LTC3704 Datasheet, PDF (12/28 Pages) Linear Technology – Wide Input Range, No RSENSE Positive-to-Negative DC/DC Controller

LTC3704
APPLICATIO S I FOR ATIO
The resistor R1 is typically chosen to be less than 1M.
For applications where the RUN pin is only to be used as
a logic input, the user should be aware of the 7V
Absolute Maximum Rating for this pin! The RUN pin can
be connected to the input voltage through an external 1M
resistor, as shown in Figure 8c, for “always on” operation.
12
+
R2
INPUT
SUPPLY OPTIONAL
FILTER
R1
CAPACITOR
–
V_IN
RUN
+
6V
–
RUN
COMPARATOR
BIAS AND
START-UP
CONTROL
1.248V
µPOWER
REFERENCE
GND
3704 F08a
Figure 8a. Programming the Turn-On and Turn-Off Thresholds Using the RUN Pin
RUN
EXTERNAL
LOGIC CONTROL
6V
1.248V
RUN
COMPARATOR
+
–
3704 F08b
Figure 8b. On/Off Control Using External Logic
+
R2
1M
INPUT
SUPPLY
V_IN
RUN
+
6V
–
RUN
COMPARATOR
–
GND 1.248V
3704 F08c
Figure 8c. External Pull-Up Resistor On
RUN Pin for “Always On” Operation
sn3704 3704fs