LT1935 LINEAR | Alldatasheet

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efficiency even at maximum power levels from a 3V input. from four alkaline cells in a SEPIC design. The LT1935 is available in a 5-lead SOT-23 package. Figure 1. 5V to 12V, 600mA Step-Up DC/DC Converter , LTC and LT are registered trademarks of Linear Technology Corporation.

1935 F01

ThinSOT is a trademark of Linear Technology Corporation.

1935 F01b

PARAMETER CONDITIONS MIN TYP MAX UNITS Feedback Voltage Measured at the FB Pin ● 1.240 1.265 1.280 V Feedback Voltage Line Regulation 2.5V ≤ VIN ≤ 16V 0.01 %/V FB Pin Bias Current V FB = VREF ● 12 60 nA Undervoltage Lockout Threshold 2.1 2.3 V Maximum Input Voltage 16 V Switching Frequency 1 1.2 1.4 MHz Maximum Duty Cycle ● 85 93 % Switch Current Limit (Note 3) 2 3.2 A Switch Saturating Voltage I SW = 2A 180 280 mV Switch Leakage Current V SW = 5V ● 0.01 1 µA SHDN Pin Input Current V SHDN = 1.8V 14 40 µA VSHDN = 0V 0.1 µA Operating Supply Current V FB = 1.5V 3 mA SHDN Supply Current V SHDN = 0V 0.1 1 µA SHDN Input High Voltage 1.8 V SHDN Input Low Voltage 0.5 V (Note 1) Operating Ambient Temperature Range Strict adherence to JDEC 020B solder attach and rework for assemblies containing lead is recommended. Consult LTC marketing for parts specified with wider operating temperature ranges. The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. VIN = 3V, VSHDN = VIN unless otherwise noted. (Note 2) ORDER PART NUMBER LT1935ES5 S5 PART MARKING LTRXTJMAX = 125°C, θJA = 113°C/ W,

ELECTRICAL CHARACTERISTICS

PACKAGE/ORDER I FOR ATIOUU WABSOLUTE AXI U RATI GSW WW U Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT1935ES5 is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40 °C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Current limit guaranteed by design and/or correlation to static test. SW 1 GND 2 TOP VIEW S5 PACKAGE 5-LEAD PLASTIC TSOT-23 FB 3

5 VIN

4 SHDN

1.28 1.27 1.26 1.25 1.24

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VFB (V) TEMPERATURE (°C) –50 FREQUENCY (MHz) 100

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1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 –25 25 75 125 TEMPERATURE (°C) –50 100 05 0–25 25 75 125 TEMPERATURE (°C) –50 UVLO (V) 2.4 2.3 2.2 2.1 2.0 1.9 1.8 25 75

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–25 0 50 100 125 DUTY CYCLE (%) CURRENT LIMIT (A)

1935 G04

SWITCH CURRENT (A) SWITCH SATURATION VOLTAGE (mV) 400 300 200 100 0.5 1.0 1.5 2.0

1935 G05

2.5 3.0 SHDN VOLTAGE (V) CURRENT LIMIT (A) 2.0

1935 G06

0.5 1.0 1.5 SHDN PIN VOLTAGE (V) SHDN PIN CURRENT (µA)

1935 G07

FEEDBACK VOLTAGE (V) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.6 1.0

1935 G08

SWITCHING FREQUENCY (MHz) TA = 25°C TA = 25°C TA = 25°C TA = 25°C TA = 85°C 50% DUTY CYCLE TA = 25°C TYP MIN TYPICAL PERFOR A CE CHARACTERISTICS UW FB Pin Voltage Oscillator Frequency Undervoltage Lockout Current Limit Switch Saturation Voltage Peak Switch Current vs SHDN Pin Voltage (Soft-Start) SHDN Pin Current Frequency Foldback

SW (Pin 1): Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. GND (Pin 2): Ground. Tie directly to local ground plane. FB (Pin 3): Feedback Pin. Reference voltage is 1.265V. FB. Set VOUT according to VOUT = 1.265V(1 + R1/R2). start function; see Applications Information section. VIN (Pin 5): Input Supply Pin. Must be locally bypassed. Figure 2. Block Diagram cycle, the SR latch is set, turning on the power switch Q1. the feedback voltage and the reference voltage of 1.265V. the output; if it decreases, less current is delivered. trolling the peak switch current during start-up.

supply 100µA when the SHDN pin reaches 1.8V. Figure 5. Transient Response with a 68pF Phase-Lead Capacitor Figure 7. Suggested Layout

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Figure 6. Adding a Resistor and Capacitor to the SHDN Pin VOUT = 5V, C2 = 20µF, Output Load = 10Ω.

(Reference LTC DWG # 05-08-1635) 1.50 – 1.75 (NOTE 4)2.80 BSC 0.30 – 0.45 TYP

5 PLCS (NOTE 3)

DATUM ‘A’ 0.09 – 0.20 (NOTE 3) S5 TSOT-23 0302 PIN ONE

2.90 BSC

(NOTE 4)

0.95 BSC

1.90 BSC

0.80 – 0.90

1.00 MAX

0.01 – 0.100.20 BSC 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING

3.85 MAX

0.62 MAX 0.95 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 1.4 MIN2.62 REF

1.22 REF

  1. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 GND VIN SW SHDN FB VIN 2.3V TO 4.8V D1L1 1.8µH 29.4k LT1935 150pF

1935 TA01

20µF 4.7µF 10k VOUT 1A, V IN = 3.3V 0.6A, VIN = 2.5V C1, C2: X5R OR X7R 6.3V D1: ON SEMI MBRM120 L1: SUMIDA CR43-1R8 ON OFF LOAD CURRENT (mA) EFFICIENCY (%) 1200400200 600 1000 800 VIN = 3.3V VIN = 2.5V Efficiency, VOUT = 5V 5V Boost Converter TYPICAL APPLICATIO SU GND VIN SW SHDN FB VIN 3.3V D1L1 4.2µH 84.5kLT1935

1935 TA02

22µF 4.7µF 10k VOUT 12V 320mA D1: ON SEMI MBRM120 L1: SUMIDA CDRH5D28-4R2 ON OFF 47pF 3.3V to 12V Boost Converter Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT/TP 0604 1K • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 2004 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com RELATED PARTS GND VIN SW SHDN FB VIN 3.3V D2A D3A D3B D2B 2.2µH 100k LT1935

1935 TA03

10µF 4.7µF 18.7k 450mA 16V 10mA –8V 10mA ON OFF 0.1µF 0.1µF 1µF 1µF C1: X5R OR X7R 6.3V C2, C4, C5, C6: X5R OR X7R 10V C3: X5R OR X7R 25V D1: MBRM120 OR EQUIVALENT D2, D3: BAT-54S OR EQUIVALENT L1: SUMIDA CDRH4D28-2R2 GND VIN SW SHDN FB VIN 3.2V TO 9V D1L1 4.7µH 29.4kLT1935

1935 TA04

47µF 2.2µF 4.7µF 4.7µHR2 10k VOUT 425mA, V IN >3.2V 500mA, VIN >3.6V 550mA, VIN >4V C1, C3: X5R OR X7R 10V C2: X5R OR X7R 6.3V ON OFF D1: ON SEMI MBRM120 L1, L2: SUMIDA CDRH4D18-4R7 8V, 16V and –8V TFT LCD Power Supply 5V SEPIC Converter TYPICAL APPLICATIO SU PART NUMBER DESCRIPTION COMMENTS LT1618 1.5A (I SW), 1.25MHz, High Efficiency Step-Up DC/DC Converter V IN: 1.6V to 18V, VOUT(MAX): 35V, IQ: 1.8mA, ISD: <1µA, MS, DFN Packages ISD: <1µA, ThinSOT Package LT1943 Quad Output, 2.6A Buck, 2.6A Boost, 0.3A Boost, V IN: 4.5V to 22V, VOUT(MAX): 40V, IQ: 10mA, 0.4A Inverter 1.2MHz TFT DC/DC Converter I SD: <35µA, TSSOP-28E Package ISD: <1µA, MS8 Package LTC3400/LTC3400B 600mA (I SW), 1.2MHz, Synchronous Step-Up DC/DC Converter V IN: 0.85V to 5V, VOUT(MAX): 5V, IQ: 19µA/300µA ISD: <1µA, ThinSOT Package LTC3401/LT3402 1A/2A(I SW), 3MHz, Synchronous Step-Up DC/DC Converter V IN: 0.5V to 5V, VOUT(MAX): 6V, IQ: 38µA, ISD: <1µA, MS Package LTC3425 5A (I SW), 8MHz, Multi-Phase Synchronous Step-Up DC/DC Converter V IN: 0.5V to 4.5V, VOUT(MAX): 5.25V, IQ: 12µA, ISD: <1µA, QFN Package LT3436 3A (I SW), 1MHz, 34V Step-Up DC/DC Converter V IN: 3V to 25V, VOUT(MAX): 34V, IQ: 0.9mA, ISD: <6µA, TSSOP-16E Package ISD: <1µA, ThinSOT Package