LT8705_15 Datasheet, PDF (44/44 Pages) Linear Technology – 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller

LT8705
Typical Application
12V Output Converter Accepts 4V to 80V Input (5.5V Minimum to Start)
V_IN
4V TO 80V
(INCREASED
V_OUT RIPPLE
FOR V_IN > 60V)
1µF
+
C_IN1
M1
×2
C_IN2
×6
TO DIODE
D_B1
0.22µF
2Ω*
15µH
M2
M3
×2
1nF
10Ω
4mΩ
1nF
10Ω
M4
TO DIODE
D_B2
0.22µF
C_OUT1A
×2
7mΩ
C_OUT1B
×3
+
V_OUT
+
12V
C_OUT3
×3
5.0A
4.5A
(V_IN
(V_IN
≥
≥
5.5V)
5.0V)
4.0A (V_IN ≥ 4.5V)
C_OUT2 ^{3.5A (V}IN ^{≥ 4.0V)}
×2
102k
38.3k
20k
4.7µF
TG1 BOOST1 SW1 BG1 CSP
CSNIN
CSPIN
100k
V_IN
SHDN
SWEN
LDO33
MODE
FBIN
RT
SS
215k
V_C
16.5k
1µF
220pF
10nF
CSN
LT8705
CLKOUT
202kHz
GND BG2 SW2 BOOST2 TG2
CSPOUT
CSNOUT
EXTV_CC
FBOUT
INTV_CC
GATEV_CC
SRVO_FBIN
SRVO_FBOUT
SRVO_IIN
SRVO_IOUT
IMON_IN
SYNC
IMON_OUT
22nF
4.7µF
4.7µF
11.3k
4.7µF
4Ω
D_B1
D_B2
TO
TO
BOOST1 BOOST2
26.1k
C_IN1: 220µF, 100V
C_IN2: 4.7µF, 100V, TDK C4532X7S2A475M
C_OUT1A, C_OUT1B: 22µF, 25V, TDK C4532X7R1E226M
C_OUT2: 100µF, 16V, SANYO OS-CON 16SA100M
C_OUT3: 470µF, 16V
D_B1, D_B2: CENTRAL SEMI CMMR1U-02-LTE
L1: 15µH, WURTH 7443631500
M1, M2: FAIRCHILD FDMS86101
M3, M4: FAIRCHILD FDMS7692
*2Ω FROM TG1 TO EACH SEPARATE M1 GATE
8705 TA03a
Efficiency vs Output Current
100
95
90
V_IN = 60V
85
V_IN = 40V
V_IN = 20V
V_IN = 12V
V_IN = 5V
80
0
1
2
3
4
5
LOAD CURRENT (A)
8705 TA03c
Input Transient (4V to 80V)
V_OUT
200mV/DIV
V_IN
20V/DIV
I_LOAD = 2A
10ms/DIV
8705 TA03c
Related Parts
PART NUMBER
LT3791-1
LTC3789
LT3758
LTC3115-1
LTM4609
DESCRIPTION
60V High Efficiency (Up to 98%) Synchronous 4-Switch
Buck-Boost DC/DC Controller
High Efficiency (Up to 98%) Synchronous 4-Switch
Buck-Boost DC/DC Controller
High Input Voltage, Boost, Flyback, SEPIC and Inverting
Controller
40V, 2A Synchronous Buck-Boost DC/DC Converter
High Efficiency Buck-Boost DC/DC µModule Regulator
COMMENTS
4.7V ≤ V_IN ≤ 60V, 1.2V ≤ 60V, Regulates V_OUT, I_OUT or I_IN, TSSOP-38
4V ≤ V_IN ≤ 38V, 0.8V ≤ V_OUT ≤ 38V, SSOP-28, 4mm × 5mm QFN-28
5.5V ≤ V_IN ≤ 100V, Positive or Negative V_OUT, 3mm × 3mm DFN-10
or MSOP-10E
2.7V ≤ V_IN ≤ 40V, 2.7V ≤ V_OUT ≤ 40V, 4mm × 5mm DFN-16, TSSOP-20
4.5V ≤ V_IN ≤ 36V, 0.8V ≤ V_OUT ≤ 34V, 15mm × 15mm × 2.8mm
44 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 950_F3_o5_r-_m7_o4_r1_e7_{information www.linear.com/LT8705}
[phone] ^● FAX: [phone] ^● www.linear.com/LT8705
8705fe
LT 0615 REV E • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2013