AP1522 Step-Up DC/DC Converter Features General Description - High Efficiency: 84% Typical - 36V High Output Voltage - Fast 1MHz Switching Frequency - Low Profile SOT23-5 Pb-Free Packaging The AP1522 is a step-up DC/DC converter in a 5-Lead low profile SOT23-5 package. The AP1522 switches at 1MHz that allows the use of tiny external components. A low 1.25V feedback voltage minimizes power loss in the current setting resistor for better efficiency. Applications - Cellular Phones - PDAs, Handhelp Computers - Digital Cameras - LCD Bias Voltage, Battery Backup - Pin Descriptions Pin Assignments Name Top View VIN SHDN SW VSS FB SHDN SW VSS FB VIN SOT23-5L Description Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. GND pin Feedback Pin. Reference voltage is 1.25V. Shutdown Pin. Tie to 0.6V or higher to enable device ； 0.5Vor less to disable device. Input Supply Pin. Must be locally bypassed. Ordering Information AP1522 X X Package Packing W: SOT23-5L Blank : Tube A : Taping This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product. Rev. 1.0 May. 5, 2005 1/8 AP1522 Step-Up DC/DC Converter Block Diagram 1 SW Comparator Driver A2 + - A1 R S Q Q1 RC + CC FB 3 + VREF 1.25V Σ - VIN 5 RAMP Generator 2 GND Shutdown SHDN 4 1MHz Oscillator Absolute Maximum Ratings Symbol Parameter Rating Unit VIN VIN Pin Voltage 10 V VSW SW Voltage 36 V VFB Feedback Pin Voltage 10 V VSHDN TJ TLEAD TOPR SHDN Pin Voltage 10 Maximum Junction Temperature 125 o C 300 o C -40 to +85 o C Power Dissipation Operating Temperature Range V o TSTG Storage Temperature Range -40 to +125 C Caution The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Anachip Corp. www.anachip.com.tw Rev. 1.0 2/8 May. 5, 2005 AP1522 Step-Up DC/DC Converter Electrical Characteristics (Ta=25°C, VIN = 5V, VSHDN = 5V, unless otherwise noted.) Symbol VIN VIN VFB IFB Parameter Minimum Operation Voltage Maximum Operation Voltage Feedback Pin Voltage Feedback Pin Bios Current Conditions Operation current Supply Current VSHDN = 0V Min. 2.5 1.225 10 - Typ. 1.25 45 2 Max. 10 1.275 100 3 Unit V V V nA mA - 0.1 1.0 µA FSW Switching frequency 0.75 1.0 1.25 MHz Duty ISW VSAT PWM Maximum Duty Cycle Switch Current Limit Switch VSAT Switch Leakage Current SHDN Pin Voltage High SHDN Pin Voltage Low SHDN Pin Bios Current 85 280 0.6 - 90 320 350 0.1 10 360 5 0.5 - % mA mV µA V V µA VSHDN VSHDN ISHDN ISW = 250mA VSW = 5V Enable Disable Typical Application Circuit L1 10uH D1 Vout=10V C2 4.7uF Vin=3.3V C1 4.7uF Option R1 70K Vin SW Vss R2 10K FB SHDN ON OFF R1 ) R2 1K < R2 < 50K VOUT=VFB (1+ Anachip Corp. www.anachip.com.tw Rev. 1.0 3/8 May. 5, 2005 AP1522 Step-Up DC/DC Converter Typical Application Circuit (Continued) Step up DC-DC Regulator L 22uH VIN 2.5V~3.3V VIN CIN 4.7uF VOUT 4.8V D 57K SW AP1522 4.7pF FB SHDN COUT 4.7uF 20K GND 1-Cell Li-lon to 3.3V SEPIC Converter L1 10uH VIN 2.5V to 4.2V C3 1uF 5 1 VIN SW C1 4.7uF AP1522 4 D1 3.3V 50mA L2 33K 10uH 4.7pF C2 10uF 3 FB SHDN 20K GND 2 4-Cell to 5V SEPIC Converter L1 10uH VIN 3V to 6V C1 4.7uF C3 1uF 5 1 VIN SW AP1522 4 FB D1 5V 40mA L2 10uH 30K 4.7pF C2 10uF 3 SHDN 10K GND 2 Anachip Corp. www.anachip.com.tw Rev. 1.0 4/8 May. 5, 2005 AP1522 Step-Up DC/DC Converter Typical Application Circuit (Continued) +20V Dual Output Converter with Output Disconnect D3 C4 1uF D2 C5 1uF D1 L1 10uH VIN 2.5V to 5V C1 4.7uF 5 1 VIN SW AP1522 4 -20V 4mA C3 1uF FB D4 20V 4mA 150K 4.7pF C2 10uF 3 SHDN 10K GND 2 Applications Information Open-Circuit Protection In the cases of output open circuit, when the R1 are disconnected from the circuit, the feedback voltage will be zero. The AP1522 will then switch at a high duty cycle resulting in a high output voltage, which may cause the SW pin voltage to exceed its maximum 36V rating. A zener diode can be used at the output to limit the voltage on the SW pin (Figure 1). The zener voltage should be larger than the maximum forward voltage of the VOUT. The current rating of the zener should be larger than 0.1mA. Inductor Selection A 10µH inductor is recommended for most AP1522 applications. Although small size and high efficiency are major concerns, the inductor should have low core losses at 1MHz and low DCR (copper wire resistance). Capacitor Selection The small size of ceramic capacitors makes them ideal for AP1522 applications. X5R and X7R types are recommended because they retain their capacitance over wider voltage and temperature ranges than other types such as Y5V or Z5U. A 4.7µF input capacitor and a 4.7µF output capacitor are sufficient for most AP1522 applications. L 22uH V IN Diode Selection Schottky diodes, with their low forward voltage drop and fast reverse recovery, are the ideal choices for AP1522 applications. The forward voltage drop of a Schottky diode represents the conduction losses in the diode, while the diode capacitance (CT or CD) represents the switching losses. For diode selection, both forward voltage drop and diode capacitance need to be considered. Schottky diodes with higher current ratings usually have lower forward voltage drop and larger diode capacitance, which can cause significant switching losses at the 1MHz switching frequency of the AP1522. A Schottky diode rated at 100mA to 200mA is sufficient for most AP1522 applications. D COUT 2uF R1 200K 4.7pF C IN 1uF VIN SW AP1522 SHDN GND FB R2 1K R3 14K Figure 1. With Open-Circuit Protection Anachip Corp. www.anachip.com.tw Rev. 1.0 5/8 May. 5, 2005 AP1522 Step-Up DC/DC Converter Typical Performance Characteristics Feedback Voltage v.s. Temperature Vin=5V; Vout=15V 1.26 1000 900 800 700 600 500 400 300 200 100 0 Feedback Voltage (V) Frequency (KHz) Frequency v.s. Temperature Vin=5V; Vout=15V 1.25 1.24 1.23 1.22 -40 10 60 110 -40 o 60 110 Temperature ( C) Supply Current v.s. Temperature Vin=5V; Vout=15V; Iout=0A Supply Current v.s. Supply Voltage Vout=15V; Iout=0A 3 3 2.5 2.5 Supply Current (mA) Supply Current (mA) 10 o Temperature ( C) 2 1.5 1 0.5 2 1.5 1 0.5 0 0 -40 10 o 60 Temperature ( C) 0 110 5 10 15 Supply Voltage (V) Efficiency v.s. Output Current Vin=5V; Vout=15V Efficiency v.s. Output Current Vin=3.3V; Vout=15V 90 85 Efficiency (%) Efficiency (%) 85 80 75 70 75 65 55 0 20 40 Output Current (mA) 0 60 20 40 60 Output Current (mA) Anachip Corp. www.anachip.com.tw Rev. 1.0 6/8 May. 5, 2005 AP1522 Step-Up DC/DC Converter Typical Performance Characteristics (Continued) Frequency v.s. Supply Voltage Vout=15V 1200 Frequency (KHz) 1000 800 600 400 200 0 0 2 4 6 8 Supply Voltage (V) 10 12 Marking Information 4 7 5 XX Y M Identification code (See Appendix) 1 2 3 Appendix Part Number AP1522 Month: A~L Package SOT23-5 Identification Code FA Year: 0-9 Anachip Corp. www.anachip.com.tw Rev. 1.0 7/8 May. 5, 2005 AP1522 Step-Up DC/DC Converter Package Information Package Type: SOT23-5L D e1 θ1(4x) 4 5 E1 A E 0.10 C 5x A2 Seating Plane A1 1 2 θ 2(4x) 3 b e With Plating b1 C C1 Gauge Plane 0.25 mm θ Base Metal L b Symbol L1 Dimensions In Millimeters Dimensions In Inches Min. Nom. Max. Min. Nom. Max. A 1.05 1.20 1.35 0.041 0.047 0.053 A1 0.05 0.10 0.15 0.002 0.004 0.006 A2 1.00 1.10 1.20 0.039 0.043 0.047 b 0.25 - 0.55 0.010 - 0.022 b1 0.25 0.40 0.45 0.010 0.016 0.018 c 0.08 - 0.20 0.003 - 0.008 c1 0.08 0.11 0.15 0.003 0.004 0.006 D 2.70 2.85 3.00 0.106 0.112 0.118 E 2.60 2.80 3.00 0.102 0.110 0.118 E1 1.50 1.60 1.70 0.059 0.063 0.067 L 0.35 0.45 0.55 0.014 0.018 0.022 L1 0.60 Ref. 0.024 Ref. e 0.95 Bsc. 0.037 Bsc. e1 θ 0o 1.90 Bsc. 5o 10o 0o 0.075 Bsc. 5o 10o θ1 3o 5o 7o 3o 5o 7o θ2 6o 8o 10o 6o 8o 10o Anachip Corp. www.anachip.com.tw Rev. 1.0 8/8 May. 5, 2005