Technology ACE707A Micro Power Step-up DC-DC Converter Description The ACE707A are Pulse Frequency Modulation (PFM) DC/DC converters. These two devices are functionally equivalent except the switching current limit. The ACE707A is for lower power systems with 100mA current limit. The ACE707A feature a wide input voltage. The operation voltage is ranged from 1V to 12V. A current limited, fixed off-time control scheme conserves operating current, resulting in high efficiency over a broad range of load current. They also feature low quiescent current, switching current limiting, low temperature coefficient, etc. Fewer tiny external components are required in the applications to save space and lower cost. Furthermore, to ease its use in different systems, a disable terminal is designed to turn on or turn off the chip. The ACE707A are available in SOT-23-5 package. Features • • • • • • • Low Quiescent Current In Active Mode (Not Switching): 17μA Typical ,In Shutdown Mode: < 1μA Low Operating VIN 1.0V Typical for ACE707A Low VCESAT Switch 70mV Typical at 70mA for ACE707A High Output Voltage: up to 34V Fixed Off-Time Control Switching Current Limiting 100mA Typical for ACE707A Operating Temperature Range: -40℃ to 85℃ Application • • • • • MP3, MP4 Battery Power Supply System LCD/OLED Bias Supply Handheld Device Portable Communication Device VER 1.2 1 Technology ACE707A Micro Power Step-up DC-DC Converter Absolute Maximum Ratings Parameter Symbol Max Unit Input voltage VIN 15 V SW Voltage VSW 36 V FB Voltage VFB VIN V 15 V 265 ℃/W 150 ℃ SHDN Pin Voltage VSHDN Thermal Resistance (Junction to Ambient, no Heat sink) RθJA Operating Junction Temperature TJ Storage Temperature Range TSG Lead Temperature (Soldering, 10sec) TLEAD ESD (Human Body Model) -65 TO 150 ℃ 260 ℃ 3000 V 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 SOT-23-5 5 1 4 2 3 Pin SOT-23-5 SW 1 GND 2 Function Switch Pin. This is the collector of the internal NPN power switch. Minimize the trace area connected to this Pin to minimize EMI Ground Pin. GND should be tied directly to ground plane for best performance Feedback Pin. Set the output voltage through this pin. The formula is FB 3 VOUT=1.23V*(1+R1/R2). Keep the loop between Vout and FB as short as possible to minimize the ripple and noise, which is beneficial to the stability and output ripple SHDN 4 VIN 5 Shutdown Control Pin. Tie this pin above 0.9V to enable the device. Tie below 0.25V to turn off the device Supply Input Pin. Bypass this pin with a capacitor as close to the device as possible VER 1.2 2 Technology ACE707A Micro Power Step-up DC-DC Converter Ordering Information Selection Guide ACE707A XX + H Halogen - free Pb - free BN : SOT-23-5 Functional Block Diagram Recommended Work Conditions Item Symbol Min Max Unit Input voltage VIN 1.0 12ut V Operating Temperature TA -40 85 ℃ VER 1.2 3 Technology ACE707A Micro Power Step-up DC-DC Converter Electrical Characteristics VIN=VSHDN=1.2V, TA=25℃, unless otherwise specified. Parameter Input Voltage Symbol VIN Quiescent Current IQ Feedback Voltage FB Comparator Hysteresis FB Pin Bias Current Output Voltage Line Regulation Switching Current Limit Switch Saturation Voltage VFB VFBH IFB LNR IL VCESAT Switch Off Time TOFF SHDN Input Threshold High SHDN Input Threshold Low Test Conditions Min 1.0 Not Switching VSHDN=0V Typ 17 1.205 VFB=1.23V 1.2V<VIN<12V 75 ISW=70mA VFB>1V VFB<0.6V 1.23 8 30 0.05 100 70 400 1.5 Max 12 30 1 1.255 80 0.1 125 120 Unit V μA V mV nA %/V mA mV nS μS 0.9 VTH V 0.25 VTL SHDN Pin Current ISHDN Switch Leakage Current ISWL VSHDN=1.2V VSHDN=5V Switch Off, VSW=5V 2 8 0.01 3 12 5 μA μA VER 1.2 4 Technology ACE707A Micro Power Step-up DC-DC Converter Typical Performance Characteristics Unless otherwise note, VIN=1.2V Junction Temperature (℃) Junction Temperature (℃) Figure 1. Quiescent Current vs. Junction Temperature Junction Temperature (℃) Figure 2. Feedback Voltage vs. Junction Temperature Shutdown Pin Voltage (V) Figure 3. Switch Off Time vs. Junction Temperature ACE707A Junction Temperature (℃) Figure 5. Switch Current Limit vs. Junction Temperature Figure 4. Shutdown Pin Current vs. Shutdown Pin Voltage ACE707A Junction Temperature (℃) Figure 6. Switch Current Limit vs. Junction Temperature VER 1.2 5 Technology ACE707A, ISMITCH=300mA Junction Temperature (℃) Figure 7. Saturation Voltage vs. Junction Temperature ACE707A Micro Power Step-up DC-DC Converter ACE707A, ISMITCH=70mA Junction Temperature (℃) Figure 8. Saturation Voltage vs. Junction Temperature Load Current (mA) Load Current (mA) Figure 9. Efficiency Figure 10. Efficiency Application Information Operating Principles ACE707A feature a constant off-time control scheme. Refer to Figure 3， the bandgap voltage VREF (1.23V typical) is used to control the output voltage. When the voltage at the FB pin drops below the lower hysteresis point of Feedback Comparator (typical hysteresis is 8mV), the Feedback Comparator enables the chip and the NPN power switch is turned on, the current in the inductor begins to ramp up and store energy in the coil while the load current is supplied by the output capacitor. Once the current in the inductor reaches the current limit, the Current-Limit Comparator resets the 400ns One-Shot which turns off the NPN switch for 400ns. The SW voltage rises to the output voltage plus a diode drop and the inductor current begins to ramp down. During this time the energy stored in the inductor is transferred to COUT and the load. After the 400ns off-time, the NPN switch is turned on and energy will be stored in the inductor again. This cycle will continue until the voltage at FB pin reaches 1.23V, the Feedback Comparator disables the chip and turns off the NPN switch. The load current is then supplied solely by output capacitor and the output voltage will decrease. When the FB pin voltage drops below the lower hysteresis point of Feedback Comparator, the Feedback Comparator enables the device and repeats the cycle described previously. Under not switching condition, the IQ of the device is about 17μA. VER 1.2 6 Technology ACE707A Micro Power Step-up DC-DC Converter The ACE707A contain additional circuitry to provide protection during start-up or under short-circuit conditions. When the FB pin voltage is lower than approximately 0.6V, the switch off-time is increased to 1.5μs and the current limit is reduced to about 250mA (70mA for ACE707A). This reduces the average inductor current and helps to minimize the power dissipation in the ACE707A power switch, in the external inductor and in the diode. The SHDN pin can be used to turn off the ACE707A and reduce the IQ to less than 1μA. In shutdown mode the output voltage will be a diode drop below the input voltage. Typical Application Vin 2.5V to 4.2V L1 10uH D1 SS14 Vout 20V R1 2M C1 4.7 uF Vin SW ACE707A SHEN FB GND C2 1uF RLOAD R2 130K C1, C2: X5R or X7R Ceramic Capacitor L1: SUMIDA CDRH4D16FB/NP-100MC or Equivalent Figure 11. ACE707A Typical Application in LCD/OLED Bias Supply ACE707A C1, C2, C3: X5R or X7R Ceramic Capacitor L1: SUMIDA CDRH4D16FB/NP-100MC or Equivalent Figure 12. ACE707A Typical Application in 1 or 2 Cells to 3.3V Boost Converter VER 1.2 7 Technology ACE707A Micro Power Step-up DC-DC Converter Packing Information SOT-23-5 VER 1.2 8 Technology ACE707A Micro Power Step-up 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