LTC3813 Datasheet, PDF (1/32 Pages) Linear Technology – 100V Current Mode Synchronous Step-Up Controller

LTC3813
100V Current Mode
Synchronous Step-Up Controller
FEATURES
n _{High Output Voltages: Up to 100V}
n _{Large 1Ω Gate Drivers}
n _{No Current Sense Resistor Required}
n _{Dual N-Channel MOSFET Synchronous Drive}
n _{±0.5% 0.8V Voltage Reference}
n _{Fast Transient Response}
n _{Programmable Soft-Start}
n _{Generates 10V Driver Supply from Input Supply}
n _{Synchronizable to External Clock}
n _{Power Good Output Voltage Monitor}
n _{Adjustable Off-Time/Frequency: tOFF(MIN) < 100ns}
n _{Adjustable Cycle-by-Cycle Current Limit}
n _{Programmable Undervoltage Lockout}
n _{Output Overvoltage Protection}
n _{28-Pin SSOP Package}
APPLICATIONS
n _{24V Fan Supplies}
n _{48V Telecom and Base Station Power Supplies}
n _{Networking Equipment, Servers}
n _{Automotive and Industrial Control Systems}
DESCRIPTION
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.
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 V_IN 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.
PARAMETER
Maximum V_OUT
MOSFET Gate Drive
INTV_CC UV⁺
INTV_CC UV ^–
LTC3813
100V
6.35V to 14V
6.2V
6V
LTC3814-5
60V
4.5V to 14V
4.2V
4V
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-Up Converter
50k
500k
V_OUT
1000pF
0.01μF
100k
100pF
I_OFF
NDRV
PGOOD
BOOST
LTC3813
V_RNG
TG
SYNC
SS
SHDN
I_TH
V_FB
SGND
SW
EXTV_CC
DRV_CC
INTV_CC
SENSE⁺
BG
SENSE^–
BGRTN
0.1μF
10μH
V_IN
+
10V TO 40V
22μF
M1
Si7850DP
V_OUT
50V/5A
D1
MBR1100
M2
Si7850DP
2x
1μF
30.9k
+
270μF
2x
499Ω
3813 TA01
Efficiency vs Load Current
100
V_IN = 36V
95
V_IN = 24V
V_IN = 12V
90
85
80
0
1
2
3
4
5
LOAD (A)
3813 TA01b
3813fb
1