B4-19

• –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

• Meets MIL-STD-704E emergency

operation and transient standards

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.

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.

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.

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

(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.

be an upset resulting in a dip in the voltage. This is non-destructive

to the unit. The converter will operate through the upset.

MRH SERIES

15 WATT

MODELS

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.