10/08/02
www.irf.com 1
ADVANCED ANALOG
HYBRID-HIGH RELIABILITY
DC/DC CONVERTERS
AHF28XX SERIES
Description
n16 to 40 VDC Input Range (28 VDC Nominal)
nSingle and Dual Outputs
n12 Watts Output Power
n 22.8 W/in3 Power Density
n Low Input / Output Noise
(50mA/60mVp-p max. respectively)
n Indefinite Short Circuit and Overload
Protection
n Wideband Control Loop for
Superior Transient Characterstics
Features
AHF
28V Input, Single and Dual Output
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 character-
istics. This feedback method is also inherently tem-
perature and r adiation insensitiv e. This gives the AHF
Series an important advantage over converters that
incorporate opto-couplers in their design.
n Constant Switching Frequency
(550KHz Nominal)
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 require-
ments of MIL-STD-704D. The basic circuit utilizes a
pulse width modulated, feed-forward topology at a nomi-
nal switching frequency of 550KHz. Input to output iso-
lation is achieved through the use of transformers in
the forward and feedback circuits.
These converters are manufactured in a facility certi-
fied to MIL-PRF-38534. All processes used to manu-
facture these converters have been qualified to enable
Advanced Analog to deliver compliant devices. Four
screening grades are available to satisfy a wide range
of requirements. The CH grade converters are fully com-
pliant to MIL-PRF-38534 class H. The HB grade con-
verters are processed to full MIL-PRF-38534 screen-
ing but do not have class H element evaluation as re-
quired by MIL-PRF-38534. Two grades are fully tested
and operate the full military temperature range without
derating of output power. Industrial and commercial
grades are also available. Variations are electrical,
mechanical and screening can be accommodated.
n No Derating for -55°C to +125°C Opertation
Extensive computer simulation using complex
modeling enables rapid design modification to
be provided. Contact Advanced Analog with spe-
cific requirements.
PD - 94541
2www.irf.com
AHF28XX Series
Specifications
For Notes to Specifications, refer to page 3
Table I. Electrical Performance Characteristics
AHF2805S
n ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300°C for 10 seconds
Case Temperature Operating -55°C to +125°C
Storage -65°C t o +135° C
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5%, CL = 0
Unless otherwise s pec if ied
Group A
Subgroups
Device
Types
Min
Max
Unit
Output volt age
VOUT
IOUT = 0
1
01
4.95
5.05
V
2,3 4.90 5.10
Output current1
IOUT
VIN = 16, 28, and 40 V dc
1,2,3
01
2400
mA
Output ripple
voltage2
VRIP
VIN = 16, 28, and 40 V dc,
B.W. = 20 Hz to 2MHz
1,2,3
01
60
mV p-p
Line regulation
VRLINE
VIN = 16, 28, and 40 V dc,
Iout = 0, 500, and 1000 mA
1,2,3
01
25
mV
Load regulation
VRLOAD
VIN = 16, 28, and 40 V dc,
IOUT = 0, 500, and 1000 mA
1,2,3
01
50
mV
Input current
IIN
IOUT = 0, inhibit (pin 1)
tied to input return (pin 7)
1,2,3
01
12
mA
I
OUT = 0,
inhibit (pin 1) = open 30
Input ripple current2
IRIP
IOUT = 1000mA
B.W. = 20 Hz to 2MHz
1,2,3
01
50
mA p-p
Efficiency
EFF
IOUT = 1000mA
1
01
76
%
2,3 74
Isolation
ISO
Input to output or any pin
To case (except pin 6) at
500V dc Tc = +25°C
1
01
100
MΩ
Capacitive load3,4
CL
No effect on dc
performance, Tc = +25°C
4
01
500
µF
Overload 5
1
01
6
Power dissipation
load fault
PD Short circuit 1,2,3 01
2
W
Switching
frequency
FS
IOUT = 1000mA
4,5,6
01
500
600
kHz
www.irf.com 3
AHF28XX Series
Table I. Electrical P erformance Characteristics - continued
Notes to Specifications
AHF2805S
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20 kHz to 2 MHz.
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 circuitr y, appearing as a shor t circuit during tur n-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. Recover y time is measured from the initiation of the transient to where VOUT has retur ned to within ±1
percent of VOUT at 50 percent load.
8. Input step transition time between 2 and 10 microseconds.
9. Tur n-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.
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5%, CL = 0
unless otherwise specified
Group A
Subgroups
Device
Types
Min
Max
Unit
Output response to
step transient load
changes6
VOTLOAD
1200 mA to/from 2400mA
4,5,6
01
-300
+300
mV pk
0 mA to/ from 1200mA 4,5,6 -500 +500 mV pk
1200 mA to/from 2400mA
4,5,6
01
70
µs
0 mA to 1200 mA 4,5,6 1200 ms
Recovery time step
transient load
changes6.7
TTLOAD
500 mA to 0 mA 4,5,6 8 ms
Output response to
transient step line
changes
VOTLINE
Input step 16 V t o/from
40 V dc, IOUT = 2400mA 4, 8
4,5,6
01
500
mV pk
Recovery time
transient step line
changes
TTLINE
Input step 16 V to/from 40Vdc
IOUT = 240 0mA 4, 7, 8
4,5,6
01
800
µs
Turn on overshoot
VTonOS
IOUT = 0 an d 2400mA
4,5,6
01
600
mV pk
Turn on delay
TonD
IOUT = 0 and 2400mA 9
4,5,6
01
20
ms
Load faul t
recovery4,9
TrLF
4,5,6
01
20
ms
Weight
35
grams
4www.irf.com
AHF28XX Series
Specifications AHF2812S
Table II. Electrical Performance Characteristics
For Notes to Specifications, refer to page 5
n ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperat ure 300°C for 10 seconds
Case Temperature Operating -55°C to +125°C
Storage -65°C t o +135° C
Limits
Test
Symbol
Conditions
-55°C ≤Tc ≤ +125° C
Vin = 28 Vdc ±5%, CL = 0
Unless otherwise speci fied
Group A
Subgroups
Device
Types Min
Max
Unit
Output vol tage
VOUT
IOUT = 0
1
01
11.88
12.12
V
2,3 11.76 12.24
Output current1
IOUT
VIN = 16, 28, and 40 V dc
1,2,3
01
1000
mA
Output ripple
voltage2
VRIP
VIN = 16, 28, and 40 V dc,
B.W. = 20 Hz to 2MHz
1,2,3
01
60
mV p-p
Line regulation
VRLINE
VIN = 16, 28, and 40 V dc,
Iout = 0, 500, and 1000 mA
1,2,3
01
50
mV
Load regulation
VRLOAD
VIN = 16, 28, and 40 V dc,
IOUT = 0, 500, and 1000 mA
1,2,3
01
50
mV
Input current
IIN
IOUT = 0, inhibit (pi n 1)
tied to input return (pin 7)
1,2,3
01
12
mA
I
OUT = 0,
inhibit (pi n 1) = open 50
Input ripple current2
IRIP
IOUT = 1000mA
B.W. = 20 Hz to 2MHz
1,2,3
01
50
mA p-p
1
78
Efficiency
EFF
IOUT = 1000mA 2,3
01 75
%
Isolation
ISO
Input to output or any pin
to cas e (except pin 6) at
500V dc Tc = +25° C
1
01
100
MΩ
Capaciti ve load3,4
CL
No effect on dc
performance, Tc = +25°C
4
01
500
µF
Overload 5
1
01
6
Power dissipation
load fault
PD Short ci rcuit 1,2,3 01
2
W
Switching
frequency
FS
IOUT = 1000mA
4,5,6
01
500
600
kHz
www.irf.com 5
AHF28XX Series
Table II. Electrical Performance Characteristics - continued AHF2812S
Notes to Specifications
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20 kHz to 2 MHz.
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 circuitr y, appearing as a shor t circuit during tur n-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. Recover y time is measured from the initiation of the transient to where VOUT has retur ned to within ±1
percent of VOUT at 50 percent load.
8. Input step transition time between 2 and 10 microseconds.
9. Tur n-on delay time measurement is for either a step application of power at the input or the removal of
a ground signal from the inhibit pin (pin 1) while power is applied to the input is unlimited.
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5%, CL = 0
unless otherwise specified
Group A
Subgroups
Device
Types
Min
Max
Unit
50 mA to/from 1000mA
4
01
-300
+300
5,6 -450 +450
0 mA to/from 500mA 4 -500 +500
Output response
to step transient
load changes6
VOTLOAD
5,6
-750 +750
mV pk
TTLOAD
50 mA to/from 1000mA
4,5,6
100
0 mA to 500 mA 4,5,6 1500
µs
Recovery time
step transient
load changes6,7
500 mA to 0 mA 4,5,6
01
10 ms
Output response
to transient step
line changes
VOTLINE
Input step 16 V to/from
40 V dc, IOUT =1000mA 4, 8
4,5,6
01
1500
mV pk
Recovery time
transient step
line changes
TTLINE
Input step 16 V to/from 40Vdc
IOUT =1000mA 4, 7, 8
4,5,6
01
800
µs
Turn on
overshoot
VTonOS
IOUT = 0 and 1000mA
4,5,6
01
600
mV pk
Turn on delay
TonD
IOUT = 0 and 1000mA 9
4,5,6
01
20
ms
Load fault
recovery4,9
TrLF
4,5,6
01
20
ms
Weight
35
grams
6www.irf.com
AHF28XX Series
Specifications
Table III. Electrical Performance Characteristics
AHF2815S
For Notes to Specifications, refer to page 7
n ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300°C for 10 seconds
Case Temperature Operating -55°C to +125°C
Storage -65°C t o +135° C
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5% , CL = 0
unless otherwise speci fied
Group A
Subgroups
Device
Types
Min
Max
Unit
Output vol tage
VOUT
IOUT = 0
1
All
14.85
15.15
V
2,3 14.70 15.30
Output current1
IOUT
VIN = 18, 28, and 40 V dc
1,2,3
All
2000
mA
Output ripple
voltage2
VRIP
VIN = 18, 28, and 40 V dc,
B.W. = 20 Hz to 2 MHz
1,2,3
All
50
mV p-p
Line regulation
VRLINE
VIN = 18, 28, and 40 V dc,
Iout = 0, 1000, and 2000 mA
1
All
±35
mV
2,3 ±75
Load regulation
VRLOAD
VIN = 18, 28, and 40 V dc,
IOUT = 0, 1000, and 2000 mA
1,2,3
All
±150
mV
Input current
IIN
IOUT = 0, inhibit (pi n 2)
tied to input return (pin 10)
1,2,3
All
18
mA
I
OUT = 0,
inhibit (pin 2) = open 50
Input ripple current2
IRIP
IOUT = 2000mA,
B.W. = 20 Hz to 2 MHz
1,2,3 All
20
mA p-p
Efficiency
EFF
IOUT = 2000mA
1
All
80
%
2,3 77
Isolation
ISO
Input to output or any pin
to cas e (except pin 7) at
500 V dc Tc = +25° C
1
All
100
MΩ
Capaciti ve load3,4
CL
No effect on dc performance,
Tc = +25°C
4
All
200
µF
Overload 5
1
All
6
Power dissipation
load fault
PD Short ci rcuit 1,2,3 All
2
W
Switc hi ng f requency
FS
IOUT = 2000mA
4,5,6
01, 04
250
300
02, 05 250 270 kHz
03, 06 275 300
www.irf.com 7
AHF28XX Series
Table III. Electrical Performance Characteristics - continued AHF2815S
Notes to Specifications
1. Parameter guaranteed by line and load regulation tests.
2. Bandwidth guaranteed by design. Tested for 20 kHz to 2 MHz.
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, appear ing as a short circuit during tur n-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 III.
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. Recover y time is measured from the initiation of the transient to where VOUT has returned to within ±1
percent of VOUT 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
a ground signal from the inhibit pin (pin 2) while power is applied to the input is unlimited.
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5%, CL = 0
unless other wise s pec i fied
Group A
Subgroups
Device
Types
Min
Max
Unit
1000 mA to/fr om 2000m A
4,5,6
-800
+800
Output response to
step transient load
Changes6
VOTLOAD
0 mA to/fro m 1000mA 4, 5,6
All
-1000 +750
mV pk
4 100
1000 mA to/fr om 2000m A 5,6
All
200
µs
4 5
Recovery time step
transient l oad
Changes6,7
TTLOAD
0 mA to/fro m 1000 mA
5,6
All
10
ms
04
05
Output response to
transient s t ep line
changes
VOTLINE
Input step 18 V to/ fro m
40 V dc, IOUT = 2000mA 4, 8
4,5,6
06
-1000
+1000
mV pk
04
05
Recovery time
transient s t ep line
changes
TTLINE
Input step 18 V to/from 40Vdc
IOUT = 2000mA 4, 7, 8
4,5,6
06
500
µs
Turn on overshoot VTonOS I
OUT = 0 and 2000mA 4,5,6 All 750 mV pk
Turn on delay
TonD I
OUT = 0 and 2000mA 9
4,5,6 All 12 ms
Load fault
recovery4,9
TrLF 4,5,6 All 12 ms
Weight 38 grams
8www.irf.com
AHF28XX Series
Specifications AHF2805D
Table IV. Electrical Performance Characteristics
For Notes to Specifications, refer to page 9
n ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300°C for 10 seconds
Case Temperature Operating -55°C to +125°C
Storage -65°C t o +135° C
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤+125°C
Vin = 28 Vdc ±5%, CL = 0
unless otherwise speci fied
Group A
Subgroups
Device
Types
Min
Max
Unit
Output vol tage VOUT I
OUT = 0 1 01 ±4. 95 ±5.05 V
2,3 ±4.90 ±5.10
Output current1,2
IOUT
VIN = 16, 28, and 40 V dc,
each output
1,2,3
01
0.12
1.08
A
Output ripple
voltage3
VRIP
VIN = 16, 28, and 40 V dc,
B.W. = 20 Hz to 2 MHz
1,2,3
01
60
mV p-p
Line regulation4
VRLINE
VIN = 16, 28, and 40 V dc,
Iout = 0, 1200, and 2400 mA
1,2,3
01
30
mV
Load regulation4
VRLOAD
VIN = 16, 28, and 40 V dc,
IOUT = 0, 1200, and 2400 mA
1,2,3
01
30
mV
Cross regulation5
VRcros
10 percent to 90 percent
load change
1,2,3
01
±10
%
Input current
IIN
IOUT = 0, inhibit (pin 1)
tied to i nput return (pin 7)
1,2,3
01
12
mA
I
OUT =0, inhibit (pi n 1) = open 60
Input ripple
current3,4
IRIP I
OUT = 2400mA
B.W. = 20 Hz to 2 MHz
1,2,3
01
50
mA p-p
Efficiency4 E
FF I
OUT = 2400mA, 1,3 75
T
C =+25°C 2 01 72 %
Isolation
ISO
Input to output or any pin
to cas e (except pin 6) at
500V dc, T C = +25°C
1
01
100
MΩ
Capaciti ve load6,7
CL
No effect on dc
performance, TC = +25°C,
total f or both outputs
4
01
200
µF
www.irf.com 9
AHF28XX Series
Table IV. Electrical Perf ormance Characteristics - continued AHF2805D
Notes to Specifications
1. Parameter guaranteed by line load and cross regulation tests.
2. Up to 90 percent of full power is available from either output provided the total output does not exceed 12W.
3. Bandwidth guaranteed by design. Tested for 20 kHz to 2 MHz.
4. Load current split equally between +VOUT and –VOUT.
5. 1.2 watt load on output under test, 1.2 watt to 10.8 watt load change on other output.
6. Capacitive load may be any value from 0 to the maximum limit without compromising dc performance.
A capacitive load in excess of the maximum limit will not disturb loop stability but may interfere with the
operation of the load fault detection circuitr y, appearing as a shor t circuit during tur n-on.
7. 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 IV.
8. 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.
9. Load step transition time between 2 and 10 microseconds.
10. Recover y time is measured from the initiation of the transient to where VOUT has retur ned to within ±1
percent of VOUT at 50 percent load.
11. Input step transition time between 2 and 10 microseconds.
12. Turn-on delay time measurement is for either a step application of power at the input or the removal of
a ground signal from the inhibit pin (pin 1) while power is applied to the input.
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤+125°C
Vin = 28 Vdc ±5%, CL = 0
unless otherwise speci fied
Group A
Subgroups
Device
Types
Min
Max
Unit
Overload, TC = +25°C 8 6 Power dissipa-
tion load fault
PD
Short circuit, TC = +25°C
1,2,3 01
2
W
Switching
frequency4
FS
IOUT = 2400mA
4,5,6
01
500
600
kHz
1200 mA to/ from 2400mA 4,5,6
-400
+400
Output response
to step transient
load changes4,9
VOTLOAD 0 mA to/from 1200 mA 4,5,6
01
-800 +800
mV pk
1200 mA to/ from 2400mA 4,5,6
01 70
Recovery time
step transient load
changes4,9,10
TTLOAD
0 mA to/ from 1200 mA 4,5,6
100
µs
Output response
transient step line
changes4,7,11
VOTLINE Input step from/to 16 to
40 V dc, IOUT =2400mA
4,5,6
01
-400
+400
mV pk
Recovery time
transient step line
changes4,7,10,11
TTLINE
Input step from/to 16 to 40 V
dc, IOUT =2400mA
4,5,6
01
1200
µs
Turn on
overshoot4
VTonOS IOUT =0 and 2400m A 4,5,6 01 600 mV pk
Turn on delay4,12
TonD I
OUT = 0 and 2400mA
4,5,6 01 25 ms
Load fault
recovery7
TrLF
4,5,6
01
25
ms
Weight
38
grams
10 www.irf.com
AHF28XX Series
Specifications AHF2812D
Table V. Electrical Performance Characteristics
For Notes to Specifications, refer to page 11
n ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300°C for 10 seconds
Case Temperature Operating -55°C to +125°C
Storage -65°C t o +135° C
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5%, CL = 0
unless otherwise speci fied
Group A
Subgroups
Device
Types
Min
Max
Unit
Output vol tage VOUT I
OUT = 0 1 01 ±11.88 ±12.12 V
2,3 ±11.76 ±12.24
Output current1,2
IOUT
VIN = 16, 28, and 40 V dc,
each output
1,2,3
01
100
900
mA
Output ripple
voltage3
VRIP
VIN = 16, 28, and 40 V dc,
B.W. = 20 Hz to 2 MHz
1,2,3
01
60
mV p-p
Line regulation4
VRLINE
VIN = 16, 28, and 40 V dc,
Iout = 0, 500, and 1000 mA
1,2,3
01
30
mV
Load regulation4
VRLOAD
VIN = 16, 28, and 40 V dc,
IOUT = 0, 500, and 1000 mA
1,2,3
01
30
mV
Cross regulation5
VRcros
10 percent to 90 percent
load change
1,2,3
01
3.0
%
Input current
IIN
IOUT = 0, inhibit (pin 1)
tied to i nput return (pin 7)
1,2,3
01
12
mA
I
OUT =0, inhibit (pi n 1) = open 60
Input ripple
current3,4
IRIP I
OUT = 1000mA
B.W. = 20 Hz to 2 MHz
1,2,3
01
50
mA p-p
Efficiency4 E
FF I
OUT = 1000mA, 1,3 77
T
C =+25°C 2 01 74 %
Isolation
ISO
Input to output or any pin
to cas e (except pin 6) at
500V dc, T C = +25°C
1
01
100
MΩ
Capaciti ve load6,7
CL
No effect on dc
performance, TC = +25°C,
total f or both outputs
4
01
200
µF
www.irf.com 11
AHF28XX Series
Table V. Electrical Performance Characteristics - continued AHF2812D
Notes to Specifications
1. Parameter guaranteed by line load and cross regulation tests.
2. Up to 90 percent of full power is available from either output provided the total output does not exceed 12W.
3. Bandwidth guaranteed by design. Tested for 20 kHz to 2 MHz.
4. Load current split equally between +VOUT and –VOUT.
5. 1.2 watt load on output under test, 1.2 watt to 10.8 watt load change on other output.
6. Capacitive load may be any value from 0 to the maximum limit without compromising dc performance.
A capacitive oad in excess of the maximum limit will not disturb loop stability but may interfere with the
operation of the load fault detection circuitr y, appearing as a shor t circuit during tur n-on.
7. 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 V.
8. 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.
9. Load step transition time between 2 and 10 microseconds.
10. Recover y time is measured from the initiation of the transient to where VOUT has retur ned to within ±1
percent of VOUT at 50 percent load.
11. Input step transition time between 2 and 10 microseconds.
12. Tur n-on delay time measurement is for either a step application of power at the input or the removal of
a ground signal from the inhibit pin (pin 1) while power is applied to the input.
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤+125°C
Vin = 28 Vdc ±5%, CL = 0
unless otherwise speci fied
Group A
Subgroups
Device
Types
Min
Max
Unit
Overload, TC = +25°C 8 6 Power dissipa-
tion load faul t
PD
Short ci rcuit, TC = +25°C
1,2,3 01
2
W
Switching
frequency4
FS
IOUT = 1000mA
4,5,6
01
500
600
kHz
500 mA to/ from 1000mA 4,5,6
-200
+200
Output response
to step transient
load changes4,9
VOTLOAD 0 mA to/from 500 mA 4,5,6
01
-800 +800
mV pk
500 mA to/ from 1000mA 4,5,6
01 70
Recovery time
step transient load
changes4,9,10
TTLOAD
0 mA to/ from 500 mA 4,5,6
1000
µs
Output response
transient step line
changes4,7,11
VOTLINE Input step from/to 16 to
40 V dc, IOUT =1000mA
4,5,6
01
-750
+750
mV pk
Recovery time
transient step line
changes4,7,10,11
TTLINE
Input step from/to 16 to 40 V
dc, IOUT =1000mA
4,5,6
01
1200
µs
Turn on
overshoot4
VTonOS IOUT =0 and 1000m A 4,5,6 01 600 mV pk
Turn on delay4,12
TonD I
OUT = 0 and 1000mA
4,5,6 01 25 ms
Load fault
recovery7
TrLF
4,5,6
01
25
ms
Weight
38
grams
12 www.irf.com
AHF28XX Series
Specifications AHF2815D
Table VI. Electrical Performance Characteristics
For Notes to Specifications, refer to page 13
n ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300°C for 10 seconds
Case Temperature Operating -55°C to +125°C
Storage -65°C t o +135° C
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤+125°C
Vin = 28 Vdc ±5%, CL = 0
Unless otherwise specified
Group A
Subgroups
Device
Types
Min
Max
Unit
Output vol tage
VOUT
IOUT = 0
1
01
±14.85
±15.15
V
2,3 ±14.70 ±15.30
Output current1,2
IOUT
VIN = 16, 28, and 40 V dc,
each output
1,2,3
01
80
720
mA
Output ripple
voltage3
VRIP
VIN = 16, 28, and 40 V dc,
B.W. = 20 Hz to 2 MHz
1,2,3
01
60
mV p-p
Line regulation4
VRLINE
VIN = 16, 28, and 40 V dc,
Iout = 0, 400, and 800 mA
1,2,3
01
35
mV
Load regulation4
VRLOAD
VIN = 16, 28, and 40 V dc,
IOUT = 0, 400, and 800 mA
1,2,3
01
35
mV
Cross regulation5
VRcros
10 percent to 90 percent
load change each output
1,2,3
01
3.0
%
Input current
IIN
IOUT = 0, inhibit (pi n 1)
tied to i nput return (pin 7)
1,2,3
01
12
mA
I
OUT = 0,
inhibit (pin 1) = open 55
Input ripple
current3,4
IRIP
IOUT = 800mA
B.W. = 20 Hz to 2 MHz
1,2,3
01
50
mA p-p
Efficiency4
EFF
IOUT = 800mA
1,3
01
78
%
2 75
Isolation
ISO Input t o output or any pin
to cas e (except pin 6) at 500
V dc, TC = +25°C
1
01
100
MΩ
Capaciti ve load6,7
CL No effect on dc
performance,
TC = +25°C, total for both
outputs
4
01
200
µF
www.irf.com 13
AHF28XX Series
1. Parameter guaranteed by line load and cross regulation tests.
2. Up to 90 percent of full power is available from either output provided the total output does not exceed 12W.
3. Bandwidth guaranteed by design. Tested for 20 kHz to 2 MHz.
4. Load current split equally between +VOUT and –VOUT.
5. 1.2 watt load on output under test, 1.2 watt to 10.8 watt load change on other output.
6. Capacitive load may be any value from 0 to the maximum limit without compromising dc performance.
A capacitive load 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 shor t circuit during turn-on.
7. 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 VI.
8. 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.
9. Load step transition time between 2 and 10 microseconds.
10. Recover y time is measured from the initiation of the transient to where VOUT has returned to within ±1
percent of VOUT at 50 percent load.
11. Input step transition time between 2 and 10 microseconds.
12. Tur n-on delay time measurement is for either a step application of power at the input or the removal of
a ground signal from the inhibit pin (pin 1) while power is applied to the input.
Table VI. Electrical Performance Characteristics - continued AHF2815D
Notes to Specifications
Limits
Test
Symbol
Conditions
-55°C ≤ Tc ≤ +125°C
Vin = 28 Vdc ±5%, CL = 0
Unless otherwise specified
Group A
Subgroups
Device
Types
Min
Max
Unit
Overload 8
6
Power dissipation
load fault
PD Short ci rcuit
1,2,3
01
2
W
Switching
frequency4
FS
IOUT = 800 mA
4,5,6
01
500
600
kHz
400 mA to/ from 800 mA
4,5,6
01
-200
+200
Output response
to step transient
load changes4,9
VOTLOAD 0 mA to/from 400 mA 4,5, 6 01 -800 +800
mV pk
400 mA to/ from 800 mA
4,5,6
01
70
Recovery time
step transient load
changes4,9,10
TTLOAD
0 mA to/ from 400 mA 4,5,6 01
500
µs
Output response
transient step line
changes4,7,11
VOTLINE Input step from/to 16 to
40 V dc, IOUT=800mA
4,5,6
01
-750
+750
mV pk
Recovery time
transient step line
changes4,7,10,11
TTLINE
Input step from/to 16 to
40Vdc, IOUT =800mA
4,5,6
01
1200
µs
Turn on
overshoot4
VTonOS
IOUT=0 and 800mA
4,5,6
01
750
mV pk
Turn on delay4,12
TonD IOUT = 0 and 800mA
4,5,6
01
25
ms
Load fault
recovery7
TrLF
4,5,6
01
25
ms
Weight
38
grams
14 www.irf.com
AHF28XX Series
AHF28XX ( Single Output ) Block Diagram
AHF28XX ( Dual Output ) Block Diagram
4
3
+Vout
Return
Pu lse Width
Modulator
Primary
Housekeeping
Supply
EMI
Filter
Under-Voltage
Detector
8
1
7
+Input
Enable
Input
Return
Error
Am p &
Ref
FB
CS
Drive
6
Case
2
3
+Vout
Retur
n
P ulse Width
Modulator
Primary
Housekeeping
Supply
EMI
Filter
Under-Voltage
Detector
8
7
+Input
Enable
Input
Return
Error
Amp &
Ref
FB
CS
Drive
4-Vout
6
Case
1
www.irf.com 15
AHF28XX Series
Application Information
Connecting the enable input (Pin 1) to input common (Pin 7)
will cause the converter to shut down. It is recommended
that the enable pin be driven by an open collector device
capable of sinking at least 400 µA of current. The open
circuit voltage of the enab le input is 15 ±1 VDC. If the inhibit
function is not used, this input can be left unconnected
because it is internally pulled-up.
Thermal Management
Assuming that there is no forced air flow, the package tem-
perature rise above ambient (∆T) may be calculated using
the following expression:
where A = the effective surface area in square inches (in-
cluding heat sink if used), P = power dissipation in watts.
The total surface area of the AHF package is 4.9 square
inches. If a worse case full load efficiency of 78% is as-
sumed, then the case temperature rise can be calculated
as follows:
Hence, if TAMBIENT = +25°C, the DC/DC converter case
temperature will be approximately 100°C if no heat sink
or air flow is provided.
Inhibit Function
∆T ≈ 80 A –0.7p 0.85 (°C)
W
Eff
PP OUT 4.31
78.01
121
1=
−=
−=
∆T = 80 (4.9)-0.7 (3.4)0.85 = 74°C
To calculate the heat sink area required to maintain a
specific case temperature rise, the above equation may
be manipulated as follows:
PKG
Α−
Ρ
∆Τ −43.1
85.0
80
A HEAT SINK =
As an example, if a maximum case temperature rise of
50°C rise above ambient is desired, then the required
effective heat sink area is:
2
43.1
85.0 .75.39.4
)4.3(80 50 in
HEATSINK =−
=Α −
16 www.irf.com
AHF28XX Series
Pin Designation
AHF28XX Case Outlines
1.450
(36.83)
0.260
(6.600)
0.030 dia., 8 pins
(0.760)
0.800
(20.32)
4
7
5
8
6
1
2
3
1.120
(28.45)
0.090 R Typ
(2.290)
0.330
(8.380)
MAX
1.105
(28.07)
0.905
(22.99)
0.705
(17.91)
0.505
(12.83)
0.205
(5.21)
Non-Flanged
Flanged
Part Numbering
A HF 2 8 0 5 S F / CH
Model
Input Volta
g
e
28 = 28V
O utput Volta
g
e
5 = ±5, 12 = ±12,
15 = ±15
Outputs
S = Single
D = Dual
Screenin
g
–
, E S, HB , C H
Packa
g
e O ption s
F = Flange
O m it for Standard
AHF28XXS AHF28XXD
Pin
No. Designation Pin
No. Designation
1 Enable 1 Enable
2 N/C 2 + Output
3 Output Return 3 Output Return
4 + Output 4 - Output
5 N/C 5 N/C
6 Case 6 Case
7 Input Return 7 Input Return
8 + Input 8 + Input
www.irf.com 17
AHF28XX Series
Available Standard Military Drawing (SMD) Cross Reference
WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, Tel: (310) 322 3331
ADVANCED ANALOG: 2270 Martin Av., Santa Clara, California 95050, Tel: (408) 727-0500
Visit us at www.irf.com for sales contact information.
Data and specifications subject to change without notice. 10/02
Available Screening Levels and Process V ariations for AHF28XX Series
* Per Commercial Standards
Requirement MIL-STD-883
Method No
Suffix ES
Suffix HB
Suffix CH
Suffix
Temperature
Range -20 to +85°C -55°C to +125°C -55°C to +125°C -55°C to +125°C
Element
Evaluation MIL-PRF-38534
Internal V i sual 2017 ∗ Yes Yes Yes
Temperature
Cycle 1010 Cond B Cond C Cond C
Constant
Acceleration 2001 500g Cond A Cond A
Burn-in 1015 48hrs @ 85°C 48hrs @ 125°C 160hrs @ 125°C 160hrs @ 125°C
Final Electrical
(Group A) MIL-PRF-
38534
25°C 25°C -55, +25, +125°C -55, +25, +125°C
Seal, Fine &
Gross 1014 ∗ Cond A, C Cond A, C Cond A, C
External
Visual 2009 ∗ Yes Yes Yes
Standardized
Military Drawing
Pin
Vendor
CAGE
Code
Vendor
Similar
Pin
5962-9160001 52467 AHF2805S/CH
5962-9456801 52467 AHF2812S/CH
5962-9456301 52467 AHF2815S/CH
5962-9211101 52467 AHF2812D/CH
5962-9235101 52467 AHF2815D/CH
