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 28V
DC
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 550
KHz. 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 50 kHz, 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.
These converters are manufactured in a facility
certified to MIL-PRF-38534. All processes used to
manufacture these converters have been qualified
to enable Lambda Advanced Analog to deliver
compliant devices. Four 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 MIL-PRF-38534
screening but do not have class H element
evaluation as required by MIL-PRF-38534. Two
grades are fully tested and operate over the full
military temperature range without derating of
output power. Industrial and commercial grades
are also available. 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
16 - 40 VDC input range
(28 VDC nominal)
s
Single and dual outputs
s
12 watts output power
s
22.8 W/in
3
power density
s
Low input/output noise
(50 mA/60 mV p-p max. respectively)
s
Indefinite short circuit and overload
protection
s
Wideband control loop for superior
transient characteristics
s
No derating for -55°C to +125°C
operation
s
Constant switching frequency
(550 kHz nominal)
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Soldering Temperature
Case Temperature
-0.5V to 50V
300°C for 10 seconds
Operating-55°C to +125°C
Storage -65°C to +135°C
AHF2812S
TABLE II. Electrical Performance Characteristics
Test
Symbol
Conditions
-55°C
≤
T
C
≤
+125°C
V
IN
= 28 V dc ±5%, C
L
= 0 unless
otherwise specified
Group A
subgroups
Device
types
Limits
Unit
Min
Output voltage
V
OUT
I
OUT
= 0
1
01
11.88
Max
12.12
V
2,3
Output current 1/
Output ripple voltage 2/
Line
regulation
Load
regulation
Input current
I
OUT
V
RIP
VR
LINE
V
IN
= 16, 28, and 40 V dc,
V
IN
= 16, 28, and 40 V dc,
B.W. = 20 Hz to 2 MHz
V
IN
= 16, 28, and 40 V dc,
I
OUT
= 0,500, and 1000 mA
V
IN
= 16, 28, and 40 V dc,
I
OUT
= 0, 500, and 1000 mA
I
OUT
= 0, inhibit (pin 1)
tied to input return (pin 7)
I
OUT
= 0,
inhibit (pin 1) = open
Input ripple current 2/
I
RIP
I
OUT
= 1000 mA,
B.W. = 20 Hz to 2 MHz
1,2,3
01
1,2,3
1,2,3
1,2,3
01
01
01
11.76
12.24
1000
60
50
mA
mV p-p
mV
VR
LOAD
1,2,3
01
50
mV
I
IN
1,2,3
01
12
mA
50
50
mA p-p
Efficiency
E
FF
I
OUT
= 1000 mA,
1
2,3
01
78
75
%
Isolation
ISO
Input to output or any pin
to case (except pin 6) at 500
V dc, T
C
= +25°C
No effect on dc performance,
T
C
= +25°C
Overload 5/
Short circuit
1
01
100
MΩ
Capacitive load 3/ 4/
Power dissipation
load fault
C
L
P
D
4
1
1,2,3
4,5,6
01
01
01
01
500
200
6
2
600
µF
W
Switching frequency
F
S
I
OUT
= 1000 mA
kHz
See footnotes at end of table.
2
AHF2812S
TABLE II. Electrical Performance Characteristics - Continued
Test
Symbol
Conditions
-55°C
≤
T
C
≤
+125°C
V
IN
= 28 V dc ±5%, C
L
= 0 unless
otherwise specified
Group A
Subgroups
Device
types
Limits
Unit
Min
Output response to step
transient load changes 6/
VO
TLOAD
500 mA to/from 1000 mA
4
5,6
0 mA to/from 500 mA
4
5,6
Recovery time, step
transient load changes
6/ 7/
TT
LOAD
500 mA to/from 1000 mA
4,5,6
01
01
-300
-450
-500
-750
Max
+300
+450
+500
+750
100
µs
mV pk
0 mA to 500 mA
500 mA to 0 mA
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:
VO
TLINE
Input step 16 V to/from
40 V dc, I
OUT
= 1000 mA 4/ 8/
Input step 16 V to/from 40 V dc
I
OUT
= 1000 mA 4/ 7/ 8/
I
OUT
= 0 and 1000 mA
I
OUT
= 0 and 1000 mA 9/
4,5,6
4,5,6
4,5,6
01
1500
10
ms
mV pk
01
1500
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
35
mV pk
ms
ms
grams
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 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 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 a ground signal from the inhibit pin (pin 1)
while power is applied to the input
is unlimited.
3
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Soldering Temperature
Case Temperature
-0.5V to 50V
300°C for 10 seconds
Operating-55°C to +125°C
Storage -65°C to +135°C
AHF2815S
TABLE III. Electrical Performance Characteristics
Test
Symbol
Conditions
-55°C
≤
T
C
≤
+125°C
V
IN
= 28 V dc ±5%, C
L
= 0 unless
otherwise specified
Group A
subgroups
Device
types
Limits
Unit
Min
Output voltage
V
OUT
I
OUT
= 0
1
All
14.85
Max
15.15
V
2,3
Output current 1/
Output ripple voltage 2/
Line
regulation
I
OUT
V
RIP
VR
LINE
V
IN
= 18, 28, and 40 V dc,
V
IN
= 18, 28, and 40 V dc,
B.W. = 20 Hz to 2 MHz
V
IN
= 18, 28, and 40 V dc,
I
OUT
= 0, 1000, and 2000 mA
1,2,3
1,2,3
1
2,3
Load
regulation
Input current
VR
LOAD
I
IN
V
IN
= 18, 28, and 40 V dc,
I
OUT
= 0, 1000, and 2000 mA
I
OUT
= 0, inhibit (pin 2)
tied to input return (pin 10)
I
OUT
= 0, inhibit (pin 2) = open
Input ripple current 2/
Efficiency
I
RIP
E
FF
I
OUT
= 2000 mA,
B.W. = 20 Hz to 2 MHz
I
OUT
= 2000 mA,
1,2,3
1
2,3
Isolation
ISO
Input to output or any pin
to case (except pin 7) at 500
V dc, T
C
= +25°C
No effect on dc performance,
T
C
= +25°C
Overload
Short circuit
Switching frequency
F
S
I
OUT
= 2000 mA
5/
1
All
All
All
1,2,3
1,2,3
All
All
All
All
All
14.70
15.30
2000
50
±35
±75
±150
18
mV
mA
mA
mV p-p
mV
50
20
80
77
100
MΩ
mA p-p
%
Capacitive load 3/ 4/
Power dissipation
load fault
C
L
P
D
4
1
1,2,3
4,5,6
All
All
All
01, 04
02, 05
03, 06
250
250
275
200
12
9
300
270
300
µF
W
kHz
See footnotes at end of table.
4
AHF2815S
TABLE III. Electrical Performance Characteristics - Continued
Test
Symbol
Conditions
-55°C
≤
T
C
≤
+125°C
V
IN
= 28 V dc ±5%, C
L
= 0 unless
otherwise specified
Group A
Subgroups
Device
types
Limits
Unit
Min
Output response to step
transient load changes 6/
VO
TLOA
D
Max
+800
+750
100
µs
mV pk
1000 mA to/from 2000 mA
0 mA to/from 1000 mA
4,5,6
4,5,6
4
All
-800
-1000
Recovery time, step
transient load changes
6/ 7/
TT
LOAD
1000 mA to/from 2000 mA
All
5,6
0 mA to/from 1000 mA
4
5,6
Output response to
transient step line changes
VO
TLINE
Input step 18 V to/from
40 V dc, I
OUT
= 2000 mA 4/ 8/
4,5,6
04
05
06
04
05
06
All
All
All
-1000
All
200
5
10
+1000
mV pk
ms
Recovery time transient
step line changes
TT
LINE
Input step 18 V to/from 40 V dc
I
OUT
= 2000 mA 4/ 7/ 8/
4,5,6
500
µs
Turn on overshoot
Turn on delay
Load fault recovery 4/ 9/
Weight
Notes:
VTon
OS
Ton
D
Tr
LF
I
OUT
= 0 and 2000 mA
I
OUT
= 0 and 2000 mA 9/
4,5,6
4,5,6
4,5,6
750
12
12
38
mV pk
ms
ms
grams
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 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 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 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/ 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 a ground signal from the inhibit pin (pin 2)
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