LTC3703-5
60V Synchronous
Switching Regulator Controller
FEATURES
DESCRIPTIO
High Voltage Operation: Up to 60V The LTC 3703-5 is a synchronous step-down switching
Large 1 Gate Drivers (with 5V Supply) regulator controller that can directly step-down voltages
No Current Sense Resistor Required from up to 60V input, making it ideal for telecom and au-
Step-Up or Step-Down DC/DC Converter tomotive applications. The LTC3703-5 drives external logic
Dual N-Channel MOSFET Synchronous Drive level N-channel MOSFETs using a constant frequency (up
Excellent Line and Load Transient Response to 600kHz), voltage mode architecture.
Programmable Constant Frequency: 100kHz to
A precise internal reference provides 1% DC accuracy. A
600kHz
high bandwidth error amplifier and patented* line feed
1% Reference Accuracy
forward compensation provide very fast line and load
Synchronizable up to 600kHz
transient response. Strong 1 gate drivers allow the
Selectable Pulse Skip Mode Operation
LTC3703-5 to drive multiple MOSFETs for higher current
Low Shutdown Current: 25A Typ
applications. The operating frequency is user program-
Programmable Current Limit
mable from 100kHz to 600kHz and can also be synchro-
Undervoltage Lockout
nized to an external clock for noise-sensitive applications.
Programmable Soft-Start
Current limit is programmable with an external resistor
16-Pin Narrow SSOP and 28-Pin SSOP Packages
and utilizes the voltage drop across the synchronous
U
MOSFET to eliminate the need for a current sense resistor.
APPLICATIO S
For applications requiring up to 100V operation, refer to
48V Telecom and Base Station Power Supplies the LTC3703 data sheet.
Networking Equipment, Servers
PARAMETER LTC3703-5 LTC3703
Automotive and Industrial Control
Maximum V 60V 100V
IN
MOSFET Gate Drive 4.5V to 15V 9.3V to 15V
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. +
V UV 3.7V 8.7V
CC
*U.S. Patent Numbers: 5408150, 5055767, 6677210, 5847554, 5481178, 6304066, 6580258;
V UV 3.1V 6.2V
Others Pending.
CC
TYPICAL APPLICATIO
High Efficiency High Voltage Step-Down Converter
V
CC
5V
Efficiency vs Load Current
+
V
IN
100
22F
6V TO 60V
MMDL770T1
MODE/SYNC V V = 12V
IN IN
+ V = 24V
IN
22F
30k
95
2
FSET BOOST
Si7850DP
10k
COMP TG
V = 42V
IN
0.1F
1000pF 470pF LTC3703-5
90
8H
FB SW
V
OUT
12k
5V
21.5k
I V 5A
1%
MAX CC
10 +
270F 85
16V
INV DRV
CC
Si7850DP
0.1F
RUN/SS BG D1
80
10F
MBR1100
0 1 2 3 4 5
100
113k
GND BGRTN
1% LOAD CURRENT (A)
1F
37053 TA04b
2200pF
37035 TA04
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EFFICIENCY (%)
U
ULTC3703-5
ABSOLUTE AXI U RATI GS
(Note 1)
Supply Voltages MODE/SYNC, INV Voltages....................... 0.3V to 15V
V , DRV .......................................... 0.3V to 15V f , FB, I , COMP Voltages ................... 0.3V to 3V
CC CC SET MAX
(DRV BGRTN), (BOOST SW) ...... 0.3V to 15V Driver Outputs
CC
BOOST (Continuous) ............................ 0.3V to 85V TG ................................ SW 0.3V to BOOST + 0.3V
BOOST (400ms) ................................... 0.3V to 95V BG ........................... BGRTN 0.3V to DRV + 0.3V
CC
BGRTN ...................................................... 5V to 0V Peak Output Current <10s BG,TG ............................ 5A
V Voltage (Continuous).......................... 0.3V to 70V Operating Temperature Range (Note 2)
IN
V Voltage (400ms) ................................. 0.3V to 80V LTC3703E-5 ........................................ 40C to 85C
IN
SW Voltage (Continuous) ............................ 1V to 70V LTC3703I-5 ....................................... 40C to 125C
SW Voltage (400ms) ................................... 1V to 80V Junction Temperature (Notes 3, 7) ....................... 125C
Run/SS Voltage .......................................... 0.3V to 5V Storage Temperature Range ................. 65C to 150C
Lead Temperature (Soldering, 10 sec.)................. 300C
UUW
PACKAGE/ORDER I FOR ATIO
TOP VIEW
ORDER PART ORDER PART
V 1 28
NUMBER BOOST NUMBER
IN
NC 2 27
TOP VIEW TG
NC 3 26
LTC3703EGN-5 SW LTC3703EG-5
MODE/SYNC 1 16 V
IN
NC 4 25
NC
LTC3703IGN-5 LTC3703IG-5
f 2
15 B00ST
SET
NC 5 24
NC
3
COMP 14 TG
MODE/SYNC 6 23
NC
FB 4 13 f 7 22
SW NC
SET
COMP 8 21
V
I 5 12 CC
V
MAX CC
FB 9 20
DRV
CC
6 11
INV DRV
CC
GN PART
I 10 19
BG
MAX
RUN/SS 7 10
BG
MARKING
INV 11 18
NC
GND 8 9
BGRTN
NC 12 17
NC
37035
RUN/SS 13 16
NC
GN PACKAGE
GND 14 15
16-LEAD NARROW PLASTIC SSOP 3703I5 BGRTN
T = 125C, = 110C/W
JMAX JA
G PACKAGE
28-LEAD PLASTIC SSOP
T = 125C, = 100C/W
JMAX JA
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25C. V = DRV = V = V = 5V, V = V = V =
A CC CC BOOST IN MODE/SYNC INV SW
BGRTN = 0V, RUN/SS = I = open, R = 25k, unless otherwise specified.
MAX SET
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V , DRV V , DRV Supply Voltage 4.1 15 V
CC CC CC CC
V V Pin Voltage 60 V
IN IN
I V Supply Current V = 0V 1.7 2.5 mA
CC CC FB
RUN/SS = 0V 25 40 A
I DRV Supply Current (Note 5) 0 5 A
DRVCC CC
RUN/SS = 0V 0 5 A
I BOOST Supply Current (Note 5) 360 500 A
BOOST
RUN/SS = 0V 0 5 A
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