LTC3616_15 Datasheet, PDF (21/28 Pages) Linear Technology – 6A, 4MHz Monolithic Synchronous Step-Down DC/DC Converter

LTC3616
Applications Information
to the actual TRACK/SS pin voltage if the voltage value
is between 0.3V and 0.6V. Note: if TRACK/SS voltage is
0.6V, either the tracking circuit or the internal reference
can be used.
During up/down tracking the output current foldback is
disabled and the PGOOD pin is always pulled down (see
Figure 9).
Efficiency Considerations
The efficiency of a switching regulator is equal to the output
power divided by the input power times 100%. It is often
useful to analyze individual losses to determine what is
limiting the efficiency and which change would produce
the most improvement. Efficiency can be expressed as:
Efficiency = 100% – (L1 + L2 + L3 + ...)
where L1, L2, etc. are the individual losses as a percent-
age of input power.
V_FB PIN ^0.6V
VOLTAGE _0V
0.6V
TRACK/SS
PIN VOLTAGE ^0.2V
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
SWITCHING
FREQUENCY
RUN STATE
3616 F08
DOWN
TRACKING
STATE
UP
TRACKING
STATE
Figure 8. DDR Pin Not Tied to S_VIN
0.45V
V_FB PIN ^0.3V
VOLTAGE _0V
0.45V
TRACK/SS ^0.3V
PIN VOLTAGE ^0.2V
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
SWITCHING
FREQUENCY
RUN STATE
3616 F09
DOWN
TRACKING
STATE
UP
TRACKING
STATE
Figure 9. DDR Pin Tied to SV_IN. Example DDR Application
For more information www.linear.com/LTC3616
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