Datasheet LT1777 (Analog Devices) - 24
| Manufacturer | Analog Devices |
| Description | Low Noise Step-Down Switching Regulator |
| Pages / Page | 24 / 24 — TYPICAL APPLICATION. Minimum PC Board Size Application. Minimum PC Board … |
| File Format / Size | PDF / 286 Kb |
| Document Language | English |
TYPICAL APPLICATION. Minimum PC Board Size Application. Minimum PC Board Area Application. RELATED PARTS. PART NUMBER
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LT1777
U TYPICAL APPLICATION Minimum PC Board Size Application
circuit is capable of delivering up to 300mA at 5V, from input voltages as high as 28V. The only disadvantage is The previously described basic applications employ power that due to the increased resistance in the inductor, the path parts which are capable of delivering the full rated circuit is no longer capable of withstanding indefinite short input supply voltage and output current capabilities of the circuits to ground. The LT1777 will still current limit at its LT1777. A substantial improvement in printed circuit nominal ILIM value, but this will overheat the inductor. board area requirements can be achieved with the circuit Momentary short circuits of a few seconds or less can still shown below. This uses a physically smaller and less be tolerated. costly power inductor and a tantalum input capacitor. This
Minimum PC Board Area Application
VIN 10 10V TO 28V + C1 C6 22 V µF IN 0.1µF 3 4 35V L1 SHDN VCC C5 0µH TO 2.2µH L2 100pF LT1777 (SEE BELOW) 200µH 12 6 V SYNC V OUT SW 5V 14 5 V V + C D C2 R1 C7 13 C4 R3 D1 100µF 36.5k FB 0.1µF 10V 1% 100pF 12k SGND C3 2200pF 7 R2 12.1k 1% C1: AVX E CASE TPSE226M035R0300 L1: SENSE INDUCTOR CAN VARY FROM 0µH TO 2.2µH 1777 TA03 C2: AVX D CASE TPSD107M010R0080 AS PER APPLICATION. SEE PREVIOUS SCHEMATICS C3, C4, C5: NPO OR X7R FOR EXAMPLES C6, C7: Z5U L2: COILCRAFT CTX200-1 OR SIMILAR D1: MOTOROLA 100V, 1A SMD SCHOTTKY MBRS1100
RELATED PARTS PART NUMBER DESCRIPTION COMMENTS
LT1076 100kHz, 2A Step-Down Switching Regulator Integrated 2A Switch, VIN Up to 46V LT1533 Ultralow Noise 1A Switching Regulator Push-Pull Design for Low Noise Isolated Supplies LT1534 Ultralow Noise 2A Switching Regulator Ultralow Noise Regulator for Boost Topologies LT1576 200kHz, 1.5A Step-Down Switching Regulator Output Up to 1.25A, Integrated Switch, SO-8 Package LTC1622 Low VIN Step-Down DC/DC Controller Fixed Frequency 550kHz Operation, MSOP Package LTC1624 High Efficiency SO-8 DC/DC Controller 200kHz Operation, VIN from 3.5V to 36V, SO-8 Package LT1676/LT1776 Wide Input Range, High Efficiency, Step-Down Voltage Regulator 7.4V to 60V Input, 100/200kHz Operation, 700mA Internal Switch 1777f LT/TP 0899 4K • PRINTED IN USA 24 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1999
U TYPICAL APPLICATION Minimum PC Board Size Application
circuit is capable of delivering up to 300mA at 5V, from input voltages as high as 28V. The only disadvantage is The previously described basic applications employ power that due to the increased resistance in the inductor, the path parts which are capable of delivering the full rated circuit is no longer capable of withstanding indefinite short input supply voltage and output current capabilities of the circuits to ground. The LT1777 will still current limit at its LT1777. A substantial improvement in printed circuit nominal ILIM value, but this will overheat the inductor. board area requirements can be achieved with the circuit Momentary short circuits of a few seconds or less can still shown below. This uses a physically smaller and less be tolerated. costly power inductor and a tantalum input capacitor. This
Minimum PC Board Area Application
VIN 10 10V TO 28V + C1 C6 22 V µF IN 0.1µF 3 4 35V L1 SHDN VCC C5 0µH TO 2.2µH L2 100pF LT1777 (SEE BELOW) 200µH 12 6 V SYNC V OUT SW 5V 14 5 V V + C D C2 R1 C7 13 C4 R3 D1 100µF 36.5k FB 0.1µF 10V 1% 100pF 12k SGND C3 2200pF 7 R2 12.1k 1% C1: AVX E CASE TPSE226M035R0300 L1: SENSE INDUCTOR CAN VARY FROM 0µH TO 2.2µH 1777 TA03 C2: AVX D CASE TPSD107M010R0080 AS PER APPLICATION. SEE PREVIOUS SCHEMATICS C3, C4, C5: NPO OR X7R FOR EXAMPLES C6, C7: Z5U L2: COILCRAFT CTX200-1 OR SIMILAR D1: MOTOROLA 100V, 1A SMD SCHOTTKY MBRS1100
RELATED PARTS PART NUMBER DESCRIPTION COMMENTS
LT1076 100kHz, 2A Step-Down Switching Regulator Integrated 2A Switch, VIN Up to 46V LT1533 Ultralow Noise 1A Switching Regulator Push-Pull Design for Low Noise Isolated Supplies LT1534 Ultralow Noise 2A Switching Regulator Ultralow Noise Regulator for Boost Topologies LT1576 200kHz, 1.5A Step-Down Switching Regulator Output Up to 1.25A, Integrated Switch, SO-8 Package LTC1622 Low VIN Step-Down DC/DC Controller Fixed Frequency 550kHz Operation, MSOP Package LTC1624 High Efficiency SO-8 DC/DC Controller 200kHz Operation, VIN from 3.5V to 36V, SO-8 Package LT1676/LT1776 Wide Input Range, High Efficiency, Step-Down Voltage Regulator 7.4V to 60V Input, 100/200kHz Operation, 700mA Internal Switch 1777f LT/TP 0899 4K • PRINTED IN USA 24 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1999
