MODELS
VDC O
UTPUT
B2-19
Size (max.): 3.005 x 1.505 x 0.400 inches (76.33 x 38.23 x 10.16 mm)
See Section B8, case U1, for dimensions.
Weight:
100 grams maximum
Screening: Standard or ES. See Section C2 for screening options,
see Section A5 for ordering information.
SINGLE
5
12
15
DUAL
5
12
15
DESCRIPTION
The MFLHP SeriesTM 28 volt DC/DC converters are rated up to 100
watts output power over a 55 to +100C temperature range with a
28 Vdc nominal input. On dual output models, up to 70% of the rated
output power can be drawn from either the positive or negative
outputs. Current sharing allows the units to be paralleled for total
power of up to 270 watts. The welded, hermetically sealed package
is only 3.005 x 1.505 x 0.400 inches, giving the series an overall
power density of up to 67 watts per cubic inch.
D
ESIGN
F
EATURES
The MFLHP 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 trans-
former in the forward path and wide bandwidth magnetic coupling in
the feedback control loop. The MFLHP Series uses a unique dual
loop feedback technique that controls output current with an inner
feedback loop and output voltage with a cascaded voltage mode
feedback loop.
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.
Tight load regulation is achieved through a wide-bandwidth
magnetic feedback circuit. The output voltage on single MFLHP
models can be easily trimmed by adding an external resistor. (See
Figure 1 for voltage changes with different resistor values.)
I
NHIBIT
The MFLHP Series converters have two TTL compatible inhibit
terminals (INH1 and INH2) that can be used to disable power
conversion, resulting in a very low quiescent input current. An open
collector TTL compatible low (<0.8 volts) is required between INH1
(pin 4) and Input Common (pin 2) to inhibit the converter. An open
collector TTL compatible low (<0.5 volts) is required between INH2
(pin 12) and Output Common (pin 8) to inhibit the converter. The
application of intermediate voltages to these pins (1.5 to 10.5 volts)
should be avoided.
C
URRENT
S
HARING AND
P
ARALLEL
O
PERATION
Multiple MFLHP converters may be used in parallel to drive a
common load (see Figure 2). In this mode of operation the load
current is shared by two or three MFLHP converters. In current
sharing mode, one MFLHP 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 shows the typical setup for two or three units in parallel.
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, 76% of the total combined power ratings of the
MFLHP converters are available at the load. Overload and short
circuit performance are not adversely affected during parallel
operation.
DC/DC C
ONVERTERS
28 V
OLT
I
NPUT
MFLHP SERIES
100 WATT
F
EATURES
55 to +100C operation
19 to 40 VDC input
Fully Isolated
Magnetic feedback
Fixed frequency, 600 kHz typical
Topology Single Ended Forward
80 V for up to 50 ms transient protection
Inhibit function input and output
Sync function input and output
Output trim on single output models
Indefinite short circuit protection
Remote sense on single output models
Up to 87% efficiency
Parallelable up to 228 watts
TYPICAL CHARACTERISTICS
SYNC IN AND INHIBIT (INH1, INH2)
RECOMMENDED OPERATING CONDITIONS
ABSOLUTE MAXIMUM RATINGS
Input Voltage
19 to 40 VDC
Power Dissipation (Pd)
20 watts
Output Power
80 to 100 watts depending on model
Lead Soldering Temperature (10 sec per lead)
300C
Storage Temperature Range (Case)
65C to +150C
B2-20
MFLHP SERIES
100 WATT
DC/DC C
ONVERTERS
Output Voltage Temperature Coefficient
100 ppm/C typical
Input to Output Capacitance
150 pF typical
Isolation
100 megohm minimum at 500 V
Audio Rejection
50 dB typical
Conversion Frequency
Free run mode 600 kHz typical
550 kHz min, 650 kHz. max
External sync range 525 to 675 kHz
Inhibit Pin Voltage (unit enabled)
INH1 = 9 to12 V, INH2 = 6 to 9 V
Input Voltage Range
19 to 40 VDC continuous
80 V for 50 msec transient
Case Operating Temperature (Tc)
55 to +100C full power
55 to +135C absolute
Derating Output Power/Current
Linearly from 100% at 100C to 0% at 135C
Electrical Characteristics: 50C to +100C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.
Sync In (525 to 675 kHz)
Duty cycle 40% min, 60% max
Logic low 0.8 V max
Logic high 4.5 V min
Referenced to input common
If not used, connect to input common
Sync Out - Referenced to input common
Inhibit (INH1, INH2) TTL Open Collector
Logic low (output disabled)
Current 10 to 5 mA
INH1 referenced to input common
Logic low 0.8 V max
INH2 referenced to output common
Logic low 0.5 V max
Logic high (output enabled)
Open collector
Notes
1. Unit will shut down above approximately 45V but will be undamaged and
will restart when voltage drops into normal range.
2. Indefinite short circuit protection not guaranteed above 100C case.
3. Recovery time is measured from application of the transient to point at
which Vout is within 1% of final value.
4. Transition time
10 s.
SINGLE OUTPUT MODELS
MFLHP2805S
MFLHP2812S
MFLHP2815S
PARAMETER
CONDITION
MIN TYP MAX
MIN
TYP MAX
MIN
TYP MAX
UNITS
OUTPUT VOLTAGE
25C
4.95
5.00
5.05
11.88 12.00 12.12
14.85 15.00 15.15
VDC
OUTPUT CURRENT
V
IN
= 19 to 40 VDC
0
--
16
0
--
7.5
0
--
6.67
A
OUTPUT POWER
V
IN
= 19 to 40 VDC
0
--
80
0
--
90
0
--
100
W
OUTPUT RIPPLE
Tc = 25C
--
15
35
--
30
75
--
30
85
VOLTAGE 10 k - 2 MHz
Tc = 55C to +100C
--
30
75
--
45
125
--
45
150
mV p-p
LINE REGULATION
V
IN
= 19 to 40 VDC
--
0
20
--
0
20
--
0
20
mV
LOAD REGULATION
NO LOAD TO FULL
--
0
20
--
0
20
--
0
20
mV
INPUT VOLTAGE
CONTINUOUS
19
28
40
19
28
40
19
28
40
VDC
NO LOAD TO FULL
TRANSIENT
1
50 ms
--
--
80
--
--
80
--
--
80
V
INPUT CURRENT
NO LOAD
--
70
120
--
50
80
--
50
80
mA
FULL LOAD
--
3.6
3.73
--
3.8
3.95
--
4.2
4.40
A
INHIBITED - INH1
--
9
14
--
9
14
--
9
14
mA
INHIBITED - INH2
--
35
70
--
35
70
--
35
70
INPUT RIPPLE
CURRENT
10 kHz - 10 MHz
--
15
50
--
15
50
--
15
50
mA pp
EFFICIENCY
Tc = 25C
77
80
--
83
86
--
84
87
--
%
LOAD FAULT
2
POWER DISSIPATION
Tc = 25C
SHORT CIRCUIT
--
15
20
--
15
20
--
15
20
W
RECOVERY
--
1.5
4
--
1.5
4
--
1.5
4
ms
STEP LOAD RESP.
50% 100% 50%
TRANSIENT
--
350
450
--
450
700
--
450
700
mV pk
RECOVERY
3
--
1.5
3.0
--
1.5
3.0
--
1.5
3.0
ms
STEP LINE RESP.
19 40 19 VDC
TRANSIENT
4
--
250
400
--
250
400
--
250
400
mV pk
RECOVERY
3
--
200
300
--
200
300
--
200
300
s
START-UP
DELAY
--
3.5
6
--
3.5
6
--
3.5
6
ms
OVERSHOOT
--
0
25
--
0
50
--
0
50
mV pk
PINS NOT USED
TR1, Master, and Slave
If not used, leave unconnected
B2-21
MFLHP SERIES
100 WATT
DC/DC C
ONVERTERS
Electrical Characteristics: 55C to +100C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.
DUAL OUTPUT MODELS
MFLHP2805D
MFLHP2812D
MFLHP2815D
PARAMETER
CONDITIONS
MIN TYP MAX
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
OUTPUT VOLTAGE
+V
OUT
4.95
5.00
5.05
11.88 12.00
12.12 14.85 15.00
15.15
VDC
Tc = 25C
V
OUT
4.92
5.00
5.08
11.82 12.00
12.18
14.77 15.00
15.23
OUTPUT CURRENT
1
EACH OUTPUT
0
--
11.2
0
--
5.3
0
--
4.67
A
V
IN
= 19 TO 40 VDC
TOTAL
0
--
16.0
0
--
7.5
0
--
6.67
OUTPUT POWER
EACH OUTPUT
0
--
56
0
--
63
0
--
70
W
V
IN
= 19 TO 40 VDC
TOTAL
0
--
80
0
--
90
0
--
100
OUTPUT RIPPLE
10 kHz - 2 MHz
VOLTAGE
+V
OUT
--
25
125
--
50
150
--
50
200
mV p-p
V
OUT
--
25
125
--
50
150
--
50
200
LINE REGULATION
+V
OUT
--
0
50
--
0
50
--
0
50
mV
V
IN
= 19 TO 40 VDC
V
OUT
--
25
100
--
25
100
--
25
100
LOAD REGULATION
+V
OUT
--
0
50
--
10
100
--
10
100
mV
NO LOAD TO FULL
V
OUT
--
25
100
--
50
200
--
50
200
CROSS REGULATION
SEE NOTE 2
--
6
8
--
2
4
--
2
4
%
Tc = 25C
SEE NOTE 3
--
3
6
--
2
4
--
2
4
INPUT VOLTAGE
CONTINUOUS
19
28
40
19
28
40
19
28
40
VDC
NO LOAD TO FULL
TRANSIENT
4
50 ms
0
--
80
0
--
80
0
--
80
V
INPUT CURRENT
NO LOAD
--
50
120
--
50
100
--
550
100
mA
Tc = 25C
FULL LOAD
--
3.6
--
3.8
--
4.2
A
INHIBITED - INH1
--
9
14
--
9
14
--
9
14
mA
INHIBITED - INH2
--
35
70
--
35
70
--
35
70
INPUT RIPPLE
CURRENT
10 kHz - 10 MHz
--
15
50
--
15
50
--
15
50
mA p-p
EFFICIENCY 25C Tc
BALANCED LOAD
77
80
--
83
86
--
84
87
--
%
LOAD FAULT
5
POWER DISSIPATION
Tc = 25C
SHORT CIRCUIT
--
15
20
--
15
20
--
15
20
W
RECOVERY
--
1.5
4.0
--
1.5
4.0
--
1.5
4.0
ms
STEP LOAD
50 %100% 50% LOAD
RESPONSE V
OUT
TRANSIENT
--
350
450
--
450
700
--
450
700
mV pk
RECOVERY
6
--
1.5
3.0
--
1.5
3.0
--
1.5
3.0
ms
STEP LINE
19 40 16 V
IN
RESPONSE V
OUT
TRANSIENT
7
--
250
400
--
250
400
--
250
400
mV pk
RECOVERY
6
--
200
300
--
200
300
--
200
300
s
STARTUP
DELAY
--
3.5
6
--
3.5
6
--
3.5
6
ms
OVERSHOOT
--
0
25
--
0
50
--
0
50
mV p
Notes
1. Up to 70% of the total output power is available from either output providing
the opposite output is simultaneously carrying 30% of the total power.
2. Effect on the negative output under the following conditions:
+P
out
30% to 70%; P
out
70% to 30%
3. Effect on the negative output under the following conditions:
+P
out
50%; P
out
10% to 50%
4. Unit will shut down above approximately 45V but will be undamaged and
will restart when voltage drops into normal range.
5. Indefinite short circuit protection not guaranteed above 100C case.
6. Recovery time is measured from application of the transient to point at
which Vout is within 1% of final value.
7. Transition time
10 s.
B2-22
MFLHP SERIES
100 WATT
DC/DC C
ONVERTERS
SINGLE OUTPUT MODELS CONNECTION DIAGRAMS - SENSE AND PARALLEL
RL
1
2
3
4
5
6
REMOTE SENSE CONNECTION
12
11
10
9
8
7
+
28V
+
Inhibit
Sync In
RL
1
2
3
4
5
6
OUTPUT VOLTAGE ADJUST CONNECTION
12
11
10
9
8
7
+
28V
+
Inhibit
Sync In
RA
Positive Input
Input Common
TR1
INH1
Sync Out
Sync In
MSTR/INH2
Slave
Pos. Sense
Sense Return
Output Common
Positive Output
Positive Input
Input Common
TR1
INH1
Sync Out
Sync In
MSTR/INH2
Slave
Pos. Sense
Sense Return
Output Common
Positive Output
RL
1
Positive Input
Input Common
TR1
INH1
Sync Out
Sync In
2
3
4
5
6
1
2
3
4
5
6
1
2
3
4
5
6
CONNECT ONLY WHEN 2 SLAVES ARE USED
12
11
10
9
8
7
12
11
10
9
8
7
12
11
10
9
8
7
+
MSTR/INH2
Slave
Pos. Sense
Sense Return
Output Common
Positive Output
MASTER
SLAVE 1
SLAVE 2
28V
+
Inhibit
Sync In
Positive Input
Input Common
TR1
INH1
Sync Out
Sync In
MSTR/INH2
Slave
Pos. Sense
Sense Return
Output Common
Positive Output
Positive Input
Input Common
TR1
INH1
Sync Out
Sync In
MSTR/INH2
Slave
Pos. Sense
Sense Return
Output Common
Positive Output
F
IGURE
1: S
ENSE
C
ONNECTIONS AND
T
RIM
T
ABLE
F
IGURE
2: P
ARALLEL
C
ONNECTIONS
PIN OUT
Angled corner indicates pin one.
1
2
3
4
5
6
12
11
10
9
8
7
TOP VIEW
MFLHP
(Pin side, marked side)
See Section B8, case U1 for dimensions.
F
IGURE
3: P
IN
O
UT
B2-23
MFLHP SERIES
100 WATT
DC/DC C
ONVERTERS
MODEL NUMBERING KEY
MFLHP 28 05 S / ES
Base Model
Input Voltage
Output Voltage
Screening
Number of Outputs
(S = single, D = dual)
(Standard screening has no designator
in this position.)
Typical Performance Curves: 25C Tc , 28 VDC Vin, 100% load, free run, unless otherwise specified.
Output (Watts)
MFLHP2805S & MFLHP2805D
Efficiency
Efficiency (%)
60
90
85
80
75
70
10
30
50
70
90
28V
40V
65
19V
F
IGURE
4
Output Power (Watts)
MFLHP2812S & MFLHP2812D
Efficiency
Efficiency (%)
60
90
85
80
75
70
10
30
50
70
90
65
19V
28V
40V
F
IGURE
5
F
IGURE
6
60
90
85
80
75
70
10
30
50
70
90
65
Output Power (Watts)
MFLHP2815S & MFLHP2815D
Efficiency
Efficiency (%)
19V
40V
28V
100
Pin
Single Output
Dual Output
1
Positive Input
Positive Input
2
Input Common
Input Common
3
Triple (TRI)
Triple (TRI)
4
Inhibit 1 (INH1)
Inhibit 1 (INH1)
5
Sync Out
Sync Out
6
Sync In
Sync In
7
Positive Output
Positive Output
8
Output Common
Output Common
9
Sense Return
Negative Output
10
Positive Sense
No connection
11
Slave
Slave
12
Master / Inhibit 2
Master / Inhibit 2
(MSTR/INH2)
(MSTR/INH2)
Pin 6 should be connected to input common if
external sync (Sync In) is not used.
Sense pins must be connected to their respective
outputs if not used.
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