LTC3857
38
3857fd
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2009
LT 0112 REV D • PRINTED IN USA
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LTC3859 Low I
Q
, Triple Output Buck/Buck-Boost Synchronous
DC/DC Controller
Outputs (≥5V) Remain in Regulation Through Cold Crank, 2.5V ≤ V
IN
≤ 38V,
V
OUT(BUCK)
Up to 24V, V
OUT(BOOST)
Up to 60V, I
Q
= 55µA,
LTC3868/LTC3868-1 Low I
Q
, Dual Output 2-Phase Synchronous
Step-Down DC/DC Controller with 99% Duty Cycle
Phase-Lockable Fixed Operating Frequency 50kHz to 900kHz,
4V ≤ V
IN
≤ 24V, 0.8V ≤ V
OUT
≤ 14V, I
Q
= 170µA,
LTC3858/LTC3858-1 Low I
Q
, Dual Output 2-Phase Synchronous
Step-Down DC/DC Controller with 99% Duty Cycle
Phase-Lockable Fixed Operating Frequency 50kHz to 900kHz,
4V ≤ V
IN
≤ 38V, 0.8V ≤ V
OUT
≤ 24V, I
Q
= 170µA,
LTC3890/LTC3890-1 60V, Low I
Q
, Dual 2-Phase Synchronous Step-Down
DC/DC Controller with 99% Duty Cycle
Phase-Lockable Fixed Operating Frequency 50kHz to 900kHz,
4V ≤ V
IN
≤ 60V, 0.8V ≤ V
OUT
≤ 24V, I
Q
= 50µA,
LTC3834/LTC3834-1 Low I
Q
, Synchronous Step-Down DC/DC Controller Phase-Lockable Fixed Operating Frequency 140kHz to 650kHz,
4V ≤ V
IN
≤ 36V, 0.8V ≤ V
OUT
≤ 10V, I
Q
= 30µA,
LTC3835/LTC3835-1 Low I
Q
, Synchronous Step-Down DC/DC Controller Phase-Lockable Fixed Operating Frequency 140kHz to 650kHz,
4V ≤ V
IN
≤ 36V, 0.8V ≤ V
OUT
≤ 10V, I
Q
= 80µA,
LT3845A Low I
Q
, High Voltage Synchronous Step-Down
DC/DC Controller
Adjustable Fixed Operating Frequency 100kHz to 500kHz,
4V ≤ V
IN
≤ 60V, 1.23V ≤ V
OUT
≤ 36V, I
Q
= 120µA, TSSOP-16
LTC3824 Low I
Q
, High Voltage DC/DC Controller, 100%
Duty Cycle
Selectable Fixed 200kHz to 600kHz Operating Frequency,
4V ≤ V
IN
≤ 60V, 0.8V ≤ V
OUT
≤ V
IN
, I
Q
= 40µA, MSOP-10E
TYPICAL APPLICATION
SENSE1
+
SENSE1
–
SENSE2
–
SENSE2
+
V
FB1
I
TH1
SGND
EXTV
CC
RUN1
RUN2
FREQ
SS2
SS1
V
FB2
TRACK/SS1
I
LIM
PHSMD
CLKOUT
PLLIN/MODE
PGOOD1
PGOOD2
BG1
SW1
BOOST1
TG1
V
IN
V
OUT
INTV
CC
PGND
TG2
BG2
BOOST2
SW2
C1
1nF
R
B1
698k
C
OUT1
, C
OUT2
: SANYO 16T0C22M
L1: SUMIDA CDEP106-6ROM
L2: SUMIDA CDEP106-6ROM
MTOP1, MTOP2: INFINEON BSZ097NO4LS
MBOT1, MBOT2: INFINEON BSZ097NO4LS
C
F1
10pF
C
ITH1A
68pF
C
SS1
0.1µF
C
ITH1
3300pF
C
INT
4.7µF
C
B1
0.47µF
C
B2
0.47µF
D1
V
IN
19V TO 28V
D2
LTC3857
L1
6µH
L2
6µH
R
SENSE1
5m
R
SENSE2
5m
MBOT1
MTOP2
MTOP1
MBOT2
3857 TA07
100k
100k
INTV
CC
C
OUT1
22µF
16V
V
OUT
12V
12.5A
C
IN
10µF
50V
C
OUT2
22µF
16V
10µF
16V
10µF
16V
R
A1
49.9k
R
ITH1
2.94k
I
TH2
V
FB1
I
TH1
10µF
50V
C2
1nF
High Efficiency 2-Phase 12V/150W Step-Down Converter
