LT1614 Inverting 600kHz Switching Regulator DESCRIPTIO FEATURES n Better Regulation Than a Charge Pump The LT 1614 is a fixed frequency, inverting mode switch- n 0.1W Effective Output Impedance ing reglator that operates from an input voltage as low as n 5V at 200mA from a 5V Input 1V. Utilizing a low noise topology, the LT1614 can gener- n 600kHz Fixed Frequency Operation ate a negative output down to 24V from a 1V to 5V input. n Operates with V as Low as 1V Fixed frequency switching ensures a clean output free IN n 1mA Quiescent Current from low frequency noise. The device contains a low- n Low Shutdown Current: 10m A battery detector with a 200mV reference and shuts down n Low-Battery Detector to less than 10m A. No load quiescent current of the LT1614 n Low V Switch: 295mV at 500mA is 1mA and the internal NPN power switch handles a CESAT 500mA current with a voltage drop of just 295mV. U APPLICATIO S High frequency switching enables the use of small induc- tors and capacitors. Ceramic capacitors can be used in n MR Head Bias many applications, eliminating the need for bulky tanta- n LCD Bias lum types. n GaAs FET Bias n 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. TYPICAL APPLICATIO C3 L1 L2 5V to 5V Converter Efficiency 1m F 22m H 22m H V IN 90 5V V V SW OUT IN 5V 80 + SHDN C1 200mA 69.8k LT1614 33m F C2 D1 V C NFB 70 33m F GND 24.9k 100k 60 1nF 1614 TA01 C1, C2: AVX TAJB336M010 50 C3: TAIYO YUDEN EMK316BJ105MF D1: MBR0520 L1, L2: MURATA LQH3C220 40 310 30 100 300 Figure 1. 5V to 5V/200mA Converter LOAD CURRENT (mA) 1614 TA02 1 EFFICIENCY (%) + U ULT1614 O ABS LUTEXAI U RATI GS (Note 1) V , SHDN, LBO Voltage ......................................... 12V Operating Temperature Range IN SW Voltage ............................................... 0.4V to 30V LT1614C ................................................. 0 C to 70 C NFB Voltage ............................................................ 3V LT1614I ............................................. 40 C to 85 C V Voltage ................................................................ 2V Extended Commercial C LBI Voltage ............................................ 0V V 1V Temperature Range (Note 2) .................. 40 C to 85 C LBI Current into FB Pin .............................................. 1mA Storage Temperature Range ................ 65 C to 150 C Junction Temperature...........................................125 C Lead Temperature (Soldering, 10 sec)................. 300 C PACKAGE/ORDER I FOR ATIO ORDER PART ORDER PART NUMBER NUMBER TOP VIEW TOP VIEW LT1614CMS8 LT1614CS8 NFB 1 8 LBO NFB 1 8 LBO LT1614IMS8 LT1614IS8 V 2 7 LBI C V 2 7 LBI C 6 V SHDN 3 IN GND 4 5 SW SHDN 3 6 V IN MS8 PACKAGE GND 4 5 SW 8-LEAD PLASTIC MSOP MS8 PART MARKING S8 PART MARKING S8 PACKAGE T = 125 C, q = 160 C/W JMAX JA 8-LEAD PLASTIC SO LTID 1614 T = 125 C, q = 120 C/W JMAX JA LTJB 1614I Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. Commercial Grade 0 C to 70 C. V = 1.5V, V = V unless A IN SHDN IN otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Quiescent Current 12 mA V = 0V 5 10 m A SHDN Feedback Voltage l 1.21 1.24 1.27 V NFB Pin Bias Current (Note 3) V = 1.24V l 2.5 4.5 7 m A NFB Reference Line Regulation 1V V 2V 0.6 1.1 %/V IN 2V V 6V 0.3 0.8 %/V IN Minimum Input Voltage 0.92 1 V Maximum Input Voltage l 6V Error Amp Transconductance D I = 5mA16 m mhos Error Amp Voltage Gain 100 V/V Switching Frequency l 500 600 750 kHz Maximum Duty Cycle 73 80 % l 70 80 % Switch Current Limit (Note 4) 0.75 1.2 A 2 U WU U W W W