PD-97389
AHP28XXD SERIES
HIGH RELIABILITY
HYBRID DC/DC CONVERTERS
Description
The AHP Series of DC/DC converters feature high power
density with no derating over the full military temperature
range. This series is offered as part of a complete family
of converters providing single and dual output voltages
and operating from nominal +28 or +270 volt inputs with
output power ranging from 80 to 120 watts. For
applications requiring higher output power, individual
converters can be operated in parallel. The internal
current sharing circuits assure equal current distribution
among the paralleled converters. This series incorporates
International Rectifier’s proprietary magnetic pulse
feedback technology providing optimum dynamic line
and load regulation response. This feedback system
samples the output voltage at the pulse width modulator
fixed clock frequency, nominally 550 KHz. Multiple
converters can be synchronized to a system clock in the
500 KHz to 700 KHz range or to the synchronization
output of one converter. Undervoltage lockout, primary
and secondary referenced inhibit, soft-start and load
fault protection are provided on all models. Also included
is input over-voltage protection, a new protection feature
unique to the AHP.
These converters are hermetically packaged in two
enclosure variations, utilizing copper core pins to
minimize resistive DC losses. Three lead styles are
available, each fabricated with International Rectifier’s
rugged ceramic lead-to-package seal assuring long term
hermeticity in the most harsh environments.
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are available in four screening
grades to satisfy a wide range of requirements. The CH
grade is fully compliant to the requirements 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., element evaluation and Periodic
Inspection (P.I.) not required. Both grades are tested to
meet the complete group “A” test specification over the
28V Input, Dual Output
AHP
Features
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16 To 40 Volt Input Range
±
5,
±
12, and
±
15 Volts Outputs Available
High Power Density - up to 70 W / in3
Up To 100 Watt Output Power
Parallel Operation with Stress and Current Sharing
Input Over-Voltage Protection
High Efficiency - to 85%
Continuous Short Circuit and Overload
Protection
External Synchronization Port
Remote Sensing Terminals
Primary and Secondary Referenced
Inhibit Functions
Line Rejection > 40 dB - DC to 50KHz
Fault Tolerant Design
Full Military Temperature Range
Ceramic Feedthru Copper Core Pins
Low Profile (0.380") Seam Welded Package
Single Output Versions Available
full military temperature range without output
power deration. Two grades with more limited
screening are also avail-able for use in less
demanding applications. Variations in electrical,
mechanical and screening can be accommodated.
Contact IR Santa Clara for special requirements.
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1
04/16/09
AHP28XXD Series
Specifications
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Soldering Temperature
Case Temperature - Operating
Case Temperature - Storage
-0.5V to 50V
300°C for 10 seconds
-55°C to +125°C
-65°C to +135°C
Static Characteristics
-55°C < T
CASE
< +125°C, 16V< V
IN
< 40V
unless otherwise specified.
Parameter
INPUT VOLTAGE
OUTPUT VOLTAGE
AHP2805D
AHP2812D
AHP2815D
AHP2805D
AHP2812D
AHP2815D
OUTPUT CURRENT
AHP2805D
AHP2812D
AHP2815D
OUTPUT POWER
AHP2805D
AHP2812D
AHP2815D
MAXIMUM CAPACITIVE LOAD
OUTPUT VOLTAGE
TEMPERATURE COEFFICIENT
OUTPUT VOLTAGE REGULATION
Line
Load
Cross
AHP2805D
AHP2812D
AHP2815D
1
1
1
1
1
1
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
Group A
Subgroups
Note 6
VIN = 28V, 100% Load
Positive Output
Negative Output
Positive Output
Negative Output
Positive Output
Negative Output
Positive Output
Negative Output
Positive Output
Negative Output
Positive Output
Negative Output
VIN = 16, 28, 40V - Notes 6, 11
Either Output
Either Output
Either Output
Total of Both Outputs - Notes 6,11
80
96
100
10,000
-0.015
-0.5
-1.0
+0.015
+0.5
+1.0
Test Conditions
Min
16
4.95
-5.05
11.88
-12.12
14.85
-15.15
4.90
-5.10
11.76
-12.24
14.70
-15.30
Nom
28
5.00
-5.00
12.00
-12.00
15.00
-15.00
Max
40
5.05
-4.95
12.12
-11.88
15.15
-14.85
5.10
-4.90
12.24
-11.76
15.30
-14.70
12.8
6.4
5.3
Unit
V
V
A
W
µF
%/°C
Each Output - Note 1
VIN = 28V, 100% Load - Notes 1, 6
Note 10
No Load, 50% Load, 100% Load
VIN = 16, 28, 40V
VIN = 16, 28, 40V - Note 12
Positive Output
Negative Output
Positive Output
Negative Output
Positive Output
Negative Output
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
-1.0
-9.0
-1.0
-5.0
-1.0
-5.0
+1.0
+9.0
+1.0
+5.0
+1.0
+5.0
%
For Notes to Specifications, refer to page 4
2
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AHP28XXD Series
Static Characteristics
(Continued)
Parameter
OUTPUT RIPPLE VOLTAGE
AHP2805D
AHP2812D
AHP2815D
INPUT CURRENT
No Load
Inhibit 1
Inhibit 2
AHP2805D
AHP2812D
AHP2815D
INPUT RIPPLE CURRENT
AHP2805D
AHP2812D
AHP2815D
CURRENT LIMIT POINT
Expressed as a percentage
of Full Rated Load
1, 2, 3
1, 2, 3
1, 2, 3
VIN = 28V, 100% Load
1
2, 3
1, 2, 3
Group A
Subgroups
1, 2, 3
1, 2, 3
1, 2, 3
Test Conditions
VIN = 16, 28, 40V, 100% Load,
BW = 10MHz
Min
Nom
Max
60
80
80
80
100
5.0
mA
50
30
30
Unit
mVpp
VIN = 28V
IOUT = 0
Pin 4 Shorted to Pin 2
Pin 12 Shorted to Pin 8
1, 2, 3
1, 2, 3
1, 2, 3
60
60
60
mApp
1
2
3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
VOUT = 90% VNOM, Equal current on
positive and negative outputs - Note 5
115
105
105
125
125
125
33
%
LOAD FAULT POWER DISSIPATION
Overload or Short Circuit
EFFICIENCY
AHP2805D
AHP2812D
AHP2815D
ENABLE INPUTS
(Inhibit Function)
Converter Off
Sink Current
Converter On
Sink Current
SWITCHING FREQUENCY
SYNCHRONIZATION INPUT
Frequency Range
Pulse Amplitude, Hi
Pulse Amplitude, Lo
Pulse Rise Time
Pulse Duty Cycle
ISOLATION
DEVICE WEIGHT
MTBF
VIN = 28V
VIN = 28V, 100% Load
W
78
82
81
-0.5
2.0
500
500
2.0
-0.5
20
100
81
84
85
0.8
100
50
100
550
600
700
10
0.8
100
80
%
Logical Low on Pin 4 or Pin 12
Note 1
Logical High on Pin 4 and Pin 12 - Note 9
Note 1
V
µA
V
µA
KHz
KHz
V
V
ns
%
MΩ
Note 1
Note 1
Input to Output or Any Pin to Case
(except Pin 3). Test @ 500VDC
Slight Variations with Case Style
MIL-HDBK-217F, AIF @ TC = 40°C
1
85
300
g
KHrs
For Notes to Specifications, refer to page 4
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3
AHP28XXD Series
Dynamic Characteristics
-55°C < T
CASE
< +125°C, V
IN
=28V
unless otherwise specified.
Parameter
LOAD TRANSIENT RESPONSE
AHP2805D
Either Output
Amplitude
Recovery
Amplitude
Recovery
AHP2812D
Either Output
Amplitude
Recovery
Amplitude
Recovery
AHP2815D
Either Output
Amplitude
Recovery
Amplitude
Recovery
LINE TRANSIENT RESPONSE
Amplitude
Recovery
TURN-ON CHARACTERISTICS
Overshoot
Delay
LOAD FAULT RECOVERY
LINE REJECTION
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
4, 5, 6
Group A
Subgroups
Notes 2, 8
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
10%
⇒
50%
50%
⇒
10%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
10%
⇒
50%
50%
⇒
10%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
10%
⇒
50%
50%
⇒
10%
Notes 1, 2, 3
VIN Step = 16
⇔
40V
VIN = 16, 28, 40V - Note 4
Enable 1, 2 on. (Pins 4, 12 high or
open)
Same as Turn On Characteristics.
MIL-STD-461D, CS101, 30Hz to 50KHz
Note 1
40
50
dB
0
4.0
12
10
%
ms
-500
500
500
mV
µs
-450
-450
450
200
450
200
400
750
200
750
200
400
750
200
750
200
400
mV
µs
mV
µs
µs
mV
µs
mV
µs
µs
mV
µs
mV
µs
µs
Test Conditions
Min
Nom
Max
Unit
-750
-750
-750
-750
Notes to Specifications:
Parameters not 100% tested but are guaranteed to the limits specified in the table.
Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within
±1%
of Vout
at 50% load.
3. Line transient transition time
≥
100
µs.
4. Turn-on delay is measured with an input voltage rise time of between 100 and 500 volts per millisecond.
5. Current limit point is that condition of excess load causing output voltage to drop to 90% of nominal.
6. Parameter verified as part of another test.
7. All electrical tests are performed with the remote sense leads connected to the output leads at the load.
8. Load transient transition time
≥
10
µs.
9. Enable inputs internally pulled high. Nominal open circuit voltage
≈
4.0V
DC
.
10. Load current split equally between +V
OUT
and -V
OUT
.
11. Output load must be distributed so that a minimum of 20% of the total output power is being provided by one of
the outputs.
12. Cross regulation measured with load on tested output at 30% of maximum load while changing the load on
other output from 30% to 70%.
1.
2.
4
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AHP28XXD Series
AHP28XXD Circuit Description
Figure I. AFL Dual Output Block Diagram
DC Input
1
Input
Filter
Primary
Bias Supply
Current
Sense
Output
Filter
Sync Output
Sync Input
Case
Input Return
5
Control
6
3
2
Error
Amp
& Ref
Share
Amplifier
11 Share
12 Enable 2
10 Trim
Output
Filter
7 + Output
8 Output Return
9
-Output
Enable 1 4
Circuit Operation and Application Information
The AHP series of converters employ a forward switched
mode converter topology. (refer to the block diagram in
Figure I.) Operation of the device is initiated when a DC
voltage whose magnitude is within the specified input voltage
limits is applied between pins 1 and 2. If pin 4 is enabled (at
a logical 1 or open) the primary bias supply will begin
generating a regulated housekeeping voltage bringing the
circuitry on the primary side of the converter to life. A
power MOSFET is used to chop the DC input voltage into a
high frequency square wave, applying this chopped voltage
to the power transformer at the nominal converter switching
frequency. By maintaining a DC voltage within specified
operating range at the input, continuous generation of the
bias voltage is assured.
The switched voltage impressed on the secondary output
transformer windings is rectified and filtered to provide the
positive and negative converter output voltages. An error
amplifier on the secondary side compares the positive output
voltage to a precision reference and generates an error
signal proportional to the difference. This error signal is
magnetically coupled through the feedback transformer into
the control section of the converter varying the pulse width
of the square wave signal driving the MOSFETs, narrowing
the pulse width if the output voltage is too high and widening
it if it is too low. These pulse width variations provide the
necessary corrections to regulate the magnitude of output
voltage within its’ specified limits.
Because the primary portion of the circuit is coupled to the
secondary side with magnetic elements, full isolation from
input to output is maintained.
Although incorporating several sophisticated and useful
ancilliary features, basic operation of the AHP28XXD
series can be initiated by simply applying an input voltage to
pins 1 and 2 and connecting the appropriate loads between
pins 7, 8, and 9. As is the case with any high power density
converter, operation should not be initiated before secure
attachment to an appropriate heat dissipator. (See
Thermal
Considerations,
page 7) Additional application information
is provided in the paragraphs following.
Inhibiting Converter Output
As an alternative to application and removal of the DC voltage
to the input, the user can control the converter output by
providing TTL compatible, positive logic signals to either of
two enable pins (pin 4 or 12). The distinction between these
two signal ports is that enable 1 (pin 4) is referenced to the
input return (pin 2) while enable 2 (pin 12) is referenced to
the output return (pin 8). Thus, the user has access to an
inhibit function on either side of the isolation barrier. Each
port is internally pulled “high” so that when not used, an
open connection on both enable pins permits normal
converter operation. When their use is desired, a logical
“low” on either port will shut the converter down.
Figure II. Enable Input Equivalent Circuit
+5.6V
100K
Disable
270K
2N3904
200K
Pin 2 or
Pin 8
Pin 4 or
Pin 12
1N4148
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