03/09/10

www.irf.com

1

HYBRID-HIGH RELIABILITY

DC-DC CONVERTER

AHF28XX SERIES

Description

Features

AHF

28V Input, Single and Dual Output

The proprietary magnetic feedback circuit provides for

an extremely wide bandwidth control loop with a high

phase margin. The closed loop frequency response of

this converter family extends to approximately 50KHz,

resulting in superior line and load transient characteristics.

This feedback method is also inherently temperature

and radiation insensitive. This gives the AHF Series

an important advantage over converters that incorporate

opto-couplers in their design.

The AHF Series of DC-DC converters feature single or

dual outputs over the full military temperature range.

No derating in output power is required, making them

suitable for use in rugged military applications. The

low profile, small outline package is ideally suited to

the tight board space requirements of many industrial

and aerospace applications. Designed for nominal

28Vdc inputs, this family of converters will meet the

requirements of MIL-STD-704D. The basic circuit

utilizes a pulse width modulated, feed-forward topology

at a nominal switching frequency of 550KHz. Input to

output isolation is achieved through the use of

transformers in the forward and feedback circuits.

Extensive computer simulation using complex modeling

enables rapid design modification to be provided.

Contact IR San Jose with specific requirements.

n 16V to 40VDC Input Range (28 VDC Nominal)

n Single and Dual Outputs

n 12W Output Power

n 22.8W/in3 Power Density

n Low Input / Output Noise

(50mA/60mVp-p max. respectively)

n Indefinite Short Circuit and Overload Protection

n Wideband Control Loop for Superior Transient

Characterstics

n No derating for -55°C to +125°C Operation

n Constant Switching Frequency (550KHz Nominal)

n Standard Microcircuit Drawings Available

Manufactured in a facility fully qualified to MIL-PRF-

38534, these converters are fabricated utilizing DSCC

qualified processes. For available screening options,

refer to device screening table in the data sheet.

Variations are electrical, mechanical and screening

can be accommodated.

PD-94541D