IR3651SPBF

Data Sheet No.PD94720 IR3651SPbF HIGH VOLTAGE SYNCHRONOUS PWM BUCK CONTROLLER Features • • • • • • • • • High Voltage Operating up to 75V Programmable Switching Frequency up to 400kHz 1A Output Drive Capability Precision Reference Voltage (1.25V) Programmable Soft-Start Programmable Over Current Protection Hiccup Current Limit Using MOSFET RDS(on) sensing External Frequency Synchronization 14-pin SOIC Package Description The IR3651 is a high voltage PWM controller designed for high performance synchronous Buck DC/DC applications. The IR3651 drives a pair of external N-MOSFETs using a programmable switching frequency up to 400kHz allows flexibility to tune the operation of the IC to meet system level requirements, and synchronization allows the simplification of system level filter design. The output voltage can be precisely regulated using the internal 1.25V reference voltage for low voltage applications. Protection such as under voltage lockout and hiccup current limit are provided to give required system level security in the event of fault conditions. Applications • • • • • 48V non-isolated DC to DC Converter Embedded Telecom Systems Networking and Computing Voltage Regulator Distributed Point of Load Power Architectures General high voltage DC/DC Converters Vaux=12V Vin: 12V-75V C3 C1 C4 C2 DRVcc Vcc SYNC Rt IR3651S Vb HDrv Vs OCset LDrv PGnd ROCset Q2 C8 C5 R1 R3 Q1 L1 Vout R5 C6 SS/SD C9 Gnd Comp Fb C7 R4 R2 C10 Typical application Circuit ORDERING INFORMATION PKG DESIG S S PACKAGE DESCRIPTION IR3651SPBF IR3651STRPBF PIN PARTS PARTS COUNT PER TUBE PER REEL 14 55 ------14 -------2500 T&R ORIANTAION Fig A 10/11/2006 IR3651SPbF ABSOLUTE MAXIMUM RATINGS (Voltages referenced to GND) • • • • • • • • Vcc, DRVcc Supply Voltage ..................................… -0.3V to 20V Vs Supply Voltage …………………………………….. -0.3V to 150V Vb Supply Voltage …………………………………….. -0.3V to Vs+20V OCset …………….…………………………………….. 10mA Storage Temperature Range ..................................... -65°C To 150°C Operating Junction Temperature Range ................... -40°C To 150°C ESD Classification …………………………………..… JEDEC, JESD22-A114 (1K) Moisture Sensitivity Level ……………………………. JEDEC Level 3 @ 260oC CAUTION: Stresses beyond 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 in the operational sections of the specifications are not implied. Package Information 14-Pin SOIC NB (S) Fb 1 Comp 2 SS/SD 3 SYNC 4 PGnd 5 Ldrv 6 DRVcc 7 14 Rt 13 Gnd 12 OCset 11 Vcc 10 Vs 9 HDrv 8 Vb ΘJA = 88.2o C/W ΘJC = 37o C/W 10/11/2006 2 IR3651SPbF Block Diagram Vcc 11 0.25V Gnd 13 4.17V SYNC 4 Rt 14 Rt Oscillator S Ct Q POR 3V 20uA R Reset Dom Bias Generator POR 3V 1.25V Vcc 8 Vb LOW VOLTAGE LEVEL SHIFT HIGH VOLTAGE LEVEL SHIFT CIRCUIT UV DETECT UV Q S R 9 HDrv 10 Vs SS/SD 3 3uA OCP Error Comp 1.25V Fb 1 Comp 2 R 0.3V S SS POR Q 64uA Max UV DETECT Vcc LOW VOLTAGE LEVEL SHIFT 7 DRVcc 25K 25K Error Amp 6 LDrv DELAY 5 PGND OCP 12 OCset PBias 10uA Fig. 1: Simplified block diagram of the IR3651 10/11/2006 3 IR3651SPbF Pin Description Pin Name 1 Fb Description Inverting input to the error amplifier. This pin is connected directly to the output of the regulator via resistor divider to set the output voltage and provide feedback to the error amplifier. Output of error amplifier. An external resistor and capacitor network is typically connected from this pin to ground to provide loop compensation. Soft start / shutdown. This pin provides user programmable soft-start function. Connect an external capacitor from this pin to ground to set the start up time of the output voltage. The converter can be shutdown by pulling this pin below 0.3V. The internal oscillator can be synchronized to an external clock via this pin. Power Ground. This pin serves as a separate ground for the MOSFET driver and should be connected to the system’s power ground plane. Output driver for low side MOSFET. This pin provides biasing for the internal low side driver. A minimum of 0.1uF, high frequency capacitor must be connected from this pin to power ground. This pin powers the high side driver and must be connected to a voltage higher than bus voltage. A minimum of 0.1uF, high frequency capacitor must be connected from this pin to switch node. Output driver for high side MOSFET Switch node. Connect this pin to the source of the upper MOSFET and the drain of the lower MOSFET. This pin is return path for the upper gate driver. This pin provides power for the internal blocks of the IC. A minimum of 0.1uF, high frequency capacitor must be connected from this pin to ground. Current limit set point. A resistor from this pin to drain of low side MOSFET will set the current limit threshold. Signal ground for internal reference and control circuitry. Connecting a resistor from this pin to ground sets the oscillator frequency. 2 3 Comp SS/SD 4 5 6 7 SYNC PGnd LDrv DRVcc 8 Vb 9 10 HDrv Vs 11 Vcc 12 13 14 OCSet Gnd Rt 10/11/2006 4 IR3651SPbF Recommended Operating Conditions Symbol Vbus Vcc DRVcc Vb to Vs Fs Tj Definition Converting Voltage Supply Voltage Supply Voltage Supply Voltage Operating Frequency Junction Temperature Min 12 4.5 10 10 100 -40 Max 75 13.2 16 16 400 125 Units V V V V kHz o C Electrical Specifications Unless otherwise specified, these specifications apply over Vcc=5V; DRVcc=Vb=12V, 0oC