FEATURE DESCRIPTIONS (CON.
)
Table 1 provides Rtrim values required for some common
output voltages, while Table 2 provides values of external
voltage source, Vtrim, for the same common output
voltages. By using a 1% tolerance trim resistor, set point
tolerance of ±2% can be achieved as specified in the
electrical specification.
Table 1
VO (V)
0.7525
1.0
1.2
1.5
1.8
2.0
2.5
3.3
5.0
Rtrim (KΩ)
Open
41.424
22.464
13.047
9.024
7.416
5.009
3.122
1.472
The amount of power delivered by the module is the
voltage at the output terminals multiplied by the output
current. When using the trim feature, the output voltage
of the module can be increased, which at the same
output current would increase the power output of the
module. Care should be taken to ensure that the
maximum output power of the module must not exceed
the maximum rated power (
Vo.set x Io.max
≤
P max
).
Voltage Margining
Output voltage margining can be implemented in the DNL
modules by connecting a resistor, R
margin-up
, from the Trim
pin to the ground pin for margining-up the output voltage
and by connecting a resistor, R
margin-down
, from the Trim pin
to the output pin for margining-down. Figure 36 shows
the circuit configuration for output voltage margining. If
unused, leave the trim pin unconnected. A calculation
tool is available from the evaluation procedure, which
computes the values of R
margin-up
and R
margin-down
for a
specific output voltage and margin percentage.
Table 2
VO (V)
0.7525
1.0
1.2
1.5
1.8
2.0
2.5
3.3
5.0
Vtrim (V)
Open
0.6835
0.670
0.650
0.630
0.6168
0.583
0.530
0.4167
Vin
Vo
Rmargin-down
Q1
On/Off
Trim
Rmargin-up
Rtrim
GND
Q2
Figure 36:
Circuit configuration for output voltage margining
PRELIMINARY DS_DNL10SIP20_10132008
11
DELTA [ DELTA ELECTRONICS, INC. ]
