PD-94541D
AHF28XX SERIES
28V Input, Single and Dual Output
HYBRID-HIGH RELIABILITY
DC-DC CONVERTER
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
requirements of MIL-STD-704D. The basic circuit
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 converters that incorporate
opto-couplers in their design.
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are fabricated utilizing DSCC
qualified processes. 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 San Jose with specific requirements.
AHF
Features
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16V to 40VDC Input Range (28 VDC Nominal)
Single and Dual Outputs
12W Output Power
22.8W/in3 Power Density
Low Input / Output Noise
(50mA/60mVp-p max. respectively)
Indefinite Short Circuit and Overload Protection
Wideband Control Loop for Superior Transient
Characterstics
No derating for -55°C to +125°C Operation
Constant Switching Frequency (550KHz Nominal)
Standard Microcircuit Drawings Available
www.irf.com
1
03/09/10
AHF28XX Series
Specifications
Absolute M axim um Ratings
Input voltage
Soldering temperature
O perating case temperature
Storage case tem perature
-0.5V to +50V
300°C for 10 seconds
-55°C to +125°C
-65°C to +135°C
AHF2803R3S
Table I. Electrical Performance Characteristics
Test
Symbol
Conditions
-55°C
≤
Tc
≤
+125°C
Vin = 28Vdc ±5%, C
L
= 0
Unless otherwise specified
Output voltage
Output current
1
2
Group A
Subgroups
Device
Types
Min
Limits
Unit
Max
3.34
3.36
3000
60
V
mA
mV p-p
V
OUT
I
OUT
V
RIP
I
OUT
= 0
V
IN
= 16, 28, and 40Vdc
V
IN
= 16, 28, and 40Vdc,
B.W. = 20 Hz to 2MHz
V
IN
= 16, 28, and 40Vdc,
Iout = 0%, 50% and 100%
rated load
V
IN
= 16, 28, and 40Vdc,
1
2,3
1,2,3
1,2,3
01
01
01
3.26
3.23
Output ripple voltage
Line regulation
VR
LINE
1,2,3
01
25
mV
Load regulation
VR
LOAD
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 2.0MHz
I
OUT
= 100% rated load
Input to output or any pin
1,2,3
01
50
mV
12
1,2,3
01
30
1,2,3
1
2,3
1
01
01
72
70
100
50
mA p-p
%
mA
Input current
I
IN
Input ripple current
Efficiency
2
I
RIP
E
FF
Isolation
ISO
to case (except pin 6)
at 500Vdc, Tc = +25°C
No effect on dc performance,
Tc = +25°C
Overload
Short circuit
I
OUT
= 100% rated load
5
01
MΩ
Capacitive load
3, 4
C
L
P
D
F
S
4
1
1,2,3
4,5,6
01
01
01
01
500
500
6.0
2.0
600
µF
W
KHz
Power dissipation
load fault
Switching frequency
For Notes to Specifications, refer to page 3
2
www.irf.com
AHF28XX Series
Table I. Electrical Performance Characteristics -
continued
Test
Symbol
Conditions
-55°C
≤
Tc
≤
+125°C
Vin = 28Vdc ±5%, C
L
= 0
Unless otherwise specified
Output response to
step transient load
6
changes
Recovery time step
transient load
6, 7
changes
Output response to
transient step line
changes
Recovery time
transient step line
changes
Turn on overshoot
Turn on delay
Load fault
recovery
Weight
4, 9
AHF2803R3S
Limits
Unit
Group A
Subgroups
Device
Types
Min
Max
+300
mVpk
+500
70
µs
µs
ms
mVpk
50% to/from 100%
VO
TLOAD
rated load
0% to/from 50%
rated load
50% to/from 100% rated load
TT
LOAD
0% to/from 50% rated load
50% to/from 0% rated load
VO
TLINE
Input step 16V to/from
40Vdc, I
OUT
= 100%
rated load
Input step 16V to/from
40Vdc, I
OUT
= 100%
rated load
I
OUT
= o and 100% rated load
I
OUT
= o and 100% rated load
9
4, 7, 8
4, 8
4,5,6
01
4,5,6
4,5,6
4,5,6
4,5,6
4,5,6
01
01
-300
-500
1200
8.0
500
TT
LINE
VTon
OS
Ton
D
Tr
LF
4,5,6
4,5,6
4,5,6
4,5,6
01
01
01
01
800
600
20
20
38
µs
mVpk
ms
ms
g
Notes to Specifications
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20KHz to 2.0MHz.
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 2.0µs and 10µs.
7. Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within ±1.0
percent of V
OUT
at 50 percent load.
8. Input step transition time between 2.0µs and 10µs.
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.
www.irf.com
3
AHF28XX Series
Specifications
Absolute M axim um Ratings
Input voltage
Soldering temperature
O perating case temperature
Storage case tem perature
-0.5V to +50V
300°C for 10 seconds
-55°C to +125°C
-65°C to +135°C
AHF2805S
Table II. Electrical Performance Characteristics
Test
Symbol
Conditions
-55°C
≤
Tc
≤
+125°C
Vin = 28Vdc ±5%, C
L
= 0
Unless otherwise specified
Output voltage
Output current
1
2
Group A
Subgroups
Device
Types
Min
Limits
Unit
Max
5.05
5.10
2400
60
V
mA
mV p-p
V
OUT
I
OUT
V
RIP
I
OUT
= 0
V
IN
= 16, 28, and 40Vdc
V
IN
= 16, 28, and 40Vdc,
B.W. = 20 Hz to 2MHz
V
IN
= 16, 28, and 40Vdc,
Iout = 0%, 50% and 100%
rated load
V
IN
= 16, 28, and 40Vdc,
1
2,3
1,2,3
1,2,3
01
01
01
4.95
4.90
Output ripple voltage
Line regulation
VR
LINE
1,2,3
01
25
mV
Load regulation
VR
LOAD
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 2.0MHz
I
OUT
= 100% rated load
Input to output or any pin
1,2,3
01
50
mV
12
1,2,3
01
30
1,2,3
1
2,3
1
01
01
76
74
100
50
mA p-p
%
mA
Input current
I
IN
Input ripple current
Efficiency
2
I
RIP
E
FF
Isolation
ISO
to case (except pin 6)
at 500Vdc, Tc = +25°C
No effect on dc performance,
Tc = +25°C
Overload
Short circuit
I
OUT
= 100% rated load
5
01
MΩ
Capacitive load
3, 4
C
L
P
D
F
S
4
1
1,2,3
4,5,6
01
01
01
01
500
500
6.0
2.0
600
µF
W
KHz
Power dissipation
load fault
Switching frequency
For Notes to Specifications, refer to page 5
4
www.irf.com
AHF28XX Series
Table II. Electrical Performance Characteristics -
continued
Test
Symbol
Conditions
-55°C
≤
Tc
≤
+125°C
Vin = 28Vdc ±5%, C
L
= 0
Unless otherwise specified
Output response to
step transient load
6
changes
Recovery time step
transient load
6, 7
changes
Output response to
transient step line
changes
Recovery time
transient step line
changes
Turn on overshoot
Turn on delay
Load fault
recovery
Weight
4, 9
AHF2805S
Limits
Unit
Group A
Subgroups
Device
Types
Min
Max
+300
mVpk
+500
70
µs
µs
ms
mVpk
50% to/from 100%
VO
TLOAD
rated load
0% to/from 50%
rated load
50% to/from 100% rated load
TT
LOAD
0% to/from 50% rated load
50% to/from 0% rated load
VO
TLINE
Input step 16V to/from
40Vdc, I
OUT
= 100%
rated load
Input step 16V to/from
40Vdc, I
OUT
= 100%
rated load
I
OUT
= o and 100% rated load
I
OUT
= o and 100% rated load
9
4, 7, 8
4, 8
4,5,6
01
4,5,6
4,5,6
4,5,6
4,5,6
4,5,6
01
01
-300
-500
1200
8.0
500
TT
LINE
VTon
OS
Ton
D
Tr
LF
4,5,6
4,5,6
4,5,6
4,5,6
01
01
01
01
800
600
20
20
38
µs
mVpk
ms
ms
g
Notes to Specifications
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20KHz to 2.0MHz.
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 2.0µs and 10µs.
7. Recovery time is measured from the initiation of the transient to where V
OUT
has returned to within ±1.0
percent of V
OUT
at 50 percent load.
8. Input step transition time between 2.0µs and 10µs.
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.
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5
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