MFW2812S [CRANE]

DC/DC CONVERTERS 28 VOLT INPUT; DC / DC转换器， 28伏特的输入


型号：	MFW2812S
厂家：	Crane Aerospace & Electronics.
描述：	DC/DC CONVERTERS 28 VOLT INPUT DC / DC转换器， 28伏特的输入转换器模拟IC 信号电路输入元件局域网
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FEATURES

• –55°C to + 85°C operation

MFW SERIES

70 WATTS

DC/DC CONVERTERS

28 VOLT NPUT

• 19 to 40 VDC input

• Fully Isolated

• Optocoupler feedback

MODELS

VDC OUTPUT

• Fixed frequency, 245 kHz typical

• Topology – Push-Pull Forward

• 50 V for up to 50 ms transient protection

• Inhibit/sync function

SINGLE

DUAL

±12

±15

TRIPLE

+5 & ±12

+5 & ±15

• Indefinite short circuit protection

• Remote sense on single models

• Up to 84% efficiency

Size (max.): 3.20 x 2.46 x 0.595 inches (81.3 x 62.5 x 15.11 mm)

See Section B8, case L, for dimensions.

Weight:

140 grams typical

Screening: Standard or ES.See Section C2 for screening

options, see Section A5 for ordering information.

DESCRIPTION

WIDE VOLTAGE RANGE

The MFW Series™ of DC/DC converters offers up to 70 watts of

power from single, dual, or triple outputs in one package. Using

hybrid thick film technology a power density of over 20 watts per

cubic inch is achieved. These devices are packaged in hermetically

sealed cold rolled steel enclosures with a tin plate finish making

them ideal for use in military, aerospace, or other high reliability

applications. Unscreened models are guaranteed to pass a gross

leak test (maximum leak rate of 0.001 atm-cc/sec). Environmentally

screened units (designated by the /ES suffix) are hermetically solder

sealed. See Section C2 for screening specifications.

All models of the MFW Series are designed to provide full power

operation over an input voltage range of 19 to 40 VDC. Operation

below an input of 19 volts, including operation in MIL-STD-704E

emergency power conditions, is possible with derated output power.

Please refer to the derating information and the low voltage drop-out

graphs (Figures 10 and 11) on the following pages.

WIDE TEMPERATURE RANGE

Full load operation of any of the MFW Series converters is available

at case temperatures of –55°C to + 85°C. Operation up to +125°C

is possible with derated output power. The MFW Series converters

are provided in a flange mount case designed to facilitate the

removal of internally generated heat. Because of this, heat sinking

requirements are minimal. Sustained full power operation does

however require that an efficient heat sink be attached to the base-

plate. Please refer to the heat sink requirements section for more

information.

DESIGN METHODOLOGY

The MFW Series converters utilize a quasi-square wave forward

converter design with a nominal switching frequency of 245 kHz.

Isolation between input and output is provided with a transformer in

the forward power loop and a wideband, temperature insensitive

optical link in the feedback control loop. Output regulation is accom-

plished with constant frequency pulse width modulation. In addition,

the load regulation of the single output models is further enhanced

through the use of remote output voltage sense pins to overcome

the adverse effects of line resistance voltage drops. Short circuit

protection is provided by detecting peak primary switching current

on a cycle by cycle basis and limiting it to approximately 130% of the

full load input current. This method results in quick and positive

current limiting under short circuit conditions.

INHIBIT/SYNC FEATURE

Standard on all models of the MFW Series is a dual mode

inhibit/sync pin. This pin serves as both an output inhibit and as a

synchronization input. In the inhibit mode an open collector TTL

compatible low (<0.8 V) will disable internal switching thereby

inhibiting the unit's output. Inhibiting in this manner results in an

extremely low quiescent current. Since a pull-up resistor is included

internally, this pin may be left open should the inhibit function not be

desired.

LOW NOISE

The MFW Series converters offer low noise on both the input and

output lines. A two section, four pole LC input filter is included to

provide very low reflected line ripple current. Adherence to MIL-

STD-461C (CE03) is possible with the addition of the FMB-461 filter.

Output ripple is maintained at less than 50 mV p-p for single and

dual output models and 85 mV for triple output models.

In a digital system it is often desirable to synchronize the input or

output ripple with the system clock. For this reason each model of

the MFW Series was designed to synchronize with a system clock

applied to the inhibit/sync pin. Please refer to the technical data

section for timing details for the external sync feature.

B4-3

MFW SERIES

70 WATT

DC/DC CONVERTERS

ABSOLUTE MAXIMUM RATINGS

SYNC AND INHIBIT

TYPICAL CHARACTERISTICS

Output Power

Sync In (245 to 370 kHz.)

• Duty cycle 70% min, 98% max

• Logic low 0.8 V max

Output Voltage Temperature Coefficient

• 150 ppm/°C, typical

Input to Output Capacitance

• 160 pF, typical

• 60 to 70 watts depending on model

Lead Soldering Temperature (10 sec per lead)

• 300°C

• Logic high 4.5 V min

Storage Temperature Range (Case)

• –55°C to +125°C

• Referenced to input common

• If sync is not used, leave unconnected

Inhibit TTL Open Collector

• Logic low (output disabled)

Inhibit pin current 1 mA max

• Referenced to input common

• Logic high (output enabled)

V = ≥ 4.5 V

Isolation

• 100 megohm minimum at 500 V

Conversion Frequency

• Free run mode 245 kHz, typical

Inhibit Pin Voltage (unit enabled)

• 4.5 to 5.5 V

RECOMMENDED OPERATING CONDITIONS

Input Voltage Range

• 19 to 40 VDC continuous (see Derating)

Case Operating Temperature (Tc)

• –55°C to +85°C full power

DERATING OUTPUT POWER/CURRENT AND INPUT VOLTAGE

Temperatures are referenced to the temperature at the converter’s baseplate

• Linearly derate output power/current from 100% at 85°C to 0% at 125°C.

• Above 105°C linearly derate steady state input voltage to 33 volts at 125°C.

• Indefinite short circuit protection is not guaranteed above 85°C case.

• Operation below an input voltage of 19 volts, including operation in MIL-

STD-704E emergency power conditions, is possible with derated output

power. See Figures 10 and 11.

Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.

SINGLE OUTPUTS

PARAMETER

MFW2805S

MFW2812S

MFW2815S

CONDITION

MIN TYP MAX

MIN. TYP MAX

UNITS

OUTPUT

VOLTAGE

FULL LOAD

4.95 5.00

5.05

12.00

11.88 12.00 12.12

14.85 15.00 15.15

VDC

OUTPUT

CURRENT

= 19 TO 40

—

5.83

—

4.67

OUTPUT

POWER

Tc = –55°C TO +85°C

OUTPUT

RIPPLE

FULL LOAD BW ≤2 MHz

mV p-p

LINE

REGULATION

= 19 TO 40

LOAD

REGULATION

NO LOAD TO FULL

INPUT

VDC

VOLTAGE

INPUT

NO LOAD

INHIBITED

—

CURRENT

INPUT REFL.

RIPPLE

FULL LOAD

BW ≤10 MHz

—

mA p-p

EFFICIENCY

—

STARTUP

DELAY

WITH LOW

IMPEDANCE SOURCE

B4-4

MFW SERIES

70 WATT

DC/DC CONVERTERS

Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.

DUAL AND TRIPLE OUTPUTS

MFW2812D

MFW2815D

MFW28512T

MFW28515T

PARAMETER

CONDITION

MIN

TYP

MAX

MIN

TYP

MAX

MIN

TYP

MAX

5.10

MIN

TYP

MAX

5.05

UNITS

OUTPUT

VOLTAGE

FULL

LOAD

MAIN

DUAL

—

4.95

5.05

4.90

4.95

VDC

±11.88 ±12.00 ±12.12 ±14.85 ±15.00 ±15.15 ±11.65 ±11.80 ±12.05 ±15.05 ±15.30 ±15.55

OUTPUT

CURRENT

MAIN

DUAL

—

2.92

—

5.5

—

2.33

—

4.4

—

4.0

1.67

10.0

4.2

—

4.0

1.33

10.0

3.33

19 TO 40

1, 2

MAIN

±DUAL

TOTAL

—

66.5

—

66.5

—

OUTPUT

POWER

1, 2

OUTPUT

RIPPLE

FULL LOAD

BW ≤ 2 MHz

MAIN

DUAL

—

mV p-p

LINE

MAIN

DUAL

—

REGULATION 19 TO 40

100

200

100

200

LOAD

NO LOAD

MAIN

DUAL

—

480

600

—

300

450

REGULATION TO FULL

CROSS

DUAL

REGULATION +PO = 3 W TO 35 W

–PO = 35 W

—

1.5

2.0

3.0

4.0

—

1.5

2.0

3.0

3.5

—

+PO = 20 W TO 50 W

–PO = 50 W TO 20 W

CROSS

MAIN +PO = 33 W

REGULATION DUAL

+PO = 3 W TO 27 W

—

2.3

6.0

—

2.3

5.0

–PO = 27 W TO 3 W

MAIN

+PO = 3 W TO 30 W

DUAL ±PO = 15 W

—

5.4

9.0

—

5.0

7.0

INPUT

VOLTAGE

VDC

INPUT

CURRENT

NO LOAD

INHIBITED

—

110

—

110

INPUT REFL.

RIPPLE

FULL LOAD

BW ≤10 MHz

—

mA p-p

EFFICIENCY

—

STARTUP

DELAY

Notes

1. On dual output models the maximum combined output power is 70 watts.

A maximum of 95% (66.5 W) is available from any single output.

2. On triple output models the maximum combined output power is 60 watts.

A maximum of 50 watts is available from a single output.

3. Balanced loads.

4. Regulation effect on the negative dual output during the defined conditions.

5. Regulation effect on both dual outputs during the defined conditions.

B4-5

MFW SERIES

70 WATT

DC/DC CONVERTERS

THERMAL MANAGEMENT

CALCULATING MAXIMUM AMBIENT TEMPERATURE

The MFW Series of DC/DC converters has an upper operating

temperature of + 85°C at the baseplate of the case. The degree of

heat sinking required to remain within this limit may be determined

from Figure 1 which shows the maximum allowed internal power

HEAT SINK RECOMMENDATIONS

An MFW Series converter in still air (other than convective currents)

and with no conductive cooling paths other than through electrical

connections at the pins will exhibit a thermal resistance of approxi-

mately 4°C / watt. In cases where this value proves to be too high it

is recommended that additional heat sinking be supplied. The

simplest method of accomplishing this is to firmly attach the

converter to a PCB thereby providing a conductive thermal path.

Secondly it is recommended that airflow be provided over the

converter. Although each situation requires a thorough thermal

analysis these two measures can reduce the thermal resistance to

as low as 2°C / watt. If calculations indicate further heat sinking is

required it is recommended that additional thermal mass be

provided either under the base plate or on top of the converter's

mounting flanges or both.

dissipation (P

vs. ambient temperature for various heat sink

DISS

thermal resistances. P

may be calculated as:

DISS

= P

/ efficiency – P

DISS

OUT OUT

The efficiency for all combinations of P

and V for the various

OUT

models may be obtained from the graphs on the preceding pages.

Example: Converter = MFW2815D, T = 70°C,

AMB

= 28 VDC, P

= 45 watts

OUT

Efficiency = 85% (From Figure 7)

= (45 / 85) – 45 = 7.95 watts

DISS

From Figure 1 we can see that this situation will require thermal

resistance of approximately 4.5°C / watt.

Conversely we may also find the maximum ambient temperature

which can be tolerated if we know the heat sink thermal resistance.

Example: Converter = MFW2805S, V = 28 VDC, P

= 45 W.

OUT

Thermal Resistance = 3°C / watt.

Efficiency = 83.5% (From Figure 3)

= (45 / 0.835) – 45 = 8.89 watts.

DISS

From Figure 1 we can see that the maximum allowed ambient

temperature is approximately 75°C.

20° 40° 60° 80° 100° 120° 140°

Degrees Centigrade

Internal Power Dissipation (max)

vs. Ambient Temperature

FIGURE 1

B4-6

MFW SERIES

70 WATT

DC/DC CONVERTERS

PIN OUT

Squared corner indicates pin one.

Single Output

Positive Input

Case Ground

Dual Output

Positive Input

Case Ground

Input Common

Inhibit/Sync In

Triple Output

Positive Input

Case Ground

Input Common

Inhibit/Sync In

Input Common

Inhibit/Sync In

Negative Sense

Positive Sense

Output Common

Positive Output

BOTTOM VIEW

MFW

Negative Output Negative Aux. Output

Positive Output Positive Aux. Output

Output Common Output Common

7, 8

9, 10

No Connection

Main (+5) Output

See Section B8, case L, for dimensions.

FIGURE 2: PIN OUT

MODEL NUMBERING KEY

MFW 28 512

Base Model

T / ES

Input Voltage

Output Voltage

(Main and Aux. Vout for triple models)

Number of Outputs

(S = single, D = dual, T = triple)

Screening

(Standard screening has no designator

in this position.)

B4-7

MFW SERIES

70 WATT

DC/DC CONVERTERS

Typical Performance Curves: 25°C Tc , 28 VDC Vin, 100% load, free run, unless otherwise specified.

20 V

19 V

28 V

40 V

Output Power (Watts)

MFW2815S Efficiency vs Line & Load

MFW2805S Efficiency vs Line & Load

MFW2812S Efficiency vs Line & Load

FIGURE 3

FIGURE 4

FIGURE 5

19 V

28 V

40 V

Output Power (Watts)

MFW2815D Efficiency vs Line & Load

MFW28512T Efficiency vs Line & Load

MFW2812D Efficiency vs Line & Load

FIGURE 6

FIGURE 7

FIGURE 8

19 V

MFW2815D

2815S

MFW2812D

283R5S

28 V

2812S

MFW28512T

MFW28515T

2805S

40 V

Output Power (Watts)

Low Line Dropout vs. Load (50 mV drop)

MFW Single Output Models

Low Line Dropout vs. Load (50 mV drop)

MFW Dual and Triple Output Models

MFW28515T Efficiency vs Line & Load

FIGURE 9

FIGURE 10

FIGURE 11

20621-001-DTS Rev A

DQ# 1016

All technical information is believed to be accurate, but no responsibility is

assumed for errors or omissions. Interpoint reserves the right to make changes in

products or specifications without notice. MFW Series is a trademark of Interpoint.

B4-8

CASE L

CASES

0.060 min

(1.52)

CASE L

TOP VIEW

Cover Placement

and

Min/Max Dimensions

See Figure 50

for pin configuration

3.20 max (81.3)

0.060 min

(1.52)

2.46 max (62.5)

0.337 min

(8.56)

0.337 min

(8.56)

Squared corner indicates pin one

Materials

Header Cold Rolled Steel/Nickel/Tin

Cover Cold Rolled Steel/Nickel/Tin

Pins

#52 alloy pins 1-4, and 9-10

#52 alloy with copper core pins 5-8

ceramic seal

Case dimensions in inches (mm)

Tolerance ±0.005 (0.13) for three decimal places

±0.01 (0.2) for two decimal places

unless otherwise specified

CAUTION

Heat from reflow or wave soldering may damage

the device. Solder pins individually with heat

application not exceeding 300°C for 10 seconds

per pin.

FIGURE 49: CASE L MAXIMUM DIMENSIONS

B8-31

CASE L

CASES

CASE L

MFW Series: Screening – Standard or ES

HR700 Series: no screening options

Squared corner indicates pin one

Solder Seal

0.141 x 6

(3.58)

2.850 (72.39)

.0.040 +0.005/-0.002

(1.02 +0.13/-0.05)

BOTTOM VIEW

1.600 (40.64)

Solder Tip-off

0.550 (13.97)

0.350 (8.89)

0.000

FIGURE 50: CASE L DIMENSIONS

B8-32

QA SCREENING

85°C PRODUCTS

TEST (85°C Products excluding HR products)

STANDARD

/ES

yes

PRE-CAP INSPECTION

Method 2017

yes

TEMPERATURE CYCLE (10 times)

Method 1010, Cond. B, -55°C to 125°C

CONSTANT ACCELERATION

Method 2001, 500 g

BURN-IN

96 hours at 70°C ambient (typical)

FINAL ELECTRICAL TEST MIL-PRF-38534, Group A

Subgroups 1 and 4: +25°C case

HERMETICITY TESTING

yes

Fine Leak, Method 1014, Cond. A

Gross Leak, Method 1014, Cond. C

yes

-3

Gross Leak, Dip (1 x 10 )

yes

FINAL VISUAL INSPECTION

Method 2009

yes

Test methods are referenced to MIL-STD-883 as determined by MIL-PRF-38534.

Applies to the following products:

MFW Series

MTW Series

MHE/MLP Series

MHL Series

MRH Series

MTO Series

MSR Series

DCH Series

FM/FMA/FMB EMI Filters

MSF EMI Filter

C2-12

MFW2812S [CRANE]

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