AFL2803.3DZ/HB [INFINEON]
DC-DC Regulated Power Supply Module, 2 Output, 66W, Hybrid;型号: | AFL2803.3DZ/HB |
厂家: | Infineon |
描述: | DC-DC Regulated Power Supply Module, 2 Output, 66W, Hybrid |
文件: | 总11页 (文件大小:241K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
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LAMBDA ADVANCED ANALOG INC.
PRELIMINARY
AFL2803.3S Series
Single Output, Hybrid - High Reliability
DC/DC Converter
DESCRIPTION
FEATURES
The AFL Series of DC/DC converters feature high
power density with no derating over the full military
temperature range. This series is offered as part of
a complete family of converters providing single and
dual output voltages and operating from nominal
+28, +50, +120 or +270 volt inputs with output
n
16 To 40 Volt Input Range
3.3 Volt Output
n
n
n
n
High Power Density - 50 W / in3
66 Watt Output Power
power ranging from 80 to 120 watts.
For
Parallel Operation with Stress and Current
Sharing
applications requiring higher output power,
individual converters can be operated in parallel.
The internal current sharing circuits assure accurate
current distribution among the paralleled converters.
This series incorporates Lambda Advanced Analog's
proprietary magnetic pulse feedback technology
providing optimum dynamic line and load regulation
response. This feedback system samples the output
voltage at the pulse width modulator fixed clock
frequency, nominally 550 KHz. Multiple converters
can be synchronized to a system clock in the 500
KHz to 700 KHz range or to the synchronization
output of one converter. Undervoltage lockout,
primary and secondary referenced inhibit, soft-start
and load fault protection are provided on all models.
n
n
n
n
n
Low Profile (0.380") Seam Welded Package
Ceramic Feedthru Copper Core Pins
High Efficiency - 72%
Full Military Temperature Range
Continuous Short Circuit and Overload
Protection
n
n
Remote Sensing Terminals
Primary and Secondary Referenced Inhibit
Functions
n
n
n
n
n
Line Rejection > 40 dB - DC to 50KHz
External Synchronization Port
Fault Tolerant Design
These converters are hermetically packaged in two
enclosure variations, utilizing copper core pins to
minimize resistive DC losses. Three lead styles are
available, each fabricated with Lambda Advanced
Analog's rugged ceramic lead-to-package seal
assuring long term hermeticity in the most harsh
environments.
Dual Output Versions Available
Standard Military Drawings Available
Manufactured in a facility fully qualified to MIL-PRF-
38534, these converters are available in four
screening grades to satisfy a wide range of
requirements. The CH grade is fully compliant to
the requirements of MIL-PRF-38534 for class H.
The HB grade processed and screened to the class
H requirement, may not necessarily meet all of the
other MIL-PRF-38534 requirements, e.g., element
evaluation and Periodic Inspections (P.I.) not
required. Both grades are tested to meet the
complete group "A" test specification over the full
military temperature range without output power
deration. Two grades with more limited screening
are also available for use in less demanding
applications. Variations in electrical, mechanical
and screening can be accommodated. Contact
Lambda Advanced Analog for special requirements.
SPECIFICATIONS
AFL2803.3S
ABSOLUTE MAXIMUM RATINGS
Input Voltage
-0.5V to 180V
Soldering Temperature
Case Temperature
300°C for 10 seconds
Operating-55°C to +125°C
Storage -65°C to +135°C
TABLE I. Electrical Performance Characteristics.
Limits
Test
Symbol
Conditions
-55°C £ TC £ +125°C
Group A
Subgroups
Device
Type
Unit
VIN = 28 V dc ±5%, CL = 0
unless otherwise specified
Min
3.27
Max
3.33
V
VOUT
IOUT = 0
1
01
01
Output voltage
3.23
3.37
2,3
20
A
1,2,3
IOUT
VIN = 16, 28, 40 v dc
Output current 6/
VIN = 16, 28, 40 v dc
B.W.= 20 Hz to 10 MHz
VRIP
1,2,3
1,2,3
01
01
30
MV p-p
mV
Output ripple voltage
Line regulation
VRLINE
VIN = 16, 28, 40 v dc
± 20
IOUT = 0, 10 A, and 20 A
Load regulation
Input current
VRLOAD
VIN = 16, 28, 40 v dc
1,2,3
1
01
01
mV
mA
± 35
IOUT = 0, 10 A, and 20 A
IN
IOUT = No load
80
2,3,
100
5
Inhibit 1, (pin 4) shorted to input
return (pin 2)
1,2,3
Inhibit 2, (pin 12) shorted to output
return (pin 8)
1,2,3
1,2,3
50
60
Input ripple current
IRIP
IOUT = 20 A
01
mA p-p
B.W.= 20 Hz to 10 MHz
Efficiency
Isolation
EFF
IOUT = 20 A
1,2,3
1
01
01
72
%
ISO
Input to output or any pin to case
(except pin 3) at
100
MW
500 V dc, TC = +25°C
Maximum
CL
No effect on dc performance, TC =
4
01
10,000
mF
Capacitive load 1/
+25°C
See footnotes at end of table.
2
AFL2803.3S
TABLE I. Electrical Performance Characteristics - Continued.
Conditions
-55°C £ TC £ +125°C
Group A
subgroups
Device
type
Test
Symbol
Limits
Unit
VIN =28 V dc ±5%, C= 0
unless otherwise specified
Min
Max
Power dissipation load fault
Current Limit Point 5/
PD
Overload 6/
Short circuit
1,2,3
1
01
01
33
W
33
ICL
VOUT = 90% VNOM
VIN = 28 V
115
125
%
2
3
105
125
115
140
FS
IOUT = 20 A
1,2,3
01
500
600
KHz
Switching frequency
Sync frequency range
4,5,6
4,5,6
01
01
500
700
KHz
Fsync
IOUT = 20 A
Output response to step
VOTLOAD
50% to/from 100%
-450
+450
mV pk
transient load changes 2/ 8/
10% to/from 50%
50% to/from 100%
-450
+450
200
Recovery time, step
TTLOAD
4,5,6
01
ms
transient load changes 2/ 8/
10% to/from 50%
400
500
500
Input step 16 V to/from 40 V dc,
IOUT = 20 A
4,5,6
4,5,6
01
01
mV pk
Output response to transient
step line changes 1/ 2/ 3/
VOTLINE
-500
Recovery time transient step
line changes 1/ 2/ 3/
ms
TTLINE
Input step 16 V to/from 40 V dc,
IOUT = 20 A
Turn on overshoot 4/
Turn on delay 4/
Load fault recovery
IOUT = 0 and 20 A
IOUT = 0 and 20 A
4,5,6
4,5,6
4,5,6
01
01
01
250
10
mV pk
ms
VTonOS
TonD
10
ms
TrLF
Notes:
1/ Parameters not tested but are guaranteed to the limits specified in the table.
2/ Recovery time is measured from the initiation of the transient to where VOUT has returned to within ± 1 percent of VOUT at 50 percent load.
3/ Line transient transition time ³ 10 microseconds.
4/ Turn on delay is measured with an input voltage rise time of between 100 and 500 volts per millisecond.
5/ Current limit point is that condition of excess load causing output voltage to drop to 90% of nominal.
6/ Parameter verified as part of another test.
7/ All electrical tests are performed with remote sense leads connected to the output lead at the load.
8/ Input step transition time ³ 100 microseconds.
9/ Enable inputs internally pulled high. Nominal open circuit voltage = 4.0VDC
.
3
AFL2803.3S Case Outlines
Case X
Case W
Pin Variation of Case Y
Case Y
Case Z
Pin Variation of Case Y
Tolerances, unless otherwise specified: .XX
.XXX
=
=
±0.010
±0.005
4
AFL2803.3S Pin Designation
Pin No.
Designation
1
2
Positive Input
Input Return
Case
3
4
Enable 1
5
Sync Output
Sync Input
6
7
Positive Output
Output Return
Negative Output
Output Voltage Trim
Share
8
9
10
11
12
Enable 2
Available Screening Levels and Process Variations for AFL 2803.3S Series.
MIL-STD-883
Method
No
Suffix
ES
Suffix
HB
Suffix
CH
Suffix
Requirement
Temperature Range
Element Evaluation
Internal Visual
-20°C to +85°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
MIL-PRF-38534
Yes
2017
1010
2001
1015
*
Yes
Cond B
Yes
Temperature Cycle
Constant Acceleration
Burn-in
Cond C
Cond C
500g
Cond A
Cond A
96hrs @ 125°C
25°C
160hrs @ 125°C
-55, +25, +125°C
160hrs @ 125°C
-55, +25, +125°C
Final Electrical (Group A)
MIL-PRF-38534
& Specification
25°C
Seal, Fine & Gross
External Visual
1014
2009
Cond A
*
Cond A, C
Yes
Cond A, C
Yes
Cond A, C
Yes
* per Commercial Standards
Part Numbering
AFL 28 03.3 S X / CH
Model
Input Voltage
Screening
–
, ES
HB, CH
Case Style
W, X, Y, Z
28 = 28V, 50 = 50V
120 = 120V, 270 = 270V
Output Voltage
Outputs
S = Single
03.3 = 3.3V, 05 = 5V
D = Dual
08 = 8V, 09 = 9V, 12V = 12V
15 = 15V, 28 =28V
5
AFL2800S Circuit Description
Figure I. AFL Single Output Block Diagram
Input
Filter
1
4
5
DC Input
Enable 1
Output
Filter
+Output
+Sense
7
Primary
Bias Supply
10
Current
Sense
Sync Output
Share
Amplifier
Control
11 Share
Error
Amp
& Ref
Sync Input
Case
6
3
2
Enable 2
FB
12
Sense
Amplifier
9
8
-Sense
Output Return
Input Return
Circuit Operation and Application Information
point of application. When the remote sensing feature
is not used, the sense leads should be connected to their
respective output terminals at the converter. Figure III.
illustrates a typical remotely sensed application.
The AFL series of converters employ a forward switched
mode converter topology. (refer to Figure I.) Operation of
the device is initiated when a DC voltage whose magnitude
is within the specified input limits is applied between pins 1
and 2. If pin 4 is enabled (at a logical 1 or open) the primary
bias supply will begin generating a regulated housekeeping
voltage bringing the circuitry on the primary side of the
converter to life. A power MOSFET is used to chop the DC
input voltage into a high frequency square wave, applying
thischoppedvoltagetothepowertransformeratthenominal
converter switching frequency. Maintaining a DC voltage
within the specified operating range at the input assures
continuous generation of the primary bias voltage.
Inhibiting Converter Output
As an alternative to application and removal of the
DC voltage to the input, the user can control the
converter output by providing TTL compatible,
positive logic signals to either of two enable pins (pin
4 or 12). The distinction between these two signal
ports is that enable 1 (pin 4) is referenced to the input
return (pin 2) while enable 2 (pin 12) is referenced to
the output return (pin 8). Thus, the user has access
to an inhibit function on either side of the isolation
barrier. Each port is internally pulled “high” so that
when not used, an open connection on both enable
pins permits normal converter operation. When their
use is desired, a logical “low” on either port will shut
the converter down.
The switched voltage impressed on the secondary output
transformer winding is rectified and filtered to generate the
converter DC output voltage. An error amplifier on the
secondary side compares the output voltage to a precision
reference and generates an error signal proportional to the
difference. Thiserrorsignalismagneticallycoupledthrough
the feedback transformer into the controller section of the
converter varying the pulse width of the square wave signal
driving the MOSFET, narrowing the width if the output
voltage is too high and widening it if it is too low, thereby
regulating the output voltage.
Figure II. Enable Input Equivalent Circuit
+5.6V
100K
1N4148
Pin 4 or
Pin 12
Disable
290K
Remote Sensing
2N3904
Connection of the + and - sense leads at a remotely located
load permits compensation for excessive resistance be-
tween the converter output and the load when their physical
separation could cause undesirable voltage drop. This
connection allows regulation to the placard voltage at the
150K
Pin 2 or
Pin 8
6
(unconnected) thereby permitting the converter to operate
at its’ own internally set frequency.
Internally,theseportsdifferslightlyintheirfunction. Inuse,
a low on Enable 1 completely shuts down all circuits in the
converter while a low on Enable 2 shuts down the secondary
side while altering the controller duty cycle to near zero.
Externally, the use of either port is transparent save for
minor differences in standby current. (See specification
table).
The sync output signal is a continuous pulse train set at
550 ±50 KHz, with a duty cycle of 15 ±5%. This signal is
referenced to the input return and has been tailored to be
compatiblewiththeAFLsyncinputport. Transitiontimes
are less than 100 ns and the low level output impedance is
less than 50 ohms. This signal is active when the DC input
voltage is within the specified operating range and the
converter is not inhibited. This output has adequate drive
reserve to synchronize at least five additional converters.
A typical connection is illustrated in Figure III.
Synchronization of Multiple Converters
When operating multiple converters, system requirements
often dictate operation of the converters at a common
frequency. To accommodate this requirement, the AFL
series converters provide both a synchronization input and
a synchronization output.
Parallel Operation — Current and Stress Sharing
Figure III. illustrates the preferred connection scheme
for operation of a set of AFL converters with outputs
operating in parallel. Use of this connection permits
equal sharing among the members of a set where total
load current exceeds the capacity of an individual AFL.
An important feature of the AFL series operating in the
The sync input port permits synchronization of an AFL
converter to any compatible external frequency source
operating between 500 and 700 KHz. This input signal
should be referenced to the input return and have a 10% to
90% duty cycle. Compatibilityrequires transitiontimesless
than 100 ns, maximum low level of +0.8 volts and a
FigureIII.PreferredConnectionforParallelOperation
1
12
Power
Enable 2
Vin
Rtn
Share
Sense
Sense
Return
Input
Case
+
-
AFL
Enable
1
Sync Out
Sync In
+
Vout
7
6
1
Optional
Synchronization
Connection
Share Bus
12
Enable
2
Vin
Rtn
Share
Sense
Sense
Return
Case
+
-
AFL
AFL
Enable
1
Sync Out
Sync In
to Load
+
Vout
7
6
1
12
Enable
2
Vin
Rtn
Share
Sense
Sense
Return
Case
+
-
Enable
1
Sync Out
Sync In
+
Vout
7
6
(Other Converters)
minimum high level of +2.0 volts. The sync output of
another converter which has been designated as the
master oscillator provides a convenient frequency source
for this mode of operation. When external synchroniza-
tion is not required, the sync in pin should be left open
parallel mode is that in addition to sharing the current,
the stress induced by temperature will also be shared.
Thus if one member of a paralleled set is operating at a
higher case temperature, the current it provides to the
load will be reduced as compensation for the tempera-
7
ture induced stress on that device.
by the following expression:
When operating in the shared mode, it is important that
symmetry of connection be maintained as an assurance of
optimum load sharing performance. Thus, converter
outputs should be connected to the load with equal lengths
of wire of the same gauge and sense leads from each
converter should be connected to a common physical point,
preferably at the load along with the converter output and
return leads. All converters in a paralleled set must have
their share pins connected together. This arrangement is
diagrammatically illustrated in Figure III. showing the
outputs and sense pins connected at a star point which is
located close as possible to the load.
−1.43
∆T
A
HEAT SINK
≈
− 3.0
0.85
80P
where
∆T = Case temperature rise above ambient
1
P = Device dissipation in Watts = POUT
Eff
−1
As an example, it is desired to maintain the case
temperature of an AFL2815S at ≤ +85°C while
operating in an open area whose ambient tempera-
ture is held at a constant +25°C; then
As a consequence of the topology utilized in the current
sharing circuit, the share pin may be used for other
functions. In applications requiring only a single converter,
the voltage appearing on the share pin may be used as a
“current monitor”. The share pin open circuit voltage is
nominally +1.00v at no load and increases linearly with
increasing output current to +2.20v at full load.
∆T = 85 - 25 = 60°C.
From the Specification Table, the worst case full
load efficiency for this device is 83%; therefore the
power dissipation at full load is given by
1
Thermal Considerations
( )
−1 = 120• 0.205 = 24.6W
P = 120•
.83
Because of the incorporation of many innovative techno-
logical concepts, the AFL series of converters is capable of
providing very high output power from a package of very
small volume. These magnitudes of power density can only
be obtained by combining high circuit efficiency with
effective methods of heat removal from the die junctions.
This requirement has been effectively addressed inside the
device; but when operating at maximum loads, a significant
amount of heat will be generated and this heat must be
conducted away from the case. To maintain the case
temperature at or below the specified maximum of 125°C,
this heat must be transferred by conduction to an appropri-
ateheatdissipaterheldinintimatecontactwiththeconverter
base-plate.
and the required heat sink area is
−1.43
60
2
A
HEAT SINK
=
− 3.0 = 71in
0.85
80• 24.6
Thus, a total heat sink surface area (including
2
fins, if any) of 71 in in this example, would limit
case rise to 60°C above ambient. A flat alumi-
num plate, 0.25" thick and of approximate
2
dimension 4" by 9" (36 in per side) would
suffice for this application in a still air environ-
ment. Note that to meet the criteria in this
example, both sides of the plate require unre-
stricted exposure to the ambient air.
Because effectiveness of this heat transfer is dependent on
theintimacyofthebaseplate-heatsinkinterface,itisstrongly
recommended that a high thermal conductivity heat trans-
ferring medium is inserted between the baseplate and
heatsink. The material most frequently utilized at the
factory during all testing and burn-in processes is sold
under the trade name of Sil-PadR 4001 . This particular
product is an insulator but electrically conductive versions
are also available. Use of these materials assures maximum
surface contact with the heat dissipater thereby compensat-
ing for any minor surface variations. While other available
types of heat conductive materials and thermal compounds
provide similar effectiveness, these alternatives are often
less convenient and are frequently messy to use.
InputFilter
The AFL2800S series converters incorporate a two
stage LC input filter whose elements dominate the
input load impedance characteristic at turn-on. The
input circuit is as shown in Figure IV.
A conservative aid to estimating the total heat sink surface
area (AHEAT SINK) required to set the maximum case
temperature rise (∆T) above ambient temperature is given
1
Sil-Pad is a registered Trade Mark of Bergquist, Minneapolis, MN
8
Figure IV. Input Filter Circuit
Figure V. Connection for Vout Adjustment.
900nH
130nH
Pin 1
Pin 2
Enable
2
Share
Sense
Sense
Return
RADJ
+
-
6 µfd
11.2 µfd
AFL28xxS
To Load
+
Vout
Attempts to adjust the output voltage to a value greater than
120% of nominal should be avoided because of the potential
of exceeding internal component stress ratings and subse-
quent operation to failure. Under no circumstance should
the external setting resistor be made less than 500W. By
remaining within this specified range of values, completely
safeoperationfullywithinnormalcomponentderatinglimits
is assured.
Examination of the equation relating output voltage and
resistor value reveals a special benefit of the circuit topology
utilizedforremotesensingofoutputvoltageintheAFL2800S
series of converters. It is apparent that as the resistance
increases, the output voltage approaches the nominal set
value of the device. In fact the calculated limiting value of
output voltage as the adjusting resistor becomes very large
is » 25mV above nominal device voltage.
Undervoltage Lockout
Aminimumvoltageisrequiredattheinputoftheconverter
to initiate operation. This voltage is set to 14.0 ± 0.5 volts.
To preclude the possibility of noise or other variations at
the input falsely initiating and halting converter operation,
a hysteresis of approximately 1.0 volts is incorporated in
this circuit. Thus if the input voltage droops to 13.0 ± 0.5
volts, the converter will shut down and remain inoperative
until the input voltage returns to »14.0 volts.
Output Voltage Adjust
In addition to permitting close voltage regulation of re-
motely located loads, it is possible to utilize the converter
sense pins to incrementally increase the output voltage
overalimitedrange.Theadjustmentsmadepossiblebythis
method are intended as a means to “trim” the output to a
voltage setting for some particular application, but are not
intended to create an adjustable output converter. These
output voltage setting variations are obtained by connect-
ing an appropriate resistor value between the +sense and
-sense pins while connecting the -sense pin to the output
return pin as shown in Figure V. below. The range of
adjustment and corresponding range of resistance values
can be determined by use of the following equation.
The consequence is that if the +sense connection is uninten-
tionally broken, an AFL28xxS has a fail-safe output voltage
of Vout + 25mV, where the 25mV is independent of the
nominal output voltage. It can be further demonstrated that
in the event of both the + and - sense connections being
broken,theoutputwillbelimitedtoVout+440mV. This440
mV is also essentially constant independent of the nominal
output voltage.
General Application Information
The AFL2800 series of converters are capable of provid-
ing large transient currents to user loads on demand.
Because the nominal input voltage range in this series is
relatively low, the resulting input current demands will be
correspondingly large. It is important therefore, that the
line impedance be kept very low to prevent steady state
and transient input currents from degrading the supply
voltage between the voltage source and the converter
input. In applications requiring high static currents and
large
NOM
V
adj
R
= 100•
OUT
NOM
V
- V
-.025
Where VNOM = device nominal output voltage, and
OUT = desired output voltage
V
Finding a resistor value for a particular output voltage,
is simply a matter of substituting the desired output
voltage and the nominal device voltage into the equation
and solving for the corresponding resistor value.
transients, it is recommended that the input leads be made of
9
adequate size to minimize resistive losses, and that a
good quality capacitor of approximately 100µfd be
connected directly across the input terminals to assure
an adequately low impedance at the input terminals.
Table I relates nominal resistance values and selected
wire sizes.
multiplied by the number of paralleled devices. By
choosing 14 or 16 gauge wire in this example the
parasitic resistance and resulting voltage drop will be
reduced to 25% or 31% of that with 20 gauge wire.
Another potential problem resulting from parasitically
induced voltage drop on the input lines is with regard to
operation of the enable 1 port. The minimum and
maximum operating levels required to operate this port
are specified with respect to the input common return
line at the converter. If a logic signal is generated with
respect to a ‘common’ that is distant from the con-
verter, the effects of the voltage drop over the return line
must be considered when establishing the worst case
TTL switching levels. These drops will effectively
impart a shift to the logic levels. In Figure VI, it can be
seen that referred to system ground, the voltage on the
input return pin is given by
Table I. Nominal Resistance Of Cu Wire
Wire Size, AWG
Resistance per ft
24 Ga
22 Ga
20 Ga
18 Ga
16 Ga
14 Ga
12 Ga
25.7 mΩ
16.2 mΩ
10.1 mΩ
6.4 mΩ
4.0 mΩ
2.5 mΩ
1.6 mΩ
eRtn = IRtn • Rp
As an example of the effects of parasitic resistance,
consider an AFL2815S operating at full power of 120
W. From the specification sheet, this device has a
minimum efficiency of 83% representing an input
power of nearly 145 W. If we consider the case where
line voltage is at its’ minimum of 16 volts, the steady
state input current necessary for this example will be
slightly greater than 9 amperes. If this device were
connected to a voltage source with 10 feet of 20 gauge
wire, theroundtrip(inputandreturn)wouldresultin0.2
Ω of resistance and 1.8 volts of drop from the source
to the converter. To assure 16 volts at the input, a
source closer to 18 volts would be required. In
applicationsusingtheparallelingoption,thisdropwillbe
Therefore, the logic signal level generated in the system
must be capable of a TTL logic high plus sufficient
additional amplitude to overcome eRtn. When the con-
verter is inhibited, IRtn diminishes to near zero and eRtn
will then be at system ground.
Incorporation of a 100 µfd capacitor at the input
terminals is recommended as compensation for the
dynamic effects of the parasitic resistance of the
input cable reacting with the complex impedance of
the converter input, and to provide an energy reser-
voir for transient input current requirements.
Figure VI. Effects of Parasitic Resistance in Input Leads
R p
R p
Iin
Vin
100
µfd
e s o u r c e
Rtn
e Rt n
IRt n
Case
Enable 1
Sync Out
Sync In
System Ground
10
NOTES
The information in this data sheet has been carefully checked and is believed to be accurate; however no
responsibility is assumed for possible errors. These specifications are subject to change without notice.
Ó
9849
Lambda Advanced Analog
2270 Martin Avenue
Santa Clara CA 95050-2781
(408) 988-4930 FAX (408) 988-2702
MIL-PRF-38534 Certified
ISO9001 Registered
l
LAMBDA ADVANCED ANALOG INC.
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