ltc3803es6-5 Linear Technology Corporation, ltc3803es6-5 Datasheet - Page 9

• Manufacturer Part Number: ltc3803es6-5
• Description: Constant Frequency Current Mode Flyback Dc/dc Controller In Thinsot
• Manufacturer: Linear Technology Corporation

OPERATIO
Powering the LTC3803-5
In the simplest case, the LTC3803-5 can be powered from
a high voltage supply through a resistor. A built-in shunt
regulator from the V
current as needed through this resistor to regulate the V
voltage to around 8.1V as long as the V
to sink more than 25mA. This shunt regulator is always
active, even when the LTC3803-5 is in shutdown, since it
serves the vital function of protecting the V
seeing too much voltage.
The V
adjacent to the IC pins with a ceramic or tantalum capaci-
CC
pin must be bypassed to ground immediately
U
CC
pin to GND will draw as much
CC
pin is not forced
CC
pin from
CC
tor. Proper supply bypassing is necessary to supply the
high transient currents required by the MOSFET gate
driver. 10μF is a good starting point.
Adjustable Slope Compensation
The LTC3803-5 injects a 5μA peak current ramp out
through its SENSE pin which can be used for slope
compensation in designs that require it. This current ramp
is approximately linear and begins at zero current at 6.5%
duty cycle, reaching peak current at 80% duty cycle.
Additional details are provided in the Applications Infor-
mation section.
LTC3803-5
38035fb
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