AFL27017DXES [INFINEON]

HYBRID-HIGH RELIABILITY DC/DC CONVERTER;
AFL27017DXES
型号: AFL27017DXES
厂家: Infineon    Infineon
描述:

HYBRID-HIGH RELIABILITY DC/DC CONVERTER

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PD-94458C  
AFL28XXD SERIES  
28V Input, Dual Output  
HYBRID-HIGH RELIABILITY  
DC/DC CONVERTER  
Description  
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 +28V or  
+270V inputs with output power ranging from 80W to  
120W. For applications requiring higher output power,  
individual converters can be operated in parallel. The  
internal current sharing circuits assure equal current  
distribution among the paralleled converters. This series  
incorporates International Rectifier’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 550KHz. Multiple converters can be  
synchronized to a system clock in the 500KHz to 700KHz  
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.  
AFL  
Features  
n 16V To 40V Input Range  
±5V, ±12V, and ±15V Outputs Available  
n High Power Density - up to 70W/in  
n Up To 100W Output Power  
n Parallel Operation with Power Sharing  
n Low Profile (0.380") Seam Welded Package  
n Ceramic Feedthru Copper Core Pins  
n High Efficiency - to 87%  
n Full Military Temperature Range  
n Continuous Short Circuit and Overload  
Protection  
n
3
n Output Voltage Trim  
n Primary and Secondary Referenced  
Inhibit Functions  
n Line Rejection > 40dB - DC to 50KHz  
n External Synchronization Port  
n Fault Tolerant Design  
n Single Output Versions Available  
n Standard Microcircuit Drawings Available  
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 International Rectifier’s  
rugged ceramic lead-to-package seal assuring long  
term hermeticity in the most harsh environments.  
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 in electrical, mechanical and screening can  
be accommodated. Contact IR Santa Clara for special  
requirements.  
www.irf.com  
1
12/18/06  
AFL28XXD Series  
Specifications  
Absolute Maximum Ratings  
Input voltage  
-0.5V to +50VDC  
300°C for 10 seconds  
-55°C to +125°C  
-65°C to +135°C  
Soldering temperature  
Operating case temperature  
Storage case temperature  
Static Characteristics -55°C < TCASE < +125°C, 16V< VIN < 40V unless otherwise specified.  
Group A  
Parameter  
INPUT VOLTAGE  
Subgroups  
Test Conditions  
Min  
Nom  
Max  
Unit  
Note 6  
16  
28  
40  
V
OUTPUT VOLTAGE  
V
= 28 Volts, 100% Load  
IN  
AFL2805D  
AFL2812D  
AFL2815D  
AFL2805D  
AFL2812D  
AFL2815D  
1
1
1
1
1
1
2, 3  
2, 3  
2, 3  
2, 3  
2, 3  
2, 3  
4.95  
-5.05  
11.88  
-12.12  
14.85  
-15.15  
4.90  
-5.10  
11.76  
-12.24  
14.70  
-15.30  
5.00  
-5.00  
12.00  
-12.00  
15.00  
-15.00  
5.05  
-4.95  
12.12  
-11.88  
15.15  
-14.85  
5.10  
-4.90  
12.24  
-11.76  
15.30  
-14.70  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
V
OUTPUT CURRENT  
OUTPUT POWER  
V
= 16, 28, 40 Volts - Notes 6, 11  
Either Output  
IN  
AFL2805D  
AFL2812D  
AFL2815D  
12.8  
6.4  
5.3  
Either Output  
Either Output  
A
Total of Both Outputs. Notes 6,11  
AFL2805D  
AFL2812D  
AFL2815D  
80  
96  
100  
W
µF  
MAXIMUM CAPACITIVE LOAD  
Each Output Note 1  
10,000  
-0.015  
OUTPUT VOLTAGE  
V
= 28 Volts, 100% Load - Notes 1, 6  
IN  
+0.015  
%/°C  
TEMPERATURE COEFFICIENT  
OUTPUT VOLTAGE REGULATION  
Note 10  
-0.5  
-1.0  
+0.5  
+1.0  
Line  
Load  
1, 2, 3  
1, 2, 3  
No Load, 50% Load, 100% Load  
V
= 16, 28, 40 Volts.  
IN  
Cross  
V
= 16, 28, 40 Volts. Note 12  
IN  
AFL2805D  
1, 2, 3  
1, 2, 3  
1, 2, 3  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
Positive Output  
Negative Output  
-1.0  
-8.0  
-1.0  
-5.0  
-1.0  
-5.0  
+1.0  
+8.0  
+1.0  
+5.0  
+1.0  
+5.0  
%
AFL2812D  
AFL2815D  
For Notes to Specifications, refer to page 4  
2
www.irf.com  
AFL28XXD Series  
Static Characteristics (Continued)  
Group A  
Parameter  
Subgroups  
Test Conditions  
Min  
Nom  
Max  
Unit  
OUTPUT RIPPLE VOLTAGE  
V
= 16, 28, 40 Volts, 100% Load,  
IN  
BW = 10MHz  
AFL2805D  
AFL2812D  
AFL2815D  
1, 2, 3  
1, 2, 3  
1, 2, 3  
60  
80  
80  
mV  
pp  
V
= 28 Volts  
INPUT CURRENT  
IN  
1
2, 3  
80  
100  
No Load  
Inhibit 1  
I
= 0  
OUT  
1, 2, 3  
5.0  
mA  
Pin 4 Shorted to Pin 2  
Pin 12 Shorted to Pin 8  
Inhibit 2  
1, 2, 3  
1, 2, 3  
50  
30  
AFL2805D  
AFL2812D, 15D  
INPUT RIPPLE CURRENT  
AFL2805D  
V
= 28 Volts, 100% Load  
IN  
1, 2, 3  
1, 2, 3  
1, 2, 3  
60  
60  
60  
mA  
pp  
AFL2812D  
AFL2815D  
V
= 90% V  
, Equal current on  
NOM  
CURRENT LIMIT POINT  
OUT  
Expressed as a percentage  
of Full Rated Load  
positive and negative outputs. Note 5  
1
2
3
115  
105  
125  
125  
115  
140  
%
V
V
= 28 Volts  
LOAD FAULT POWER DISSIPATION  
IN  
IN  
1, 2, 3  
33  
W
%
Overload or Short Circuit  
EFFICIENCY  
AFL2805D  
AFL2812D  
AFL2815D  
= 28 Volts, 100% Load  
1, 2, 3  
1, 2, 3  
1, 2, 3  
78  
82  
81  
81  
84  
85  
ENABLE INPUTS  
(Inhibit Function)  
Converter Off  
Sink Current  
1, 2, 3  
1, 2, 3  
Logical Low on Pin 4 or Pin 12  
Note 1  
Logical High on Pin 4 and Pin 12 - Note 9 2.0  
Note 1  
-0.5  
0.8  
100  
50  
V
µA  
V
Converter On  
Sink Current  
100  
µA  
SWITCHING FREQUENCY  
1, 2, 3  
500  
550  
600  
KHz  
SYNCHRONIZATION INPUT  
Frequency Range  
1, 2, 3  
1, 2, 3  
1, 2, 3  
500  
2.0  
-0.5  
700  
10  
0.8  
100  
80  
KHz  
V
V
ns  
%
Pulse Amplitude, Hi  
Pulse Amplitude, Lo  
Pulse Rise Time  
Note 1  
Note 1  
20  
Pulse Duty Cycle  
ISOLATION  
1
Input to Output or Any Pin to Case  
(except Pin 3). Test @ 500VDC  
100  
MΩ  
DEVICE WEIGHT  
MTBF  
Slight Variations with Case Style  
85  
g
MIL-HDBK-217F, AIF @ T = 70°C  
C
300  
KHrs  
For Notes to Specifications, refer to page 4  
www.irf.com  
3
AFL28XXD Series  
Dynamic Characteristics -55°C < TCASE < +125°C, VIN=28V unless otherwise specified.  
Group A  
Subgroups  
Parameter  
Test Conditions  
Min  
Nom  
Max  
Unit  
LOAD TRANSIENT RESPONSE  
Note 2, 8  
Load Step 50% 100%  
4, 5, 6  
4, 5, 6  
-450  
-450  
450  
200  
mV  
µs  
AFL2805D  
Amplitude  
Recovery  
Either Output  
4, 5, 6  
4, 5, 6  
Load Step 10%  
50%  
450  
200  
400  
mV  
Amplitude  
Recovery  
10% 50%  
50%  
µs  
µ
s
10%  
4, 5, 6  
4, 5, 6  
Load Step 50%  
100%  
-750  
-750  
750  
200  
mV  
µs  
AFL2812D  
Either Output  
Amplitude  
Recovery  
4, 5, 6  
4, 5, 6  
Load Step 10% 50%  
10% 50%  
750  
200  
400  
mV  
µs  
µs  
Amplitude  
Recovery  
50% 10%  
4, 5, 6  
4, 5, 6  
Load Step 50% 100%  
-750  
-750  
750  
200  
mV  
µs  
AFL2815D  
Either Output  
Amplitude  
Recovery  
4, 5, 6  
4, 5, 6  
Load Step 10% 50%  
10% 50%  
750  
200  
400  
mV  
µs  
µs  
Amplitude  
Recovery  
50% 10%  
LINE TRANSIENT RESPONSE  
Note 1, 2, 3  
-500  
500  
500  
mV  
Amplitude  
Recovery  
V
Step = 16 40 Volts  
IN  
µ
s
TURN-ON CHARACTERISTICS  
V
= 16, 28, 40 Volts. Note 4  
IN  
Overshoot  
Delay  
4, 5, 6  
4, 5, 6  
Enable 1, 2 on. (Pins 4, 12 high or  
open)  
250  
10  
mV  
ms  
0
4.0  
50  
LOAD FAULT RECOVERY  
LINE REJECTION  
Same as Turn On Characteristics.  
MIL-STD-461D, CS101, 30Hz to 50KHz  
Note 1  
40  
dB  
Notes to Specifications:  
1. Parameters not 100% tested but are guaranteed to the limits specified in the table.  
2. Recovery time is measured from the initiation of the transient to where V has returned to within ±1.0% of  
out  
V
at 50% load.  
out  
3. Line transient transition time 100µs.  
4. Turn-on delay is measured with an input voltage rise time of between 100V and 500V 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 the remote sense leads connected to the output leads at the load.  
8. Load transient transition time 10µs.  
9. Enable inputs internally pulled high. Nominal open circuit voltage 4.0VDC.  
10. Load current split equally between +V  
and -V  
.
out  
out  
11. Output load must be distributed so that a minimum of 20% of the total output power is being provided by one of  
the outputs.  
12. Cross regulation measured with load on tested output at 20% of maximum load while changing the load on  
other output from 20% to 80%.  
4
www.irf.com  
AFL28XXD Series  
Block Diagram  
Figure I. Dual Output  
Input  
Filter  
Output  
Filter  
1
4
+ Output  
+ Input  
7
Current  
Sense  
Primary  
Bias Supply  
Output Return  
-Output  
8
9
Enable 1  
Output  
Filter  
Sync Output  
5
Share  
Amplifier  
Control  
Share  
11  
Error  
Amp  
& Ref  
Sync Input  
Case  
6
3
2
12 Enable 2  
Output Voltage  
10  
Trim  
Input Return  
series can be initiated by simply applying an input voltage to  
pins 1 and 2 and connecting the appropriate loads between  
pins 7, 8, and 9. As is the case with any high power density  
converter, operation should not be initiated before secure  
attachment to an appropriate heat dissipator. (See Thermal  
Considerations, page 7) Additional application information  
is provided in the paragraphs following.  
Circuit Operation and Application Information  
The AFL series of converters employ a forward switched  
mode converter topology. (refer to the block diagram in  
Figure I.) Operation of the device is initiated when a DC  
voltage whose magnitude is within the specified input voltage  
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 this chopped voltage to  
the power transformer at the nominal converter switching  
frequency. By maintaining a DC voltage within specified  
operating range at the input, continuous generation of the  
bias voltage is assured.  
Inhibiting Converter Output (Enable)  
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 windings is rectified and filtered to provide the  
positive and negative converter output voltages. An error  
amplifier on the secondary side compares the positive output  
voltage to a precision reference and generates an error  
signal proportional to the difference. This error signal is  
magnetically coupled through the feedback transformer into  
the control section of the converter varying the pulse width  
of the square wave signal driving the MOSFETs, narrowing  
the pulse width if the output voltage is too high and widening  
it if it is too low. These pulse width variations provide the  
necessary corrections to regulate the magnitude of output  
voltage within its’ specified limits.  
Figure II. Enable Input Equivalent Circuit  
+5.6V  
100K  
1N4148  
Pin 4 or  
Pin 12  
Disable  
200K  
Because the primary portion of the circuit is coupled to the  
secondary side with magnetic elements, full isolation from  
input to output is maintained.  
2N3904  
220K  
Although incorporating several sophisticated and useful  
ancilliary features, basic operation of the AFL28XXD series  
Pin 2 or  
Pin 8  
www.irf.com  
5
AFL28XXD Series  
Internally, these ports differ slightly in their function. In use,  
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 to the user  
save for minor differences in idle current. (See specification  
table).  
than 100ns, maximum low level of +0.8V and a minimumigh  
level of +2.0V. 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 synchronization is not indicted, the sync in  
pin should be left open (unconnected) thereby permitting  
the converter to operate at its’ own internally set frequency.  
Synchronization of Multiple Converters  
The sync output signal is a continuous pulse train set at  
550 ± 50KHz, with a duty cycle of 15 ± 5%. This signal is  
referenced to the input return and has been tailored to be  
compatible with the AFL sync input port. Transition times  
are less than 100ns and the low level output impedance is  
less than 50. This signal is active when the DC input  
voltage is within the specified operating range and the  
converter is not inhibited. This synch output has adequate  
drive reserve to synchronize at least five additional  
converters. A typical synchronization connection option is  
illustrated in Figure III.  
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  
output.  
The sync input port permits synchronization of an AFL  
connverter to any compatible external frequency source  
operating between 500KHz and 700KHz. This input signal  
should be referenced to the input return and have a 10% to  
90% duty cycle. Compatibility requires transition times less  
Figure III. Preferred Connection for Parallel Operation  
1
12  
Power  
Input  
Enable 2  
Share  
Vin  
Rtn  
Case  
Trim  
AFL  
AFL  
Enable 1  
Sync Out  
Sync In  
- Output  
Return  
+ Output  
7
6
1
Optional  
Synchronization  
Connection  
Share Bus  
12  
Enable 2  
Share  
Vin  
Rtn  
Case  
Trim  
Enable 1  
Sync Out  
Sync In  
- Output  
Return  
+ Output  
to Negative Load  
to Positive Load  
7
6
1
12  
Enable 2  
Share  
Vin  
Rtn  
Case  
Trim  
AFL  
Enable 1  
Sync Out  
Sync In  
- Output  
Return  
+ Output  
7
6
(Other Converters)  
feature of the AFL series operating in the 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 temperature induced stress on that  
device.  
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 current  
sharing among the members of a set whose load current  
exceeds the capacity of an individual AFL. An important  
6
www.irf.com  
AFL28XXD Series  
A conservative aid to estimating the total heat sink surface  
When operating in the shared mode, it is important that  
symmetry of connection be maintained as an assurance of area (AHEAT SINK) required to set the maximum case  
optimum load sharing performance. Thus, converter outputs temperature rise (T) above ambient temperature is given  
by the following expression:  
should be connected to the load with equal lengths of wire of  
the same gauge and 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 output and return 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  
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 “total current  
monitor”. The share pin open circuit voltage is nominally  
+1.00V at no load and increases linearly with increasing  
total output current to +2.20V at full load. Note that the current  
we refer to here is the total output current, that is, the sum  
of the positive and negative outout currents.  
1
1  
P = Device dissipation in Watts = POUT  
Eff  
As an example, assume that it is desired to operate an  
AFL2815D in a still air environment where the ambient  
temperature is held to a constant +25°C while holding the  
case temperature at TC +85°C; then case temperature  
rise is  
Thermal Considerations  
T = 85 - 25 = 60°C  
Because of the incorporation of many innovative  
technological 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  
appropriate heat dissipater held in intimate contact with the  
converter base-plate.  
From the Specification Table, the worst case full load  
efficiency for AFL2815D is 83% at 100W: thus, power  
dissipation at full load is given by  
1
P = 100•  
1 = 1000.205 = 20.5W  
(
)
.83  
and the required heat sink area is  
1.43  
60  
A
HEAT SINK  
=
3.0 = 56.3 in2  
Since the effectiveness of this heat transfer is dependent  
on the intimacy of the baseplate/heatsink interface, it is  
strongly recommended that a high thermal conductivity heat  
transferring 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  
8020.50.85  
Thus, a total heat sink surface area (including fins, if any) of  
2
56 in in this example, would limit case rise to 60°C above  
ambient. A flat aluminum plate, 0.25" thick and of approximate  
1
trade name of Sil-Pad® 400 . This particular product is an  
2
dimension 4" by 7" (28 in per side) would suffice for this  
insulator but electrically conductive versions are also  
available. Use of these materials assures maximum surface  
contact with the heat dissipater thereby compensating 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 can be somewhat messy to use.  
application in a still air environment. Note that to meet the  
criteria in this example, both sides of the plate require  
unrestricted exposure to the +25°C ambient air.  
1
Sil-Pad is a registered Trade Mark of Bergquist, Minneapolis, MN  
www.irf.com  
7
AFL28XXD Series  
Input Filter  
Table 1. Output Voltage Trim Values and Limits  
The AFL28XXD series converters incorporate a two stage  
LC input filter whose elements dominate the input load  
impedance characteristic during the turn-on sequence. The  
input circuit is as shown in Figure IV.  
AFL2805D  
AFL2812D  
AFL2815D  
Vout Radj  
Vout Radj  
Vout Radj  
5.5  
5.4  
0
12.5  
12.4  
12.3  
12.2  
12.1  
12.0  
11.7  
11.3  
10.8  
10.6  
10.417  
0
15.5  
15.4  
15.3  
15.2  
15.1  
15.0  
14.6  
14.0  
13.5  
13.0  
12.917  
0
12.5K  
33.3K  
75K  
200K  
47.5K  
127K  
285K  
760K  
975K  
288K  
72.9K  
29.9K  
0
62.5K  
167K  
375K  
1.0M  
1.2M  
325K  
117K  
12.5K  
0
Figure IV. Input Filter Circuit  
5.3  
5.2  
5.1  
900nH  
130nH  
5.0  
Pin 1  
Pin 2  
4.9  
190K  
65K  
23K  
2.5K  
0
4.8  
4.7  
6 µfd  
11.2 µfd  
4.6  
4.583  
Note that the nominal magnitude of output voltage resides in  
the middle of the table and the corresponding resistor value  
is set to . To set the magnitude greater than nominal, the  
adjust resistor is connected to output return. To set the  
magnitude less than nominal, the adjust resistor is connected  
to the positive output. (Refer to Figure V.)  
Undervoltage Lockout  
A minimum voltage is required at the input of the converter  
to initiate operation. This voltage is set to 14V ± 0.5V. To  
preclude the possibility of noise or other variations at the  
input falsely initiating and halting converter operation, a  
hysteresis of approximately 1.0V is incorporated in this  
circuit. Thus if the input voltage droops to 13V ± 0.5V, the  
converter will shut down and remain inoperative until the  
input voltage returns to 14V.  
For output voltage settings that are within the limits, but  
between those listed in Table I, it is suggested that the  
resistor values be determined empirically by selection or by  
use of a variable resistor. The value thus determined can  
then be replaced with a good quality fixed resistor for  
permanent installation.  
Output VoltageAdjust  
When use of this adjust feature is elected, the user should  
be aware that the temperature performance of the converter  
output voltage will be affected by the temperature  
performance of the resistor selected as the adjustment  
element and therefore, is advised to employ resistors with a  
tight temperature coefficient of resistance.  
By use of the trim pin (10), the magnitude of output voltages  
can be adjusted over a limited range in either a positive or  
negative direction. Connecting a resistor between the trim  
pin and either the output return or the positive output will  
raise or lower the magnitude of output voltages. The span  
of output voltage adjustment is restricted to the limits shown  
in Table I.  
General Application Information  
The AFL28XXD series of converters are capable of  
providing 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  
transients, it is recommended that the input leads be made  
of 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.  
Figure V. Connection for VOUT Adjustment  
12  
Enable 2  
Share  
RADJ  
-
Trim  
+
AFL28xxD  
- Vout  
To  
Loads  
Return  
+ Vout  
7
Connect Radj to + to increase, - to decrease  
8
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AFL28XXD Series  
Table 2. Nominal Resistance of Cu Wire  
Another potential problem resulting from parasitically  
induced voltage drop on the input lines is with regard to  
the 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 converter, 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,  
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 m  
6.4 mΩ  
4.0 mΩ  
2.5 m  
the voltage on the input return pin is given by  
1.6 mΩ  
As an example of the effects of parasitic resistance,  
consider an AFL2815D operating at full power of 100W.  
From the specification sheet, this device has a minimum  
efficiency of 83% which represents an input power of more  
than 120W. If we consider the case where line voltage is at  
its’ minimum of 16V, the steady state input current necessary  
for this example will be slightly greater than 7.5A. If this  
device were connected to a voltage source with 10 feet of  
20 gauge wire, the round trip (input and return) would result  
in 0.2of resistance and 1.5V of drop from the source to  
the converter. To assure 16V at the input, a source closer  
to 18V would be required. In applications using the paralleling  
option, this drop will be 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  
eRtn = IRtn RP  
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 converter is inhibited,  
IRtn diminishes to near zero and eRtn will then be at system  
ground.  
Incorporation of a 100µfd 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 reservoir for transient input current  
requirements.  
reduced to 25% or 31% of that with 20 gauge wire.  
Figure VI. Problems of Parasitic Resistance in input Leads  
Rp  
Rp  
Iin  
Vin  
100  
µfd  
esource  
Rtn  
eRtn  
IRtn  
Case  
Enable 1  
Sync Out  
Sync In  
System Ground  
www.irf.com  
9
AFL28XXD Series  
Mechanical Outlines  
Case X  
Case W  
Pin Variation of Case Y  
3.000  
ø 0.128  
2.760  
0.050  
0.050  
0.250  
0.250  
1.000  
1.000  
Ref  
1.260 1.500  
0.200 Typ  
Non-cum  
Pin  
ø 0.040  
Pin  
ø 0.040  
0.220  
2.500  
0.220  
0.525  
2.800  
2.975 max  
0.238 max  
0.42  
0.380  
Max  
0.380  
Max  
Case Y  
Case Z  
Pin Variation of Case Y  
1.150  
0.300  
ø 0.140  
0.25 typ  
0.050  
0.050  
0.250  
0.250  
1.000  
Ref  
1.500 1.750 2.00  
1.000  
Ref  
0.200 Typ  
Non-cum  
Pin  
ø 0.040  
Pin  
ø 0.040  
0.220  
0.220  
1.750  
2.500  
0.375  
0.36  
2.800  
2.975 max  
0.525  
0.238 max  
0.380  
Max  
0.380  
Max  
Tolerances, unless otherwise specified: .XX  
.XXX  
=
=
±0.010  
±0.005  
BERYLLIAWARNING: These converters are hermetically sealed; however they contain BeO substrates and should not be ground or subjected to any other  
operations including exposure to acids, which may produce Beryllium dust or fumes containing Beryllium  
10  
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AFL28XXD Series  
Pin Designation  
Designation  
Pin #  
1
2
+ Input  
Input Return  
Case Ground  
Enable 1  
3
4
5
Sync Output  
Sync Input  
+ Output  
6
7
8
Output Return  
- Output  
9
10  
11  
12  
Output Voltage Trim  
Share  
Enable 2  
Standard Microcircuit Drawing Equivalence Table  
Standard Microcircuit  
Drawing Number  
5962-95795  
IR Standard  
Part Number  
AFL2805D  
5962-95796  
AFL2812D  
5962-94724  
AFL2815D  
www.irf.com  
11  
AFL28XXD Series  
Device Screening  
Requirement  
MIL-STD-883 Method No Suffix  
ES  
HB  
CH  
Temperature Range  
Element Evaluation  
Non-Destructive  
Bond Pull  
-20°C to +85°C -55°C to +125°C  
-55°C to +125°C -55°C to +125°C  
MIL-PRF-38534  
2023  
N/A  
N/A  
N/A  
N/A  
Class H  
N/A  
N/A  
N/A  
Internal Visual  
Temperature Cycle  
Constant Acceleration  
PIND  
2017  
1010  
Yes  
Cond B  
500 Gs  
N/A  
Yes  
Cond C  
3000 Gs  
N/A  
Yes  
Cond C  
3000 Gs  
N/A  
N/A  
N/A  
2001, Y1 Axis  
2020  
N/A  
Burn-In  
1015  
N/A  
48 hrs@hi temp 160 hrs@125°C 160 hrs@125°C  
Final Electrical  
( Group A )  
MIL-PRF-38534  
& Specification  
MIL-PRF-38534  
1014  
25°C  
25°C  
-55°C, +25°C,  
+125°C  
N/A  
-55°C, +25°C,  
+125°C  
10%  
PDA  
N/A  
Cond A  
N/A  
N/A  
Cond A, C  
N/A  
Seal, Fine and Gross  
Radiographic  
External Visual  
Cond A, C  
N/A  
Cond A, C  
N/A  
2012  
2009  
Yes  
Yes  
Yes  
Notes:  
 Best commercial practice  
‚ Sample tests at low and high temperatures  
ƒ -55°C to +105°C for AHE, ATO, ATW  
Part Numbering  
AFL 28 05 D X /CH  
Screening Level  
Model  
(Please refer to Screening Table)  
No suffix, ES, HB, CH  
Input Voltage  
28 = 28V  
50 = 50V  
120 = 120V  
270 = 270V  
Case Style  
W, X, Y, Z  
Output  
D = Dual  
Output Voltage  
05 = ±5V  
12 = ±12V  
15 = ±15V  
WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, Tel: (310) 322 3331  
IR SANTA CLARA: 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. 12/2006  
12  
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