PD-94541E
AHF SERIES
HYBRID-HIGH RELIABILITY
DC-DC CONVERTER
28V Input, Single/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 require-
ments of many industrial and aerospace applications.
Designed for nominal 28Vdc inputs, this family of converters
will meet the requirements of MIL-STD-704D. The basic cir-
cuit utilizes a pulse width modulated, feed-forward topology
at a nominal switching frequency of 550KHz. Input to output
isolation 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 characteristics. This feedback method
is also inherently temperature and radiation insensitive. This
gives the AHF Series an important advantage over convert-
ers that incorporate opto-couplers in their design.
Manufactured in a facility fully qualified to MIL-PRF-38534,
these converters are fabricated utilizing DLA qualified process.
For available screening options, refer to device screening
table in the data sheet. Variations are electrical, mechanical
and screening can be accommodated.
Extensive computer simulation using complex modeling
enables rapid design modification to be provided. Contact IR
HiRel San Jose with specific requirements.
AHF
Features
16V to 40V
DC
Input Range (28V
DC
Nominal)
Single
and Dual Outputs
12W Output Power
22.8W/in
3
Power Density
Low
Input / Output Noise
(50mA / 60mV
P-P
max. respectively)
Indefinite
Short Circuit and Overload Protection
Wideband
Control Loop for Superior Transient
Characteristics
No
derating for -55°C to +125°C Operation
Constant Switching Frequency
(550kHz Nominal)
Standard
Microcircuit Drawings Available
1
2017-05-08
AHF SERIES
(28V Input, Single/Dual Output)
Specifications
Absolute Maximum Ratings
Input Voltage
Soldering temperature
Operating case temperature
Storage case temperature
-0.5Vdc to +50V
DC
+300°C for 10 seconds
-55°C to +125°C
-65°C to +135°C
AHF2803R3S
Table I. Electrical Performance Characteristics
Parameter
Symbol
Conditions
-55°C
T
C
+125°C
V
IN
= 28 V
DC
± 5%, C
L
= 0
Unless otherwise specified
I
OUT
= 5% of rated load
V
IN
= 16, 28, and 40Vdc
V
IN
= 16, 28, and 40Vdc
V
IN
= 16, 28, and 40Vdc,
B.W. = 20 Hz to 2MHz
V
IN
= 16, 28, and 40Vdc,
I
OUT
= 5%, 50% and 100%
rated load
V
IN
= 16, 28, and 40Vdc,
I
OUT
= 5%, 50% and 100%
rated load
I
OUT
= 0, Inhibit (Pin 1)
tied to Input Return (Pin 7)
I
OUT
= 0,
Inhibit (Pin 1) = open
I
OUT
= 100% rated load
B.W. = 20 Hz to 2 MHz
I
OUT
= 100% rated load
Input to output or any pin
to case (except Pin 6) at
500Vdc T
C
= +25°C
No effect on dc performance,
T
C
= +25°C
Overload
5
Short circuit
F
S
I
OUT
= 100% rated load
Limits
Group A
Subgroups
1
2,3
1,2,3
1,2,3
1,2,3
1,2,3
Device
Types
Unit
Min
3.26
3.23
Max
3.34
3.36
3030
10
60
25
V
mA
W
mVp-p
mV
Output voltage
Output current
1
Output power
Output ripple voltage
2
Line regulation
V
OUT
I
OUT
P
OUT
V
RIP
VR
LINE
01
01
01
01
01
Load regulation
VR
LOAD
1,2,3
01
50
mV
12
1,2,3
01
30
1,2,3
1
2,3
01
01
70
68
01
100
M
50
mAp-p
mA
Input current
I
IN
Input ripple current
2
Efficiency
I
RIP
E
FF
%
Isolation
ISO
1
Capacitive load
3,4
Power dissipation
load fault
Switching frequency
C
L
P
D
4
1
1,2,3
4,5,6
01
01
01
01
500
500
6.0
2.0
600
µF
W
kHz
For Notes to Electrical Performance Characteristics, refer to page 3
2
2017-05-08
AHF SERIES
(28V Input, Single/Dual Output)
Table I. Electrical Performance Characteristics (continued)
Conditions
-55°C
T
C
+125°C
V
IN
= 28 V
DC
± 5%, C
L
= 0
unless otherwise specified
50% to/from 100% rated
load
5% to/from 50% rated load
TT
LOAD
50% to/from 100% rated
load
5% to 50% rated load
50% to 5% rated load
Output response to
transient step line
changes
Recovery time
transient step line
changes
Turn on overshoot
Turn on delay
Load fault recovery
4,9
Weight
Notes to Table I:
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20kHz to 2MHz.
3. Capacitive load may be any value from 0 to the maximum limit without compromising dc performance.
A capacitive in excess of the maximum limit will not disturb loop stability but may interfere with the
operation of the load fault detection circuitry, appearing as a short circuit during turn-on.
4. Parameter shall be tested as part of design characterization and after design or process changes.
Thereafter, parameters shall be guaranteed to the limits specified in Table I.
5. An overload is that condition with a load in excess of the rated load but less than that necessary to trigger the short
circuit protection and is the condition of maximum power dissipation.
6. Load step transition time between 2 and 10 microseconds.
7. Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within ±1 percent of V
OUT
at 50 percent load.
8. Input step transition time between 2 and 10 microseconds.
9. Turn-on delay time measurement is for either a step application of power at the input or the removal of ground signal
from the Inhibit Pin (Pin 1) while power is applied to the input is unlimited.
VO
TLINE
Input step 16V to/from
40Vdc, I
OUT
= 100% rated
load
4, 8
Input step 16V to/from
40Vdc, I
OUT
= 100% rated
load
4, 7, 8
I
OUT
= 5 and 100% rated
load
I
OUT
= 5 and 100% rated
load
9
AHF2803R3S
Limits
Device
Types
Unit
Min
-300
01
-500
Max
+300
mVpk
+500
70
01
1200
8.0
µs
µs
ms
Parameter
Symbol
Group A
Subgroups
4,5,6
4,5,6
4,5,6
4,5,6
4,5,6
4,5,6
Output response to
step transient load
changes
6
Recovery time step
transient load
changes
6.7
VO
TLOAD
01
500
mVpk
TT
LINE
4,5,6
01
800
µs
VTon
OS
Ton
D
Tr
LF
4,5,6
4,5,6
4,5,6
01
01
01
600
20
20
38
mVpk
ms
ms
g
3
2017-05-08
AHF SERIES
(28V Input, Single/Dual Output)
Specifications
Absolute Maximum Ratings
Input Voltage
Soldering temperature
Operating case temperature
Storage case temperature
-0.5Vdc to +50V
DC
+300°C for 10 seconds
-55°C to +125°C
-65°C to +135°C
AHF2805S
Table II. Electrical Performance Characteristics
Parameter
Symbol
Conditions
-55°C
T
C
+125°C
V
IN
= 28 V
DC
± 5%, C
L
= 0
Unless otherwise specified
I
OUT
= 0
V
IN
= 16, 28, and 40Vdc
V
IN
= 16, 28, and 40Vdc
V
IN
= 16, 28, and 40Vdc,
B.W. = 20 Hz to 2MHz
V
IN
= 16, 28, and 40Vdc,
I
OUT
= 0, 50% and 100%
rated load
V
IN
= 16, 28, and 40Vdc,
I
OUT
= 0, 50% and 100%
rated load
I
OUT
= 0, Inhibit (Pin 1)
tied to Input Return (Pin 7)
I
OUT
= 0,
Inhibit (Pin 1) = open
I
OUT
= 100% rated load
B.W. = 20 Hz to 2 MHz
I
OUT
= 100% rated load
Input to output or any pin
to case (except Pin 6) at
500Vdc T
C
= +25°C
No effect on dc performance,
T
C
= +25°C
Overload
5
Short circuit
F
S
I
OUT
= 100% rated load
Limits
Group A
Subgroups
1
2,3
1,2,3
1,2,3
1,2,3
1,2,3
Device
Types
Unit
Min
4.95
4.90
Max
5.05
5.10
2400
12
60
25
V
mA
W
mVp-p
mV
Output voltage
Output current
1
Output power
Output ripple voltage
2
Line regulation
V
OUT
I
OUT
P
OUT
V
RIP
VR
LINE
01
01
01
01
01
Load regulation
VR
LOAD
1,2,3
01
50
mV
12
1,2,3
01
30
1,2,3
1
2,3
01
01
76
74
01
100
M
50
mAp-p
mA
Input current
I
IN
Input ripple current
2
Efficiency
I
RIP
E
FF
%
Isolation
ISO
1
Capacitive load
3,4
Power dissipation
load fault
Switching frequency
C
L
P
D
4
1
1,2,3
4,5,6
01
01
01
01
500
500
6.0
2.0
600
µF
W
kHz
For Notes to Electrical Performance Characteristics, refer to page 5
4
2017-05-08
AHF SERIES
(28V Input, Single/Dual Output)
Table II. Electrical Performance Characteristics (continued)
Parameter
Symbol
Conditions
-55°C
T
C
+125°C
V
IN
= 28 V
DC
± 5%, C
L
= 0
unless otherwise specified
50% to/from 100% rated
load
0% to/from 50% rated load
TT
LOAD
50% to/from 100% rated
load
0% to 50% rated load
50% to 0% rated load
Output response to
transient step line
changes
Recovery time
transient step line
changes
Turn on overshoot
Turn on delay
Load fault recovery
4,9
Weight
Notes to Table II:
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20kHz to 2MHz.
3. Capacitive load may be any value from 0 to the maximum limit without compromising dc performance.
A capacitive in excess of the maximum limit will not disturb loop stability but may interfere with the
operation of the load fault detection circuitry, appearing as a short circuit during turn-on.
4. Parameter shall be tested as part of design characterization and after design or process changes.
Thereafter, parameters shall be guaranteed to the limits specified in Table II.
5. An overload is that condition with a load in excess of the rated load but less than that necessary to trigger the short
circuit protection and is the condition of maximum power dissipation.
6. Load step transition time between 2 and 10 microseconds.
7. Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within ±1 percent of V
OUT
at 50 percent load.
8. Input step transition time between 2 and 10 microseconds.
9. Turn-on delay time measurement is for either a step application of power at the input or the removal of ground signal
from the Inhibit Pin (Pin 1) while power is applied to the input is unlimited.
VO
TLINE
Input step 16V to/from
40Vdc, I
OUT
= 100% rated
load
4, 8
Input step 16V to/from
40Vdc, I
OUT
= 100% rated
load
4, 7, 8
I
OUT
= 0 and 100% rated
load
I
OUT
= 0 and 100% rated
load
9
Limits
Group A
Subgroups
4,5,6
01
4,5,6
4,5,6
4,5,6
4,5,6
4,5,6
01
-500
+500
70
1200
8.0
µs
µs
ms
Device
Types
Unit
Min
-300
Max
+300
mVpk
AHF2805S
Output response to
step transient load
changes
6
Recovery time step
transient load
changes
6.7
VO
TLOAD
01
500
mVpk
TT
LINE
4,5,6
01
800
µs
VTon
OS
Ton
D
Tr
LF
4,5,6
4,5,6
4,5,6
01
01
01
600
20
20
38
mVpk
ms
ms
g
5
2017-05-08
