ULQ-1.2/15-D48 Datel, Inc., ULQ-1.2/15-D48 Datasheet - Page 6

• Manufacturer Part Number: ULQ-1.2/15-D48
• Description: DC/DC Power Converters
• Manufacturer: Datel, Inc.

Output overvoltage protection is monitored at the output voltage pin, not
the Sense pin. Therefore, excessive voltage differences between V
Sense in conjunction with trim adjustment of the output voltage can cause the
overvoltage protection circuitry to activate (see Performance Specifi cations
for overvoltage limits). Power derating is based on maximum output current
and voltage at the converter's output pins. Use of trim and sense functions
can cause output voltages to increase, thereby increasing output power
beyond the conveter's specifi ed rating, or cause output voltages to climb into
the output overvoltage region. Therefore, the designer must ensure:
Trimming Output Voltage
ULQ converters have a trim capability (pin 6) that enables users to adjust
the output voltage from +10% to –20% (refer to the trim equations and trim
graphs that follow). Adjustments to the output voltage can be accomplished
via a trim pot (Figure 5) or a single fi xed resistor as shown in Figures 6 and 7.
A single fi xed 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 open.
A single resistor connected from the Trim pin (pin 6) to the +Sense (pin 7) will
increase the output voltage. A resistor connected from the Trim Pin (pin 6) to
the –Sense (pin 5) will decrease the output voltage.
Trim adjustments greater than the specifi ed +10%/–20% can have an
adverse affect on the converter’s performance and are not recommended.
Excessive voltage differences between V
trim adjustment of the output voltage, can cause the overvoltage protection
circuitry to activate (see Performance Specifi cations for overvoltage limits).
Temperature/power derating is based on maximum output current and volt-
age at the converter's output pins. Use of the trim and sense functions can
cause output voltages to increase, thereby increasing output power beyond
the converter's specifi ed rating, or cause output voltages to climb into the
output overvoltage region. Therefore:
The Trim pin (pin 6) is a relatively high impedance node that can be suscep-
tible to noise pickup when connected to long conductors in noisy environ-
ments. In such cases, a 0.22µF capacitor can be added to reduce this long
lead effect.
XLQ Series
(V
(V
1
2
3
OUT
OUT
–INPUT
ON/OFF
CONTROL
+INPUT
at pins) × (I
at pins) x (I
Figure 5. Trim Connections Using A Trimpot
OUT
OUT
+OUTPUT
–OUTPUT
) ≤ rated output power
) ≤ rated output power
+SENSE
–SENSE
TRIM
OUT
8
7
6
5
4
and Sense, in conjunction with
TURNS
5-22
LOAD
OUT
and
1 5 - 2 5 A M P , S I N G L E O U T P U T D C / D C C O N V E R T E R S
6
Note: Resistor values are in kΩ. Adjustment accuracy is subject to resistor
tolerances and factory-adjusted output accuracy. V
Figure 7. Trim Connections To Decrease Output Voltages Using Fixed Resistors
Figure 6. Trim Connections To Increase Output Voltages Using Fixed Resistors
R
R
R
R
R
R
T
T
T
T
T
T
UP
UP
UP
UP
UP
UP
(kΩ) =
(kΩ) =
(kΩ) =
(kΩ) =
(kΩ) =
(kΩ) =
1
2
3
1
2
3
–INPUT
ON/OFF
CONTROL
+INPUT
–INPUT
ON/OFF
CONTROL
+INPUT
1.308(V
6.23(V
7.44(V
8.28(V
13.3(V
10(V
V
V
V
V
V
V
O
O
O
O
O
O
O
O
O
O
O
O
ULQ-1.2/15-D48 & ULQ-1.2/25-D48
– 1.2
ULQ-1.5/15-D48, ULQ-1.5/25-D24 & D48
ULQ-1.8/15-D48, ULQ-1.8/25-D24 & D48
– 1.5
– 1.8
ULQ-2.5/15-D48, ULQ-2.5/20-D24 & D48
– 1.226)
– 2.5
ULQ-3.3/15-D48, ULQ-3.3/20-D24 & D48
– 3.3
– 2
– 1.226)
– 1.226)
– 1.226)
– 1.226)
– 0.793)
ULQ-2/15-D48, ULQ-2/15-D24 & D48
Trim Equations
+OUTPUT
–OUTPUT
+OUTPUT
–OUTPUT
+SENSE
–SENSE
+SENSE
–SENSE
–1.413
–10.2
–10.2
–10.2
–10.2
–10.2
TRIM
TRIM
8
7
6
5
4
8
7
6
5
4
R
R
R
R
R
R
R
T
T
T
T
T
T
TRIM DOWN
R
DOWN
DOWN
DOWN
DOWN
DOWN
DOWN
TRIM UP
(kΩ) =
(kΩ) =
(kΩ) =
(kΩ) =
(kΩ) =
(kΩ) =
O
= desired output voltage.
1.2 – V
1.5 – V
1.8 – V
2.5 – V
3.3 – V
2 – V
1.037
10.15
12.26
16.31
7.64
9.12
LOAD
LOAD
O
O
O
O
O
O
–1.413
–10.2
–10.2
–10.2
–10.2
–10.2