LTC3632 LINER [Linear Technology], LTC3632 Datasheet - Page 6

• Manufacturer Part Number: LTC3632
• Description: High Effi ciency, High Voltage 20mA Synchronous Step-Down Converter
• Manufacturer: LINER [Linear Technology]

PIN FUNCTIONS
LTC3632
TYPICAL PERFORMANCE CHARACTERISTICS
SW (Pin 1): Switch Node Connection to Inductor. This
pin connects to the drains of the internal power MOSFET
switches.
V
should be tied between this pin and GND (Pin 8).
I
pin to ground sets the peak current trip threshold. Leave
fl oating 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 fl oating, the ramp time defaults to an internal 0.75ms
soft-start.
6
VOLTAGE
SET
OUTPUT
IN
1V/DIV
(Pin 2): Main Supply Pin. A ceramic bypass capacitor
(Pin 3): Peak Current Set Input. A resistor from this
Soft-Start Waveforms
C
SS
= 0.047μF
5ms/DIV
3632 G19
100mV/DIV
20mA/DIV
CURRENT
VOLTAGE
OUTPUT
LOAD
Load Step Transient Response
V
V
IN
OUT
= 10V
= 5V
1ms/DIV
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
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.
FB
(Pin 6): Output Voltage Feedback. Connect to an
3632 G20
INDUCTOR
CURRENT
20mA/DIV
VOLTAGE
OUTPUT
2V/DIV
Short-Circuit Response
V
V
IN
OUT
= 10V
= 5V
200μs/DIV
3632fb
3632 G21