12/13/06

www.irf.com

1

HYBRID-HIGH RELIABILITY

DC/DC CONVERTER

AHV28XX SERIES

Description

n 80V Transient Input (100 msec max.)

n 50V DC Input (Continous)

n 16V to 40V DC Input Range

n Single, Dual and Triple Outputs

n 15W Output Power

(No Temperature Derating)

n Low Input / Output Noise

n Full Military Temperature Range

n Wideband PWM Control Loop

n Magnetic Feedback

n Low Profile Hermetic Package (0.405”)

n Short Circuit and Overload Protection

n Constant Switching Frequency (500KHz)

n True Hermetic Package (Parallel Seam

Welded, Ceramic Pin Feedthru)

n Standard Microcircuit Drawings Available

Features

AHV

28V Input, Single, Dual and Triple Output

The AHV Series of DC/DC converters are designed to

replace the AHE/ATO family of converters in applications

requiring compliance to MIL-STD-704A through E, in

particular the input surge requirement of 80V specified to

withstand transient input voltage of 80V. No input voltage

or output power derating is necessary over the full military

temperature range.

These converters are packaged in an extremely rugged,

low profile package that meets all requirements of MIL-

STD-883 and MIL-PRF-38534. Parallel seam weld sealing

and the use of ceramic pin feed thru seals assure long

term hermeticity after exposure to extended temperature

cycling.

The basic circuit is a push-pull forward topology using

power MOSFET switches. The nominal switching

frequency is 500KHz. A unique current injection circuit

assures current balancing in the power switches. All AHV

series converters use a single stage LC input filter to

attenuate input ripple current. A low power 11.5V series

regulator provides power to an epitaxial CMOS custom

pulse width modulator integrated circuit. This single

integrated circuit provides all PWM primary circuit

functions. Power is transferred from primary to secondary

through a ferrite core power transformer. An error voltage

signal is generated by comparing a highly stable reference

voltage with the converter output voltage and drives the

PWM through a unique wideband magnetic feedback

circuit. This proprietary feedback circuit provides an

extremely wide bandwidth, high gain control loop, with

high phase margin. The feedback control loop gain is

insensitive to temperature, radiation, aging, and variations

in manufacturing. The transfer function of the feedback

circuit is a function of the feedback transformer turns ratio

which cannot change when subjected to environmental

extremes.

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 in electrical,

mechanical and screening can be accommodated.

Contact IR Santa Clara for special requirements.

PD-94583A