AP1509 150KHz, 2A PWM BUCK DC/DC CONVERTER Description Pin Assignments The AP1509 series are monolithic IC designed for a step- (Top View) down DC/DC converter, and own the ability of driving a 2A load without additional transistor. It saves board space. The external shutdown function can be controlled by logic V GND 1 8 IN level and then come into standby mode. The internal compensation makes feedback control having good line and GND 7 Output 2 load regulation without external design. Regarding protected AP1509 function, thermal shutdown is to prevent over temperature FB 3 6 GND operating from damage, and current limit is against over current operating of the output switch. If current limit function SD 4 5 GND occurs and V is down below 0.5V, the switching frequency FB will be reduced. The AP1509 series operates at a switching frequency of 150KHz thus allow smaller sized filter SOP-8L components than what would be needed with lower frequency switching regulators. Other features include a guaranteed +4% tolerance on output voltage under specified input voltage and output load conditions, and +15% on the oscillator frequency. The output version included fixed 3.3V, 5V, 12V, and an adjustable type. The chips are available in a standard 8-lead SOP-8 package. Features Applications Simple High-Efficiency Step-Down Regulator Output Voltage: 3.3V, 5V, 12V and Adjustable Output On-Card Switching Regulators Version Positive to Negative Converter Adjustable Version Output Voltage Range, 1.23V to 18V+4% 150KHz +15% Fixed Switching Frequency Voltage Mode Non-Synchronous PWM Control Thermal-Shutdown and Current-Limit Protection ON/OFF Shutdown Control Input Operating Voltage can be up to 22V Output Load Current: 2A SOP-8L Packages Low Power Standby Mode Built-in Switching Transistor On Chip SOP-8L: Available in Green Molding Compound (No Br, Sb) Lead Free Finish/ RoHS Compliant (Note 1) Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at AP1509 150KHz, 2A PWM BUCK DC/DC CONVERTER Typical Application Circuit (1) Fixed Type Circuit FB 12V 3 3.3V/2A L1 DC Input 47uH Output Output Load AP1509- 12 V Inductor 33 IN 4 56 7 8 SD GND GND GND GND Co C IN D1 Capacitor Capacitor Schottky Diode (2) Adjustable Type Circuit R2 1K R1 1K FB 12V L1 3 2.5V/2A DC Input 39uH Output Output Load 12AP1509 V Inductor IN 4 56 7 8 D1 SD GND GND GND GND C Co IN Schottky Capacitor Capacitor Diode R1 V = V (1 + ) OUT FB R2 V = 1.23V FB R2 = 1K ~ 3K (3) Delay Start Circuit R2 1K R1 1K FB 12V L1 3 2.5V/2A DC Input 39uH Output Output Load V IN 12AP1509 Inductor C DELAY 4 56 7 8 0.1uF D1 SD GND GND GND GND Co Schottky R DELAY Capacitor C IN Diode 10K Capacitor 2 of 13 June 2010 AP1509 Diodes Incorporated www.diodes.com Document number: DS31016 Rev. 4 - 2