11/20/02
www.irf.com 1
ADVANCED ANALOG
HYBRID-HIGH RELIABILITY
DC/DC CONVERTERS
AHV28XX SERIES
Description
G6E 80 Transient Input (100 msec max.)
G6E 50 VDC Input (Continous)
G6E 16 to 40 VDC Input Range
G6E Single, Dual and Triple Outputs
G6E 15 Watts Output Power
(No Temperature Derating)
G6E Low Input / Output Noise
G6E Full Military Temperature Range
G6E Wideband PWM Control Loop
G6E Magnetic Feedback
G6E Low Profile Hermetic Package (0.405”)
G6E Short Circuit and Overload Protection
G6E Constant Switching Frequency (500KHz)
G6E True Hermetic Package (Parallel Seam
Welded, Ceramic Pin Feedthru)
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 applica-
tions requiring compliance to MIL-STD-704A through
E, in particular the input surge requirement of 80 volts
specified to withstand transient input voltage of 80 volts.
No input voltage or output power derating is necessary
over the full military temperature range.
These converters are packaged in an extremely rug-
ged, 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 feedthru seals as-
sure 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 fre-
quency 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 11.5volt
series regulator provides power to an epitaxial CMOS
custom pulse width modulator integrated circuit. This
single integrated circuit provides all PWM primary cir-
cuit functions. Power is transferred from primary to sec-
ondary through a ferrite core power transformer. An
error voltage signal is generated by comparing a highly
stable reference voltage with the converter output volt-
age 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, radia-
tion, aging, and variations in manufacturing. The trans-
fer function of the feedback circuit is a function of the
feedback transformer turns ratio which cannot change
when subjected to environmental extremes.
The CH grade is fully compliant to the require-
ments of MIL-PRF-38534 for class H. The HB
grade is processed and screened to the class H
requirement, but may not necessarily meet all of
the other MIL-PRF-38534 requirements, e.g., el-
ement evaluation and Periodic Inspection (P.I.)
not required. Both grades are tested to meet the
complete group “A” test specification over the full
military temperature range without output power
deration. Two grades with more limited screen-
ing are also available for use in less demanding
applications. Variations in electrical, mechanical
and screening can be accommodated. Contact
Advanced Analog for special requirements.
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are available in four screen-
ing grades to satisfy a wide range of requirements.
PD - 94583