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Data Sheet No.PD60231 revA
IR3621 & (PbF)
2-PHASE / DUAL SYNCHRONOUS PWM CONTROLLER WITH OSCILLATOR SYNCHRONIZATION AND PRE-BIAS STARTUP
FEATURES
Dual Synchronous Controller with 180! Out of Phase Operation Configurable to 2-Independent Outputs or Current Share Single Output Voltage Mode Control Current Sharing Using Inductor's DCR Selectable Hiccup or Latched Current Limit using MOSFET's RDS(on) sensing Latched Over-Voltage Protection Pre-Bias Start Up Programmable Switching Frequency up to 500KHz Two Independent Soft-Starts/Shutdowns Precision Reference Voltage 0.8V Power Good Output External Frequency Synchronization Thermal Protection
DESCRIPTION
The IR3621 IC combines a dual synchronous buck controller and drivers, providing a cost-effective, high performance and flexible solution. The IR3621 operates in 2-Phase mode to produce either 2-independent output voltages or current share single output for high current application. The 180! out-of-phase operation allows the reduction of input and output capacitance. Other key features include two independently programmable soft-start functions to allow system level sequencing of output voltages in various configurations. The pre-bias protection feature prevents the discharge of the output voltage and possible damage to the load during start-up when a preexisting voltage is present at the output. Programmable switching frequency up to 500KHz per phase allows flexibility to tune the operation of the IC to meet system level requirements, and synchronization allows the simplification of system level filter design. Protection features such as selectable hiccup or latched current limit, and under voltage lock-out are provided to give required system level security in the event of a fault condition.
APPLICATIONS
Embedded Networking & Telecom Systems Distributed Point-of-Load Power Architectures 2-Phase Power Supply Graphics Card DDR Memory Applications
Vin
Vin
Rt Comp1
HDrv1 OCSet1 LDrv1 PGnd1
Rt Comp1
HDrv1 OCSet1 LDrv1 PGnd1 Vout1
Comp2 SS1 / SD SS2 / SD Gnd
IR3621
HDrv2 OCSet2 LDrv2 PGnd2
Vin
Vout
Comp2 SS1 / SD SS2 / SD
IR3621
HDrv2 OCSet2 LDrv2
Vin
Vout2
Gnd
PGnd2
Current share, single output configuration
2-independent output voltage configuration
Figure 1 - Typical application of IR3621 in current share single output and 2-independent output voltage configuration
ORDERING INFORMATION
PKG DESIG M M F F PART NUMBER IR3621M IR3621MTR IR3621F IR3621FTR LEADFREE PART NUMBER IR3621MPbF IR3621MTRPbF N/A N/A PIN COUNT 32 32 28 28 www.irf.com PARTS PER TUBE 73 -----50 -----PARTS PER REEL -----6000 -----2500 T&R Orientation Fig A
1
IR3621 & (PbF)
ABSOLUTE MAXIMUM RATINGS
Vcc, VCL Supply Voltage ........................................... VcH1 and VcH2 Supply Voltage ................................ PGOOD.................................................................... Storage Temperature Range ...................................... Junction Temperature Range ....