LT1616 600mA, 1.4MHz Step-Down Switching Regulator in SOT-23 FEATURES DESCRIPTIO n Wide Input Range: 3.6V to 25V The LT 1616 is a current mode PWM step-down DC/DC n 5V at 400mA from 7V to 25V Input converter with internal 0.6A power switch, packaged in a n 3.3V at 400mA from 4.7V to 25V Input tiny 6-lead SOT-23. The wide input range of 3.6V to 25V n Fixed Frequency 1.4MHz Operation makes the LT1616 suitable for regulating a wide variety of n Uses Tiny Capacitors and Inductors power sources, from 4-cell batteries and 5V logic rails to n Internally Compensated unregulated wall transformers and lead-acid batteries. Its n Low Shutdown Current: <1A high operating frequency allows the use of tiny, low cost n Low V Switch: 220mV at 300mA inductors and ceramic capacitors. With its internal com- CESAT n Tiny 6-Lead SOT-23 Package pensation eliminating additional components, a complete 400mA step-down regulator fits onto 0.15 square inches U of PC board area. APPLICATIO S The constant frequency current mode PWM architecture n Wall Transformer Regulation and stable operation with ceramic capacitors results in n Local Logic Supply Conversion: low, predictable output ripple. Current limiting provides 12V to 5V protection against shorted outputs. The low current (<1A) 12V or 5V to 3.3V, 2.5V or 1.8V shutdown provides complete output disconnect, enabling n Distributed Supply Regulation easy power management in battery-powered systems. n Digital Cameras , LTC and LT are registered trademarks of Linear Technology Corporation. n Battery-Powered Equipment TYPICAL APPLICATIO 3.3V Step-Down Converter Efficiency D2 100 5 1 V IN V BOOST IN 4.5V TO 25V 90 C3 V = 5V V = 12V IN IN L1 LT1616 0.01F 10H 4 6 V OUT 80 OFF ON SHDN SW 3.3V 300mA: V = 4.5V TO 25V IN GND FB V = 20V R1 D1 IN 400mA: V = 4.7V TO 25V 70 IN 16.5k 23 60 C1 C2 R2 1F 10F 10k 50 C1: TAIYO-YUDEN TMK316BJ105 1616 TA01 40 C2: TAIYO-YUDEN JMK316BJ106ML D1: ON SEMICONDUCTOR MBR0530 D2: 1N4148 30 100 200 500 L1: SUMIDA CR43-100 0 300 400 LOAD CURRENT (mA) 1616 G02 1 EFFICIENCY (%) U ULT1616 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) Input Voltage (V ) ................................................. 25V ORDER PART IN NUMBER BOOST Pin Voltage ................................................. 35V TOP VIEW BOOST Pin Above SW Pin ...................................... 25V LT1616ES6 BOOST 1 6 SW SHDN Pin ............................................................... 25V GND 2 5 V IN FB Voltage ................................................................ 6V FB 3 4 SHDN Current Into FB Pin ............................................... 1mA S6 PART MARKING S6 PACKAGE Operating Temperature Range (Note 2) .. 40C to 85C 6-LEAD PLASTIC SOT-23 Maximum Junction Temperature .......................... 125C LTNB T = 125C, = 250C/ W JMAX JA Storage Temperature Range ................. 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C Consult factory for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. A V = 10V, V = 15V, unless otherwise noted. (Note 2) IN BOOST PARAMETER CONDITIONS MIN TYP MAX UNITS Undervoltage Lockout 3.35 3.6 V Feedback Voltage l 1.225 1.25 1.275 V FB Pin Bias Current V = Measured V + 10mV l 150 600 nA FB REF Quiescent Current Not Switching 1.9 2.5 mA Quiescent Current in Shutdown V = 0V 0.01 2 A SHDN Reference Line Regulation V = 5V to 25V 0.005 %/V IN Switching Frequency V = 1.1V l 1 1.4 1.8 MHz FB Frequency Shift Threshold on FB Pin f = 700kHz 0.44 V SW Maximum Duty Cycle l 80 87 % Switch Current Limit (Note 3) 630 850 mA Switch V I = 300mA 220 350 mV CESAT SW Switch Leakage Current 10 A Minimum Boost Voltage Above Switch I = 300mA 1.6 2.5 V SW BOOST Pin Current I = 300mA 7 12 mA SW SHDN Input Voltage High 1.8 V SHDN Input Voltage Low 0.4 V SHDN Bias Current V = 3V 8 15 A SHDN V = 0V 0.01 0.1 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 the device may be impaired. Slope compensation reduces current limit at higher duty cycle. Note 2: The LT1616E is guaranteed to meet performance specifications from 0C to 70C. Specifications over the 40C to 85C operating temperature range are assured by design, characterization and correlation with statistical process controls. 2 U WWW