LT3461A_15 LINER
Document overview
- Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 8
Technical content
■ Digital Cameras ■ CCD Bias Supply ■ XDSL Power Supply ■ TFT-LCD Bias Supply ■ Local 5V or 12V Supply ■ Medical Diagnostic Equipment ■ Battery Backup 5V to 12V, 70mA Step-Up DC/DC Converter Efficiency VIN 10µH 261k 30.1k 1µF 15pF 1µF VOUT 12V 70mA VIN VOUT SW FBSHDN GND LT3461A
3461 TA01a
■ Integrated Schottky Rectifier ■ Fixed Frequency 1.3MHz/3MHz Operation ■ High Output Voltage: Up to 38V ■ Low VCESAT Switch: 260mV at 250mA ■ 12V at 70mA from 5V Input ■ 5V at 115mA from 3.3V Input ■ Wide Input Range: 2.5V to 16V ■ Uses Small Surface Mount Components ■ Low Shutdown Current: <1µA ■ Soft-Start ■ Low Profile (1mm) SOT-23 (ThinSOT TM ) Package 1.3MHz/3MHz Step-Up DC/DC Converters with Integrated Schottky in ThinSOT The LT 3461/LT3461A are general purpose fixed fre- quency current mode step-up DC/DC converters. Both devices feature an integrated Schottky and a low V CESAT switch allowing a small converter footprint and lower parts cost. The LT3461 switches at 1.3MHz while the LT3461A switches at 3MHz. These high switching frequencies en- able the use of tiny, low cost and low height capacitors and inductors. The constant switching frequency results in predictable output noise that is easy to filter, and the inductor based topology ensures an input free from switch- ing noise typically present with charge pump solutions. The high voltage switch in the LT3461/LT3461A is rated at 40V making the device ideal for boost converters up to 38V. The LT3461/LT3461A are available in a low profile (1mm) SOT-23 package. , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. LOAD CURRENT (mA) EFFICIENCY (%)
3461 TAO1b
VIN = 5V VIN = 3.3V
PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage 2.5 V Maximum Operating Voltage 16 V Feedback Voltage 1.235 1.255 1.275 V
- 1.225 1.280 V Feedback Line Regulation 0.005 %/V FB Pin Bias Current ● 40 100 nA Supply Current FB = 1.3V, Not Switching 2.8 3.6 mA SHDN = 0V 0.1 0.5 µA Switching Frequency (LT3461A) ● 2.1 3.0 3.9 MHz Switching Frequency (LT3461) ● 1.0 1.3 1.7 MHz Maximum Duty Cycle (LT3461A) ● 82 % Maximum Duty Cycle (LT3461) ● 92 % Switch Current Limit 300 420 600 mA Switch VCESAT ISW = 250mA 260 350 mV Switch Leakage Current V SW = 5V 0.01 1 µA Schottky Forward Voltage I SCHOTTKY = 250mA 800 1100 mV Schottky Reverse Leakage V OUT – SW = 40V 0.03 4 µA SHDN Voltage High 1.5 V SHDN Voltage Low 0.4 V SHDN Pin Bias Current 35 50 µA Operating Ambient ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W (Note 1) ELECTRICAL CHARACTERISTICSThe ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VIN = 3V, VSHDN = 3V, unless otherwise noted. Consult LTC Marketing for parts specified with wider operating temperature ranges. ORDER PART NUMBER S6 PART MARKING LTAHG LTAEB LT3461AES6 LT3461ES6 TJMAX = 125°C, θJA = 150°C ON BOARD OVER GROUND PLANE, θJC = 120°C/W Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3461E/LT3461AE is guaranteed to meet 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.
6 VIN
5 VOUT
4 SHDN
TEMPERATURE (°C) FB VOLTAGE (V) 1.28 1.27 1.26 1.25 1.24 1.23 1.22 3461a G03 DUTY CYCLE (%) CURRENT LIMIT (mA) 9080604020 3461a G02 30 50 70 480 360 240 120 3461a G06 TEMPERATURE (°C) –60 –40 FREQUENCY (MHz) 3.9 3.6 3.3 3.0 2.7 2.4 2.1 20 60 3461a G04 –20 0 40 80 100 SHDN PIN VOLTAGE (V) 1.3 CURRENT LIMIT (mA) 1.9 2.3 3461a G05 1.5 1.7 2.1 480 420 360 300 240 180 120 TA = 25°C TA = 25°C SHDN PIN VOLTAGE (V) SHDN PIN CURRENT (µA) 1648 1 2 320 280 240 200 160 120 TA = 25°C –40 20 60–20 0 40 80 100 TEMPERATURE (°C) FREQUENCY (MHz) 1.6 1.5 1.4 1.3 1.2 1.1 1.0 3461a G01 –40 20 60–20 0 40 80 100 TYPICAL PERFOR A CE CHARACTERISTICSUW Oscillator Frequency (LT3461A) Current Limit FB Pin Voltage Current Limit in Soft-Start Mode VSW 5V/DIV VOUT 50mV/DIV 0.2µs/DIV 3461a G08 ILOAD = 60mA 70mA VOUT 100mV/DIV 50µs/DIV 3461a G09 ILOAD 35mA Switching Waveform Circuit of Figure 4 Load Transient Response Circuit of Figure 4 SHDN Pin Current Oscillator Frequency (LT3461)
- exp06 12 1 π where L is the inductance, r is the resistance of the inductor and C is the output capacitance. Table 3 gives inrush peak currents for some component selections.
Table 3. Inrush Peak Current
3461 F01a
3461 F01b
maximum output current when compared to the LT3461. more important, the LT3461A will be the better choice.
Use twice this value for the LT3461. capacitor is sufficient for most applications. capacitor values from 10pF to 22pF work well. Figure 4. 5V to 12V with Soft-Start Circuit (LT3461A)
3.3V to 5V Step-Up Converter (LT3461A) 3.3V to 5V Step-Up Converter Efficiency VIN 3.3V 4.7µH 45.3k 15k 1µF 15pF 1µF VOUT 115mA VIN VOUT SW FBSHDN GND LT3461A C1, C2: TAIYO YUDEN X7R LMK212BJ105 L1: MURATA LQH32CN4R7M33 OR EQUIVALENT 3461a TA03a OFF ON LOAD CURRENT (mA) EFFICIENCY (%) 3461a TA03b 6030 120 90 TYPICAL APPLICATIO SU 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. PACKAGE DESCRIPTIO U 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 1.50 – 1.75 (NOTE 4)2.80 BSC 0.30 – 0.45
6 PLCS (NOTE 3)DATUM ‘A’
0.09 – 0.20 (NOTE 3) S6 TSOT-23 0302
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 PIN ONE ID NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.62 MAX 0.95 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 1.4 MIN2.62 REF
1.22 REF
Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2003 LT/TP 1004 1K PRINTED IN USA RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1615/LT1615-1 300mA/80mA (I SW) Constant Off-Time, V IN: 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, High Efficiency Step-Up DC/DC Converter I SD <1µA, ThinSOT Package LT1944/LT1944-1 Dual Output 350mA/100mA (I SW), Constant Off-Time, V IN: 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, High Efficiency Step-Up DC/DC Converter I SD <1µA, MS 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 LT3460 0.32A (I SW), 1.3MHz, High Efficiency Step-Up DC/DC Converter V IN: 2.5V to 16V, VOUT(MAX) = 36V, IQ = 2mA, ISD <1µA, SC70, ThinSOT Packages LT3465/LT3465A Constant Current, 1.2MHz/2.7MHz, High Efficiency White LED V IN: 2.7V to 16V, VOUT(MAX) = 34V, IQ = 1.9mA, Boost Regulator with Integrated Schottky Diode I SD <1µA, ThinSOT Package TYPICAL APPLICATIO SU Low Profile (1mm) 3.3V to 15V Step-Up Converter 3.3V to 15V Efficiency VIN 3.3V 10µH 332k 30.1k 2.2µF 22pF 1µF VOUT 15V 25mA VIN VOUT SW FBSHDN GND LT3461A C1: TAIYO YUDEN LMK107BJ105KA C2: TAIYO YUDEN EMK316BJ225KD (X5R) L1: MURATA LQH2MCN100K02 3461a TA04a OFF ON LOAD CURRENT (mA) EFFICIENCY (%) 3461a TA04b 1052 0 3 0 15 25 VIN 47µH 280k 10k 0.47µF 50V 22pF 1µF VOUT 36V 18mA VIN VOUT SW FBSHDN GND LT3461 C1: TAIYO YUDEN X7R LMK212BJ105 C2: MURATA GRM42-6X7R474K50 L1: MURATA LQH32CN470
3461 TA05a
LOAD CURRENT (mA) EFFICIENCY (%)
3461 TA05b
5V to 36V Step-Up Converter (LT3461) 5V to 36V Efficiency 3.3V to ±5V Dual Output Converter VIN 3.3V 4.7µH 45.3k 15k 15pF 1µF VIN VOUT SW FBSHDN GND LT3461A OFF ON
3461 TA06
1µF 1µF 1µF –5V 15mA VOUT 100mA C1, C2, C3, C4: TAIYO YUDEN JMK107BJ105 D1, D2: PHILIPS PMEG2005EB L1: MURATA LQH2MCN4R7M02 10Ω