LTC3873-5 Datasheet, PDF (5/16 Pages) Linear Technology – No RSENSETM Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller

TYPICAL PERFORMANCE CHARACTERISTICS
LTC3873-5
Frequency vs Temperature
250
V_IN = 5V
230
210
190
170
150
–60 –40 –20 0 20 40 60 80 100 120
TEMPERATURE (°C)
3873-5 G09
Maximum Sense Threshold
vs Temperature
300
IPRG = V_IN
250
200
IPRG = FLOAT
150
IPRG = GND
100
50
0
–60 –40 –20 0 20 40 60 80 100 120
TEMPERATURE (°C)
38735 G10
PIN FUNCTIONS (TS8/DD8)
IPRG (Pin 1/Pin 4): Current Sense Limit Select Pin.
I_TH (Pin 2/Pin 3): This pin serves as the error amplifier
compensation point. Nominal voltage range for this pin
is 0.7V to 1.9V.
V_FB (Pin 3/Pin 2): This pin receives the feedback voltage
from an external resistor divider across the output.
GND (Pin 4/Pin 1): Ground Pin.
NGATE (Pin 5/Pin 8): Gate Drive for the External N-Channel
MOSFET. This pin swings from 0V to V_IN.
V_CC (Pin 6/Pin 7): Supply Pin. This pin must be closely
decoupled to GND (Pin 4).
RUN/SS (Pin 7/Pin 6): Shutdown and External Soft-Start
Pin. In shutdown, all functions are disabled and the NGATE
pin is held low.
SW (Pin 8/Pin 5): Switch node connection to inductor and
current sense input pin through external slope compensa-
tion resistor. Normally, the external N-channel MOSFET’s
drain is connected to this pin.
Exposed Pad (NA/Pin 9): Ground. Must be soldered to PCB
for electrical contact and rated thermal performance.
38735fb
5