ACE722 2A Step-down DC-DC Converter Description ACE722 is a current mode PWM step-down DC-DC converter, which has an internal 2A power switch. It has the wide input voltage range of 3.6V to 20V, so it can suit for regulating a wide variety of power source. ACE722 make of a PWM control circuit, a reference voltage unit, an error amplifier, a protection circuit, Chip Enable circuit, and under voltage lockout circuit. A low ripple, high efficiency step-down DC-DC converter can be easily composed of this IC with only several external components, or an inductor, a diode and capacitors. Output Voltage can be adjusted with external resistors. ACE722 has the cycle-by-cycle current limit circuit; current limiting provides protection against shorted output. The low current (<5uA) shutdown provides complete output disconnect, enabling easy power management in battery powered systems. Features Range of Input Voltage: 3.6V~20V Built-in 90mΩ Power MOSFET <5uA Shutdown Current Oscillation Frequency: 500KHz High efficiency: 90% 2.5A Peak Current Limit Cycle by Cycle Operating Temperature Range: -40℃ ~85℃ Demo Board Available Application Power source for hand-held communication equipment, cameras video instruments such as VCRs, camcorders. Power source for battery-powered equipment Power source for household electrical appliance Absolute Maximum Ratings Parameter Max Unit Supply Voltage 23 V SW Pin Voltage 25 V CE Pin Voltage -0.3V to Vin+0.3V V FB Pin Voltage -0.3V to 6V V Operating Ambient Temperature Range -40 OC to 85 OC O O Storage temperature - 65 C to 150 C Thermal resistance: θJA 150 O O C O C C/W VER 1.6 1 ACE722 2A Step-down DC-DC Converter Packaging Type SOP-8 Description SOP-8 1 8 2 7 3 6 4 5 Function 1 NC Not Connected 2 VIN Power Supply Pin 3 SW Switching Node: PWM output connection to inductor 4 GND Ground Pin 5 FB Pin for Feedback Voltage 6 NC Not Connected 7 CE Chip Enable Pin (Active with “H”) 8 NC Not Connected Pin Description ACE722 XX + H Halogen - free Pb - free FM : SOP-8 Block Diagram VER1.6 2 ACE722 2A Step-down DC-DC Converter Electrical Characteristics (Test Conditions: TA=25℃, VIN=12V, unless otherwise noted.) Parameter Symbol Under Voltage Lockout VUVLO Feedback Voltage VFB FB Pin Bias Current IFB Supply Current Quiescent Current in Shutdown Reference Line Regulation Typ Max Units 3.35 3.6 V 1.25 1.275 V VFB=1.25V 150 600 nA VFB=1.3V, VCE=VIN 2 VCE=0V 2 △VFB/△V VIN=5V to 20V 0.08 %/V IQ Conditions Min 1.225 mA 5 uA Feedback Voltage Temperature Coefficient Oscillator Frequency △VFB/△T -40℃≦Topt≦85℃ ±100 ppm/℃ FOSC_MAX VFB=1.1Vvfb 500 KHz Frequency Shift Threshold on FB Pin FOSCTH FSW=200K 0.44 V Max Duty Cycle DMX 97 % Switch Current Limit Static P-Channel MOSFER On State Resistance Switch Leakage Current ILIMIT 2.5 A Rds_on 90* mΩ CE “H” Input Current ICEH VCE=3V CE “L” Input Current ICEL VCE=0V CE “H” Input Voltage VCEH VIN=12V CE “L” Input Voltage VCEL VIN=12V ISW 1 uA 6.7 15 uA 0.03 0.1 uA 1.8 V 0.4 V Typical Application VER1.6 3 ACE722 2A Step-down DC-DC Converter Demo Board Bom No. Reference Type Specification 1 C1 Capacitor MLCC 10uF; SMD 0805 2 C2 Capacitor MLCC 10uF; SMD 0805 3 D1 Diode SS34; 40V, 3A; SMD, Shielding 4 L1 Inductor 10uH; 3A; SMD; Shielding 5 IC1 IC ACE722; SMD SOP-8 6 R1 Resistor SMD 0805; 30K; 1% 7 R2 Resistor SMD 0805; 10K; 1% Note Layout consideration Careful PCB layout is critical to achieving low switching losses and clean, stable operation. The switching power stage requires particular attention. If possible, mount all the power components on one side of the board, with their ground terminals as close to one another as possible. Keep the high-current paths short, especially the distance between Cin and the Vin (GND) terminals. It is essential for stable, jitter-free operation, showing as the following figure. The ESR of Cin should be smaller enough and the capacitance of Cin should be large enough for filtering the switching noise across power path, a 10uF ceramic capacitor is recommended. Keep the trace connecting to SW terminal wide enough for heat dissipation, if possible, it is better to place some vias connected to the bottom copper for enhancement. Route high-speed switching nodes, for example SW terminal, away from sensitive analog trace (eg. FB terminal). VER1.6 4 ACE722 2A Step-down DC-DC Converter Demo Board Measurement Efficiency vs. Load Current (VOUT=5V) Load Regulation (VOUT=5V) Load Current (mA) Load Current (mA) CE Pin Bias Current vs. CE Pin Voltage Feedback Voltage vs. Supply Voltage CE Pin Voltage (V) Supply Voltage (V) Quiesent Current vs. Supply Voltage Supply Current vs. Supply Voltage (VCE=0V) Supply Voltage (V) (VFB=1.3V, VCE=VIN) Supply Voltage (V) VER1.6 5 ACE722 2A Step-down DC-DC Converter Frequency vs. Temperature Feedback Voltage vs. Temperature Temperature Temperature Transient Loading Response VER1.6 6 ACE722 2A Step-down DC-DC Converter Packing Information SOP-8 VER1.6 7 ACE722 2A Step-down 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/ VER1.6 8