LT1931/LT1931A 1.2MHz/2.2MHz Inverting DC/DC Converters in ThinSOT FEATURES DESCRIPTIO Fixed Frequency 1.2MHz/2.2MHz Operation The LT 1931/LT1931A are the industrys highest power Very Low Noise: 1mV Output Ripple inverting SOT-23 current mode DC/DC converters. Both P-P 5V at 350mA from 5V Input parts include a 1A integrated switch allowing high current 12V at 150mA from 5V Input outputs to be generated in a small footprint. The LT1931 Uses Small Surface Mount Components switches at 1.2MHz while the LT1931A switches at 2.2MHz. Wide Input Range: 2.6V to 16V These high speeds enable the use of tiny, low cost Low Shutdown Current: <1A capacitors and inductors 2mm or less in height. The Low V Switch: 400mV at 1A LT1931 is capable of generating 5V at 350mA or 12V CESAT Pin-for-Pin Compatible with the LT1611 at 150mA from a 5V supply, while the LT1931A can TM Low Profile (1mm) ThinSOT Package generate 5V at 300mA using significantly smaller induc- tors. Both parts are easy pin-for-pin upgrades for higher U power LT1611 applications. APPLICATIO S The LT1931/LT1931A operate in a dual inductor inverting Disk Drive MR Head Bias topology that filters both the input side and output side Digital Camera CCD Bias current. Very low output voltage ripple approaching 1mV P-P LCD Bias can be achieved when ceramic output capacitors are used. GaAs FET Bias Fixed frequency switching ensures a clean output free Local Low Noise/Low Impedance Negative Supply from low frequency noise typically present with charge pump solutions. The low impedance output remains within 1% of nominal during large load steps. The 36V switch allows V to V differential of up to 34V. IN OUT The LT1931/LT1931A are available in the 5-lead ThinSOT package. , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO C2 Efficiency L1A L1B 1F 10H 10H V 100 IN 5V 95 D1 V 90 V SW IN OUT 5V SHDN 85 350mA R1 C4 LT1931 29.4k C1 220pF 80 4.7F C3 NFB 75 22F GND R2 70 10k 65 60 C1: TAIYO YUDEN X5R JMK212BJ475MG 1931 F01 55 C2: TAIYO YUDEN X5R LMK212BJ105MG C3: TAIYO YUDEN X5R JMK325BJ226MM 50 D1: ON SEMICONDUCTOR MBR0520 0 50 100 150 200 250 300 350 L1: SUMIDA CLS62-100 LOAD CURRENT (mA) 1931 TA01 Figure 1. 5V to 5V, 350mA Inverting DC/DC Converter 1931fa 1 EFFICIENCY (%) U ULT1931/LT1931A UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) V Voltage .............................................................. 16V TOP VIEW IN SW Voltage ................................................0.4V to 36V SW 1 5 V IN NFB Voltage ............................................................. 2V GND 2 Current Into NFB Pin............................................ 1mA NFB 3 4 SHDN SHDN Voltage .......................................................... 16V S5 PACKAGE 5-LEAD PLASTIC TSOT-23 Maximum Junction Temperature .......................... 125C T = 125C, = 150C/ W JMAX JA Operating Temperature Range (Note 2) .. 40C to 85C Storage Temperature Range ................. 65C to 150C ORDER PART NUMBER S5 PART MARKING Lead Temperature (Soldering, 10 sec).................. 300C LT1931ES5 LTRA LT1931AES5 LTSP LT1931IS5 LTBZF LT1931AIS5 LTBZG Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: