PD-97388
AHP28XXS SERIES
HIGH RELIABILITY
HYBRID DC/DC CONVERTERS
Description
The AHP Series of DC/DC converters feature high power
density without derating over the full military temperature
range. This series is offered as lower cost alternatives to
the legendary AFL series with improved performance
for new design applications. The AHPs are form, fit and
functional replacement to the AFL series. The new AHP
series offers a full compliment of single and dual output
voltages operating from nominal +28 or +270 volt inputs
with output power ranging from 66 to 120 watts. For
applications requiring higher output power, multiple
converters can be operated in parallel. The internal
current sharing circuits assure equal current distribution
among the paralleled converters. Same as the AFL, the
AHP 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. Under-voltage 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 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 fully processed
and screened to the class H requirement, but does not
have material element evaluated to the class H
requirement. Both grades are tested to meet the
28V Input, Single Output
AHP
Features
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
n
16 To 40 Volt Input Range
3.3, 5,
8
, 9,12,15 and
28
Volts Outputs Available
High Power Density - up to 84 W / in3
Up To 120 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
Dual Output Versions Available
complete group “A” test specification over the full
military temperature range without output power
de-rating. Two grades with more limited screening
are also available for use in less demanding
applications. Variations in electrical, mechanical
and screening can be accommodated. Please
contact IR Santa Clara for special requirements.
www.irf.com
1
04/16/09
AHP28XXS 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
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
OUTPUT CURRENT
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
OUTPUT POWER
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
MAXIMUM CAPACITIVE LOAD
OUTPUT VOLTAGE
TEMPERATURE COEFFICIENT
OUTPUT VOLTAGE REGULATION
AHP2828S
Line
All Others
Line
Load
OUTPUT RIPPLE VOLTAGE
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
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
VIN = 16, 28, 40V, 100% Load,
BW = 10MHz
Note 1
VIN = 28V, 100% Load – Notes 1, 6
10,000
-0.015
+0.015
1
1
1
1
1
1
1
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
VIN = 16, 28, 40V - Note 6
Group A
Subgroups
Note 6
VIN = 28V, 100% Load
3.27
4.95
7.92
8.91
11.88
14.85
27.72
3.23
4.90
7.84
8.82
11.76
14.70
27.44
3.30
5.00
8.00
9.00
12.00
15.00
28.00
3.33
5.05
8.08
9.09
12.12
15.15
28.28
3.37
5.10
8.16
9.18
12.24
15.30
28.56
Test Conditions
Min
16
Nom
28
Max
40
Unit
V
V
20
16
10
10
9.0
8.0
4.0
66
80
80
90
108
120
112
A
Note 6
W
µF
%/°C
No Load, 50% Load, 100% Load
VIN = 16, 28, 40V
-70
-20
-1.0
+70
+20
+1.0
30
30
40
40
45
50
100
mV
mV
%
mVpp
For Notes to Specifications, refer to page 4
2
www.irf.com
AHP28XXS Series
Static Characteristics
(Continued)
Parameter
INPUT CURRENT
No Load
Inhibit 1
Inhibit 2
INPUT RIPPLE CURRENT
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
CURRENT LIMIT POINT
As a percentage of full rated load
1
2, 3
1, 2, 3
1, 2, 3
1,
1,
1,
1,
1,
1,
1,
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
Group A
Subgroups
VIN = 28V
IOUT = 0
Pin 4 Shorted to Pin 2
Pin 12 Shorted to Pin 8
VIN = 28V, 100% Load, BW = 10MHz
Test Conditions
Min
Nom
Max
80
100
5.0
50
60
60
60
60
60
60
60
Unit
mA
mApp
1
2
3
1, 2, 3
VOUT = 90% VNOM, VIN = 28V, Note 5
115
105
125
125
115
140
33
%
LOAD FAULT POWER
DISSIPATION
Overload or Short Circuit
EFFICIENCY
AHP2803R3S
AHP2805S
AHP2808S
AHP2809S
AHP2812S
AHP2815S
AHP2828S
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
W
1,
1,
1,
1,
1,
1,
1,
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
2, 3
VIN = 28V, 100% Load
72
78
79
80
80
81
81
-0.5
2.0
500
500
2.0
-0.5
20
100
74
81
82
83
84
85
84
0.8
100
50
100
550
600
700
10
0.8
100
80
%
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
1, 2, 3
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 = 70°C
1
85
300
g
KHrs
For Notes to Specifications, refer to page 4
www.irf.com
3
AHP28XXS Series
Dynamic Characteristics
-55°C < T
CASE
< +125°C, V
IN
=28V
unless otherwise specified.
Group A
Subgroups
LOAD TRANSIENT RESPONSE
AHP2803R3S / AHP2805S
Amplitude
Recovery
Amplitude
Recovery
AHP2808S
Amplitude
Recovery
Amplitude
Recovery
AHP2809S
Amplitude
Recovery
Amplitude
Recovery
AHP2812S
Amplitude
Recovery
Amplitude
Recovery
AHP2815S
Amplitude
Recovery
Amplitude
Recovery
AHP2828S
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
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
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
Load Step 50%
⇔
100%
Load Step 10%
⇔
50%
Note 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
-500
-500
-600
-600
-750
-750
-750
-750
-1200
-1200
450
200
450
400
500
200
500
400
600
200
600
400
750
200
750
400
750
200
750
400
1200
200
1200
400
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
mV
µs
Note 2, 8
Test Conditions
Min
Nom
Max
Unit
Notes to Specifications:
1.
2.
3.
4.
5.
6.
7.
8.
9.
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
V
OUT
at 50% load.
Line transient transition time
≥
100
µs.
Turn-on delay is measured with an input voltage rise time of between 100 and 500 volts per millisecond.
Current limit point is that condition of excess load causing output voltage to drop to 90% of nominal.
Parameter verified as part of another test.
All electrical tests are performed with the remote sense leads connected to the output leads at the load.
Load transient transition time
≥
10
µs.
Enable inputs internally pulled high. Nominal open circuit voltage
≈
4.0V
DC
.
4
www.irf.com
AHP28XXS Series
AHP28XXS Circuit Description
Figure I. AHP Single Output Block Diagram
DC Input 1
Input
Filter
Primary
Bias Supply
Current
Sense
Sync Output
5
Control
FB
Enable 1
4
Output
Filter
7
10
+Output
+Sense
Sync Input 6
Case
3
Error
Amp
& Ref
Share
Amplifier
Sense
Amplifier
11 Share
12 Enable 2
9
8
-Sense
Output Return
Input Return 2
Circuit Operation and Application Information
The AHP series of converters employ a forward switched
mode converter topology. (refer to Figure I.) Operation of
the device is initiated when a DC voltage whose magnitude
is within the specified input 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. Maintaining a DC voltage
within the specified operating range at the input assures
continuous generation of the primary bias voltage.
The switched voltage impressed on the secondary output
transformer winding is rectified and filtered to generate the
converter DC output voltage. An error amplifier on the
secondary side compares the 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 controller section of the
converter varying the pulse width of the square wave signal
driving the MOSFET, narrowing the width if the output voltage
is too high and widening it if it is too low, thereby regulating
the output voltage.
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
Pin 4 or
Pin 12
1N4148
290K
2N3904
200K
Pin 2 or
Pin 8
Disable
Remote Sensing
Connection of the
+
and
-
sense leads at a remotely located
load permits compensation for excessive resistance
between the converter output and the load when their
physical separation could cause undesirable voltage drop.
This connection allows regulation to the placard voltage at
the point of application. When the remote sensing feature is
not used the sense leads should be connected to their
respective output terminals at the converter. Figure III.
illustrates a typical remotely sensed application.
Internally, these ports differ slightly in their function. In use,
a low on Enable 1 completely shuts down all circuits in the
converter, while a low on Enable 2 shuts down the secondary
side while altering the controller duty cycle to near zero.
Externally, the use of either port is transparent save for
minor differences in standby current. (See specification table).
www.irf.com
5
