View AFL270XXD_1099171.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

PD - 94461B
AFL270XXD SERIES ADVANCED ANALOG HIGH RELIABILITY HYBRID DC/DC CONVERTERS
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 +28 or +270 volt inputs with output power ranging from 80 to 120 watts. 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 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. 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 Advanced Analog's rugged ceramic lead-to-package seal assuring long term hermeticity in the most harsh environments. Manufactured in a facility fully qualified to MIL-PRF38534, 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-H38534 for class H. The HB grade is processed and screened to the class H requirement, but may not necessarily meet all of the other MIL-PRF-38534 requirements, e.g., element evaluation and Periodic Inspection (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 avail-
270V Input, Dual Output
AFL Features
n n n n n n n n n n n n n n n n n 160 To 400 Volt Input Range 5, 12, and 15 Volts Outputs Available High Power Density - up to 70 W / in3 Up To 100 Watt Output Power Parallel Operation with Power Sharing Low Profile (0.380") Seam Welded Package Ceramic Feedthru Copper Core Pins High Efficiency - to 87% Full Military Temperature Range Continuous Short Circuit and Overload Protection Output Voltage Trim Primary and Secondary Referenced Inhibit Functions Line Rejection > 60 dB - DC to 50KHz External Synchronization Port Fault Tolerant Design Single Output Versions Available Standard Military Drawings Available
able for use in less demanding applications. Variations in electrical, mechanical and screening can be accommodated. Contact Advanced Analog for special requirements.
www.irf.com
1
09/11/02
AFL270XXD Series
Specifications
ABSOLUTE MAXIMUM RATINGS Input Voltage Soldering Temperature Case Temperature -0.5V to 500V 300C for 10 seconds Operating Storage -55C to +125C -65C to +135C
Static Characteristics -55C < TCASE < +125C, 160V< VIN < 400V unless otherwise specified.
Parameter INPUT VOLTAGE OUTPUT VOLTAGE AFL27005D AFL27012D AFL27015D AFL27005D AFL27012D AFL27015D OUTPUT CURRENT AFL27005D AFL27012D AFL27015D OUTPUT POWER AFL27005D AFL27012D AFL27015D MAXIMUM CAPACITIVE LOAD OUTPUT VOLTAGE TEMPERATURE COEFFICIENT OUTPUT VOLTAGE REGULATION Line Load Cross AFL27005D AFL27012D AFL27015D 1, 2, 3 1, 2, 3 1, 2, 3 Each Output Note 1 VIN = 270 Volts, 100% Load - Notes 1, 6 Note 10 No Load, 50% Load, 100% Load VIN = 160, 270, 400 Volts. VIN = 160, 270, 400 Volts. Note 12 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 % % % % % % 5,000 -0.015 -0.5 -1.0 +0.015 +0.5 +1.0 1 1 1 1 1 1 2, 3 2, 3 2, 3 2, 3 2, 3 2, 3 Group A Subgroups Note 6 VIN = 270 Volts, 100% Load Positive Output Negative Output Positive Output Negative Output Positive Output Negative Output Positive Output Negative Output Positive Output Negative Output Positive Output Negative Output VIN = 160, 270, 400 Volts - Notes 6, 11 Either Output Either Output Either Output Total of Both Outputs. Notes 6,11 80 96 100 W W W fd %/C % % 12.8 6.4 5.3 A A A 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 V V V V V V V V V V V V Test Conditions Min 160 Nom 270 Max 400 Unit V
1, 2, 3 1, 2, 3
For Notes to Specifications, refer to page 4
2
www.irf.com
AFL270XXD Series
Static Characteristics (Continued)
Parameter OUTPUT RIPPLE VOLTAGE AFL27005D AFL27012D AFL27015D 1, 2, 3 1, 2, 3 1, 2, 3 Group A Subgroups Test Conditions VIN = 160, 270, 400 Volts, 100% Load, BW = 10MHz Min Nom Max Unit
60 80 80
mVpp mVpp mVpp
INPUT CURRENT No Load Inhibit 1 Inhibit 2 INPUT RIPPLE CURRENT AFL27005D AFL27012D AFL27015D CURRENT LIMIT POINT Expressed as a Percentage of Full Rated Load 1 2 3 1, 2, 3 1, 2, 3 1, 2, 3 1 2, 3 1, 2, 3 1, 2, 3
VIN = 270 Volts IOUT = 0 Pin 4 Shorted to Pin 2 Pin 12 Shorted to Pin 8 VIN = 270 Volts, 100% Load
10.00 12.00 3.00 5.00
mA mA mA mA
60 70 80 VOUT = 90% VNOM , Current split equally on positive and negative outputs. Note 5
mApp mApp mApp
115 105 125
125 115 140
% % %
LOAD FAULT POWER DISSIPATION Overload or Short Circuit EFFICIENCY AFL27005D AFL27012D AFL27015D ENABLE INPUTS (Inhibit Function) Converter Off Sink Current Converter On Sink Current SWITCHING FREQUENCY SYNCHRONIZATION INPUT Frequency Range Pulse Amplitude, Hi Pulse Amplitude, Lo Pulse Rise Time Pulse Duty Cycle ISOLATION DEVICE WEIGHT MTBF
VIN = 270 Volts 1, 2, 3 30 W
VIN = 270 Volts, 100% Load 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 1, 2, 3 Note 1 Note 1 1 Input to Output or Any Pin to Case (except Pin 3). Test @ 500VDC Slight Variations with Case Style MIL-HDBK-217F, AIF @ TC = 70C 300 Logical Low on Pin 4 or Pin 12 Note 1 Logical High on Pin 4 and Pin 12 - Note 9 Note 1 78 82 83 -0.5 2.0 500 500 2.0 -0.5 20 100 85 550 82 85 87 0.8 100 50 100 600 700 10 0.8 100 80 % % % V A V A KHz KHz V V nSec % M gms KHrs
For Notes to Specifications, refer to page 4
www.irf.com
3
AFL270XXD Series
Dynamic Characteristics -55C < TCASE < +125C, VIN=270V unless otherwise specified.
Parameter LOAD TRANSIENT RESPONSE AFL2805D Either Output Amplitude Recovery Amplitude Recovery AFL2812D Either Output Amplitude Recovery Amplitude Recovery AFL2815D Either Output Amplitude Recovery Amplitude Recovery 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 4, 5, 6 Group A Subgroups Note 2, 8 Load Step 50% 100% Load Step 10% 50% 10% 50% 50% 10% Load Step 50% 100% Load Step 10% 50% 10% 50% 50% 10% Load Step 50% 100% Load Step 10% 50% 10% 50% 50% 10% -450 -450 450 200 450 200 400 750 200 750 200 400 750 200 750 200 400 mV Sec mV Sec Sec mV Sec mV Sec Sec mV Sec mV Sec Sec Test Conditions Min Nom Max Unit
-750 -750
-750 -750
LINE TRANSIENT RESPONSE Amplitude Recovery TURN-ON CHARACTERISTICS Overshoot Delay LOAD FAULT RECOVERY LINE REJECTION 4, 5, 6 4, 5, 6
Note 1, 2, 3 VIN Step = 160 400 Volts VIN = 160, 270, 400 Volts. Note 4 Enable 1, 2 on. (Pins 4, 12 high or open) Same as Turn On Characteristics. MIL-STD-461D, CS101, 30Hz to 50KHz Note 1 60 70 dB 50 75 250 120 mV mSec -500 500 500 mV Sec
Notes to Specifications: Parameters not 100% tested but are guaranteed to the limits specified in the table. Recovery time is measured from the initiation of the transient to where Vout has returned to within 1% of Vout at 50% load. 3. Line transient transition time 100 Sec. 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 the remote sense leads connected to the output leads at the load. 8. Load transient transition time 10 Sec. 9. Enable inputs internally pulled high. Nominal open circuit voltage 4.0VDC. 10. Load current split equally between +Vout and -Vout. 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%. 1. 2.
4
www.irf.com
AFL270XXD Series
AFL270XXD Circuit Description
Figure I. AFL Dual Output Block Diagram
DC Input 1 Input Filter Primary Bias Supply Current Sense Output Filter Sync Output Sync Input Case Input Return 5 Control 6 3 2 Error Amp & Ref Share Amplifier 11 Share 12 Enable 2 10 Trim Output Filter 7 + Output
Enable 1 4
8 Output Return
9
-Output
Circuit Operation and Application Information
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 pins 4 and 12 are 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. Two power MOSFETs used to chop the DC input voltage into a high frequency square wave, apply this chopped voltage to the power transformer. As this switching is initiated, a voltage is impressed on a second winding of the power transformer which is then rectified and applied to the primary bias supply. When this occurs, the input voltage is excluded from the bias voltage generator and the primary bias voltage becomes internally generated. 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. Because the primary portion of the circuit is coupled to the secondary side with magnetic elements, full isolation from input to output is maintained.
Although incorporating several sophisticated and useful ancilliary features, basic operation of the AFL270XXDseries 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. Of course, operation of any converter with high power density should not be attempted before secure attachment to an appropriate heat dissipator. (See Thermal Considerations, page 7)
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.
Figure II. Enable Input Equivalent Circuit
+5.6V 100K Pin 4 or Pin 12 1N4148
290K 2N3904 150K Pin 2 or Pin 8
Disable
www.irf.com
5
AFL270XXD 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). 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 synchronization is not indicted, the sync in pin should be left unconnected thereby permitting the converter to operate at its' own internally set frequency. 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 compatible with the AFL sync input port. Transition times 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 synch output has adequate drive reserve to synchronize at least five additional converters. A typical synchronization connection option 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 output. 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. Compatibility requires transition times less th an 100 ns, maximum low level of +0.8 volts and a minimum high
Figure III. Preferred Connection for Parallel Operation
Power Input
1 12
Vin Rtn Case Enable 1 Sync Out Sync In
Enable 2 Share
AFL
Trim - Output Return + Output
7
Optional Synchronization Connection
6
Share Bus
1 12
Vin Rtn Case Enable 1 Sync Out Sync In
6
Enable 2 Share
AFL
Trim - Output Return + Output
7
to Negative Load to Positive Load
1
12
Vin Rtn Case Enable 1 Sync Out Sync In
6
Enable 2 Share
AFL
Trim - Output Return + Output
7
(Other Converters)
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 fea-
ture 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.
6
www.irf.com
AFL270XXD Series
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 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. 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 "totall 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. 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 by the following expression:
. T -143 - 3.0 A HEAT SINK 80P 0.85
where T = Case temperature rise above ambient 1 P = Device dissipation in Watts = POUT - 1 Eff
As an example, assume that it is desired to operate an AFL27015D while holding the case temperature at TC +85C in an area where the ambient temperature is held to a constant +25C; then
Thermal Considerations
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 125C, this heat must be transferred by conduction to an appropriate heat dissipater held in intimate contact with the converter base-plate. 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 trade name of Sil-Pad 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 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.
1Sil-Pad is a registered Trade Mark of Bergquist, Minneapolis, MN
T = 85 - 25 = 60C
From the Specification Table, the worst case full load efficiency for this device is 83% @ 100 watts: thus, power dissipation at full load is given by
1 - 1 = 100 * ( 0.205) = 20.5W P = 100 * .83
and the required heat sink area is
-1.43
60 A HEAT SINK = 80 * 20.5 0.85
- 3.0 = 56.3 in 2
Thus, a total heat sink surface area (including fins, if any) of 56 in2 in this example, would limit case rise to 60C above ambient. A flat aluminum plate, 0.25" thick and of approximate dimension 4" by 7" (28 in2 per side) would suffice for this 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 +25C ambient air.
www.irf.com
7
AFL270XXD Series
Input Filter
The AFL270XXD series converters incorporate a single 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.
Table 1. Output Voltage Trim Values and Limits
AFL27005D Vout 5.5 5.4 5.3 8.4H 5.2 5.1 5.0 4.9 0.54fd 4.8 4.7 4.6 4.583 Radj 0 12.5K 33.3K 75K 200K 190K 65K 23K 2.5K 0 AFL27012D Vout 12.5 12.4 12.3 12.2 12.1 12.0 11.7 11.3 10.8 10.6 10.417 Radj 0 47.5K 127K 285K 760K 975K 288K 72.9K 29.9K 0 AFL27015D Vout 15.5 15.4 15.3 15.2 15.1 15.0 14.6 14.0 13.5 13.0 12.917 Radj 0 62.5K 167K 375K 1.0M 1.2M 325K 117K 12.5K 0
Figure IV. Input Filter Circuit
Pin 1
Pin 2
Undervoltage Lockout
A minimum voltage is required at the input of the converter to initiate operation. This voltage is set to 150 5 volts. To preclude the possibility of noise or other variations at the input falsely initiating and halting converter operation, a hysteresis of approximately 10 volts is incorporated in this circuit. Thus if the input voltage droops to 140 5 volts, the converter will shut down and remain inoperative until the input voltage returns to 150 volts.
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.) 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. 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.
Output Voltage Adjust
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.
Figure V. Connection for VOUT Adjustment
12
Enable 2 Share
R ADJ
AFL270XXD
Trim - Vout Return + Vout
+ To Loads
7
Connect Radj to + to increase, - to decrease
8
www.irf.com
AFL270XXD Series
AFL270XXD Case Outlines
Case X Case W
Pin Variation of Case Y
3.000 2.760
o 0.128
0.050 0.250
12
0.050
7
0.25 typ
12
7
BERYLLIA WARNING: 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
www.irf.com
1 6
0.250
1.260 1.500
1.000 Ref
0.200 Typ Non-cum Pin o 0.040
1.000
2.500
0.220
0.220 2.800 0.525
Pin o 0.040
2.975 max 0.238 max
0.42
0.380 Max
0.380 Max
Case Y
1.150 0.300 o 0.140 0.050
Case Z
Pin Variation of Case Y
0.050
0.250
1 6
0.250
1.500 1.750 2.00
1.000 Ref
0.200 Typ Non-cum Pin o 0.040
1.000 Ref
Pin o 0.040
1.750 2.500
0.375
0.220
0.220 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
9
AFL270XXD Series
Available Screening Levels and Process Variations for AFL270XXD Series.
Requirement Temperature Range Element Evaluation Internal Visual Temperature Cycle Constant Acceleration Burn-in Final Electrical (Group A) 2017 1010 2001 1015 MIL-PRF-38534 & Specification 1014 2009 48hrs @ 85C 25C u Cond B 500g 48hrs @ 125C 25C u Cond C Cond A 160hrs @ 125C -55, +25, +125C MIL-STD-883 Method No Suffix -20C to +85C ES Suffix -55C to +125C HB Suffix -55C to +125C CH Suffix -55C to +125C MIL-H-38534 u Cond C Cond A 160hrs @ 125C -55, +25, +125C
Seal, Fine & Gross External Visual
Cond C
Cond A, C u
Cond A, C u
Cond A, C u
* per Commercial Standards AFL270XXD Pin Designation
Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 Designation Positive Input Input Return Case Enable 1 Sync Output Sync Input Positive Output Output Return Negative Output Output Voltage Trim Share Enable 2
Part Numbering
AFL 270 05 D X / CH
Model Input Voltage
270 = 270V 28 = 28V
Screening Case Style
W, X, Y, Z
- , ES HB, CH
Output Voltage
05 = 5V, 12 = 12V, 15 = 15V
Outputs
S = Single D = Dual
AFL270XXD to Standard Military Drawing Equivalence Table
AFL27005D AFL27012D AFL27015D 5962-9550101 5962-9951801 5962-9553201
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. 09/02
10
www.irf.com

▲Up To Search▲

Price & Availability of AFL270XXD

	To Download AFL270XXD Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .