LTC3632_15 Datasheet, PDF (6/22 Pages) Linear Technology – High Efficiency, High Voltage 20mA Synchronous Step-Down Converter

LTC3632
TYPICAL PERFORMANCE CHARACTERISTICS
Soft-Start Waveforms
OUTPUT
VOLTAGE
1V/DIV
C_SS = 0.047µF 5ms/DIV
Load Step Transient Response
Short-Circuit Response
OUTPUT
VOLTAGE
100mV/DIV
LOAD
CURRENT
20mA/DIV
3632 G19
V_IN = 10V
V_OUT = 5V
1ms/DIV
OUTPUT
VOLTAGE
2V/DIV
INDUCTOR
CURRENT
20mA/DIV
3632 G20
V_IN = 10V
V_OUT = 5V
200µs/DIV
3632 G21
PIN FUNCTIONS
SW (Pin 1): Switch Node Connection to Inductor. This
pin connects to the drains of the internal power MOSFET
switches.
V_IN (Pin 2): Main Supply Pin. A ceramic bypass capacitor
should be tied between this pin and GND (Pin 8).
I_SET (Pin 3): Peak Current Set Input. A resistor from this
pin to ground sets the peak current trip threshold. Leave
floating for the maximum peak current (50mA). Short this
pin to ground for the minimum peak current (10mA). A
1µA current is sourced out of this pin.
SS (Pin 4): Soft-Start Control Input. A capacitor to ground
at this pin sets the ramp time to full current output dur-
ing start-up. A 5.5µA current is sourced out of this pin. If
left floating, the ramp time defaults to an internal 0.75ms
soft-start.
RUN (Pin 5): Run Control Input. A voltage on this pin
above 1.2V enables normal operation. Forcing this pin
below 0.7V shuts down the LTC3632, reducing quiescent
current to approximately 3µA.
V_FB (Pin 6): Output Voltage Feedback. Connect to an
external resistive divider to divide the output voltage down
for comparison to the 0.8V reference.
HYST (Pin 7): Run Hysteresis Open-Drain Logic Output.
This pin is pulled to ground when RUN (Pin 5) is below
1.2V. This pin can be used to adjust the RUN pin hysteresis.
See Applications Information.
GND (Pin 8, Exposed Pad Pin 9): Ground. The exposed
pad must be soldered to the printed circuit board ground
plane for optimal electrical and thermal performance.
3632fc
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