G5503 Global Mixed-mode Technology Inc. 300KHz, 3A Buck Converter The G5503 is a voltage-mode buck PWM converter capable of driving up to 3A loads over a wide input supply range. High efficiency is obtained through the use of a low RDS(ON) P-channel power switch. The internal compensation makes feedback control have excellent line and load regulation characteristics without external designs. Features Voltage Mode Asynchronous PWM Control 3.3V, 5V and Adjustable Output Version Operation Voltage can be up to 20V Adjustable Version Output Voltage Range, 0.8V to 16V±2% 300KHz Fixed Frequency Internal Oscillator Built-in Switching Transistor on Chip 3A Output Load Current Thermal Shutdown and Current Limit Protection ON/OFF Shutdown Control Iq of Low Power Standby Mode 1µA Available in SOP-8 Packages It uses a fixed switching frequency of 300KHz. The output voltage is 3.3V, 5V and an user-programmable version via an external resistive voltage divider. The built-in soft-start can reduce inrush current on the input source at turn on. The device also has built-in current-limit, thermal shutdown, under-voltage lockout and an ON/OFF logic-control that can power down the regulator to a shutdown mode. When current limit function occurred and VFB is down to 0.3V below, the device changes switching frequency to 120KHz to protect IC from damage. Applications Simple high-efficiency step-down regulator On-card switching regulators Positive to negative converter G5503 is available in SOP-8 package. General Description Ordering Information ORDER NUMBER MARKING VOLTAGE TEMP. RANGE PACKAGE (Pb free) G5503-ADJP11U G5503-33P11U 5503A 5503B Adjustable 3.3V -40°C~85°C -40°C~85°C SOP-8 SOP-8 G5503-50P11U 5503C 5.0V -40°C~85°C SOP-8 Note: P1: SOP-8 1: Bonding Code U: Tape & Reel Pin Configuration Typical Application Circuit G5503 FB 8 1 NC EN 2 7 GND NC 3 6 LX G5503 VIN 6V~18V 470µF 1µF 4 5 SOP-8 NC VOUT = 0.8 x ( 1 + R1 R2 D1 SCD36 R1/31.25K 220µF 1µF* VOUT 3.3V/2A FB EN GND IN 33µH LX IN R2/10K ) * optional TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 0.1 May 02, 2008 1