LT1614 Inverting 600kHz Switching Regulator UFEATURESDESCRIPTIO ■ Better Regulation Than a Charge Pump The LT®1614 is a fixed frequency, inverting mode switch- ■ 0.1 Ω Effective Output Impedance ing reglator that operates from an input voltage as low as ■ – 5V at 200mA from a 5V Input 1V. Utilizing a low noise topology, the LT1614 can gener- ■ 600kHz Fixed Frequency Operation ate a negative output down to – 24V from a 1V to 5V input. ■ Operates with V Fixed frequency switching ensures a clean output free IN as Low as 1V ■ 1mA Quiescent Current from low frequency noise. The device contains a low- ■ Low Shutdown Current: 10µA battery detector with a 200mV reference and shuts down ■ Low-Battery Detector to less than 10µA. No load quiescent current of the LT1614 ■ Low V is 1mA and the internal NPN power switch handles a CESAT Switch: 295mV at 500mA 500mA current with a voltage drop of just 295mV. UAPPLICATIO S High frequency switching enables the use of small induc- tors and capacitors. Ceramic capacitors can be used in ■ MR Head Bias many applications, eliminating the need for bulky tanta- ■ LCD Bias lum types. ■ GaAs FET Bias ■ Positive-to-Negative Conversion The LT1614 is available in 8-lead MSOP or SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. UTYPICAL APPLICATIO C3 L1 L2 1µF 5V to – 5V Converter Efficiency 22µH 22µH VIN 90 5V V V IN SW OUT – 5V + 80 SHDN C1 69.8k 200mA LT1614 33µF C2 V D1 C NFB + 33µF 70 GND 24.9k 100k 1nF 60 EFFICIENCY (%) C1, C2: AVX TAJB336M010 1614 TA01 50 C3: TAIYO YUDEN EMK316BJ105MF D1: MBR0520 L1, L2: MURATA LQH3C220 40 3 10 30 100 300 Figure 1. 5V to – 5V/200mA Converter LOAD CURRENT (mA) 1614 TA02 1
