input Voltage VIN 4.75 25 V Output Voltage VOUT 0.8 21 V Operating Junction Temperature TJ -40 125 ℃ VER 1.2 3 ACE722A Technology 2A PWM BUCK DC-DC Converter Electrical Characteristics (Vcc=12V, VOUT=5V, TA=25℃, unless otherwise noted.) Parameter Input Voltage Shutdown Quiescent Current Quiescent Current Feedback Voltage Feedback Bias Current Switch Current Limit Oscillator Frequency Frequency of Current Limit or Short Circuit Protection Error Amplifier Voltage Gain Error Amplifier Transconductance Symbol VIN ISHDN IQ VFB IFB ILIM fosc VEN=0.4V VEN=2V, VFB=1.3V VIN=5V to 25V VFB=1.3V fosc1 VFB<0.52V EN Pin Input Leakage Current GV GS VH VL IEN Internal PMOS ON Resistance RDSON Maximum Duty Cycle DMAX Thermal Shutdown Thermal Shutdown Hysteresis TOTSD THYS EN Pin Threshold Conditions Min 4.75 0.784 2.5 336 Typ 44 1.3 0.8 -0.1 3.4 420 Max Units 25 V 60 μA 2 mA 0.816 V -0.5 μA A 504 kHz 40 kHz 1000 700 -5 0.7 -10 V/V μA/V V V μA 130 150 mΩ 100 % 1.5 VEN=2.5V VIN=12V VFB=0.65V VEN=12V,IOUT=2A VFB=0.65V, ISW=0.1A 155 20 ℃ ℃ Typical Performance Characteristics VCC=12V, VOUT=5V, TA=25℃, unless otherwise specified Output Current (A) Figure 1. Efficiency vs. Output Current Temperature (℃) Figure 2. Operation Frequency vs. Temperature VER 1.2 4 ACE722A Technology Input Voltage (V) Figure 3. Supply Quiescent Current vs. Input Voltage Input Voltage (V) Figure 5. Shutdown Quiescent Current vs. Input Voltage Temperature (℃) Figure 7. Feedback Voltage vs. Temperature 2A PWM BUCK DC-DC Converter Input Voltage (V) Figure 4. Efficiency vs. Input Voltage Temperature (℃) Figure 6. OCP Current Limit vs. Temperature Input Voltage (V) Figure 8. OCP Current Limit vs. Input Voltage VER 1.2 5 ACE722A Technology Temperature (℃) 2A PWM BUCK DC-DC Converter Output Current (A) Figure 9. OCP Frequency vs. Temperature Figure 10. Output Voltage vs. Output Current Typical Application (VIN=12V, VOUT=5V, IOUT=2A) ACE722A Figure 11. Typical Application 1 of ACE722A Applied with Ceramic Input and Output Capacitors VER 1.2 6 ACE722A Technology 2A PWM BUCK DC-DC Converter ACE722A Figure 12. Typical Application 2 of ACE722A Applied with Electrolytic Input and Output Capacitors VER 1.2 7 ACE722A Technology 2A PWM BUCK DC-DC Converter Packing Information SOP-8 VER 1.2 8 ACE722A Technology 2A PWM BUCK DC-DC Converter Notes ACE does not assume any responsibility for use as critical components in life support devices or systems without the express written approval of the president and general counsel of ACE Electronics Co., LTD. As sued herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and shoes failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. ACE Technology Co., LTD. http://www.ace-ele.com/ VER 1.2 9