LT8708-1
36
Rev 0
D16899-0-6/18(0)
© ANALOG DEVICES, INC. 2018
RELATED PARTS
TYPICAL APPLICATION
+
–
+
–
CSPOUT
CSNOUT
EXTV
CC
VOUTLOMON
FBOUT
INTV
CC
ICN
ICP
GATEV
CC
IMON_ON
IMON_OP
IMON_INP
IMON_INN
CLKOUT
SYNC
SS
RT
V
C
MODE
CSNIN
TG1 BOOST1 SW1 BG1CSP CSN
LT8708
GND BG2 SW2 BOOST2 TG2
CSPIN
V
INCHIP
SHDN
FBIN
VINHIMON
SWEN
LDO33
DIR
RVSOFF
FWD (3V)
RVS (0V)
CSPOUT
CSNOUT
EXTV
CC
INTV
CC
ICN
ICP
GATEV
CC
IMON_ON
IMON_OP
IMON_INP
IMON_INN
CLKOUT
SYNC
SS
RT
V
C
MODE
CSNIN
TG1 BOOST1 SW1 BG1 CSP CSN
LT8708-1
GND BG2 SW2 BOOST2 TG2
CSPIN
V
INCHIP
SHDN
FBIN
VOUTLOMON
FBOUT
VINHIMON
DIR
LDO33
SWEN
RVSOFF
+
+
3.3nF
D
B1
D
B2
TO
LT8708’S
BOOST1
TO
LT8708’S
BOOST2
TO DIODE
D
B1
LD033
V
BAT2
87081 TA02a
10V
TO 16V
BATTERY
V
BAT1
24V TO 55V
BATTERY
TO DIODE
D
B2
LD033
I
OUT
I
IN
M1–M4, M8–M11: INFINEON BSC010N04LS
C
OUT3
, C
IN3
: 470μF, 50V
C
IN2
, C
IN7
,
C
OUT1
, C
OUT5
: 10µF, 50V, X7R
D
B1
, D
B2
, D
B3
, D
B4
: CENTRAL SEMI CMMR1U-02-LTE
L1, L2: 10μH, COILCRAFT SER2918H-103KL
XOR: DIODES INC. 74AHC1G86SE-7
M5–M7: T2N7002AK, TOSHIBA
C
IN4
, C
IN5
,
C
OUT6
, C
OUT7
: SUNCON, 18μF, 40V
40HVP18M
*SEE THE UNI AND
BIDIRECTIONAL
CONDUCTION
SECTION OF THE LT8708
DATA SHEET
D
B3
D
B4
TO
LT8708-1’S
BOOST1
TO
LT7081’S
BOOST2
TO DIODE
D
B3
TO DIODE
D
B4
LD033
LD033
POWER TRANSFER
DECISION LOGIC
100k
16.9k
M6
M5
18.2k
M7
XOR
68.1k
220pF
4.7μF
127k
100k
20k
54.9k
1nF
68nF
10k
365k
1μF
4.7nF
30.1k
47nF
17.4k
4.7nF
22nF
13.3k
200Ω
4.7μF
3.3Ω
4.7μF
100nF
47nF
100Ω
12.1k
133k
12.1k
93.1k
17.8k
C
OUT3
C
OUT2
C
OUT4
×2
C
OUT1
2mΩ
1Ω
0.22μF
M4
M2
M3
L1
10μH
1Ω
1.5mΩ
10Ω
10Ω
1nF
1nF
1Ω
0.22μF
1Ω
M1
C
IN3
C
IN2
C
IN1
C
IN4
×2
5mΩ
1μF
100nF
47nF
100Ω
20k
340k
DIR_CTRL
340k
17.4k
200Ω
4.7nF
17.4k
200Ω
4.7nF
4.7μF
127k
100k
54.9k
470pF
12nF
10k
365k
1μF
4.7nF
17.4k
4.7nF
17.4k
4.7nF
17.4k
4.7μF
3.3Ω
4.7μF
100nF
47nF
100Ω
C
OUT6
C
OUT7
×2
C
OUT5
2mΩ
1Ω
0.22μF
M11
M9
M10
L2, 10μH
1Ω
1.5mΩ
10Ω
10Ω
1nF
1nF
1Ω
0.22μF
1Ω
M8
C
IN7
C
IN6
C
IN5
×2
5mΩ
1μF
100nF
47nF
100Ω
20k
340k
120kHz
17.4k
200Ω
10nF
120kHz
23.7k
3.3nF
PHASE 2
PHASE 3
PHASE 4
**4-PHASE CLOCK
SIGNALS FROM
CLOCK CHIP
SUCH AS LTC6909
CLK1
CLK2
CLK3
CLK4
SEE MORE DETAILS OF THIS APPLICATION ON PAGE 33.
4-Phase 48V to 12V Bidirectional Dual Battery System with FHCM and RHCM
PART NUMBER DESCRIPTION
COMMENTS
80V Synchronous 4-Switch Buck-Boost DC/DC
Controller with Flexible Bidirectional Capability
2.8V (Need EXTV
CC
> 6.4V) ≤ V
IN
≤ 80V, 1.3V ≤ V
OUT
≤ 80V, 5mm × 8mm,
QFN-40
80V V
IN
and V
OUT
Synchronous 4-Switch Buck-
Boost DC/DC Controller
2.8V ≤ V
IN
≤ 80V, Input and Output Current Monitor, 5mm × 7mm QFN-38 and
TSSOP-38 Packages
150V V
IN
and V
OUT
Synchronous 4-Switch Buck-
Boost Controller
4.5V ≤ V
IN
≤ 150V, 1.2V ≤ V
OUT
≤ 150V, Up to 99% Efficiency Drives Logic-Level
or STD Threshold MOSFETs, TSSOP-38 Package
60V, Triple Output, Buck/Buck/Boost Synchronous
Controller with 29µA Burst Mode I
Q
4.5V (Down to 2.2V after Start-Up) ≤ V
IN
≤ 60V, V
OUT
Up to 60V,
Buck V
OUT
Range: 0.8V to 60V, Boost V
OUT
Up to 60V
150V Low I
Q
, Synchronous Step-Down
DC/DC Controller with 100% Duty Cycle
4V ≤ V
IN
≤ 140V, 150V ABS Max, PLL Fixed Frequency 50kHz to 900kHz,
0.8V ≤ V
OUT
≤ 60V, Adjustable 5V to 10V Gate Drive, I
Q
= 40μA,
4mm × 5mm QFN-24, TSSOP-24, TSSOP-38(31) Packages
Bidirectional Multiphase DC/DC Synchronous Buck
or Boost On-Demand Controller
V
IN
/V
OUT
Up to 100V, Ideal for High Power 48V/12V Automotive Battery
Applications