LTC3813
100V Current Mode
Synchronous Step-Up Controller
FEATURES
DESCRIPTION
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The LTC3813 is a synchronous step-up switching regulator
controller that can generate output voltages up to 100V.
The LTC3813 uses a constant off-time peak current control
architecture with accurate cycle-by-cycle current limit,
without requiring a sense resistor.
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High Output Voltages: Up to 100V
Large 1Ω Gate Drivers
No Current Sense Resistor Required
Dual N-Channel MOSFET Synchronous Drive
±0.5% 0.8V Voltage Reference
Fast Transient Response
Programmable Soft-Start
Generates 10V Driver Supply from Input Supply
Synchronizable to External Clock
Power Good Output Voltage Monitor
Adjustable Off-Time/Frequency: tOFF(MIN) < 100ns
Adjustable Cycle-by-Cycle Current Limit
Programmable Undervoltage Lockout
Output Overvoltage Protection
28-Pin SSOP Package
A precise internal reference provides ±0.5% DC accuracy.
A high bandwidth (25MHz) error amplifier provides very
fast line and load transient response. Large 1Ω gate drivers
allow the LTC3813 to drive multiple MOSFETs for higher
current applications. The operating frequency is selected
by an external resistor and is compensated for variations
in VIN and can also be synchronized to an external clock
for switching-noise sensitive applications. A shutdown pin
allows the LTC3813 to be turned off, reducing the supply
current to 240μA.
APPLICATIONS
PARAMETER
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MOSFET Gate Drive
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LTC3813
LTC3814-5
100V
60V
6.35V to 14V
4.5V to 14V
6.2V
4.2V
6V
4V
Maximum VOUT
24V Fan Supplies
48V Telecom and Base Station Power Supplies
Networking Equipment, Servers
Automotive and Industrial Control Systems
INTVCC UV +
INTVCC
UV –
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
Efficiency vs Load Current
High Efficiency High Voltage Step-Up Converter
50k
500k
PGOOD
VRNG
BOOST
LTC3813
SYNC
1000pF
SHDN
0.1μF
VOUT
50V/5A
SW
DRVCC
D1
MBR1100
INTVCC
ITH
100k
SGND
SENSE–
BGRTN
1μF
VIN = 12V
90
85
30.9k
+
M2
Si7850DP
2x
BG
VIN = 24V
95
22μF
M1
Si7850DP
SENSE+
VFB
100pF
TG
EXTVCC
SS
0.01μF
+
10μH
VIN = 36V
VIN
10V TO 40V
NDRV
IOFF
EFFICIENCY (%)
VOUT
100
499Ω
270μF
2x
80
0
1
2
3
LOAD (A)
4
5
3813 TA01b
3813 TA01
3813fb
1
