uwr-3.3 C&D Technologies., uwr-3.3 Datasheet - Page 6

• Manufacturer Part Number: uwr-3.3
• Description: Single Output, High-density, 3.3vout And 5 Vout, 26-40 Watt, Dc/dc Converters
• Manufacturer: C&D Technologies.

Trimming Output Voltage
to adjust the output voltages ±5%. Adjustments to the output voltages
can be accomplished via a trim pot (Figure 5) or a single fixed resistor as
shown in Figures 6 and 7. A single fixed resistor can increase or decrease
the output voltage depending on its connection. Resistors should be located
close to the converter and have TCR's less than 100ppm/°C to minimize
sensitivity to changes in temperature. If the trim function is not used, leave
the trim pin floating.
will decrease the output voltage. A resistor connected from the Trim (pin 8)
to the –Output (pin 7) , –Sense where applicable, will increase the output
voltage.
affect on the converter’s performance and are not recommended. Exces-
sive trim adjustment of the output voltage can cause the overvoltage pro-
tection circuitry to activate (see Performance Specifications for overvoltage
limits). Power derating is based on maximum output current and voltage
at the converter's output pins. Use of trim can cause output voltages to
increase thereby increasing output power beyond the UWR's specified
rating or cause output voltages to climb into the output overvoltage region.
Therefore:
figure 6. Trim Connections To Decrease Output Voltages Using fixed Resistors
UWR 26-40W converters have a trim capability (pin 8) that allows users
A single resistor connected from the Trim (pin 8) to the +Output (pin 6),
Trim adjustments greater than the specified ±5% can have an adverse
2
4
1
2
4
1
(V
OUT
–INPUT
ON/OFF
CONTROL
+INPUT
–INPUT
ON/OFF
CONTROL
+INPUT
at pins) x (I
figure 5. Trim Connections Using A Trimpot
OUT
+OUTPUT
–OUTPUT
+OUTPUT
–OUTPUT
) <= rated output power
TRIM
TRIM
6
8
7
6
8
7
R
TRIM DOWN
www.murata-ps.com
TURNS
20kΩ
5-22
Single Output, High-Density, 3.3V
LOAD
LOAD
figure 7. Trim Connections To Increase Output Voltages Using fixed Resistors
Note: Resistor values are in kΩ. Accuracy of adjustment is subject to the
tolerances of resistors and factory-adjusted output accuracy.
2
4
1
–INPUT
ON/OFF
CONTROL
+INPUT
Technical enquiries email: [e-mail], tel:
R
OUT
R
T
Trim Equations for 3.3 Volt Models
T
DOWN
Trim Equations for 5 Volt Models
DOWN
V
and 5 V
R
O
R
(kΩ) =
UWR 26-40W Series
T
(kΩ) =
= desired output voltage.
T
UP
UP
+OUTPUT
–OUTPUT
(kΩ) =
+SENSE
–SENSE
(kΩ) =
TRIM
OUT
2.49(V
2.49(V
5 – V
, 26-40 Watt, DC/DC Converters
3.3 – V
V
6
8
7
V
O
6.25
O
O
3.06
O
– 5
MDC_UWR26-40W_B02 Page 6 of 10
– 2.51)
O
– 3.3
R
– 1.23)
TRIM UP
O
–16.9
–13
–16.9
–13
LOAD
[phone]