LT3688
28
3688f
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2011
LT 0111 • PRINTED IN USA
RELATED PARTS
PART NUMBER DESCRIPTION COMMENTS
LT3640 35V, 55V MAX, Dual (1.3A, 1.1A), 2.5MHz High Effi ciency Step-
Down DC/DC Converter with POR Reset and Watchdog Timer
V
IN
Min = 4V, V
IN
Max = 35V, Transient to 55V, V
OUT(MIN)
= 0.6V,
I
Q
= <290µA, I
SD
= <1µA, 4mm × 5mm QFN-28 TSSOP-28E Package
LT3689/LT3689–5 36V, 60V Transient Protection, 800mA, 2.2MHz High Effi ciency
MicroPower Step-Down DC/DC Converter with POR Reset and
Watchdog Timer
V
IN
Min = 3.6V, V
IN
Max = 36V, Transient to 60V, V
OUT(MIN)
= 0.8V,
I
Q
= 75µA, I
SD
= <1µA, 3mm × 3mm QFN-16 Package
LT3686 37V, 55Vmax, 1.2A, 2.5MHz High Effi ciency Step-Down DC/DC
Converter
V
IN
Min = 3.6V, V
IN
Max = 37V, Transient to 55V, V
OUT(MIN)
= 1.21V,
I
Q
= 1.1mA, I
SD
= <1µA, 3mm × 3mm DFN-10 Package
LT3682 36V, 60Vmax, 1A, 2.2MHz High Effi ciency Micropower Step-
Down DC/DC Converter
V
IN
Min = 3.6V, V
IN
Max = 36V, V
OUT(MIN)
= 0.8V,
I
Q
= 75µA, I
SD
= <1µA, 3mm × 3mm DFN-12 Package
LT3971 38V, 1.2A (I
OUT
), 2MHz, High Effi ciency Step-Down DC/DC
Converter with only 2.8uA of Quiescent Current
V
IN
Min = 4.2V, V
IN
Max = 38V, V
OUT(MIN)
= 1.2V,
I
Q
= 2.8µA, I
SD
= <1µA, 3mm × 3mm DFN-10, MSOP-10E Package
LT3991 55V, 1.2A (I
OUT
), 2MHz, High Effi ciency Step-Down DC/DC
Converter with only 2.8uA of Quiescent Current
V
IN
Min = 4.2V, V
IN
Max = 55V, V
OUT(MIN)
= 1.2V,
I
Q
= 2.8µA, I
SD
= <1µA, 3mm × 3mm DFN-10, MSOP-10E Package
LT3970 40V, 350mA (I
OUT
), 2MHz, High Effi ciency Step-Down DC/DC
Converter with only 2.5uA of Quiescent Current
V
IN
Min = 4.2V, V
IN
Max = 40V, V
OUT(MIN)
= 1.2V,
I
Q
= 2.5µA, I
SD
= <1µA, 2mm × 3mm DFN-10, MSOP-10E Package
LT3990 60V, 350mA (I
OUT
), 2MHz, High Effi ciency Step-Down DC/DC
Converter with only 2.5uA of Quiescent Current
V
IN
Min = 4.2V, V
IN
Max = 60V, V
OUT(MIN)
= 1.2V,
I
Q
= 2.5µA, I
SD
= <1µA, 3mm × 3mm DFN-10, MSOP-16E Package
TYPICAL APPLICATION
CONFIG
V
IN
LT3688
GND
BIASEN/UVLO
BST1
C2
0.22µF
ON OFF
C1
4.7µF
V
OUT1
5V
800mA
V
IN
6V TO 36V
C4
22µF
C6
10pF
C7
10pF
L1
18µH
L2
12µH
R1
523k
R2
100k
R3
340k
R4
100k
C8
1nF
C9
1nF
µP
C3
0.22µF
SW1
DA1
D2D1
BST2
SW2
DA2
FB1
RUN/SS1
WDE
WDI
WDO
RST1
RST2
I/O
I/O
RESET
FB2
RUN/SS2
C
WDT
C
POR1
C
POR2
RT
SYNC
C5
22µF
C12
1nF
3688 TA06
C10
4.7nF
C11
4.7nF
R5
49.9k
C1-C5: X5R OR X7R
D1, D2: DFLS140
f
SW
= 1MHz: 7V < V
IN
< 21V
V
OUT2
3.3V
800mA
1MHz 5V and 3.3V Regulator with Power-On Reset and Watchdog Timers
