LTC3805-5 Linear Technology, LTC3805-5 Datasheet - Page 6

• Manufacturer Part Number: LTC3805-5
• Description: Adjustable Frequency Current Mode Flyback DC/DC Controller
• Manufacturer: Linear Technology

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PIN FUNCTIONS
LTC3805-5
SSFLT (Pin 1): Soft-Start Pin. A capacitor placed from
this pin to GND (Exposed Pad) controls the rate of rise of
converter output voltage during start-up. This capacitor is
also used for time out after a fault prior to restart.
I
operating voltage range is clamped between 0.7V and
1.9V.
FB (Pin 3): Receives the feedback voltage from an external
resistor divider across the output.
RUN (Pin 4): An external resistor divider connects this pin
to V
FS (Pin 5): A resistor connected from this pin to ground
sets the frequency of operation.
SYNC (Pin 6): Input to synchronize the oscillator to an
external source.
6
TH
(Pin 2): Error Amplifi er Compensation Point. Normal
IN
and sets the thresholds for converter operation.
I
control, it monitors the switch current, using the voltage
across an external current sense resistor. Pin 7 also injects
a current ramp that develops slope compensation voltage
across an optional external programming resistor.
OC (Pin 8): Overcurrent Pin. Connect this pin to the ex-
ternal switch current sense resistor. An additional resistor
programs the overcurrent trip level.
V
V
GATE (Pin 10): Gate Drive for the External N-Channel
MOSFET. This pin swings from GND to V
Exposed Pad (Pin 11): Ground. A capacitor must closely
decouple GND to V
cal ground on PCB.
SENSE
CC
CC
(Pin 9): Supply Pin. A capacitor must closely decouple
to GND (Exposed Pad).
(Pin 7): Performs two functions: for current mode
CC
(Pin 9). Must be soldered to electri-
CC
.
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