![](http://datasheet.mmic.net.cn/70000/LSM-2-5-16-D12_datasheet_2356504/LSM-2-5-16-D12_6.png)
LSM-16A D12 Series
N O N - I S O L A T E D , 1 3 - 8 0 W S M T D C / D C C O N V E R T E R S
6
Figure 7.Trim Connections Using Fixed Resistors
Figure 6.Trim Connections Using a Trimpot
Trim Equations
Note: Resistor values are in k
. Accuracy of adjustment is subject to
tolerances of resistors and factory-adjusted, initial output accuracy.
VO = desired output voltage. VO
NOM = nominal output voltage.
Note: Install either a xed trim-up resistor
or a xed trim-down resistor depending upon
desired output voltage.
“T” Model LSM-T/16-D12
This version of the LSM 16A series offers a special output voltage trimming
feature which is fully compatible with competitive units. The output voltage
may be varied from 0.75 to 5 Volts using a single external trim-up resis-
tor connected from the Trim input to Output Common. If no trim resistor is
attached (Trim pin open), the output is 0.7525 Volts.
The trim may also be adjusted using an external reference voltage connected
to the Trim input.
As with other trim adjustments, use a 1% metal lm precision resistor with
low temperature coefcient (±100 ppm/°C or less) mounted close to the
converter with short leads. Also be aware that the output accuracy is ±2%
(typical) therefore you may need to vary this resistance slightly to achieve
your desired output setting.
The resistor trim up equation for the LSM-T/16-D12 is as follows:
10500
RTUP (
) = ___________ –1000
VO – 0.7525
Where VO is the desired output voltage.
The LSM-T/16-D12 xed resistance values to set the output values are:
VO
0.7525V
1.0V
1.2V
1.5V
1.8V
2.5V
3.3V
5.0V
RT (k
) Open 41.424 22.46 13.05 9.024 5.009 3.122 1.472
CAUTION: To retain proper regulation, do not exceed the 5 Volt output.
Voltage Trim
The LSM-T/16-D12 may also be trimmed using an external voltage applied
between the Trim input and Output Common. Be aware that the internal
“l(fā)oad” impedance looking into trim pin is approximately 5k
. Therefore, you
may have to compensate for this in the source resistance of your external
voltage reference.
The equation for this voltage adjustment is:
VTRIM = 0.7 –(0.0667 x (VO – 0.7525))
The LSM-T/16-D12 xed trim voltages to set the output voltage are:
VO
0.7525V 1.0V
1.2V
1.5V
1.8V
2.5V
3.3V
5.0V
VT (V) Open
0.6835 0.670 0.650 0.630 0.583 0.530 0.4166