Datasheet LT1372, LT1377 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | 500kHz and 1MHz High Efficiency 1.5A Switching Regulators |
| Pages / Page | 12 / 1 — FEATURES. DESCRIPTIO. Faster Switching with Increased Efficiency. Uses … |
| File Format / Size | PDF / 203 Kb |
| Document Language | English |
FEATURES. DESCRIPTIO. Faster Switching with Increased Efficiency. Uses Small Inductors: 4.7. APPLICATIO S. TYPICAL APPLICATIO
Model Line for this Datasheet
Text Version of Document
LT1372/LT1377 500kHz and 1MHz High Efficiency 1.5A Switching Regulators
U FEATURES DESCRIPTIO
■
Faster Switching with Increased Efficiency
The LT®1372/LT1377 are monolithic high frequency ■
Uses Small Inductors: 4.7
µ
H
switching regulators. They can be operated in all standard ■ All Surface Mount Components switching configurations including boost, buck, flyback, ■ Only 0.5 Square Inch of Board Space forward, inverting and “Cuk.” A 1.5A high efficiency switch ■ Low Minimum Supply Voltage: 2.7V is included on the die, along with all oscillator, control and ■ Quiescent Current: 4mA Typ protection circuitry. All functions of the LT1372/LT1377 ■ Current Limited Power Switch: 1.5A are integrated into 8-pin SO/PDIP packages. ■ Regulates Positive or Negative Outputs The LT1372/LT1377 typically consumes only 4mA quies- ■ Shutdown Supply Current: 12µA Typ cent current and has higher efficiency than previous parts. ■ Easy External Synchronization High frequency switching allows for very small inductors ■ 8-Pin SO or PDIP Packages to be used. All surface mount components consume less than 0.5 square inch of board space.
U APPLICATIO S
New design techniques increase flexibility and maintain ■ Boost Regulators ease of use. Switching is easily synchronized to an exter- ■ CCFL Backlight Driver nal logic level source. A logic low on the shutdown pin ■ Laptop Computer Supplies reduces supply current to 12µA. Unique error amplifier ■ Multiple Output Flyback Supplies circuitry can regulate positive or negative output voltage ■ Inverting Supplies while maintaining simple frequency compensation tech- niques. Nonlinear error amplifier transconductance re- duces output overshoot on start-up or overload recovery. Oscillator frequency shifting protects external compo- nents during overload conditions. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO 12V Output Efficiency 5V-to-12V Boost Converter
100 5V D1 V L1* IN = 5V 4.7µH MBRS120T3 V † OUT 90 5 12V VIN R1 4 8 ON V 53.6k S/S SW OFF 80 1% *FOR LT1372 USE 10µH LT1372/LT1377 COILCRAFT DO1608-472 (4.7µH) OR 2 + + C1** FB COILCRAFT DT3316-103 (10µH) OR C4** 70 22µF 22µF SUMIDA CD43-4R7 (4.7µH) OR EFFICIENCY (%) GND VC SUMIDA CD73-100KC (10µH) OR 6, 7 1 R2 **AVX TPSD226M025R0200 60 6.19k C2 †MAX I 1% OUT 0.047µF L1 IOUT (LT1377) IOUT (LT1372) R3 C3 4.7µH 0.25A NA 50 2k 0.0047µF 10 0.35A 0.29A 0.01 0.1 1 µH OUTPUT CURRENT (A) LT1372 • TA01 LT1372 • TA02 1
U FEATURES DESCRIPTIO
■
Faster Switching with Increased Efficiency
The LT®1372/LT1377 are monolithic high frequency ■
Uses Small Inductors: 4.7
µ
H
switching regulators. They can be operated in all standard ■ All Surface Mount Components switching configurations including boost, buck, flyback, ■ Only 0.5 Square Inch of Board Space forward, inverting and “Cuk.” A 1.5A high efficiency switch ■ Low Minimum Supply Voltage: 2.7V is included on the die, along with all oscillator, control and ■ Quiescent Current: 4mA Typ protection circuitry. All functions of the LT1372/LT1377 ■ Current Limited Power Switch: 1.5A are integrated into 8-pin SO/PDIP packages. ■ Regulates Positive or Negative Outputs The LT1372/LT1377 typically consumes only 4mA quies- ■ Shutdown Supply Current: 12µA Typ cent current and has higher efficiency than previous parts. ■ Easy External Synchronization High frequency switching allows for very small inductors ■ 8-Pin SO or PDIP Packages to be used. All surface mount components consume less than 0.5 square inch of board space.
U APPLICATIO S
New design techniques increase flexibility and maintain ■ Boost Regulators ease of use. Switching is easily synchronized to an exter- ■ CCFL Backlight Driver nal logic level source. A logic low on the shutdown pin ■ Laptop Computer Supplies reduces supply current to 12µA. Unique error amplifier ■ Multiple Output Flyback Supplies circuitry can regulate positive or negative output voltage ■ Inverting Supplies while maintaining simple frequency compensation tech- niques. Nonlinear error amplifier transconductance re- duces output overshoot on start-up or overload recovery. Oscillator frequency shifting protects external compo- nents during overload conditions. , LTC and LT are registered trademarks of Linear Technology Corporation.
U TYPICAL APPLICATIO 12V Output Efficiency 5V-to-12V Boost Converter
100 5V D1 V L1* IN = 5V 4.7µH MBRS120T3 V † OUT 90 5 12V VIN R1 4 8 ON V 53.6k S/S SW OFF 80 1% *FOR LT1372 USE 10µH LT1372/LT1377 COILCRAFT DO1608-472 (4.7µH) OR 2 + + C1** FB COILCRAFT DT3316-103 (10µH) OR C4** 70 22µF 22µF SUMIDA CD43-4R7 (4.7µH) OR EFFICIENCY (%) GND VC SUMIDA CD73-100KC (10µH) OR 6, 7 1 R2 **AVX TPSD226M025R0200 60 6.19k C2 †MAX I 1% OUT 0.047µF L1 IOUT (LT1377) IOUT (LT1372) R3 C3 4.7µH 0.25A NA 50 2k 0.0047µF 10 0.35A 0.29A 0.01 0.1 1 µH OUTPUT CURRENT (A) LT1372 • TA01 LT1372 • TA02 1
