LT8705
TYPICAL APPLICATION
12V Output Converter Accepts 4V to 80V Input (5.5V Minimum to Start)
M1
×2
15µH
V
7mΩ
OUT
12V
M4
V
IN
4V TO 80V
(INCREASED
+
+
5.0A (V ≥ 5.5V)
IN
OUT3
M3
C
IN2
×6
C
C
OUT1B
×3
M2
C
IN1
4.5A (V ≥ 5.0V)
IN
C
×2
OUT1A
×2
×2
TO DIODE
TO DIODE
V
RIPPLE
OUT
4.0A (V ≥ 4.5V)
IN
IN
D
D
+
FOR V > 60V)
IN
B1
B2
3.5A (V ≥ 4.0V)
C
OUT2
1nF
1nF
10Ω
10Ω
×3
0.22µF
0.22µF
4mΩ
2Ω*
102k
TG1 BOOST1 SW1 BG1 CSP
CSNIN
CSPIN
CSN
GND BG2 SW2 BOOST2 TG2
CSPOUT
4.7µF
CSNOUT
V
IN
EXTV
CC
SHDN
SWEN
LDO33
MODE
FBIN
RT
FBOUT
100k
INTV
11.3k
CC
CC
GATEV
4.7µF
4.7µF
LT8705
SRVO_FBIN
SRVO_FBOUT
SRVO_IIN
4Ω
C
C
C
C
C
: 220µF, 100V
IN1
IN2
38.3k
SS
SRVO_IOUT
IMON_IN
: 4.7µF, 100V, TDK C4532X7S2A475M
, C : 22µF, 25V, TDK C4532X7R1E226M
D
D
B2
B1
OUT1A OUT1B
: 100µF, 16V, SANYO OS-CON 16SA100M
: 470µF, 16V
4.7µF
OUT2
OUT3
TO
TO
IMON_OUT
V
BOOST1 BOOST2
CLKOUT
202kHz
SYNC
C
D
, D : CENTRAL SEMI CMMR1U-02-LTE
B1 B2
20k
215k
16.5k
L1: 15µH, WURTH 7443631500
M1, M2: FAIRCHILD FDMS86101
M3, M4: FAIRCHILD FDMS7692
*2Ω FROM TG1 TO EACH SEPARATE M1 GATE
26.1k
22nF
4.7µF
1µF
220pF
10nF
8705 TA03a
Efficiency vs Output Current
Input Transient (4V to 80V)
100
95
90
85
80
V
OUT
200mV/DIV
V
IN
20V/DIV
V
V
V
V
V
= 60V
= 40V
= 20V
= 12V
= 5V
IN
IN
IN
IN
IN
8705 TA03c
0
1
2
3
4
5
I
= 2A
10ms/DIV
LOAD
LOAD CURRENT (A)
8705 TA03c
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
4.7V ≤ V ≤ 60V, 1.2V ≤ 60V, Regulates V , I
LT3791-1
LTC3789
LT3758
60V High Efficiency (Up to 98%) Synchronous 4-Switch
Buck-Boost DC/DC Controller
or I , TSSOP-38
IN
OUT OUT
IN
High Efficiency (Up to 98%) Synchronous 4-Switch
Buck-Boost DC/DC Controller
4V ≤ V ≤ 38V, 0.8V ≤ V
≤ 38V, SSOP-28, 4mm × 5mm QFN-28
IN
OUT
High Input Voltage, Boost, Flyback, SEPIC and Inverting
Controller
5.5V ≤ V ≤ 100V, Positive or Negative V , 3mm × 3mm DFN-10
IN
OUT
or MSOP-10E
LTC3115-1
LTM4609
40V, 2A Synchronous Buck-Boost DC/DC Converter
High Efficiency Buck-Boost DC/DC µModule Regulator
2.7V ≤ V ≤ 40V, 2.7V ≤ V
≤ 40V, 4mm × 5mm DFN-16, TSSOP-20
≤ 34V, 15mm × 15mm × 2.8mm
IN
OUT
OUT
4.5V ≤ V ≤ 36V, 0.8V ≤ V
IN
8705p
LT 0113 • PRINTED IN USA
44 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/8705
●
●
(408)432-1900 FAX: (408) 434-0507 www.linear.com/8705
LINEAR TECHNOLOGY CORPORATION 2013
Linear [ Linear ]
