F
EATURES
• –55°C to +85°C operation
• 19 to 36 VDC input or
16 to 36 VDC input typical
• Fully isolated
• Magnetic feedback
• Fixed frequency, 375 kHz typical
• Topology – Single Ended Forward
• 50 V for 50 ms transient protection
• Inhibit function
• Output trim
• Indefinite short circuit protection
• Radiation hardened to
10
13
neutrons/sq cm neutron fluence
10
11
rads(Si)/sec dose rate
10
5
rads(Si) total dose
• Meets MIL-STD-704E emergency
operation and transient standards
DC/DC C
ONVERTERS
28 V
OLT
I
NPUT
SINGLE
5
12
15
MRH SERIES
15 WATT
MODELS
VDC O
UTPUT
DUAL
±12
±15
TRIPLE
+5 & ±12
+5 & ±15
Size (max.): Non-flanged, case F3
1.950 x 1.350 x 0.455 inches (49.53 x 34.29 x 11.56 mm)
Flanged, case J3
2.720 x 1.350 x 0.455 inches (69.09 x 34.29 x 11.56 mm)
See Section B8, cases F3 and J3, for dimensions.
Weight:
50 grams typical
Screening: Standard or ES. See Section C2 for screening options and Section
A5 for ordering information.
DESCRIPTION
The MRH Series™ of DC/DC converters offers up to 15 watts of
power in a radiation hardened design. The low profile MRH
converters are manufactured in Interpoint’s fully certified and quali-
fied MIL-STD-1772 production facility and packaged in hermetically
sealed steel cases. They are ideal for use in programs requiring
high reliability, small size, and high levels of radiation hardening.
The MRH converters are switching regulators which use a quasi-
square wave, single ended forward converter design with a nominal
switching frequency of 375 kHz, typical. Close regulation (main
output line regulation is 0.05%) is maintained with advanced
constant frequency pulse width modulation design techniques.
With a 16 to 36 VDC input range and triple outputs of +5 VDC and
either ±12 or ±15 VDC, MRH converters are suitable for a wide
range of airborne, naval, and ground based applications. The
MRH’s feed-forward compensation topology provides high levels
(50 dB nominal) of input-to-output ripple rejection.
The MRH converters provide full power operation from –55°C to
+85°C with derated operation to +125°C. Flanged and non-flanged
package configurations are available with optional environmental
screening.
I
NHIBIT
F
UNCTION
The MRH Series incorporates an inhibit terminal that can be used
to disable internal switching. The converter is inhibited when a logic
low (≤ 0.8 V) signal is applied to the TTL open collector compatible
inhibit pin. In the inhibit mode the inhibit pin current requirement is
less than –2 mA. The converter resumes normal operation when a
logic high (≥ 2.4 V) signal or open circuit is applied to the inhibit pin.
The open circuit voltage of the inhibit is 5 to 6 volts.
O
UTPUT
V
OLTAGE
T
RIM
The output voltage on single output models can be trimmed upward
by as much as 5% of nominal by connecting a resistor between pin
3 and 4.
R
ADIATION
H
ARDENED
The MRH DC/DC converters are designed to provide continuous
normal operation through radiation levels associated with proximity
to thermonuclear events. The converters will operate normally in
environments with up to 10
13
neutrons per square centimeter
neutron fluence, 10
11
rads (Si) per second dose rate, and 10
5
rads
(Si) total dose. These levels of radiation tolerance make the MRH
converters suitable for electronics in tactical programs where oper-
ation in high radiation environments is required.
At the highest dose rating (10
11
rads (Si)/sec dose rate) there will
be an upset resulting in a dip in the voltage. This is non-destructive
to the unit. The converter will operate through the upset.
B4-19
MRH SERIES
15 WATT
ABSOLUTE MAXIMUM RATINGS
DC/DC C
ONVERTERS
INHIBIT
Inhibit TTL Open Collector
• Logic low (output disabled)
Inhibit pin current
≤
–2 mA
• Referenced to input common
• Logic high (output enabled)
Open collector
TYPICAL CHARACTERISTICS
Output Voltage Temperature Coefficient
• 250 ppm/°C max
Input to Output Capacitance
• 100 p, typical
Current Limit
• 125% of full load typical
Isolation
• 100 megohm minimum at 500 V
Conversion Frequency
• 375 kHz. typical
Inhibit Pin Voltage (unit enabled)
• 5 to 6 V
Radiation (will operate through)
• Neutron fluence 10
13
neutrons/ sq. cm.
• Radiation dose rate 10
11
rads (Si) /sec
• Total dose 10
5
rads (Si)
Power Dissipation (Pd)
• 5W
Output Power
• 15 watts
Lead Soldering Temperature (10 sec per lead)
• 300°C
Storage Temperature Range (Case)
• –65°C to +125°C
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range
• Continuous
16 to 40 VDC MRH28XXS and MRH2812D
19 to 40 VDC MRH2815D
16 to 36 VDC MRH285XXT
• 50 V for 50 msec transient
Case Operating Temperature (Tc)
• –55°C to +85°C full power
• –55°C to +125°C absolute
DERATING OUTPUT POWER/CURRENT AND INPUT VOLTAGE
Temperatures are referenced to the temperature at the converter’s baseplate
• Linearly derate output power/current from 100% at 85°C to 0% at 125°C.
• Above 105°C linearly derate steady state input voltage to 33 V and
transient voltage to 38 V, at 125°C.
• Operation below an input voltage of 19 volts, including operation in MIL-
STD-704E emergency power conditions, is possible with derated
output power. See Figures 9 and 10.
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
SINGLE OUTPUT MODELS
PARAMETER
OUTPUT VOLTAGE
OUTPUT CURRENT
OUTPUT POWER
OUTPUT RIPPLE
LINE REGULATION
LOAD REGULATION
1
INPUT VOLTAGE
2
–55°C TO +85°C
MIN. TO MAX. V
IN
10 kHz TO 2 MHz
16 TO 40 V
IN
MIN. LOAD TO FULL
NO LOAD TO FULL
TRANSIENT 50 ms
INPUT CURRENT
NO LOAD
FULL LOAD
INHIBITED
INPUT RIPPLE
CURRENT
EFFICIENCY
LOAD FAULT
3
POWER DISSIPATION
START-UP
SHORT CIRCUIT
OVERLOAD
DELAY
10 kHz TO10 MHz
—
73
—
—
—
25
75
5
5
3
50
—
—
—
10
—
76
—
—
—
25
78
5
5
3
50
—
—
—
10
—
78
—
—
—
25
80
5
5
3
50
—
—
—
10
ms
mA p-p
%
W
CONDITIONS
MIN
4.95
0.05
0.25
—
—
—
16
—
—
—
—
MRH2805S
TYP
5.0
—
—
40
5
5
28
—
50
—
22
MAX
5.05
3.0
15
70
10
30
40
50
60
750
25
MIN
11.88
0.02
0.25
—
—
—
16
—
—
—
—
MRH2812S
TYP
12
—
—
25
5
5
28
—
50
—
22
MAX
12.12
1.25
15
50
20
30
40
50
60
730
25
MIN
14.85
0.016
0.25
—
—
—
19
—
—
—
—
MRH2815S
TYP
15
—
—
25
5
5
28
—
50
—
22
MAX
15.15
1.0
15
50
20
30
40
50
60
720
25
mA
UNITS
VDC
A
W
mV p-p
mV
mV
VDC
V
Notes
1. Load regulation is not guaranteed below minimum load.
2. Converter should not be inhibited or operated below 12 Vin above 10
4
rads (Si) total dose.
3. Indefinite short circuit protection is not guaranteed above 85°C case.
B4-20
DC/DC C
ONVERTERS
DUAL AND TRIPLE OUTPUT MODELS
PARAMETER
OUTPUT VOLTAGE
CONDITION
MAIN
AUX.
OUTPUT CURRENT
1
–55°C TO +85°C
OUTPUT POWER
1
MAIN
AUX.
MAIN
AUX.
TOTAL
OUTPUT RIPPLE
VOLTAGE, 10 kHz - 2 MHz
LINE REGULATION
V
IN
= MIN. TO MAX.
LOAD REGULATION
2
NO LOAD TO FULL
INPUT VOLTAGE
3
MAIN
AUX.
MAIN
AUX.
MAIN
AUX.
CONTINUOUS
TRANSIENT 50 ms
INPUT CURRENT
NO LOAD
FULL LOAD
INHIBITED
INPUT RIPPLE
CURRENT
EFFICIENCY
LOAD FAULT
4
POWER DISSIPATION
START-UP
SHORT CIRCUIT
OVERLOAD
DELAY
10 kHz TO 2 MHz
—
76
—
—
—
25
78
5
5
3
50
—
—
—
10
—
76
—
—
—
25
78
5
5
3
50
—
—
—
10
—
70
—
—
—
25
72
5
5
3
50
—
—
—
10
—
70
—
—
—
MRH2812D
MIN
TYP
MAX
MRH2815D
MIN
TYP
MAX
MRH2812T
MIN
+4.95
TYP
+5.0
MAX
+5.05
MIN
MRH SERIES
15 WATT
MRH2815T
TYP
MAX
UNITS
VDC
A
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
+11.88 +12.0 +12.12
–11.82 –12.0 –12.18
+0.01 +0.625 +1.0
–0.01 –0.625
—
—
0.25
—
—
—
—
—
—
16
—
—
—
—
7.5
7.5
—
40
40
5
20
5
10
28
—
55
—
22
–1.0
12
12
15
60
60
20
100
30
100
40
50
70
700
25
+14.85 +15.0 +15.15
+4.95 +5.0 +5.05
–14.77 –15.0 –15.23 ±11.50 ±12.0 ±12.50 ±14.40 ±15.0 ±15.60
+0.008 +0.50
–0.008 –0.50
—
—
0.25
—
—
—
—
—
—
19
—
—
—
—
7.5
7.5
—
40
40
5
20
5
10
28
—
55
—
22
+0.8
–0.8
12
12
15
60
60
20
100
30
100
40
50
70
700
25
+0.40 +1.80 +2.00
±0.00 ±0.25 ±0.50
2
0
2
–
–
—
—
—
—
16
—
—
—
—
9
3
–
50
30
5
200
5
200
28
—
70
—
23
10
6
15
75
50
10
400
10
400
36
40
80
770
25
+0.40 +1.80 +2.00
±0.00 ±0.20 ±0.40
2
0
2
–
–
—
—
—
—
16
—
—
—
—
9
3
–
30
30
5
250
5
250
28
—
85
—
23
10
6
15
50
50
10
500
10
500
36
40
95
778
25
W
mV p-p
mV
mV
VDC
V
mA
25
72
5
5
3
50
—
—
—
10
mA p-p
%
W
ms
Notes
1. Maximum combined output power is 15 watts for both dual and triple models.
Dual output models: The maximum specification is the total output current/power.
Up to 80% of that total is available from either output provided the positive output maintains a minimum of 20% of the total power used.
Triple output models: The maximum combined power of the auxiliaries is 6 watts, of which 100% is available from either output.
2. Load regulation is not guaranteed below minimum load.
3. Converter should not be inhibited or operated below 12 Vin above 10
4
rads (Si) total dose.
4. Indefinite short circuit protection is not guaranteed above 85°C case.
PIN OUT
Dot on top of cover indicates pin one.
Pin
1
2
3
4
5
6
7
8
9
10
Single Output
Positive Input
No connection
Trim
Output Common
Positive Output
No connection
Case Ground
Inhibit
No connection
Input Common
Dual Output
Positive Input
No connection
Negative Output
Output Common
Positive Output
No connection
Case Ground
Inhibit
No connection
Input Common
Triple Output
Positive Input
Main (+5) Output
Output Common
Neg. Aux. Output
Pos. Aux. Output
No connection
Case Ground
Inhibit
No connection
Input Common
1
2
3
4
5
BOTTOM VIEW
MRH
FLANGED AND NON-FLANGED
See Section B8, cases F3 and J3, for dimensions.
10
9
8
7
6
Dotted line
outlines flanged
package option.
F
IGURE
1: P
IN
O
UT
B4-21
MRH SERIES
15 WATT
DC/DC C
ONVERTERS
MRH
Base Model
Input Voltage
28 12 T
F / ES
MODEL
NUMBERING
KEY
Output Voltage
(Aux. Vout for triple models)
Number of Outputs
(S = single, D = dual, T = triple)
Case Option
(Non-flanged case has no designator in
this position)
Screening
(Standard screening has no designator
in this position.)
Typical Performance Curves: 25°C Tc , 28 VDC Vin, 100% load, unless otherwise specified.
90
80
16V
90
16V
80
74
72
70
16
Efficiency (%)
Efficiency (%)
Efficiency (%)
68
66
64
62
60
58
28
36
70
40V
28V
60
50
40
70
28V
60
50
40
36V
4
6
8
10
12
14 15
4
6
8
10
12
14 15
56
5 6
8
10
12
14 15
Output Power (Watts)
Output Power (Watts)
Output Power (Watts)
MRH2805S Efficiency
MRH2815D Efficiency
MRH2815T Efficiency
F
IGURE
2
10
35
8
6
4
2
0
–2
–4
–6
–8
–10
1
10
Frequency (kHz)
100
F
IGURE
3
±Aux.
Output Voltage (% of nominal)
0
–1
–2
–3
–4
–5
–6
–7
–8
–9
0
1
F
IGURE
4
Attenuation (dB)
45
50
55
60
65
70
75
80
85
0.1
–Vout (% of nominal)
40
0
3
6
9
12
Pos. Output Power (Watts)
15 12
9
6
3
Neg. Output Power (Watts)
15
0
2
3
4
5
6
7
8
9
Main Output Power (Watts)
Audio Rejection, MRH Series
MRH2815T Aux. Reg. vs. Main Load
MRH2815D Neg. Output Cross Reg.
F
IGURE
5
±
Aux. Ouptut Voltage (% of nominal)
5
4
15.5
F
IGURE
6
15
F
IGURE
7
Input Voltage (Volts)
3
2
1
0
-1
-2
-3
-4
-5
Input Voltage (Volts)
2
4
6
8
10
12 14 15
+AUX
15.0
14.5
14.0
13.5
13.0
12.5
14
–AUX
13
12
0
1
2
3
4
5
6
Pos. Aux. Output Power (Watts)
6
5
4
3
2
1
0
Neg. Aux. Output Power (Watts)
12.0
11
1
3
5
7
9
11 13 15
Output Power (Watts)
50 mV Drop
Output Power (Watts)
MRH2805S Low Line Dropout
MRH2815T Low Line Dropout
MRH2815T Aux. Output with Unbalanced Loads
F
IGURE
8
F
IGURE
9
F
IGURE
10
B4-22
23821-001-DTS Rev A
DQ# 1020
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 specifications without notice. MRH Series is a trademark of Interpoint.
Copyright © 1994 - 1999 Interpoint. All rights reserved.
CASE F
C
ASES
Dot on top of case indicates pin one
Materials
Header Case F1
Cold Rolled Steel/Nickel/Gold
Cases F2 - F4
Cold Rolled Steel/Nickel/Tin
Cover Case F1
Kovar/Nickel
Cases F2 - F4
Cold Rolled Steel/Nickel/Tin
Pins
#52 alloy (all cases)
MHV Series Triple – compression glass seal
MTR Series Triple, case F1 – ceramic seal
MTR Series Triple, case F2 – compression glass seal
HUM40 – compression glass seal or ceramic seal
Case F3 – compression glass seal
Case F4 – compression glass seal or ceramic seal
Case dimensions in inches (mm)
Tolerance
±0.005
(0.13) for three decimal places
±0.01
(0.2) for two decimal places
unless otherwise specified
CASE F
BOTTOM VIEW
See Figures 20 - 23 for pin configuration
1.350 max
(34.29)
1.950 max
(49.53)
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
19: C
ASE
F M
AXIMUM
D
IMENSIONS
BOTTOM VIEW CASE F1
MTR Series Triple and MHV Series Triple: Screening – Standard, ES, or 883
Bathtub
Platform
Dot on top of case indicates pin one
1.170
(29.72)
0.040 dia.
(1.02)
MHV
Series
MTR
Series
Seam Seal
1
2
3
4
5
10
0.170
(4.32)
0.000
0.25 (6.4)
0.405 max
(10.29)
0.000
0.000
0.170
(4.32)
9
8
7
6
0.570
(14.48)
0.970
(24.64)
1.370
(34.80)
0.405 max
(10.29)
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.
B8-12
0.25 (6.4)
F
IGURE
20: C
ASE
F1
1.770
(44.96)
0.000
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