advertisement 5V to 3.3V Circuit Collection – Design Note 91 Richard Markell and Craig Varga High Efficiency 3.3V Regulator INPUT VOLTAGE 5V + 6 VIN 7 3 IPGM SHDN 8 3.3V Battery-Powered Supply with Shutdown 8 3w 22μF* 25V LBIN 50μH† GND 1N5818 + 2w 47μF** 16V 4 * AVX TPSD226K025 ** AVX TPSD476K016 † COILTRONICS CTX50-4 OUT 1 LT1121-3.3 5V 5 1 VOUT LTC1174-3.3 2 5 LBOUT SW IN 0.1μF + 1μF SOLID TANTALUM SHDN GND VOUT 3.3V 425mA 3 VSHDN (PIN 5) OUTPUT < 0.25 OFF > 2.8 ON NC ON 1174 TA04 The LTC ®1174-3.3 current mode DC/DC converter provides efficiencies better than 90% over a wide load current range while requiring only 1μA in Shutdown. 3.3V OUT 150mA LT1121 • TA01 The LT1121-3.3 low dropout linear regulator provides up to 150mA output current with 30μA quiescent current. 3.3V Supply with Shutdown 5 IN OUT 1 + LT1129-3.3 VIN > 4V 4 3.3V OUT 700mA SENSE 2 3.3μF SOLID TANTALUM SHDN The LT1129-3.3 low dropout linear regulator provides more output current (to 700mA) with only a slight increase in quiescent current (50μA). GND 3 VSHDN (PIN 4) OUTPUT < 0.25 OFF > 2.8 ON NC ON LT1129 • TA01 LT1585 Linear Regulator Optimized for Desktop Pentium Processor Applications 1 INPUT 5V + U1* LT1585CT VOUT VIN ADJ C1, C2 220μF 10V SANYO OS-CON (2w) *IOUT = 7A, LT1584 IOUT = 4A, LT1585 IOUT = 3A, LT1587 R1 110Ω 1/2% 3 R2 189Ω 1/2% PLACE IN SOCKET CAVITY 2 + C3 0.33μF SMD C10 TO C19 1μF SMD (10) + C4 TO C9 100μF 10V AVX TYPE TPS (6) OUTPUT 3.38V μP LOAD Linear regulator circuits provide simple solutions with superior transient performance for desktop resident Pentium processorbased systems DN91 • TA01 L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. 11/94/91_conv Data Sheet Download www.linear.com Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com For applications help, call (408) 432-1900 dn91f_conv LT/GP 1194 160K • PRINTED IN THE USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 © LINEAR TECHNOLOGY CORPORATION 1994 INPUT 5V C1 3300pF R1 510Ω VIN 5V C8 100pF C13 1μF C5 220pF 4 6 10 C2 0.1μF NDRIVE SENSE – SENSE + LTC1148 PDRIVE C9 1000pF R7 5.1k 9 C7 3300pF 11 12 SGND VFB PGND CT ITH SHDN VIN 3 C5 2200pF Q2 Si9410DY Q1 Si9430DY D1 MBRS140T3 L1 16μH C6 22μF w 2 10V R2 0.033Ω + C9 100pF C3 220μF 10V R4 60.4k 1% R3 105k 1% + C4 220μF 10V C10 TO C15 + 1μF SMD (6w) C16 TO C20 220μF 10V AVX TYPE TPS (5w) PLACE IN μP SOCKET CAVITY AN54 • TA09 μP LOAD This circuit achieves >90% efficiency using an LTC1148 synchronous switching regulator which consumes a mere 180μA quiescent current. D2 MBR120T3 C6 0.22μF 2 3 7 6 5 4 LTC1266 SENSE – SENSE + LBIN LBO TDRV 8 9 13 14 1 11 12 10 15 16 PWRVIN BDRV SHDN SGND VFB PGND PINV ITH CT VIN BINH C10 1000pF D1 MBR120T3 C5 1μF Q2 Si9410 Q3 Si9410 C12 220μF w 2 10V D3 MBRS320T3 R9 5.76k 1% R3 100Ω Q1 Si9410 L1 6μH + R10 100Ω R4 0.015Ω R6 10k 1% + C10 TO C19 + 1μF SMD (10) C20 TO C25 100μF 10V AVX TYPE TPS (6) PLACE IN μP SOCKET CAVITY CONNECT SENSE INPUT AT μP VCC PINS μP LOAD VOUT 3.38V 7A NOTE UNLESS OTHERWISE SPECIFIED: ALL RESISTORS OHMS 5%, 1/8W, CHIP 1206 ALL CAPACITORS CERAMIC, 10%, CHIP 1206 ALL POLARIZED CAPACITORS TANTALUM, 20% SMT, LOW ESR, AVX TPS-SERIES DN91 • TA02 C1 TO C4 330μF 6.3V (4) R5 100Ω SENSE The LTC1266 drives N-channel MOSFETs directly and provides 7A output current at efficiencies greater than 90%. LTC1266 Switching Regulator Converts 5V to 3.38V at 7A for Pentium and Other High Speed μPs 14 7 8 1 + LTC1148 5V to 3.38V Pentium Power Solution 3.5A Output Current