POWER LOSS (mW)
LTC3897-2
PolyPhase Synchronous Boost Controller
with Input/Output Protection
FEATURES DESCRIPTION
n
Input Supply Range: 4.5V to 65V (Up to 75V Surge) The LTC 3897-2 is a synchronous boost DC/DC controller
n
Reverse Input Protection to 40V with surge stopper and ideal diode controller.
n
Inrush Current Control, Overcurrent Protection and
The boost controller drives two N-channel power MOSFET
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 inrush 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
n voltage holdup or peak detection. It controls the forward
5mm9mm QFN-44 Package with High Voltage
voltage drop across the MOSFET and minimizes reverse
PinSpacing
current flow.
APPLICATIONS
The differences between the LTC3897-2 and LTC3897 are
shown in Table1.
n
Industrial
All registered trademarks and trademarks are the property of their respective owners. Protected
n
Automotive
by U. S. Patents, including 5408150, 5481178, 5705919, 5929620, 6144194, 6177787,
6580258.
n
Military/Avionics
n
Telecommunications
TYPICAL APPLICATION
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
LTC3897-2 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
38972 TA01b
8.66k
SW2
I
TH
1F
TG2
475k
INTV V
PINS NOT SHOWN IN THIS CIRCUIT: CC FB
38972 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
Rev. A
1
Document Feedback For more information www.analog.com
EFFICIENCY (%)LTC3897-2
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
V , SGEN ................................................... 40V to 76V
IN
+
V , IS , IS , .........................................................76V
BIAS
+ +
SENSE1 , SENSE2 , SENSE1 , SENSE2 ..................65V
44 43 42 40 39 38 37
CS ............................................................... 40V to 76V
DGEN 1 36 SG
SG, DG (Note 8) ...........................CS 0.3V to CS + 10V PLLIN/MODE 2
FREQ 34 VIN
3
BOOST1 and BOOST2 .................................0.3V to 71V
PHASMD 4
SW1 and SW2 ............................................... 5V to 65V
I 5 32 TG1
LIM
BG1, BG2, TG1, TG2 ........................................... (Note 9)
+
SENSE1 6 31 SW1
RUN, DGEN ................................................ 0.3V to 76V
SENSE1 7 30 BOOST1
45
PLLIN/MODE, TMR, V , SPFB .................... 0.3V to 6V
FB
DTC
8 GND
INTV ......................................................... 0.3V to 6V
CC DRVUV 9 28 BG1
EXTV ...................................................... 0.3V to 14V DRVSET 10 27 V
BIAS
CC
INTV 11 26 EXTV
DRV , (BOOST1-SW1), (BOOST2-SW2) ....0.3V to 11V CC CC
CC
+
RUN 12 25 DRV
CC
(SENSE1 -SENSE1 ),
I 24 BG2
+ 13
TH
(SENSE2 -SENSE2 ) ............................. 0.3V to 0.3V
SENSE2 14
I , SS, I , FREQ,
LIM TH
15 16 17 18 20 21 22
PHASMD, DTC .......................0.3V to INTV + 0.3V
CC
DRVUV, DRVSET ........................0.3V to INTV + 0.3V
CC
Operating Junction Temperature Range
(Notes 2, 3) ........................................ 40C to 150C UHG PACKAGE
44(38)-LEAD (5mm 8mm) PLASTIC QFN
Storage Temperature Range .................. 65C to 150C
= 36C/W
JA
EXPOSED PAD (PIN 45) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC3897EUHG-2#PBF LTC3897EUHG-2#TRPBF 38972 38-Lead (5mm 8mm) Plastic QFN 40C to 125C
LTC3897IUHG-2#PBF LTC3897IUHG-2#TRPBF 38972 38-Lead (5mm 8mm) Plastic QFN 40C to 125C
LTC3897HUHG-2#PBF LTC3897HUHG-2#TRPBF 38972 38-Lead (5mm 8mm) Plastic QFN 40C to 150C
Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
Rev. A
2
For more information www.analog.com
+
SENSE2
SGEN
V
FB TMR
SS
SPFB
CLKOUT
IS
+
TG2
IS
SW2
DG
BOOST2
CS