Data Sheet No. 94715 IR3637ASPbF 1% ACCURATE SYNCHRONOUS PWM CONTROLLER FEATURES DESCRIPTION 0.8V Reference Voltage The IR3637A controller IC is designed to provide a simple Operates with a single 5V Supply synchronous Buck regulator for on-board DC to DC ap- Internal 600KHz Oscillator plications in a small 8-pin SOIC. The output voltage can Soft-Start Function be precisely regulated using the internal 0.8V reference Fixed Frequency Voltage Mode voltage for low voltage applications. Short Circuit Protection The IR3637A operates at a fixed internal 600KHz switch- ing frequency to reduce the component size. APPLICATIONS The device features under-voltage lockout for both input supplies, an external programmable soft-start function Computer Peripheral Voltage Regulator as well as output under-voltage detection that latches Memory Power supplies off the device when an output short is detected. Graphics Card Low cost on-board DC to DC TYPICAL APPLICATION 12V 5V C1 C3 C2 Vc Vcc HDrv Q1 L1 D1 SS/SD Vout C4 Q2 C6 LDrv IR3637A Comp R3 C5 Fb Gnd R2 R1 Figure 1 - Typical application of IR3637A. ORDERING INFORMATION PKG PACKAGE PIN PARTS PARTS T & R DESIG DESCRIPTION COUNT PER TUBE PER REEL Oriantation S IR3637ASPbF 8 95 ------ Fig A S IR3637ASTRPbF 8 ------- 2500 www.irf.com 1IR3637ASPbF ABSOLUTE MAXIMUM RATINGS Vcc Supply Voltage ................................................ 16V Vc Supply Voltage .................................................. 25V Storage Temperature Range ..................................... -65C To 150C Operating Junction Temperature Range ..................... 0C To 125C ESD Classification ................................................. HBM Class 2 (2KV) JEDEC Standard Moisture Sensitivity Level ........................................ JEDEC Level 1 260C CAUTION: Stresses above those listed inAbsolute Maximum Rating may cause permanent damage to the device. PACKAGE INFORMATION Recommended Operating Conditions Parameter Min Max Units Fb 1 8 SS/SD Vcc 4.5 5.5 V Vcc 2 7 Comp Vc 8 14 V LDrv 3 6 Vc Gnd 4 5 HDrv JA=154C/W JC=41.2C/W ELECTRICAL SPECIFICATIONS Unless otherwise specified, these specifications apply over Vcc=5V, Vc=12V and 0C<Tj<125C. PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS Feedback Voltage Fb Voltage VFB V 0.792 0.808 0.800 25C<Tj<75C 0.789 0.811 V 0C<Tj<125C 0.800 Fb Voltage Line Regulation LREG 4.5<Vcc<5.5 % 0.1 UVLO UVLO Threshold - Vcc UVLO Vcc Supply Ramping Up V 4.0 4.4 4.2 UVLO Hysteresis - Vcc V 0.25 UVLO Threshold - Vc UVLO Vc Supply Ramping Up 3.1 3.5 V 3.3 UVLO Hysteresis - Vc V 0.2 UVLO Threshold - Fb UVLO Fb Fb Ramping Down V 0.3 0.5 0.4 Supply Current Vcc Dynamic Supply Current Dyn Icc Freq=600KHz, CL=1500pF mA 4 16 7 Vc Dynamic Supply Current Dyn Ic Freq=600KHz, CL=1500pF mA 6 20 15 Vcc Static Supply Current ICCQ SS=0V 1 6 mA 3.3 Vc Static Supply Current ICQ SS=0V mA 0.5 4.7 1 Soft-Start Section Charge Current SSIB SS=0V -15 -35 A -25 Shutdown Threshold SD V 0.4 www.irf.com 2