SP6121 Datasheet | Sipex

FEATURES - Optimized for Single Input Voltage - 3V to 5.5V 8 PDRV VCC 1 - High Efficiency: Greater than 95% possible SP6121 GND 2 7 NDRV - Accurate, 500k Hz Fixed Frequency Operation 6 ISET VFB 3 8 Pin SOIC - Fast Transient Response 4 5 ISENSE P - 500µA, IQ (25µA in Shutdown) - Internal, 0.4 V/ms, Soft Start Circuit - Precision 1% Reference Now Available in Lead Free Packaging - Resistor Programmable Output Voltage APPLICATIONS - Lossless Adjustable Current Limit with - Supply Bias for - High Side RDS(ON) Sensing - DSP - 0% to 100% Duty Cycle Range - Microprocessor Core - High Side PMOS Switch Negates Need for - I/O & Logic - External Charge Pump - Video Cards - Output Over Voltage Protection - Board Level Supply in - Hiccup Mode Current Limit Protection Distributed Power Systems DESCRIPTION The SP6121 is a fixed frequency, voltage mode, synchronous PWM controller designed to work from a single 5V or 3.3V input supply, providing excellent AC and DC regulation for high efficiency power conversion. The operating frequency is internally set at 500k Hz, permitting the use of small, surface mount inductors and capacitors. Requiring only few external ponents, the SP6121 packaged in an 8-pin SOIC, is especially suited for low voltage applications where cost, small size and high efficiency are critical. With its low voltage capability and inherent 100% duty cycle operation, the SP6121 allows low dropout operation in the event of a low input supply voltage condition. TYPICAL APPLICATION CIRCUIT RVCC 5 ® RSET 2.3k Q1 1.8µH L1 Q2 DS CIN 47µF Ceramic 6.3V 3.3V VIN CB 3.3µF VCC GND VFB P RZ 10k CZ 3.7n F PDRV SP6121 U1 NDRV ISET ISENSE 1.9V 8A VOUT COUT 470µF x 2 R1 5.2k R2 10k CP 50p F Q1 = FAIRCHILD FDS6375 Q2 = FAIRCHILD FDS6690A DS = STMICROELECTRONICS STPS2L25BU Date: 5/25/04 L1 = PANASONIC ETQ-P6F1R6SFA COUT = SANYO...