MQFL-28-15D Datasheet, PDF (13/18 Pages) SynQor Worldwide Headquarters – HIIGH RELLIIABIILLIITTY DC/DC CONVERTTER

Technical Specification
MQFL-28-15D
Output: ±15 V
Current: 8 A Total
their outputs connected in parallel may exhibit hiccup operation
at light loads. Consult factory for details.
OUTPUT VOLTAGE TRIM: If desired, it is possible to increase
or decrease the MQFL dual converter’s output voltage from its
nominal value. To increase the output voltage a resistor, Rup,
should be connected between the TRIM pin (pin 10) and the OUT-
PUT RETURN pin (pin 8), as shown in Figure D. The value of this
resistor should be determined according to the following equa-
tion:
( ) ^{Rup = 10 x}
Vnom – 2.5
Vout – Vnom
– 2 x Vnom + 5
where:
Vnom = the converter’s nominal output voltage,
Vout = the desired output voltage (greater than Vnom), and
Rup is in kiloOhms (kW).
The maximum value of output voltage that can be achieved is
15.5V.
To decrease the output voltage a resistor, Rdown, should be con-
nected between the TRIM pin and the POSITIVE OUTPUT pin (pin
7), as shown in Figure D. The value of this resistor should be
determined according to the following equation:
[ ] [ ] ^{Rdown = 10 x}
Vnom
2.5
–1
x
Vout – 2.5
Vnom – Vout
–
5
where:
Vnom = the converter’s nominal output voltage,
Vout = the desired output voltage (less than Vnom), and
Rdown is in kiloOhms (kW).
10,000.0
1,000.0
100.0
10.0
Trim Down Configuration
Trim Up Configuration
1.0
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
Change in Vout (V)
Figure E: Change in Output Voltage Graph
As the output voltage is trimmed up, it produces a greater voltage
stress on the converter’s internal components and may cause the
converter to fail to deliver the desired output voltage at the low
end of the input voltage range at the higher end of the load cur-
rent and temperature range. Please consult the factory for
details. Factory trimmed converters are available by request.
INPUT UNDER-VOLTAGE LOCKOUT: The MQFL converter
has an under-voltage lockout feature that ensures the converter
will be off if the input voltage is too low. The threshold of input
voltage at which the converter will turn on is higher that the
threshold at which it will turn off. In addition, the MQFL converter
will not respond to a state of the input voltage unless it has
remained in that state for more than about 200µs. This hysteresis
and the delay ensure proper operation when the source imped-
ance is high or in a noisy enviroment.
28Vdc
+
–
open
means
on
1
+VIN
2
IN RTN
3
CASE
4
ENA 1
5
SYNC OUT
6
SYNC IN
MQFL
12
ENA 2
11
SHARE
10
TRIM
9
– VOUT
8
OUT RTN
7
+VOUT
Rup
Rdown
open
means
on
+
Load
–
+
Load
–
Figure D: Typical connection for output voltage trimming.
Product # MQFL-28-15D
Phone [phone]
www.synqor.com
Doc.# 005-2MQ150D Rev. A 10/23/07
Page 13