Q48DW3R312NRFA Datasheet, PDF (11/14 Pages) Delta Electronics, Inc. – Delphi Series Q48DW, 45W Quarter Brick, Dual Output DC/DC Power Modules: 1.2V/13A and 3.3V/8A

FEATURES DESCRIPTIONS (CON.)
Figure 25: Circuit configuration for trim-down (decrease
output voltage)
If the external resistor is connected between the TRIM
and RTN, the output voltage (Vout1) set point decreases
(Fig.25). Refer to the table below for the external resistor
values.
Trim Resistor
(Vout Increase)
Vout1 R_trim-up [KΩ]
1.2
Open
1.32
14.4
Trim Resistor
(Vout Decrease)
Vout1
1.2
R_trim-down [KΩ]
Open
1.08
18.7
To trim up, connect trim resistor (R_trim-up) from trim pin to
Vout1(+) (1.2v). The trim equation is
R_trim-up = [Vo / (0.538Vo - 0.648)] - 6.81 Unit: K
Example: If the 1.2V output is trimmed up to +1.3V, connect
the R_trim-up from trim pin to Vout1(+). The value of the
R_trim-up is:
R_trim-up = [1.3/ (0.538*1.3-0.648)]-6.81= 25.29-6.81= 18.5K
To trim down, connect trim resistor (R_trim-down) from trim pin
to RTN (power ground). The trim equation is
R_trim-down = [Vo / (0.362-0.296Vo)]-6.81
Unit: K
Example: If the 1.2V is trimmed down to 1.1V, connect the
R_trim-down from trim pin to RTN (Power ground). The value
of R_trim-down is:
R_trim-down = [1.1/(0.362-0.296*1.1)]-6.81=30.22-6.81= 23.4K
When using the trim function and the output voltage of
the module is increased, this will increase the power
output of the module with the same output current. Care
should be taken to ensure that the maximum output
power of the module remains at or below the maximum
rated power.
DS_Q48DW3R312_07202006
11