DN91 - 5V to 3.3V Circuit Collection

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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
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