LTC3810
100V Current Mode
Synchronous Switching
Regulator Controller
FEATURES
DESCRIPTION
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The LTC3810 is a synchronous step-down switching
regulator controller that can directly step-down voltages
from up to 100V, making it ideal for telecom and automo-
tive applications. The LTC3810 uses a constant on-time
valley current control architecture to deliver very low duty
cycles with accurate cycle-by-cycle current limit, without
requiring a sense resistor.
High Voltage Operation: Up to 100V
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Large 1Ω Gate Drivers
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No Current Sense Resistor Required
Dual N-Channel MOSFET Synchronous Drive
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Extremely Fast Transient Response
0.5% 0.8V Voltage Reference
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Programmable Output Voltage Tracking/Soft-Start
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Generates 10V Driver Supply from Input Supply
A precise internal reference provides 0.5% DC accuracy. A
highbandwidth(25MHz)erroramplifierprovidesveryfast
line and load transient response. Large 1Ω gate drivers
allow the LTC3810 to drive multiple MOSFETs for higher
current applications. The operating frequency is selected
by an external resistor and is compensated for variations
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Synchronizable to External Clock
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Selectable Pulse Skip Mode Operation
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Power Good Output Voltage Monitor
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Adjustable On-Time/Frequency: t
< 100ns
ON(MIN)
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Adjustable Cycle-by-Cycle Current Limit
Programmable Undervoltage Lockout
Output Overvoltage Protection
28-Pin SSOP Package
in V and can also be synchronized to an external clock
IN
forswitching-noisesensitiveapplications.Ashutdownpin
allows the LTC3810 to be turned off, reducing the supply
current to 240μA.
APPLICATIONS
Integratedbiascontrolgeneratesgatedrivepowerfromthe
input supply during start-up and when an output short-
circuit occurs, with the addition of a small external SOT23
MOSFET. When in regulation, power is derived from the
output for higher efficiency.
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48V Telecom and Base Station Power Supplies
Networking Equipment, Servers
Automotive and Industrial Control Systems
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L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents
including 5481178, 5847554, 6304066, 6476589, 6580258, 6677210, 6774611.
TYPICAL APPLICATION
High Efficiency High Voltage Step-Down Converter
Efficiency vs Load Current
V
IN
15V TO 100V
100
R
ON
261k
+
V = 50V
IN
C
22μF
100k
IN
V
= 25V
IN
I
ON
M3
95
90
85
NDRV
ZXMN10A07F
V
= 75V
IN
PGOOD
BOOST
LTC3810
V
RNG
M1
L1
10μH
TG
Si7456DP
0.1μF
C
SS
V
MODE/SYNC
SS/TRACK
SHDN
OUT
SW
1000pF
12V/6A
EXTV
DRV
INTV
CC
CC
R
FB1
14k
+
CC
+
D1
MBR1100
80
SENSE
C
OUT
I
TH
0
1
2
3
4
5
6
5pF
M2
Si7456DP
270μF
LOAD (A)
200k
BG
V
FB
3810 TA01b
–
SENSE
BGRTN
47pF
R
FB2
1k
SGND
1μF
3810 TA01
3810fb
1