LTC1701/LTC1701B 1MHz Step-Down DC/DC Converters in SOT-23 FEATURES DESCRIPTIO n Tiny 5-Lead SOT-23 Package The LTC 1701/LTC1701B are the industrys first SOT-23 n Uses Tiny Capacitors and Inductor step-down, current mode, DC/DC converters. Intended for n High Frequency Operation: 1MHz low to medium power applications, they operate from 2.5V n High Output Current: 500mA to 5.5V input voltage range and switch at 1MHz, allowing n Low R Internal Switch: 0.28W the use of tiny, low cost capacitors and inductors 2mm or DS(ON) n High Efficiency: Up to 94% less in height. The output voltage is adjustable from 1.25V n Current Mode Operation for Excellent Line to 5V. A built-in 0.28W switch allows up to 0.5A of output TM and Load Transient Response current at high efficiency. OPTI-LOOP compensation n Short-Circuit Protected allows the transient response to be optimized over a wide n Low Quiescent Current: 135m A (LTC1701) range of loads and output capacitors. n Low Dropout Operation: 100% Duty Cycle The LTC1701 incorporates automatic power saving Burst n Ultralow Shutdown Current: I < 1m A TM Q Mode operation to reduce gate charge losses when the n Peak Inductor Current Independent of Inductor Value load current drops below the level required for continuous n Output Voltages from 5V Down to 1.25V operation. The LTC1701B operates continuously to very low load currents to provide low ripple at the expense of U light load efficiency. With no load, the LTC1701 draws only APPLICATIO S 135m A. In shutdown, both devices draw less than 1m A, n PDAs/Palmtop PCs making them ideal for current sensitive applications. n Digital Cameras Their small size and switching frequency enables a n Cellular Phones complete DC/DC converter function to consume less than n Portable Media Players 0.3 square inches of PC board area. n PC Cards , LTC and LT are registered trademarks of Linear Technology Corporation. n Handheld Equipment Burst Mode and OPTI-LOOP are trademarks of Linear Technology Corporation. TYPICAL APPLICATION Efficiency Curve L1 4.7H V V 100 IN OUT 2.5V TO (2.5V/ V SW V = 3.3V IN IN 95 5.5V 500mA) V = 2.5V OUT D1 90 R4 R2 LTC1701 1M 121k LTC1701 85 + C1 + 80 10F C2 I /RUN V 47F TH FB 75 R3 GND R1 LTC1701B 70 5.1k 121k C3 65 330pF 60 C1: TAIYO YUDEN JMK316BJ106ML 1701 F01a 55 C2: SANYO POSCAP 6TPA47M D1: MBRM120L 50 L1: SUMIDA CD43-4R7 1 10 100 1000 LOAD CURRENT (mA) Figure 1. 2.5V/500mA Step-Down Regulator 1701 F01b 1 EFFICIENCY (%) U ULTC1701/LTC1701B UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART (Voltages Referred to GND Pin) TOP VIEW NUMBER V Voltage (Pin 5).......................................0.3V to 6V IN SW 1 5 V IN I /RUN Voltage (Pin 4) ..............................0.3V to 3V TH GND 2 LTC1701ES5 V Voltage (Pin 3) ......................................0.3V to 3V FB V 3 4 I /RUN FB TH LTC1701BES5 V SW (Max Switch Voltage) ................8.5V to 0.3V IN S5 PACKAGE Operating Temperature Range (Note 2) .. 40 C to 85 C 5-LEAD PLASTIC SOT-23 S5 PART Junction Temperature (Note 5)............................. 125 C MARKING T = 125 C, q = 250 C/W JMAX JA Storage Temperature Range ................. 65 C to 150 C LTKG SEE THE APPLICATION Lead Temperature (Soldering, 10 sec).................. 300 C INFORMATION SECTION LTUD Consult factory for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 3.3V, R = 1Meg (from V to I /RUN) unless otherwise A IN ITH/RUN IN TH specified. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Operating Voltage Range 2.5 5.5 V IN I Feedback Pin Input Current (Note 3) 0.1 m A FB V Feedback Voltage (Note 3) l 1.22 1.25 1.28 V FB D V Reference Voltage Line Regulation V = 2.5V to 5V (Note 3) 0.04 0.1 %/V LINE REG IN D V Output Voltage Load Regulation Measured in Servo Loop, V = 1.5V, (Note 3) 0.01 0.70 % LOAD REG ITH Measured in Servo Loop, V = 1.9V, (Note 3) 0.80 1.50 % ITH Input DC Supply Current (Note 4) Active Mode V = 0V 185 300 m A FB Sleep Mode V = 1.4V (LTC1701 only) 135 200 m A FB Shutdown V = 0V 0.25 1 m A ITH/RUN V Run Threshold High I Ramping Down 1.4 1.6 V ITH/RUN TH/RUN Run Threshold Low I Ramping Up 0.3 0.6 V TH/RUN I Run Pullup Current V = 1V 50 100 300 m A ITH/RUN ITH/RUN I Peak Switch Current Threshold V = 0V 0.9 1.1 A SW(PEAK) FB R Switch ON Resistance V = 5V, V = 0V 0.28 W DS(ON) IN FB V = 3.3V, V = 0V 0.30 W IN FB V = 2.5V, V = 0V 0.35 W IN FB I Switch Leakage Current V = 5V, V = 0V, V = 0V 0.01 1 m A SW(LKG) IN ITH/RUN FB t Switch Off-Time 400 500 600 ns OFF Note 1: Absolute Maximum Ratings are those values beyond which the life Note 3: The LTC1701/LTC1701B are tested in a feedback loop which of a device may be impaired. servos V to the midpoint for the error amplifier without R = 1MHz FB ITH/RUN (V = 1.7V unless otherwise specified). Note 2: The LTC1701E/LTC1701BE guaranteed to meet performance ITH specifications from 0 C to 70 C. Specifications over the 40 C to 85 C Note 4: Dynamic supply current is higher due to the internal gate charge operating temperature range are assured by design, characterization and being delivered at the switching frequency. correlation with statistical process controls. Note 5: T is calculated from the ambient T and power dissipation P J A D according to the following formula: LTC1701ES5/LTC1701BES5: T = T + (P 250 C/W) J A D 2 U WWW