B4-19
F
EATURES
55C to +85C 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
DESCRIPTION
The MRH SeriesTM 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 55C to
+85C with derated operation to +125C. 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.
DC/DC C
ONVERTERS
28 V
OLT
I
NPUT
MRH SERIES
15 WATT
MODELS
VDC O
UTPUT
SINGLE
5
12
15
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.
RECOMMENDED OPERATING CONDITIONS
ABSOLUTE MAXIMUM RATINGS
INHIBIT
Power Dissipation (Pd)
5 W
Output Power
15 watts
Lead Soldering Temperature (10 sec per lead)
300C
Storage Temperature Range (Case)
65C to +125C
B4-20
MRH SERIES
15 WATT
DC/DC C
ONVERTERS
TYPICAL CHARACTERISTICS
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)
55C to +85C full power
55C to +125C absolute
Inhibit TTL Open Collector
Logic low (output disabled)
Inhibit pin current
2 mA
Referenced to input common
Logic high (output enabled)
Open collector
Electrical Characteristics: 25C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
SINGLE OUTPUT MODELS
MRH2805S
MRH2812S
MRH2815S
PARAMETER
CONDITIONS
MIN TYP MAX
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
OUTPUT VOLTAGE
4.95
5.0
5.05
11.88
12
12.12
14.85
15
15.15
VDC
OUTPUT CURRENT
55C TO +85C 0.05
--
3.0
0.02
--
1.25
0.016
--
1.0
A
OUTPUT POWER
MIN. TO MAX. V
IN
0.25
--
15
0.25
--
15
0.25
--
15
W
OUTPUT RIPPLE
10 kHz TO 2 MHz
--
40
70
--
25
50
--
25
50
mV p-p
LINE REGULATION
16 TO 40 V
IN
--
5
10
--
5
20
--
5
20
mV
LOAD REGULATION
1
MIN. LOAD TO FULL
--
5
30
--
5
30
--
5
30
mV
INPUT VOLTAGE
2
NO LOAD TO FULL
16
28
40
16
28
40
19
28
40
VDC
TRANSIENT 50 ms
--
--
50
--
--
50
--
--
50
V
INPUT CURRENT
NO LOAD
--
50
60
--
50
60
--
50
60
FULL LOAD
--
--
750
--
--
730
--
--
720
mA
INHIBITED
--
22
25
--
22
25
--
22
25
INPUT RIPPLE
CURRENT
10 kHz TO10 MHz
--
25
50
--
25
50
--
25
50
mA p-p
EFFICIENCY
73
75
--
76
78
--
78
80
--
%
LOAD FAULT
3
SHORT CIRCUIT
--
5
--
--
5
--
--
5
--
W
POWER DISSIPATION
OVERLOAD
--
5
--
--
5
--
--
5
--
START-UP
DELAY
--
3
10
--
3
10
--
3
10
ms
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 85C case.
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)
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 85C to 0% at 125C.
Above 105C linearly derate steady state input voltage to 33 V and
transient voltage to 38 V, at 125C.
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.
DUAL AND TRIPLE OUTPUT MODELS
MRH2812D
MRH2815D
MRH2812T
MRH2815T
PARAMETER
CONDITION
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
OUTPUT VOLTAGE
MAIN
+11.88 +12.0 +12.12
+14.85 +15.0 +15.15
+4.95
+5.0
+5.05
+4.95
+5.0 +5.05
AUX.
11.82 12.0 12.18
14.77 15.0 15.23 11.50 12.0 12.50 14.40 15.0 15.60
VDC
OUTPUT CURRENT
1
MAIN
+0.01 +0.625
+1.0
+0.008 +0.50
+0.8
+0.40 +1.80 +2.00
+0.40 +1.80 +2.00
A
55C TO +85C
AUX.
0.01 0.625
1.0
0.008 0.50
0.8
0.00
0.25 0.50
0.00 0.20 0.40
OUTPUT POWER
1
MAIN
--
7.5
12
--
7.5
12
2
9
10
2
9
10
AUX.
--
7.5
12
--
7.5
12
0
3
6
0
3
6
W
TOTAL
0.25
--
15
0.25
--
15
2
15
2
15
OUTPUT RIPPLE
MAIN
--
40
60
--
40
60
50
75
30 50
VOLTAGE, 10 kHz - 2 MHz
AUX.
--
40
60
--
40
60
30
50
30
50
mV p-p
LINE REGULATION
MAIN
--
5
20
--
5
20
--
5
10
--
5
10
mV
V
IN
= MIN. TO MAX.
AUX.
--
20
100
--
20
100
--
200
400
--
250
500
LOAD REGULATION
2
MAIN
--
5
30
--
5
30
--
5
10
--
5
10
mV
NO LOAD TO FULL
AUX.
--
10
100
--
10
100
--
200
400
--
250
500
INPUT VOLTAGE
3
CONTINUOUS
16
28
40
19
28
40
16
28
36
16
28
36
VDC
TRANSIENT 50 ms
--
--
50
--
--
50
--
--
40
--
--
40
V
INPUT CURRENT
NO LOAD
--
55
70
--
55
70
--
70
80
--
85
95
FULL LOAD
--
--
700
--
--
700
--
--
770
--
--
778
mA
INHIBITED
--
22
25
--
22
25
--
23
25
--
23
25
INPUT RIPPLE
CURRENT
10 kHz TO 2 MHz
--
25
50
--
25
50
--
25
50
--
25
50
mA p-p
EFFICIENCY
76
78
--
76
78
--
70
72
--
70
72
--
%
LOAD FAULT
4
SHORT CIRCUIT
--
5
--
--
5
--
--
5
--
--
5
--
W
POWER DISSIPATION
OVERLOAD
--
5
--
--
5
--
--
5
--
--
5
--
START-UP
DELAY
--
3
10
--
3
10
--
3
10
--
3
10
ms
B4-21
MRH SERIES
15 WATT
DC/DC C
ONVERTERS
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 85C case.
Electrical Characteristics: 25C Tc, 28 VDC Vin, 100% load, unless otherwise specified.
PIN OUT
Pin
Single Output
Dual Output
Triple Output
1
Positive Input
Positive Input
Positive Input
2
No connection
No connection
Main (+5) Output
3
Trim
Negative Output
Output Common
4
Output Common Output Common
Neg. Aux. Output
5
Positive Output
Positive Output
Pos. Aux. Output
6
No connection
No connection
No connection
7
Case Ground
Case Ground
Case Ground
8
Inhibit
Inhibit
Inhibit
9
No connection
No connection
No connection
10
Input Common
Input Common
Input Common
Dot on top of cover indicates pin one.
BOTTOM VIEW
MRH
FLANGED AND NON-FLANGED
See Section B8, cases F3 and J3, for dimensions.
10
9
8
7
6
1
2
3
4
5
Dotted line
outlines flanged
package option.
F
IGURE
1: P
IN
O
UT
MRH 28 12 T F / ES
Base Model
Input Voltage
Output Voltage
Screening
Number of Outputs
Case Option
(Non-flanged case has no designator in
this position)
(S = single, D = dual, T = triple)
(Aux. Vout for triple models)
(Standard screening has no designator
in this position.)
B4-22
DC/DC C
ONVERTERS
Typical Performance Curves: 25C Tc , 28 VDC Vin, 100% load, unless otherwise specified.
F
IGURE
5
F
IGURE
7
85
0.1
1
10
100
80
75
70
65
60
55
45
40
35
50
Audio Rejection, MRH Series
Attenuation (dB)
Frequency (kHz)
9
0
9
8
7
6
5
4
3
2
1
0
1
2
3
4
5
6
7
8
Main Output Power (Watts)
MRH2815T Aux. Reg. vs. Main Load
Aux. Output Voltage (% of nominal)
Output Power (Watts)
MRH2805S Efficiency
Efficiency (%)
40
90
80
70
60
50
4
15
16V
28V
40V
6
8
10
12
14
F
IGURE
2
40
90
80
70
60
50
4
15
6
8
10
12
14
28V
36V
16V
Output Power (Watts)
MRH2815D Efficiency
Efficiency (%)
F
IGURE
3
10
10
6
2
2
6
8
4
0
4
8
MRH2815D Neg. Output Cross Reg.
Vout (% of nominal)
0
3
6
9
12
15
Pos. Output Power (Watts)
15
12
9
6
3
0
Neg. Output Power (Watts)
F
IGURE
6
F
IGURE
4
56
5
15
58
60
62
64
66
68
70
72
74
36
28
16
6
8
10
12
14
Output Power (Watts)
MRH2815T Efficiency
Efficiency (%)
5
4
3
2
1
0
-1
-2
-3
-4
-5
+AUX
AUX
MRH2815T Aux. Output with Unbalanced Loads
Aux. Ouptut Voltage (% of nominal)
0
1
2
3
4
5
6
Pos. Aux. Output Power (Watts)
6
5
4
3
2
1
0
Neg. Aux. Output Power (Watts)
F
IGURE
8
12.0
15
2
12.5
13.0
13.5
14.0
14.5
15.0
4
6
8
10
12
14
15.5
Output Power (Watts)
50 mV Drop
MRH2805S Low Line Dropout
Input Voltage (Volts)
F
IGURE
9
F
IGURE
10
14
13
12
11
1
3
5
7
9
11
13 15
15
Output Power (Watts)
MRH2815T Low Line Dropout
Input Voltage (Volts)
MRH SERIES
15 WATT
MODEL
NUMBERING
KEY
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.
B8-12
CASE F
C
ASES
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.
Dot on top of case indicates pin one
10
9
8
7
6
0.000
0.170
(4.32)
1.170
(29.72)
0.000
0.170
(4.32)
0.570
(14.48)
0.970
(24.64)
1.370
(34.80)
1.770
(44.96)
1
2
3
4
5
0.040 dia.
(1.02)
0.000
0.25 (6.4)
MTR
Series
MHV
Series
0.405 max
(10.29)
0.000
0.405 max
(10.29)
Bathtub
Platform
MTR Series Triple and MHV Series Triple: Screening Standard, ES, or 883
BOTTOM VIEW CASE F1
Seam Seal
0.25 (6.4)
Dot on top of case indicates pin one
F
IGURE
20: C
ASE
F1
F
IGURE
19: C
ASE
F M
AXIMUM
D
IMENSIONS
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.
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