LTC3615 Datasheet, PDF (23/32 Pages) Linear Technology – Dual 4MHz, 3A Synchronous Step-Down DC/DC Converter

LTC3615
Applications Information
External Reference Input (DDR Mode)
If SRLIM is tied to SV_IN, the TRACK/SS pin can be used
as an external reference input between 0.3V and 0.5V, if
desired (see Figure 13).
In DDR mode, the maximum slew rate is selected. If
V_TRACK/SS is within 0.3V and 0.5V, the PGOOD function
is enabled. If V_TRACK/SS is less than 0.3V, the output cur-
rent foldback is disabled and the PGOOD pin is always
pulled down.
V_FB PIN ^0.6V
VOLTAGE _0V
0.6V
TRACK/SS
PIN VOLTAGE ^0.1V
0V
V_IN
RUN PIN
VOLTAGE
0V
SV_IN PIN ^VIN
VOLTAGE
0V
SHUTDOWN SOFT-START
STATE
STATE
t_SS > 1ms
RUN STATE
TIME
REDUCED
RUN STATE
SWITCHING
FREQUENCY
3615 F13
DOWN-
UP-
TRACKING TRACKING
STATE
STATE
Figure 13. Tracking if V_SRLIM Is Low
0.45V
V_FB PIN ^0.3V
VOLTAGE _0V
0.45V
TRACK/SS ^0.3V
PIN VOLTAGE ^0.1V
0V
V_IN
RUN PIN
VOLTAGE
0V
SV_IN PIN ^VIN
VOLTAGE
0V
SHUTDOWN SOFT-START
STATE
STATE
t_SS > 1ms
EXTERNAL
VOLTAGE
REFERENCE 0.45V
RUN STATE
TIME
REDUCED
RUN STATE
SWITCHING
FREQUENCY
DOWN-
UP-
3615 F14
TRACKING TRACKING
STATE
STATE
Figure 14. Tracking if V_SRLIM Is Tied to SV_IN
3615f
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