G5217 Global Mixed-mode Technology Inc. 24V Input Voltage-Mode Buck PWM Controller Features General Description The G5217 provides complete control and protection for a DC-DC converter for high power applications. It is designed to drive two N-channel MOSFETs in a synchronous-rectified buck topology. The G5217 integrates all of the control, bootstrap diode and protection functions into a single package. Drives Two N-Channel MOSFETs Operates at 5V to 24V Supply Voltage Internal Bootstrap Diode Circuit Voltage-Mode PWM Control Fast Transient Response 0.8V, 2% Accuracy Reference Voltage Internal Soft Start Constant 300kHz Switching Frequency Over-Current Fault Monitors by Using Low-Side MOSFET RDS(ON) Output Under-Voltage Protection The G5217 provides simple, single feedback loop, voltage-mode control with fast transient response. It includes a 300kHz free-running triangle-wave oscillator. The error amplifier features a 15MHz gain-bandwidth product which provides high converter bandwidth for fast transient performance. The resulting PWM duty ratio ranges from 0% to 80%. The reference voltage is 0.8V, 2% accuracy. Applications 16V to 30V Input High Power DC-DC Regulators Low-Voltage Distributed Power Supplies The G5217 has internal soft start and executes cycle-by-cycle current limit during soft start interval. The G5217 monitors the current by using the RDS(ON) of the low-side MOSFET which eliminates the need for a current sensing resistor. The under-voltage protection function monitors voltage at FB pin. The over-current and under-voltage events after soft-start interval trigger hiccup mode protection. Ordering Information ORDER NUMBER G5217P11U Note: P1: SOP-8 1: Bonding Code U: Tape & Reel Pin Configuration MARKING TEMP. RANGE PACKAGE (Green) G5217 -40°C~ +85°C SOP-8 Typical Application Circuit 5V ~ 24V 220µF G5217 10Ω G5217 UGATE 1 8 BOOT LX 2 7 VCC LGATE 3 6 OCSET GND 4 5 FB VCC BOOT 4.7µF 0.1µF UGATE ROCSET 3µH VO=13.5V LX OCSET LGATE 2000µF 620Ω SHDN SOP-8 FB GND 39Ω TEL: 886-3-5788833 http://www.gmt.com.tw Ver: 0.2 Jan 13, 2010 1 10nF