AHF28XX Datasheet, PDF (1/17 Pages) International Rectifier – 28V Input, Single and Dual Output

PD - 94541
ADVANCED ANALOG
HYBRID-HIGH RELIABILITY
DC/DC CONVERTERS
AHF28XX SERIES
28V Input, Single and Dual Output
Description
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 require-
ments of MIL-STD-704D. The basic circuit utilizes a
pulse width modulated, feed-forward topology at a nomi-
nal switching frequency of 550KHz. Input to output iso-
lation is achieved through the use of transformers in
the forward and feedback circuits.
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 character-
istics. This feedback method is also inherently tem-
perature and radiation insensitive. This gives the AHF
Series an important advantage over converters that
incorporate opto-couplers in their design.
These converters are manufactured in a facility certi-
fied to MIL-PRF-38534. All processes used to manu-
facture these converters have been qualified to enable
Advanced Analog to deliver compliant devices. Four
screening grades are available to satisfy a wide range
of requirements.The CH grade converters are fully com-
pliant to MIL-PRF-38534 class H. The HB grade con-
verters are processed to full MIL-PRF-38534 screen-
ing but do not have class H element evaluation as re-
quired by MIL-PRF-38534. Two grades are fully tested
and operate the full military temperature range without
derating of output power. Industrial and commercial
grades are also available. Variations are electrical,
mechanical and screening can be accommodated.
AHF
Features
n 16 to 40 VDC Input Range (28 VDC Nominal)
n Single and Dual Outputs
n 12 Watts Output Power
n 22.8 W/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 Opertation
n Constant Switching Frequency
(550KHz Nominal)
Extensive computer simulation using complex
modeling enables rapid design modification to
be provided. Contact Advanced Analog with spe-
cific requirements.
www.irf.com
1
10/08/02