Datasheet
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UWS Series
Sixteenth-brick DOSA-Compatible,
Wide Input Isolated DC-DC Converters
MDC_UWS Series.D03 Page 24 of 25
OUTPUT VOLTAGE ADJUSTMENT
DOWN
RT (k:) =
Where ∆%
_(
× 100
)_
– 10.22
∆%
511
Trim Down
Trim Equations
Trim Up
UP
RT (k:) =
–
1.225 × ∆%
5.11 × VNOM × (100 + ∆%)
∆%
511
– 10.22
VNOM – VDES
VNOM
Note: “∆%” is always a positive value.
“V
NOM” is the nominal, rated output voltage.
“V
DES” is the desired, changed output voltage.
Figure 6. Trim Connections To Increase Output Voltages
LOAD
R
TRIM UP
+VOUT
+VIN
–VIN
ON/OFF
CONTROL
TRIM
+SENSE
–VOUT
–SENSE
LOAD
R
TRIM DOWN
+VOUT
+VIN
–VIN
ON/OFF
CONTROL
TRIM
+SENSE
–VOUT
–SENSE
Figure 7. Trim Connections To Decrease Output Voltages
Sense is included on UWS-3.3/15-D48 and UWS-5/10-Q48. Connect Trim to the respective Vout pin if sense is not installed.
+Vcc
13V CIRCUIT
5V CIRCUIT
–VIN
O N /O F F
C O N TR O L
+VIN
Figure 5. Driving the Negative Logic On/Off Control Pin
(simplifi ed circuit)
On/Off Control
The input-side, remote On/Off Control function can be ordered to operate with
either logic type:
Positive ("P" suffi x) logic models are enabled when the On/Off pin is left
open or is pulled high (see specifi cations) with respect to the –Input as per
Figure 4. Positive-logic devices are disabled when the on/off pin is pulled low
with respect to the –Input.
Negative (“N” suffi x) logic devices are off when the On/Off pin is left open
or is pulled high (see specifi cations), and on when the pin is pulled low with
respect to the –Input. See specifi cations.
Dynamic control of the remote on/off function is best accomplished with
a mechanical relay or an open-collector/open-drain drive circuit (optically
isolated if appropriate). The drive circuit should be able to sink appropriate
current (see Performance Specifi cations) when activated and withstand ap-
propriate voltage when deactivated. Applying an external voltage to pin 2 when
no input power is applied to the converter can cause permanent damage to the
converter.