MOR SERIES
120 WATT
DC/DC CONVERTERS
PIN DESCRIPTIONS AND FUNCTIONS
TRIM
Trim
3
RT
7
10
TRIM UP
Both single and dual output
models include a trim function.
Output voltage can be trimmed
from 60% up to 110% of nominal
V out . When trimming up, do not
exceed the maximum output
power. When trimming down, do
not exceed the maximum output
current.
Positive Output
Positive Sense
MOR
Single
Output
PIN OUT
9
8
Sense Return
Pin
Single Output
Dual Output
Output Common
TRIM
DOWN
1
2
Positive Input
Input Common
Trim
Positive Input
Input Common
Case
FIGURE 3:TRIM – SINGLE
Trim
RT
10
3
TRIM UP
7
8
Positive Output
4
Inhibit 1(INH1)
Sync Out
Inhibit 1(INH1)
Sync Out
MOR
Dual
Output
Output Common
5
Trim Formulas
TRIM DOWN
6
Sync In
Sync In
9
Negative Output
V
o
Trim Up: α =
V
o nominal
, 1.0 ≤ α ≤ 1.1
7
Positive Output
Positive Output
V
2.5
o
FIGURE 4:TRIM – DUAL
8
Output Common Output Common
(
(kΩ) =
– 1
)
• 20
R
– 50
T
(α -1)
9
Sense Return
Positive Sense
Share
Negative Output
Trim
On dual models the positive
output is regulated and the
negative output is transformer
coupled (cross-regulated) to the
positive output. When trimming
the duals, both output voltages
will be adjusted equally.
Example:
V
= 5.0,
V
o
= 5.25,
o nominal
10
11
12
α = 1.05,
R
= 390 kΩ
T
Share
V
o
Trim Down: α =
, 0.6 ≤ α ≤ 1.0
V
o nominal
Inhibit 2 (INH2)
Inhibit 2 (INH2)
50 • α – 30
1 – α
R
(kΩ) =
T
Example:
V
= 5.0, V = 4.5,
o nominal o
POSITIVE INPUT AND INPUT COMMON
α = 0.9,
R = 150 kΩ
T
Steady state voltage range is 16 to 40 VDC. Transient range is 40
to 50 V for a maximum of 120 msec. Low voltage lockout prevents
the units from operating below approximately 15.5 VDC input
voltage to keep system current levels smooth, especially during
initialization or re-start operations. All models include a soft-start
function to prevent large current draw and minimize overshoot.
INHIBIT 1 AND 2
Two inhibit terminals disable switching, resulting in no output and
very low quiescent input current. The two inhibit pins allow access
to an inhibit function on either side of the isolation barrier to help
maintain isolation.
CASE AND EXTERNAL INPUT FILTERS
Internal 500 V capacitors are connected between the case and
input common and between the case and output common. See
Figure 1.
Positive
An open collector is
Input
required for inter-
facing with both of
the inhibit pins.
Applying an open-
collector TTL logic
low to either inhibit
pin will inhibit the
converter. Applying
an open collector
TTL logic high or
leaving the pins
200 Ω
20 k
12 V
Interpoint’s FME filters are recommended to meet CE03 require-
ments for reflected input line current. When using an external
input filter it is important that the case of the filter and the case of
the converter be connected through as low as an impedance as
possible. Direct connection of the baseplates to chassis ground is
the best connection. If connected by a single trace, the trace
should be as wide as it is long.
10 k
Inhibit 1
VCC
Input
Common
MOR Input Side
FIGURE 5: INHIBIT – INPUT SIDE
open will enable the converter. Inhibit 1 is referenced to Input
Common, while Inhibit 2 is referenced to Sense Return on the
output side.
1, 2, 3
10, 11, 12
1
2
Positive Input
Positive Output
Positive Input
MOR
Single or Dual
Output
VS
FME28-461
EMI Filter
The
open
circuit
~
~
28V
Voltage
E/A
Current
Limit
voltage for Inhibit 1 is
13 V and for Inhibit 2 it
is 8 V. Float the inhibit
pin(s) if not used. The
required logic low
voltage level is 0.2
maximum.
10 k
4, 5, 6
Input Common
7, 8, 9
Case*
Input Common
Output Common
200 Ω
Feedback
Inhibit 2
Chassis Ground
V
FIGURE 2: EXTERNAL FILTER CONNECTION
Sense
Return
MOR Output Side
FIGURE 6: INHIBIT – OUTPUT SIDE
5
CRANE [ Crane Aerospace & Electronics. ]
