MODELS

SINGLE

5

12

15

DUAL

±12

±15

DESCRIPTION

The MHE Series™ and the MLP 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 components are required for operation. MHE Series and

MLP 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

hermetically sealed and are screened as described in Section C2.

The MHE Series and MLP Series converters are pulse-width modu-

lated 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 tran-

sients 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/MLP Series converters ideal for either

battery or aircraft power applications.

An inhibit function is provided on MHE/MLP 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/MLP Series

converters against short circuits.

MHE/MLP 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

requirements 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/MLP 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.

MHE/MLP SERIES

20 WATT

B4-13

Size (max.): Non-flanged 2.125 x 1.125 x 0.495 MHE (case H6) inches

or 0.417 MLP (case H4)

(53.98 x 28.58 x 12.57 (MHE) or 10.59 (MLP) mm)

Flanged 2.910 x 1.125 x 0.495 MHE (case K7) inches

or 0.417 MLP (case K5)

(73.91 x 28.58 x 12.57 (MHE) or 10.59 (MLP) mm)

See Section B8, cases H4, H6, K5, and K7, for dimensions.

Weight:

50 grams typical

Screening:

Standard or ES. See Section C2 for screening options, see

Section A5 for ordering information.

• –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