LT1611 Inverting 1.4MHz Switching Regulator in SOT-23 DESCRIPTIO FEATURES n Very Low Noise: 1mV Output Ripple The LT 1611 is the industrys first inverting 5-lead SOT-23 PP n 5V at 150mA from a 5V Input current mode DC/DC converter. Intended for use in small, n Better Regulation Than a Charge Pump low power applications, it operates from an input voltage n Effective Output Impedance: 0.14W as low as 1.1V and switches at 1.4MHz, allowing the use n Uses Tiny Capacitors and Inductors of tiny, low cost capacitors and inductors 2mm or less in n Internally Compensated height. Its small size and high switching frequency enable n Fixed Frequency 1.4MHz Operation the complete DC/DC converter function to consume less n Low Shutdown Current: <1m A than 0.25 square inches of PC board area. Capable of n Low V Switch: 300mV at 300mA generating 5V at 150mA from a 5V supply or 5V at CESAT n Tiny 5-Lead SOT-23 Package 100mA from a 3V supply, the LT1611 replaces nonregulated charge pump solutions in many applications. U The LT1611 operates in a dual inductor inverting topology APPLICATIO S which filters the input side as well as the output side of the n MR Head Bias DC/DC converter. Fixed frequency switching ensures a n Digital Camera CCD Bias clean output free from low frequency noise typically present n LCD Bias with charge pump solutions. No load quiescent current of n GaAs FET Bias the LT1611 is 3mA, while in shutdown quiescent current n Positive-to-Negative Conversion drops to 0.5m A. The 36V switch allows V to V IN OUT differential of up to 33V. The LT1611 is available in the 5-lead SOT-23 package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO C2 L1A L1B Transient Response 1F 22m H 22m H V IN 5V D1 V V SW OUT IN 5V SHDN 150mA R1 V + OUT 1200pF LT1611 29.4k C1 20mV/DIV 22m F C3 NFB AC COUPLED 22m F GND R2 10k 150mA LOAD CURRENT 50mA C1: AVX TAJB226M010 1611 TA01 100m s/DIV 1611 F10 C2: TAIYO YUDEN LMK212BJ105MG C3: TAIYO YUDEN JMK325BJ226MM (1210 SIZE) D1: MBR0520 L1: SUMIDA CLS62-220 OR 2 MURATA LQH3C220 (UNCOUPLED) Figure 1. 5V to 5V, 150mA Low Noise Inverting DC/DC Converter 1 U ULT1611 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) ORDER PART V Voltage .............................................................. 10V IN TOP VIEW NUMBER SW Voltage ................................................0.4V to 36V SW 1 5 V IN NFB Voltage ............................................................. 3V LT1611CS5 GND 2 Current into NFB Pin ............................................. 1mA NFB 3 4 SHDN SHDN Voltage .......................................................... 10V S5 PACKAGE Maximum Junction Temperature .......................... 125 C S5 PART MARKING 5-LEAD PLASTIC SOT-23 Operating Temperature Range LTES T = 125 C, q = 256 C/W JMAX JA Commercial ............................................. 0 C to 70 C Extended Commercial (Note 2)........... 40 C to 85 C Storage Temperature Range ................. 65 C to 150 C Consult factory for Industrial and Military grade parts. Lead Temperature (Soldering, 10 sec).................. 300 C ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 1.5V, V = V unless otherwise noted. A IN SHDN IN PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage 0.9 1.1 V Maximum Operating Voltage 10 V NFB Pin Bias Current V = 1.23V l 2.7 4.7 6.7 m A NFB Feedback Voltage l 1.205 1.23 1.255 V Quiescent Current V = 1.5V, Not Switching 3 4.5 mA SHDN Quiescent Current in Shutdown V = 0V, V = 2V 0.01 0.5 m A SHDN IN V = 0V, V = 5V 0.01 1.0 m A SHDN IN Reference Line Regulation 1.5V V 10V 0.02 0.2 %/V IN Switching Frequency l 1.0 1.4 1.8 MHz Maximum Duty Cycle l 82 86 % Switch Current Limit (Note 3) 550 800 mA Switch V I = 300mA 300 350 mV CESAT SW Switch Leakage Current V = 5V 0.01 1 m A SW SHDN Input Voltage High 1V SHDN Input Voltage Low 0.3 V SHDN Pin Bias Current V = 3V 25 50 m A SHDN V = 0V 0 0.1 m A SHDN Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: Current limit guaranteed by design and/or correlation to static test. of a device may be impaired. Slope compensation reduces current limit at higher duty cycle. Note 2: C grade device specifications are guaranteed over the 0 C to 70 C temperature range. In addition, C grade device specifications are assured over the 40 C to 85 C temperature range by design or correlation, but are not production tested. 2 U W U W U WW