POWER LOSS (mW)
LTC3897
PolyPhase Synchronous
Boost Controller with Input/
Output Protection
Fea T Descrip T
n
Input Supply Range: 4.5V to 65V (Up to 75V Surge) The LTC 3897 is a synchronous boost DC/DC controller
n
Reverse Input Protection to 40V with surge stopper and ideal diode controller.
n
In-Rush Current Control, Overcurrent Protection
The boost controller drives two N-channel power MOSFET
and Output Disconnect for Boost Converter
stages out-of-phase to reduce input and output capacitor
n
Input Voltage Surge Protection with Adjustable
requirements, allowing the use of smaller inductors than
Clamp Voltage
the single-phase equivalent. Synchronous rectification
n
Onboard Ideal Diode Controller
reduces power loss and eases thermal requirements.
n
Low Quiescent Current: 55A
n The surge stopper controls the gate of an external N-channel
2-Phase Operation Reduces Required Input and
MOSFET to protect against high voltage input transients and
Output Capacitance and Noise
n provides in-rush current control, overcurrent protection and
Output Voltage Up to 60V
n output disconnect for the boost converter. The integrated
Adjustable Gate Drive Level 5V to 10V (OPTI-DRIVE)
ideal diode controller drives another N-channel MOSFET to
for Logic-Level or Standard Threshold FETs
n replace a Schottky diode for reverse input protection and
No External Bootstrap Diodes Required
voltage holdup or peak detection. It controls the forward
voltage drop across the MOSFET and minimizes reverse
a T
current flow.
n
Industrial
The LTC3897 is available in thermally-enhanced 38-pin
n
Automotive
leadless QFN or 38-lead TSSOP packages.
n
Military/Avionics
L, LT, LTC, LTM, Linear Technology, the Linear logo, Burst Mode, LTspice, OPTI-LOOP and
PolyPhase are registered trademarks and No R is a trademark of Linear Technology
SENSE
Corporation. All other trademarks are the property of their respective owners. Protected by U. S.
Patents, including 5408150, 5481178, 5705919, 5929620, 6144194, 6177787, 6580258.
Typical a T
24V/10A 2-Phase Synchronous Boost Converter with Surge Protection and Reverse Protection Efficiency and Power Loss
vs Output Current
REVERSE CURRENT PROTECTION (IDEAL DIODE)
5m 3.5H
INPUT VOLTAGE SURGE PROTECTION
REVERSE INPUT VOLTAGE PROTECTION
100 100k
IN-RUSH/OVERCURRENT PROTECTION
BURST EFFICIENCY
90
V
IN 2m +
V SENSE1
BIAS
6V TO
80 10k
55V
SENSE1
33F 549k
70
BG1
SPFB
0.1F
60 1k
10
12.1k
BURST LOSS
BOOST1
50
SW1
10nF 40 100
IS
+
IS TG1
30
5m 3.5H
V
OUT
DG V = 12V
IN
24V
+ 20 10
V = 24V
CS OUT
SENSE2
10A
Burst Mode OPERATION
SG
LTC3897 SENSE2 10
FIGURE 17 CIRCUIT
V
IN
220F
BG2
0 1
0.1F
RUN 0.1F
0.001 0.01 0.1 1 10
SS
OUTPUT CURRENT (A)
BOOST2
15nF
3897 G02
8.66k
SW2
I
TH
1F
TG2
475k
INTV V
PINS NOT SHOWN IN THIS CIRCUIT: CC FB
3897 TA01a
DRV
PLLIN/MODE, I , PHASMD, CC
LIM
24.9k
4.7F
CLKOUT, EXTV , SGEN, DGEN
CC
DTC
DRVSET
V OPERATES THROUGH TRANSIENTS UP TO 75V.
IN DRVUV FREQ GND TMR
WHEN V > 24V, V FOLLOWS V UP TO 57V. 1nF
IN OUT IN
3897f
1
For more information www.linear.com/LTC3897
EFFICIENCY (%)
ion pplica
ions pplica
ion uresLTC3897
a Te Maxi Mu M r a T
(Note 1)
V , SGEN .................................................. 40V to 76 V INTV ......................................................... 0.3V to 6V
IN CC
+
V , IS , IS , .........................................................76V EXTV ...................................................... 0.3V to 14V
BIAS CC
+ +
SENSE1 , SENSE2 , SENSE1 , SENSE2 ..................65V DRV , (BOOST1-SW1), (BOOST2-SW2) ....0.3V to 11V
CC
+
CS ............................................................... 40V to 76V (SENSE1 -SENSE1 ),
+
SG, DG (Note 8) ...........................CS 0.3V to CS + 10V (SENSE2 -SENSE2 ) ............................. 0.3V to 0.3V
BOOST1 and BOOST2 .................................0.3V to 71V I , SS, I , FREQ,
LIM TH
SW1 and SW2 ............................................... 5V to 65V PHASMD, DTC .......................0.3V to INTV + 0.3V
CC
BG1, BG2, TG1, TG2 ........................................... (Note 9) DRVUV, DRVSET ........................0.3V to INTV + 0.3V
CC
RUN, DGEN ................................................ 0.3V to 76V Operating Junction Temperature Range
PLLIN/MODE, TMR, V , SPFB .................... 0.3V to 6V (Notes 2, 3) ........................................ 40C to 150C
FB
Storage Temperature Range .................. 65C to 150C
p in c F T
TOP VIEW
TOP VIEW
SGEN 1 38 TMR
DGEN 2 37 SPFB
PLLIN/MODE 3 36 IS
38 37 36 35 34 33 32
+
FREQ 4 35 IS
FREQ 1 31 DG
PHASMD 5 34 DG
PHASMD 2 30 CS
I 6 33 CS
LIM
I 3 29 SG
LIM
+
+
SENSE1 7 32 SG
SENSE1 4 28 V
IN
SENSE1 8 31 V
IN SENSE1 5 27 TG1
DTC 9 30 TG1 DTC SW1
6 26
39
39
GND
DRVUV 10 29 SW1 DRVUV 7 25 BOOST1
GND
DRVSET 8 24 BG1
DRVSET 11 28 BOOST1
INTV 9 23 V
INTV 12 27 BG1 CC BIAS
CC
RUN 10 22 EXTV
CC
RUN 13 26 V
BIAS
I 21 DRV
11
TH CC
I 14 25 EXTV
CC
TH
20
SENSE2 12 BG2
SENSE2 15 24 DRV
CC
13 14 15 16 17 18 19
+
SENSE2 16 23 BG2
V 17 22 BOOST2
FB
SS 18 21 SW2
CLKOUT 19 20 TG2
UHF PACKAGE
38-LEAD (5mm 7mm) PLASTIC QFN
FE PACKAGE
38-LEAD PLASTIC TSSOP
= 34C/W
JA
= 28C/W
JA
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
3897f
2
For more information www.linear.com/LTC3897
+
SENSE2 PLLIN/MODE
V DGEN
FB
SGEN
SS
CLKOUT TMR
TG2 SPFB
SW2 IS
+
BOOST2 IS
ion igura on
ings bsolu