Crane Aerospace & Electronics Power Solutions
MFL single and dual dc-dc converters
28 VoLt input - 65 Watt
Features
parallel operation with current share,
up to 3 units (up to 185 watts)
•
-55° to +125°C operation
•
16 to 40 VDC input
•
Transient protection up to 80 V for 50 ms
- converter will shut down above
approximately 45 volts in
•
Fully isolated, magnetic feedback
•
Fixed high frequency switching
•
Remote sense or output trim on
single output models
•
Inhibit function
•
Sync in and Sync Out
MODELS
VDC OuTPuT
•
Indefinite short circuit protection
•
High power density with up to 87% efficiency
SINGLE
3.3
5
12
15
28
DuAL
±5
±12
±15
The Interpoint™ MFL Series™ 28-volt dc-dc converters are rated
up to 65 watts. On dual output models up to 70% of the rated
output power can be drawn from either the positive or negative
output. These hermetically sealed converters are offered with
standard screening, “ES” screening, or fully compliant to “883”
MIL-PRF-38534 Class H screening. See “Table 9: Element
Evaluation” on page 13 and “Table 10: Environmental
Screening” on page 14. Standard microcircuit drawings (SMD)
are available. See “Table 3: SMD Number Cross Reference” on
page 5.
description
The additional secondary current mode feedback loop improves
transient response in a manner similar to primary current mode
control and allows for ease of paralleling, but without the cost
and complexity.
The constant frequency, pulse-width modulated converters use
a quasi-square wave single-ended forward design. Tight load
regulation is achieved through a wide-bandwidth magnetic
feedback circuit. The output on single MFL models can be
trimmed (see Figure 1 on page 2 for voltage changes with
different resistor values).
D
esign
F
eatures
The MFL Series converters are switching regulators that use a
quasi-square wave, single ended forward converter design with a
constant switching frequency of 600 kHz.
Isolation between input and output circuits is provided with a
transformer in the forward path and a wide bandwidth magnetic
coupling in the feedback control loop. The MFL uses a unique
dual loop feedback technique that controls output current with
an inner feedback loop and an output voltage with a cascaded
voltage mode feedback loop.
i
nhibit
The MFL Series converters have two inhibit terminals (INH1 and
INH2) that can be used to disable power conversion, resulting in
a very low quiescent input current and no generation of switching
noise. See Table 5 on page 6 for inhibit specifications.
s
ync
Converters may be synced to an external clock (525 to 675 kHz)
or to one another by using the sync in or out pins. The nominal
free-run switching frequency is 600 kHz.
Crane Aerospace & Electronics
Power Solutions – Interpoint Products
10301 Willows Road NE, Redmond, WA 98052
+1.425.882.3100 • power@crane-eg.com
www.craneae.com/interpoint
Page 1 of 14
MFL Rev AB - 2013.11.05
Crane Aerospace & Electronics Power Solutions
MFL single and dual dc-dc converters
28 VoLt input - 65 Watt
c
urrent
s
hare anD
p
arallel
o
peration
Note that synchronizing the units together (though shown in the
figure) is not required for current sharing operation. A second
slave unit may be placed in parallel with a master and slave; this
requires the TRI pin (pin 3) of the master unit to be connected to
the SNS RTN pin (pin 9).
When paralleled, up to 95% of the total combined power ratings
of the MFL converters is available at the load. Overload and short
circuit performance are not adversely affected during parallel
operation.
Multiple MFL converters may be used in parallel to drive a
common load (see Figure 2 on page 3). Only single output
models with SENSE and SNS RTN can be used in the share
mode. In this mode of operation the load current is shared by
two or three MFL converters. In current sharing mode, one MFL
converter is designated as a master. The SLAVE pin (pin 11) of
the master is left unconnected and the MSTR/INH2 pin (pin 12)
of the master is connected to the SLAVE pin (pin 11) of the slave
units. The units designated as slaves have the MSTR/INH2 pin
(pin 12) connected to the SNS RTN pin (pin 9). Figure 2 on page
3 shows the typical setup for two or three units in parallel.
28V
Inhibit
Sync In
+
–
1
2
3
4
5
6
Positive Input
Input Common
TRI
INH1
Sync Out
Sync In
Pos. Sense
10
9
Sense Return
8
Output Common
7
Positive Output
MSTR/INH2
12
Slave
11
–
+
RL
REMOTE SENSE CONNECTION
28V
Inhibit
Sync In
+
–
1
2
3
4
5
6
Positive Input
Input Common
TRI
INH1
Sync Out
Sync In
MSTR/INH2
12
11
Slave
10
Pos. Sense
9
Sense Return
8
Output Common
7
Positive Output
RA
–
+
RL
OUTPUT VOLTAGE ADJUST CONNECTION
V
OuT
INCREASE
VOLTS
0.1
0.2
0.3
0.4
0.5
3.3 V
66
131
196
262
349
R
A
(OHMS)
5V
77
153
230
307
396
12 V
27
55
82
109
139
15 V
21
43
64
86
109
Notes:
1. When using remote sense for voltage
compensation or when using remote sense
for trim, the output will drift over temperature.
Contact Applications Engineering for more
information powerapps@crane-eg.com.
2. Do not exceed the maximum rated power.
F
igure
1: s
ense
c
onnections anD
t
rim
t
able
– s
ingle
o
utput
m
oDels
www.craneae.com/interpoint
Page 2 of 14
MFL Rev AB - 2013.11.05
Crane Aerospace & Electronics Power Solutions
MFL single and dual dc-dc converters
28 VoLt input - 65 Watt
28V
Inhibit
Sync In
+
–
1
2
3
4
5
6
Positive Input
Input Common
TRI
INH1
Sync Out
Sync In
MSTR/INH2
12
Slave
11
Pos. Sense
Sense Return
Positive Output
10
9
8
7
MASTER
–
+
RL
Output Common
CONNECT ONLY WHEN 2 SLAVES ARE USED
1
2
3
4
5
6
Positive Input
Input Common
TRI
INH1
Sync Out
Sync In
SLAVE 1
Output Common
8
7
Positive Output
Pos. Sense
10
Sense Return
9
MSTR/INH2
12
Slave
11
1
2
3
4
5
6
Positive Input
Input Common
TRI
INH1
Sync Out
Sync In
SLAVE 2
Output Common
8
7
Positive Output
Pos. Sense
10
Sense Return
9
MSTR/INH2
12
Slave
11
Notes
1. No one converter may carry more than its maximum rated current.
2. Although 95% of the maximum current of paralleled converters is available, individual converter operation, load and layout may affect
the actual current shared. Contact Applications Engineering for more information powerapps@crane-eg.com.
F
igure
2: p
arallel
c
onnections
– s
ingle
o
utput
m
oDels
www.craneae.com/interpoint
Page 3 of 14
MFL Rev AB - 2013.11.05
Crane Aerospace & Electronics Power Solutions
MFL single and dual dc-dc converters
28 VoLt input - 65 Watt
pin out
pin
1
2
3
4
5
6
7
8
9
10
11
12
single output
Positive Input
Input Common
Triple (TR1)
Inhibit 1 (INH1)
Sync Out
Sync In
Positive Output
Output Common
Sense Return
Positive Sense
Slave
Master/Inhibit 2
(MSTR/INH2)
MFL2828s only
Positive Input
Input Common
Triple (TR1)
Inhibit 1 (INH1)
Sync Out
Sync In
Positive Output
No connection
Output Common
No connection
Slave
Master/Inhibit 2
(MSTR/INH2)
t
able
1: p
in
o
ut
dual output
Positive Input
Input Common
Triple (TR1)
Inhibit 1 (INH1)
Sync Out
Sync In
Positive Output
Output Common
Negative Output
No connection
Slave
Master/Inhibit 2
(MSTR/INH2)
TR1
pins not in use
Leave unconnected
Leave unconnected
Leave unconnected
Connect to Input Common
Connect to Output Common
Connect to Positive Output
Leave unconnected
Leave unconnected
Inhibit 1 (INH1)
Sync Out
Sync In
Sense Return
Positive Sense
Slave
Master/Inhibit 2
(MSTR/INH2)
t
able
2: p
ins not in
u
se
Angled corner indicates pin one.
1
2
3
4
5
6
12
11
TOP VIEW
MFL
(Pin side, marked side)
See case u for dimensions.
10
9
8
7
F
igure
3: p
in
o
ut
www.craneae.com/interpoint
Page 4 of 14
MFL Rev AB - 2013.11.05
Crane Aerospace & Electronics Power Solutions
MFL single and dual dc-dc converters
28 VoLt input - 65 Watt
ModeL nuMbering key
Base Model
Input Voltage
MFL
28 05 S / 883
S
tandard
M
icrocircuit
d
rawing
(SMd)
5962-0621301HXC
5962-9316301HXC
5962-9316201HXC
5962-9316101HXC
5962-9319101HXC
5962-9319201HXC
5962-9319301HXC
sMd nuMbers
MFL S
erieS
S
iMiLar
P
art
Output Voltage
MFL283R3S/883
MFL2805S/883
MFL2812S/883
MFL2815S/883
MFL2805D/883
MFL2812D/883
MFL2815D/883
Number of Outputs
(S = single, D = dual)
Screening
(Standard screening has no designator
in this position.)
F
igure
4: m
oDel
n
umbering
K
ey
For exact specifications for an SMD product, refer to the
SMD drawing. SMDs can be downloaded from: ffdwww.
landandmaritime.dla.mil/programs/smcr
t
able
3: smD n
umber
c
ross
r
eFerence
t
o
category
options
FiLL in For
ModeL #
deterMine the ModeL nuMber enter one oPtion FroM
each category in the ForM beLow
.
output Voltage
1
number of
outputs
2
S
D
case options
3
(u, leave blank)
V
screening
4
(standard, leave blank)
ES
883
ModeL nuMber options
base Model and
input Voltage
3R3, 05, 12, 15, 28
MFL28
05, 12, 15
MFL28
/
Notes:
1. Output Voltage: An R indicates a decimal point. 3R3 is 3.3 volts out. The value of 3R3 is only available in single output models.
2. Number of Outputs: S is a single output and D is a dual output.
3. Case Options: For the standard case (case u) leave the case option blank. For case option V, insert the letter V in the case option position.
4. Screening: For standard screening leave the screening option blank. For other screening options, insert the desired screening level. For more
information see “Table 9: Element Evaluation” on page 13 and “Table 10: Environmental Screening” on page 14. MFL2828S is not available on
an SMD.
t
able
4: m
oDel
n
umber
o
ptions
www.craneae.com/interpoint
Page 5 of 14
MFL Rev AB - 2013.11.05
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