DatasheetsPDF.com

LT1941 Dataheets PDF



Part Number LT1941
Manufacturers Linear Technology
Logo Linear Technology
Description Triple Monolithic Switching Regulator
Datasheet LT1941 DatasheetLT1941 Datasheet (PDF)

www.DataSheet4U.com LT1941 Triple Monolithic Switching Regulator FEATURES s s DESCRIPTIO s s s s s s s Wide Input Range: 3.5V to 25V Three Switching Regulators with Internal Power Switches: 3A Step-Down, 2A Step-Down, 1.5A Inverting/Boost Antiphase Switching Reduces Ripple Independent Shutdown/Soft-Start Pins Independent Power Good Indicators Ease Supply Sequencing Input Voltage Power Good Indicators Monitor Input Supply Uses Small Inductors and Ceramic Capacitors Constant 1.1MHz Switchi.

  LT1941   LT1941



Document
www.DataSheet4U.com LT1941 Triple Monolithic Switching Regulator FEATURES s s DESCRIPTIO s s s s s s s Wide Input Range: 3.5V to 25V Three Switching Regulators with Internal Power Switches: 3A Step-Down, 2A Step-Down, 1.5A Inverting/Boost Antiphase Switching Reduces Ripple Independent Shutdown/Soft-Start Pins Independent Power Good Indicators Ease Supply Sequencing Input Voltage Power Good Indicators Monitor Input Supply Uses Small Inductors and Ceramic Capacitors Constant 1.1MHz Switching Frequency Thermally Enhanced 28-Lead TSSOP Package The LT®1941 is a triple current mode DC/DC converter with internal power switches. Two of the regulators are step-down converters with 3A and 2A power switches. The third regulator can be configured as a boost, inverter or SEPIC converter and has a 1.5A power switch. All three converters are synchronized to a 1.1MHz oscillator. The two step-down converters run with opposite phases, reducing input ripple current. The output voltages are set with external resistor dividers and each regulator has independent shutdown and soft-start circuits. Each regulator generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs. The high switching frequency offers several advantages by permitting the use of small inductors and ceramic capacitors. Small inductors and capacitors lead to a very small triple output solution. The constant switching frequency, combined with low impedance ceramic capacitors, result in low, predictable output ripple. With its wide input voltage range of 3.5V to 25V, the LT1941 regulates a broad array of power sources from 4-cell batteries and 5V logic rails to unregulated wall transformers, lead acid batteries and distributed-power supplies. U APPLICATIO S s s s s s s Cable Modems DSL Modems Distributed Power Regulation Wall Transformer Regulation Disk Drives DSP Power , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO VIN 4.7V TO 14V 130k 100k VOUT1 100k PGOOD1 VOUT2 100k 100k PGOOD1 PGOOD2 PGOOD3 0.22µF 3.3µH VOUT2 3.3V 1.4A 5GOOD 12GOOD 3µH 13.7k 3300pF 33µF 7.32k 3.3k 1.5nF 0.22µF 5GOOD BOOST1 PGOOD2 BOOST2 SW2 FB2 VC2 1000pF 10k 2.49k 22µF 1.5nF 12GOOD PGOOD3 LT1941 SW1 FB1 VC1 VOUT1 1.8V 2.4A 10.7k RUNSS1 RUNSS2 SW3 BIAS1 BIAS2 VC3 FB3 RUNSS3 GND NFB 22µH VOUT3* –12V 350mA 10µF 1µF 22µH 133k 13.7k 22nF 10µF *240mA AT VIN = 5V, 550mA AT VIN = 12V 1.5nF 1.5k 1941 F01 Figure 1. Triple Output Power Supply: 3.3V, 1.8V, –12V 1941f U Start-Up Waveforms with Sequencing RUN/SS 2V/DIV VOUT1 2V/DIV VOUT2 5V/DIV VOUT3 10V/DIV IVIN(AVE) 1A/DIV PGOOD2 5V/DIV 1941 F01b U 1 LT1941 www.DataSheet4U.com ABSOLUTE (Note 1) AXI U RATI GS U U W PACKAGE/ORDER I FOR ATIO TOP VIEW VIN VIN SW1 SW1 BOOST1 PGOOD1 VC1 FB1 PGOOD2 1 2 3 4 5 6 7 8 9 29 28 BIAS2 27 SW3 26 PGND 25 VIN 24 BOOST2 23 SW2 22 VIN 21 PGOOD3 20 FB3 19 NFB 18 VC3 17 5GOOD 16 12GOOD 15 BIAS1 VIN Pin ...................................................... (– 0.3V), 25V BOOST Pin Voltage .................................................. 35V BOOST Above SW Pin .............................................. 25V BIAS1, BIAS2 Pins ................................................... 25V PGOOD, 5GOOD, 12GOOD Pins ............................... 25V RUN/SS, VC, FB, NFB Pins .......................................... 3V SW1, SW2 Voltage .................................................... VIN SW3 Voltage ............................................................ 40V Maximum Junction Temperature (Note 6) ............ 125°C Operating Ambient Temperature Range (Note 2) .................................................. –40°C to 85°C Storage Temperature Range .................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................... 300°C ELECTRICAL CHARACTERISTICS PARAMETER Minimum Operating Voltage VIN Quiescent Current BIAS1 Quiescent Current BIAS2 Quiescent Current Shutdown Current Reference Voltage Line Regulation VC Source Current VC Sink Current VC Clamp Voltage Switching Frequency Switching Phase Foldback Frequency RUN/SS Current RUN/SS Threshold 5GOOD Threshold 5GOOD Voltage Output Low 5GOOD Leakage 12GOOD Threshold VIN Rising The q denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN, VBIAS1, VBIAS2 = 5V, VBOOST1, VBOOST2 = 8V, unless otherwise noted. (Note 2) CONDITIONS q Not Switching Not Switching Not Switching VRUNSS1,2,3 = 0V 5V < VIN < 25V VC = 0.6V VC = 0.6V q SW1 to SW2 SW1 to SW3 VFB = 0V I5GOOD = 125µA, VIN = 4V V5GOOD = 2V VIN Rising 2 U W W W ORDER PART NUMBER LT1941EFE VC2 10 FB2 11 RUN/SS1 12 RUN/SS2 13 RUN/SS3 14 FE PACKAGE 28-LEAD PLASTIC TSSOP TJMAX = 125°C, θJA = 25°C/ W EXPOSED PAD (PIN 29) IS GND MUST BE SOLDERED TO PCB Consult LTC Marketing for parts specified with wider operating temperature ranges. MIN TYP 3.1 2 5 1.6 50 0.01 100 10.


LTC2928 LT1941 LTC3703-5


@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site.
(Privacy Policy & Contact)