F
EATURES
• –55°C to +85°C operation
• 10 to 16 VDC input or
16 to 36 VDC input typical
• Fully isolated
• Opto-coupler feedback
• Fixed frequency 125 kHz typical
• Topology – Push-Pull Forward
• Transient protection
50 V for up to 50 ms 28 Vin models
• Inhibit function
• Indefinite short circuit protection
• Trimmable output on single models
• Up to 83% efficiency
DC/DC C
ONVERTERS
12
AND
28 V
OLT
I
NPUT
MHE SERIES 20
WATT
MODELS
VDC O
UTPUT
SINGLE
DUAL
5
±12
12
±15
15
Size (max.): Non-flanged 2.125 x 1.125 x 0.495 (case H6) inches
(53.98 x 28.58 x 12.57 mm)
Flanged 2.910 x 1.125 x 0.495 (case K7) inches
(73.91 x 28.58 x 12.57 mm)
See Section B8, cases H6 and K7, for dimensions.
Weight:
50 grams typical
Screening: Standard or ES. See Section C2 for screening options, see
Section A5 for ordering information.
DESCRIPTION
The MHE Series™ DC/DC converters offer the high efficiencies
associated with switching regulators, yet have full isolation and the
excellent regulation typical of linear regulators. No external compo-
nents are required for operation. MHE Series converters are built
using thick-film hybrid technology, and are sealed in metal packages
for military, aerospace, and other high-reliability applications.
Unscreened models are solder sealed and are guaranteed to pass
a gross leak test (maximum leak rate of 1 x 10
-3
atm.-cc/sec).
Environmentally screened models are hermetically sealed and are
screened as described in Section C2.
The MHE Series converters are pulse-width modulated switching
regulators operating in the forward mode, with a nominal switching
frequency of 125 to 140 kHz. Isolation is achieved through the use
of a transformer in the forward power circuit, and an optocoupler is
used in the feedback/control loop. The full load output power is
available over the full input voltage range. Short-term transients of
50 volts will not impair normal operation for 28 volt input models.
The efficiency is typically greater than 80% over the entire input
voltage range and from approximately 25% of full load to full load.
This feature makes the MHE Series converters ideal for either
battery or aircraft power applications.
An inhibit function is provided on MHE Series converters to allow
power shutdown and startup from a logic input. The unit is inhibited
when the inhibit input pin (pin 2) is connected to the input common
(pin 10). The open circuit voltage of the inhibit pin is 8 to 10 VDC for
12 V input models or 11 to 13 VDC for 28 V input models. During
inhibit, the input inhibit pin must sink approximately 1 mA. In the
inhibit mode, converter output drops to less than 1 V and the input
current is typically 8 mA.
Automatic current limiting circuitry protects the MHE Series
converters against short circuits.
MHE Series converters are rated to operate at full load up to a case
temperature of 85°C, with the output power derated linearly to zero
at 115°C. Because of the unit’s high efficiency, heat sinking require-
ments are minimized, but due consideration should be given to
removing self-generated heat when operating the device at
maximum ratings. To increase dissipation, heat conducting material
(PCB, copper sheet, heat sink, etc.) should be brought into contact
with the converter’s baseplate.
When the MHE Series converters are used in applications requiring
full power operation for extended periods of time, or in shock and
vibration environments, it is highly recommended that the flange-
mount option be used. This option provides improved thermal
transfer capabilities as well as a mechanically secure mounting
configuration.
1
MHE SERIES
20 WATT
ABSOLUTE MAXIMUM RATINGS
Output Power
• 10 to 20 watts depending on model
Lead Soldering Temperature (10 sec per lead)
• 300°C
Storage Temperature Range (Case)
• –55°C to +125°C
DC/DC C
ONVERTERS
INHIBIT
Inhibit TTL Open Collector
• Logic low (output disabled)
Logic low voltage
≤0.8
V
• Referenced to input common
• Logic high (output enabled)
Open collector
TYPICAL CHARACTERISTICS
Output Voltage Temperature Coefficient
• 150 ppm/°C, typical
Input to Output Capacitance
• 60 pF, typical
Current Limit
• 125% of full load, typical
Isolation
• 100 megohm minimum at 500 V
Conversion Frequency
• 125 kHz, typical
Inhibit Pin Voltage (unit enabled)
• 11 to 13 V MHE28XXX
• 8 to 10 V MHE12XXX
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range
Continuous
• 17 to 40 VDC MHE28XXX
• 10 to 16 VDC MHE12XXX
Transient
• 50 V for 50 msec on 28 V input models
Case Operating Temperature (Tc)
• –55°C to +85°C full power
Derating Output Power/Current
• Linearly from 100% at 85°C to 0% at 115° C
• MHE28XXX models derate by 33% at 16 Vin
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
SINGLE OUTPUT MHE12XX MODELS
PARAMETER
OUTPUT VOLTAGE
OUTPUT CURRENT
OUTPUT POWER
OUTPUT RIPPLE
VOLTAGE
LINE REGULATION
LOAD REGULATION
INPUT VOLTAGE
INPUT CURRENT
INPUT RIPPLE
CURRENT
EFFICIENCY
CONDITION
–55°C TO +85°C
–55°C TO +85°C
0 TO 1 MHz
V
IN
MIN TO MAX
NO LOAD TO FULL
CONTINUOUS
TRANSIENT 50 ms
NO LOAD
10 kHz – 2 MHz
MIN
4.95
—
—
—
—
—
10
—
—
—
78
MHE1205S
TYP
5.00
—
—
35
2
10
12
—
—
30
81
MAX
5.05
3
15
70
5
20
16
—
24
80
—
MIN
11.88
—
—
—
—
—
10
—
—
—
79
MHE1212S
TYP
12.00
—
—
35
3
5
12
—
—
30
82
MAX
12.12
1.25
15
70
10
15
16
—
32
80
—
MHE1215S
MIN
14.85
—
—
—
—
—
10
—
—
—
80
TYP
15.00
—
—
35
3
10
12
—
—
30
83
MAX UNITS
15.15 VDC
1.0
A
15
70
10
20
16
—
32
80
—
W
mV p-p
mV
mV
VDC
V
mA
mA p-p
%
Note:
1. Guaranteed by design, not tested.
2
DC/DC C
ONVERTERS
SINGLE AND DUAL MHE28XX MODELS
PARAMETER
OUTPUT VOLTAGE
OUTPUT CURRENT
2
OUTPUT POWER
2
OUTPUT RIPPLE
VOLTAGE
LINE REGULATION
LOAD REGULATION
INPUT VOLTAGE
INPUT CURRENT
INPUT RIPPLE
CURRENT
EFFICIENCY
CONDITIONS
–55 TO +85°C
–55 TO +85°C
0 - 1 MHz
V
IN
MIN TO MAX
NO LOAD TO FULL
CONTINUOUS
TRANSIENT 50 ms
NO LOAD
10 kHz - 2 MHz
MHE2805S
MHE2812S
MHE2815S
MHE2812D
MHE SERIES
20 WATT
MHE2815D
UNITS
VDC
A
W
mV p-p
mV
mV
VDC
V
mA
mA p-p
%
Electrical Characteristics: 25°C Tc, 28 VDC Vin (12 Vin for 12 V models), 100% load, unless otherwise specified.
MIN TYP MAX MIN TYP MAX MIN TYP MAX
MIN
TYP MAX
MIN
TYP MAX
4.95 5.00 5.05 11.88 12.00 12.12 14.85 15.00 15.15 ±11.88 ±12.00 ±12.12 ±14.85 ±15.00 ±15.15
—
—
3.0
—
— 1.67
—
— 1.33
—
—
±0.63
—
—
±0.5
—
—
—
—
17
—
—
—
78
—
35
2
10
28
—
—
20
81
15
60
10
20
40
50
18
50
—
—
—
—
—
17
—
—
—
79
—
60
3
5
28
—
—
25
82
20
80
10
15
40
50
30
50
—
—
—
—
—
17
—
—
—
80
—
30
3
5
28
—
—
25
83
20
60
10
15
40
50
30
50
—
—
—
—
—
17
—
—
—
76
—
30
3
5
28
—
—
25
79
15
50
12
15
40
50
35
50
—
—
—
—
—
17
—
—
—
76
—
30
3
5
28
—
—
25
79
15
50
15
15
40
50
35
50
—
Note
1. Guaranteed by design, not tested.
2. On dual output models at least 25% of the load should be on the positive output.
3
MHE SERIES
20 WATT
Pin
1
2
3
4
5
6
7
8
9
10
Single Output
Positive Input
Inhibit
Output Adjust
Output Common
Positive Output
No connection
No connection
Case Ground
No connection
Input Common
DC/DC C
ONVERTERS
PIN OUT
Dual Output
Positive Input
Inhibit
Positive Output
Output Common
Negative Output
No connection
No connection
Case Ground
No connection
Input Common
Squared corner and dot on
top of cover indicate pin one.
1
2
3
4
5
BOTTOM VIEW
MHE
10
9
8
7
6
Dotted line outlines flanged package option.
See Section B8, case H6 and K7 for dimensions.
F
IGURE
1: P
IN
O
UT
MODEL NUMBERING KEY
MHE
Base Model
Input Voltage
Output Voltage
Number of Outputs
(S = single, D = dual)
Case Option
(Non-flanged case has no designator in
this position)
Screening
(Standard screening has no designator
in this position.)
28 12 S
F / ES
OUTPUT ADJUSTMENT RESISTOR VALUES
FOR MHE2805S AND MLP2805S
Resistance
Pin 3 to 4
Output Voltage
Increase (%)
0
+1%
+2%
+3%
+4%
+5%
∞
390K
145K
63K
22K
0
Output Adjustment all single output models:
The output can be adjusted upward by using the output
adjust (pin3). The resistance between output adjust (pin 3)
and output common (pin 4) will determine the magnitude of
the increase in the output.
The table above is applicable
only to MHE2805S.
4
MHE Series Rev D 20060630
All technical information is believed to be accurate, but no responsibility is assumed for
errors or omissions. Interpoint reserves the right to make changes in products or spec-
ifications without notice. MHE Series is a trademark of Interpoint Corporation.
Copyright © 1995 - 2006 Interpoint Corporation. All rights reserved.
C
ASES
Dot on top of case indicates pin one
CASE H
CASE H
BOTTOM VIEW
See Figures 29 – 34
for pin configurations.
1.125 max
(28.58)
2.125 max
(53.98)
Materials
Header Cold Rolled Steel/Nickel/Gold
cases H1 and H2
Cold Rolled Steel/Nickel/Tin
cases H3, H4, and H5
Cover Kovar/Nickel
cases H1 and H2
Cold Rolled Steel/Nickel/Tin
cases H3, H4, and H5
Pins
#52 alloy
ceramic seal
case H1
case H2 (except MHV Series Single and Dual)
compression glass seal
MHV Series Single and Dual
case H3, H4, H5
Case dimensions in inches (mm)
Tolerance
±0.005
(0.13) for three decimal places
±0.01
(0.3) for two decimal places
unless otherwise specified
CAUTION
Heat from reflow or wave soldering may damage
the device. Solder pins individually with heat
application not exceeding 300°C for 10 seconds
per pin.
F
IGURE
28: C
ASE
H M
AXIMUM
D
IMENSIONS
BOTTOM VIEW CASE H1
FMC EMI Filter: Screening – Standard, ES, or 883
SFMC EMI Filter: Screening – Space Standard, H, or K
Seam Seal
0.040 dia
(1.02)
1.110 (28.19)
0.955 (24.26)
1
0.555 (14.1)
5
0.155 (3.94)
0.000
0.400 max.
(10.16)
0.000
0.25
±0.03
(6.4
±0.8)
0.000
0.245
(6.22)
1.845
(46.86)
2.090
(53.01)
4
2
3
Squared corner and dot on top
of case indicate pin one.
F
IGURE
29: C
ASE
H1
Note: Although every effort has been made to render the case drawings at actual size, variations in the printing process may cause some distortion. Please refer
to the numerical dimensions for accuracy.
B8-17
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