AHE2800S Series
DESCRIPTION
The AHE2800S Series of DC/DC converters feature
high power density and an extended temperature
range for use in military and industrial applications.
Designed to MIL-STD-704 input requirements,
these devices have nominal 28V
DC
inputs with +5v,
+12v and +15v single outputs to satisfy a wide range
of requirements. The circuit design incorporates a
pulse width modulated push-pull topology operating
in the feed-forward mode at a nominal switching
frequency of 250 KHz. Input to output isolation is
achieved through the use of transformers in the
forward and feedback circuits.
The advanced feedback design provides fast loop
response for superior line and load transient charac-
teristics and offers greater reliability and radiation
tolerance than devices incorporating optical feed-
back circuits.
Three standard temperature grades are offered with
screening options. Refer to Part Number section.
They can be provided in a standard plug-in package
for PC mounting or in a flanged package for more
severe environments.
These converters are manufactured in a facility
fully qualified to MIL-PRF-38534. All processes used
to manufacture these converters have been
qualified to enable Lambda Advanced Analog to
deliver compliant devices. Two screening grades are
available to satisfy a wide range of requirements.
The CH grade converters are fully compliant to
MIL-PRF-38534 class H. The HB grade converters
are processed to full class H screening but do not
have class H element evaluation as required by
MIL-PRF-38534. Both grades are fully tested and
operate over the full military temperature range
without derating of output power. Variations in
electrical, mechanical and screening can be
accommodated. Extensive computer simulation
using complex modeling enables rapid design
modification to be provided. Contact Lambda
Advanced Analog with specific requirements.
Hybrid - High Reliability
DC/DC Converters
FEATURES
s
17-40V
DC
input range
(28V
DC
nominal)
s
5V, 12V and 15V outputs available
s
Indefinite short circuit and overload
protection
s
17W/in
3
power density
s
15 and 20 watts output power models
s
Fast loop response for superior transient character-
istics
s
Operating temperature range from
-55°C to + 125°C available
s
Popular industry standard pin-out
s
Resistance seam welded case for superior long
term hermeticity
s
Efficiencies up to 84%
s
Shutdown from external signal
s
Military screening
s
325,000 hour MTBF at 85°C (AUC)
SPECIFICATIONS
T
CASE
= -55°C to +85°C, V
IN
= + 28V ±5% unless otherwise specified.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
1
Power Output
Soldering
Temperature Range
1
-0.5V to +50V
Internally Limited, 17.5W typical for AHE2805S, 22.5W typical for AHE2812S and AHE2815S
300°C for 10 seconds
Operating
-55°C to +125°C case
Storage
-65°C to + 135°C
Conditions
-55°C - Tc - +85°C, V
IN
- 28 V
DC
Parameter
±5%, C=0, unless otherwise specified
AHE2805S
Min
Typ
Max
AHE2812S
Min
Typ
Max
AHE2815S
Min
Typ
Max
Units
STATIC CHARACTERISTICS
OUTPUT
V
IN
= 17
TO
40 V
DC
Voltage
I
OUT
= 0
TO
Full Load
Current
Ripple
Full Load, DC to 1MHz
Accuracy
T
CASE
= 25°C, I
OUT
= 0
Power
1
REGULATION
Line
Load
INPUT
Voltage Range
4
Current
Ripple Current
EFFICIENCY
CAPACITIVE LOAD
LOAD FAULT POWER
DISSIPATION
4
ISOLATION
Input to Output @ 500V
DC
V
IN
= 17 to 40V
DC
I
OUT
= 0 to Full Load
4.90
0.0
4.95
15
5.10
3000
20
60
5.00
5.05
5.00
11.76
0.0
11.88
20
12.24
1667
30
60
12.00 12.12
12.00
14.70
0.0
14.85
20
15.30
1333
30
60
15.00 15.15
15.00
V
DC
mA
DC
mVpp
V
DC
W
%
%
V
DC
mA
DC
mA
DC
mV p-p
%
µF
±0.5
±0.5
17.0
28.0
8
20
80
500
82
±1.0
±1.0
40.0
18
35
50
17.0
±0.5
±0.5
28.0
8
25
79
200
83
±1.0
±1.0
40.0
18
35
50
17.0
±0.5
±0.5
28.0
8
25
80
200
84
±1.0
±1.0
40.0
18
35
50
Inhibited
No Load
Full Load
T
CASE
= +25°C
Half Load to Full Load
No effect on performance
6
100
100
6
100
6
W
MΩ
DYNAMIC CHARACTERISTICS
STEP LOAD CHANGES
Output
50% Load 100% Load
Transient
No Load 50% Load
50% Load No Load
2
50% Load 100% Load
Recovery
No Load 50% Load
50% Load No Load
STEP LINE CHANGES
Output
Transient
Recovery
2
TURN-ON
Overshoot
Delay
3
LOAD FAULT RECOVERY
4
WEIGHT
Input step 17 to 40V
DC
Input step 40 to 17V
DC
Input step 17 to 40V
DC
Input step 40 to 17V
DC
V
IN
= 17 to 40V
DC
I
OUT
= 0 to Full Load
V
IN
= 17 to 40V
DC
Standard Package
Flange Package
±150
-300
+300
25
500
7
+180
-600
400
400
0
8
8
55
58
500
14
14
±200
-400
+400
25
500
7
+180
-600
400
400
300
8
8
55
58
600
14
14
±200
-400
+400
25
500
7
+180
-600
400
400
300
8
8
500
14
14
55
58
mVpk
mVpk
mVpk
µsec
µsec
msec
mVpk
mVpk
µsec
µsec
mVpk
msec
msec
grams
grams
Notes:
1. Above +85°C case temperature, derate output power linearly to 0 and maximum input voltage linearly to 42V at 115°C case.
2. 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. See typical waveforms.
3. Turn-on delay time measurement is for either an application of power at the input or a signal at the shutdown pin.
4. For operation at 16V
DC
, derate output power by 33%.
2
SPECIFICATIONS
T
CASE
= -55°C to +105°C, V
IN
= + 28V ±5% unless otherwise specified.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
5
Power Output
Soldering
Temperature Range
1
-0.5V to +50V
Internally Limited, 17.5W typical for AHE2805S/ES, 22.5W typical for AHE2812S/ES and AHE2815S/ES
300°C for 10 seconds
Operating
-55°C to +125°C case
Storage
-65°C to + 135°C
Conditions
-55°C - Tc - +105°C, V
IN
- 28 V
DC
Parameter
±5%, C=0, unless otherwise specified
AHE2805S/ES
Min
Typ
Max
AHE2812/ES
Min
Typ
Max
AHE2815S/ES
Min
Typ
Max
Units
STATIC CHARACTERISTICS
OUTPUT
V
IN
= 17
TO
40 V
DC
Voltage
I
OUT
= 0
TO
Full Load
Current
Ripple
Full Load, DC to 1MHz
Accuracy
T
CASE
= 25°C, I
OUT
= 0
Power
1
REGULATION
Line
Load
INPUT
Voltage Range
4
Current
Ripple Current
EFFICIENCY
CAPACITIVE LOAD
LOAD FAULT POWER
DISSIPATION
4
ISOLATION
Input to Output @ 500V
DC
V
IN
= 17 to 40V
DC
I
OUT
= 0 to Full Load
4.90
0.0
4.95
15
5.10
3000
20
60
5.00
5.05
5.00
11.76
0.0
11.88
20
12.24
1667
30
60
12.00 12.12
12.00
14.70
0.0
14.85
20
15.30
1333
30
60
15.00 15.15
15.00
V
DC
mA
DC
mVpp
V
DC
W
%
%
V
DC
mA
DC
mA
DC
mV p-p
%
µF
±0.5
±0.5
17.0
28.0
8
20
78
500
82
±1.0
±1.0
40.0
18
35
50
17.0
±0.5
±0.5
28.0
8
25
79
200
83
±1.0
±1.0
40.0
18
35
50
17.0
±0.5
±0.5
28.0
8
25
80
200
84
±1.0
±1.0
40.0
18
35
50
Inhibited
No Load
Full Load
T
CASE
= +25°C
Half Load to Full Load
No effect on performance
6
100
100
6
100
6
W
MΩ
DYNAMIC CHARACTERISTICS
STEP LOAD CHANGES
Output
50% Load 100% Load
Transient
No Load 50% Load
50% Load No Load
2
50% Load 100% Load
Recovery
No Load 50% Load
50% Load No Load
STEP LINE CHANGES
Output
Transient
Recovery
2
TURN-ON
Overshoot
Delay
3
LOAD FAULT RECOVERY
4
WEIGHT
Input step 17 to 40V
DC
Input step 40 to 17V
DC
Input step 17 to 40V
DC
Input step 40 to 17V
DC
V
IN
= 17 to 40V
DC
I
OUT
= 0 to Full Load
V
IN
= 17 to 40V
DC
Standard Package
Flange Package
±150
-300
+300
25
500
7
+180
-600
400
400
0
8
8
60
65
500
14
14
±200
-400
+400
25
500
7
+180
-600
400
400
300
8
8
60
65
600
14
14
±200
-400
+400
25
500
7
+180
-600
400
400
300
8
8
60
65
750
14
14
mVpk
mVpk
mVpk
µsec
µsec
msec
mVpk
mVpk
µsec
µsec
mVpk
msec
msec
grams
grams
Notes:
1. Above +105°C case temperature, derate output power linearly to 0 at 125°C case.
2. 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. See typical waveforms.
3. Turn-on delay time measurement is for either an application of power at the input or a signal at the shutdown pin.
4. For operation at 16V
DC
, derate output power by 33%.
5. Above +85°C case temperature, derate maximum input voltage linearly to 33V at +125°C case.
3
SPECIFICATIONS
T
CASE
= -55°C to +125°C, V
IN
= + 28V ±5% unless otherwise specified.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
1
Power Output
Soldering
Temperature Range
1
-0.5V to +50V
Internally Limited, 17.5W typical for AHE2805S/HB&CH, 22.5W typical for AHE2812S/HB&CH and AHE2815S/HB&CH
300°C for 10 seconds
Operating
-55°C to + 125°C case
Storage
-65°C to + 135°C
Conditions
-55°C - Tc - +125°C, V
IN
- 28 V
DC
Parameter
±5%, C=0, unless otherwise specified
AHE2805S/HB&CH
Min
Typ
Max
AHE2812S/HB&CH
Min
Typ
Max
AHE2815S/HB&CH
Min
Typ
Max
Units
STATIC CHARACTERISTICS
OUTPUT
V
IN
= 17
TO
40 V
DC
Voltage
I
OUT
= 0
TO
Full Load
Current
Ripple
Full Load, DC to 1MHz
Accuracy
T
CASE
= 25°C, I
OUT
= 0
Power
1
REGULATION
Line
Load
INPUT
Voltage Range
4
Current
Ripple Current
EFFICIENCY
CAPACITIVE LOAD
LOAD FAULT POWER
DISSIPATION
ISOLATION
V
IN
= 17 to 40V
DC
T
CASE
= 25°C
I
OUT
= 0 to Full Load
4.90
0.0
4.95
15
5.10
3000
20
60
5.00
5.05
5.00
11.76
0.0
11.88
20
30
12.24
1667
30
60
12.00 12.12
12.00
14.70
0.0
14.85
20
40
15.30
1333
30
60
15.00 15.15
15.00
V
DC
mA
DC
mV p-p
V
DC
W
1025
10
17.0
28.0
8
20
80
500
82
1000
4.5
6
100
5
50
40.0
18
35
50
60
50
30
120
40.0
18
35
50
75
50
mv
35
150
40.0
18
35
50
mv
V
DC
mA
DC
mA
DC
mV p-p
%
µF
17.0
Inhibited
No Load
Full Load
T
CASE
= +25°C Full Load
No effect on performance
Short Circuit T
C
= 25°C
Overload T
C
= 25°C
Input to Output @ 500V
DC
28.0
8
25
17.0
28.0
8
25
80
200
83
1000
4.5
6
80
200
84
1000
4.5
6
W
W
MΩ
100
100
DYNAMIC CHARACTERISTICS
STEP LOAD CHANGES
50% Load 100% Load
Output T
C
= 25°C
Transient
No Load 50% Load
50% Load No Load
2
50% Load 100% Load
Recovery
No Load 50% Load
50% Load No Load
STEP LINE CHANGES
Output T
C
= 25°C
Transient
Recovery
2
TURN-ON
Overshoot
Delay
3
LOAD FAULT RECOVERY
4
WEIGHT
Input Step 17 to 40V
DC
Input Step 40 to 17V
DC
Input Step 17 to 40V
DC
Input Step 40 to 17V
DC
V
IN
= 17 to 40V
DC
I
OUT
= 0 to Full Load
V
IN
= 17 to 40V
DC
Standard Package
Flange Package
±150
-300
+300
25
100
±300
-500
+500
70
200
5
+300
-1000
800
800
550
10
10
55
58
±200
-400
+400
25
500
±300
-500
+500
70
1500
5
+500
-1500
800
800
600
10
10
55
58
±200
-400
+400
25
500
±300
-500
+500
70
1500
5
+500
-1500
800
800
500
10
10
55
58
mVpk
mVpk
mVpk
µsec
µsec
msec
mVpk
mVpk
µsec
µsec
mVpk
msec
msec
grams
grams
+180
-600
400
400
0
8
8
+180
-600
400
400
300
8
8
+180
-600
400
400
300
8
8
Notes:
1. Above +125°C case temperature, derate output power linearly to 0 at 135°C case.
2. 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. See typical waveforms.
3. Turn-on delay time measurement is for either an application of power at the input or a signal at the shutdown pin.
4. For operation at 16V
DC
, derate output power by 33%.
4
BLOCK DIAGRAM
1
INPUT
FILTER
OUTPUT
FILTER
5
2
9
CONTROLLER
ERROR
AMP
& REF
3
10
4
APPLICATION INFORMATION
Inhibit Function
Connecting the inhibit input (Pin 2) to input common
(Pin 10) will cause the converter to shut down. It is
recommended that the inhibit pin be driven by an
open collector device capable of sinking at least
400µA of current. The open circuit voltage of the
inhibit input is 11.5 ±1VDC.
EMI Filter
An optional EMI filter (AFC461) will reduce the input
ripple current to levels below the limits imposed by
MIL-STD-461 CEO3.
Device Synchronization
Whenever multiple DC/DC converters are utilized in
a single system, significant low frequency noise
may be generated due to slight difference in the
switching frequencies of the converters (beat fre-
quency noise). Because of the low frequency nature
of this noise (typically less than 10KHz), it is difficult
to filter out and may interfere with proper operation
of sensitive systems (communications, radar or
telemetry). Lambda Advanced Analog offers an option
which provides synchronization of multiple AHE/ATW/
ATO type converters, thus eliminating this type of noise.
To take advantage of this capability, the system
designer must assign one of the converters as the
master. Then, by definition, the remaining convert-
ers become slaves and will operate at the masters’
switching frequency. The user should be aware that
the synchronization system is fail-safe; that is, the
slaves will continue operating should the master
frequency be interrupted for any reason. The layout
must be such that the synchronization output (pin 9)
of the master device is connected to the synchroni-
zation input (pin 9) of each slave device. It is
advisable to keep this run short to minimize the
possibility of radiating the 250KHz switching fre-
quency.
The appropriate parts must be ordered to utilize this
feature. After selecting the converters required for
the system, an ‘MSTR’ suffix is added for the master
converter part number and an ‘SLV’ suffix is added
for slave part number. See Part Number section.
Output Adjust (AHE2805) only
The output voltage of the AHE2805 can be adjusted
upward by connecting Output Adjust (Pin 3) and
Output Common (Pin 4) as shown in Table 1.
Resistance
Pin 3 to 4
×
390k
145k
63k
22k
0
Output Voltage
Increase %
0
+ 1%
+ 2%
+ 3%
+ 4%
+ 5%
Table 1 Output adjustment resistor values
5
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