LTC3703-5_15 Datasheet, PDF (1/32 Pages) Linear Technology – 60V Synchronous Switching Regulator Controller

LTC3703-5
60V Synchronous
Switching Regulator Controller
FEATURES
■ _{High Voltage Operation: Up to 60V}
■ _{Large 1Ω Gate Drivers (with 5V Supply)}
■ _{No Current Sense Resistor Required}
■ _{Step-Up or Step-Down DC/DC Converter}
■ _{Dual N-Channel MOSFET Synchronous Drive}
■ _{Excellent Line and Load Transient Response}
■ _{Programmable Constant Frequency: 100kHz to}
600kHz
■ _{±1% Reference Accuracy}
■ _{Synchronizable up to 600kHz}
■ _{Selectable Pulse Skip Mode Operation}
■ _{Low Shutdown Current: 25µA Typ}
■ _{Programmable Current Limit}
■ _{Undervoltage Lockout}
■ _{Programmable Soft-Start}
■ _{16-Pin Narrow SSOP and 28-Pin SSOP Packages}
U
APPLICATIO S
■ _{48V Telecom and Base Station Power Supplies}
■ _{Networking Equipment, Servers}
■ _{Automotive and Industrial Control}
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
*U.S. Patent Numbers: 5408150, 5055767, 6677210, 5847554, 5481178, 6304066, 6580258;
Others Pending.
DESCRIPTIO
The LTC^®3703-5 is a synchronous step-down switching
regulator controller that can directly step-down voltages
from up to 60V input, making it ideal for telecom and au-
tomotive applications. The LTC3703-5 drives external logic
level N-channel MOSFETs using a constant frequency (up
to 600kHz), voltage mode architecture.
A precise internal reference provides 1% DC accuracy. A
high bandwidth error amplifier and patented* line feed
forward compensation provide very fast line and load
transient response. Strong 1Ω gate drivers allow the
LTC3703-5 to drive multiple MOSFETs for higher current
applications. The operating frequency is user program-
mable from 100kHz to 600kHz and can also be synchro-
nized to an external clock for noise-sensitive applications.
Current limit is programmable with an external resistor
and utilizes the voltage drop across the synchronous
MOSFET to eliminate the need for a current sense resistor.
For applications requiring up to 100V operation, refer to
the LTC3703 data sheet.
PARAMETER
Maximum V_IN
MOSFET Gate Drive
V_CC UV⁺
V_CC UV^–
LTC3703-5
60V
4.5V to 15V
3.7V
3.1V
LTC3703
100V
9.3V to 15V
8.7V
6.2V
TYPICAL APPLICATIO
High Efficiency High Voltage Step-Down Converter
V_CC
5V
1000pF
30k
10k
470pF
21.5k
12k
1%
100Ω
113k
1%
2200pF
0.1µF
MODE/SYNC V_IN
FSET BOOST
COMP
TG
LTC3703-5
FB
SW
I_MAX
VCC
INV
DRV_CC
RUN/SS
BG
GND BGRTN
+
22µF
MMDL770T1
V_IN
6V TO 60V
+
Si7850DP
22µF
×2
0.1µF
8µH
10Ω
10µF
1µF
Si7850DP
270µF ⁺
16V
D1
MBR1100
V_OUT
5V
5A
37035 TA04
Efficiency vs Load Current
100
V_IN = 12V
95
V_IN = 24V
V_IN = 42V
90
85
80
0
1
2
3
4
5
LOAD CURRENT (A)
37053 TA04b
37035fa
1