SC121 Low Voltage Synchronous Boost Regulator POWER MANAGEMENT Features Description Input voltage 0.7V to 4.5V The SC121 is a high efficiency, low noise, synchronous Minimum start-up voltage 0.85V step-up DC-DC converter that provides boosted voltage Output voltage fi xed at 3.3V adjustable from 1.8V levels in low-voltage handheld applications. The wide to 5.0V input voltage range allows use in systems with single Peak input current limit 1.2A NiMH or alkaline battery cells as well as in systems with Output current at 3.3 V 80mA with V = 1.0V, higher voltage battery supplies. It features an internal OUT IN 190mA with V = 1.5V 1.2A switch and synchronous rectifi er to achieve up to IN Forced PWM operation at all loads 94% effi ciency and to eliminate the need for an external Effi ciency up to 94% Schottky diode. The output voltage can be set to 3.3V Internal synchronous rectifi er with internal feedback, or to any voltage within the speci- No forward conduction path during shutdown fi ed range using a standard resistor divider. Switching frequency 1.2MHz The SC121 operates exclusively in Pulse Width Modulation Soft-start startup current limiting (PWM) mode for low ripple and fi xed-frequency switching. Shutdown current 0.1A (typ) Output disconnect capability is included to reduce leakage Ultra-thin 1.5 2.0 0.6 (mm) MLPD-UT-6 package current, improve effi ciency, and eliminate external com- Lead-free and halogen-free ponents sometimes needed to disconnect the load from WEEE and RoHS compliant the supply during shutdown. Applications Low quiescent current is maintained with a high 1.2MHz MP3 players operating frequency. Small external components and the Smart phones and cellular phones space saving MLPD-UT-6, 1.52.00.6 (mm) package Palmtop computers and handheld instruments make this device an excellent choice for small handheld PCMCIA cards and memory cards applications that require the longest possible battery life. Digital cordless phones Personal medical products Wireless VoIP phones Small motors Typical Application Circuit L1 IN LX Single EN OUT 3.3V Cell (1.2V) GND FB C IN C OUT SC121 April 13, 2010 2010 Semtech Corporation 1SC121 Pin Confi guration MLPD-UT Ordering Information Device Package (1)(2) SC121ULTRT MLPD-UT-6 1.52 SC121EVB Evaluation Board LX 1 6 OUT TOP VIEW Notes: 2 (1) Available in tape and reel only. A reel contains 3,000 devices. GND 5 FB (2) Lead-free packaging, only. Device is WEEE and RoHS compliant, T and halogen-free. 3 4 IN EN MLPD-UT 1.52, 6 LEAD = 84C/W JA Marking Information MLPD-UT 121 yw MLPD-UT 1.52, 6 LEAD yw = date code 2