MODELS

VDC O

UTPUT

B4-9

Size (max.): 2.720 x 1.350 x 0.505 inches (69.09 x 34.29 x 12.83 mm)

See Section B8, case J5, for dimensions.

Weight:

60 grams max.

Screening: Standard or ES. See Section C2 for screening options,

see Section A5 for ordering information.

EATURES

· 55°C to +85°C operation
· 18 to 40 VDC input

(19 to 40 VDC MTW2805S)

· Fully Isolated
· Optocoupler feedback
· Fixed frequency
· Topology Push-Pull Forward
· 50 V for up to 50 ms transient protection
· Inhibit function
· Indefinite short circuit protection
· Remote sense on MTW2805S model
· Up to 86% efficiency

SINGLE

12
15

DUAL

±12
±15

DESCRIPTION

The MTW SeriesTM of DC/DC converters offer the high efficiency
and wide input voltage range of switching regulators with the isola-
tion, excellent output regulation, and low output noise typical of
linear regulators without requiring the use of external components.
MTW converters are built using thick-film hybrid technology and are
sealed in metal packages for military, aerospace and other high-reli-
ability applications. Unscreened models are sealed with solder and
are guaranteed to pass a gross leak test (maximum leak rate of 1 x
10

-3

atm.-cc/sec). Environmentally screened models (/ES) are

hermetically sealed with solder and will pass a fine leak and gross
leak test as described in Section C2.

MTW converters use a constant frequency pulse-width modulated
switching regulator design operating in the forward mode with a
clock switching frequency of 240 to 300 kHz. Isolation is achieved
through the use of a transformer in the forward power circuit and an
optocoupler in the feedback control loop. The full load output power
of 30 watts is available over the entire 18 to 40 VDC (19 to 40 VDC
for MTW2805S) input range. On dual output models, up to 90% of
full power is available from either output up to a combined total of 30
watts. Input transients of 50 V to up to 50 ms. duration will not impair
normal operation.

Efficiency is high over the entire input voltage range and from
approximately 25% of full load to full load (see typical efficiency
curves).

MTW converters are provided with indefinite short circuit protection
through the use of current limiting techniques. When the output
current reaches approximately 125% of the full rated load, the
output voltage begins to reduce to protect the converter. The
converter can sustain a true short circuit condition indefinitely.

With temperatures measured at the baseplate, the MTW Series is
rated for full power operation from 55°C to +85°C with the power
derated linearly to 0 at 115°C. The MTW's flanged case facilitates
removal of heat and provides for mechanically secure mounting.In
applications requiring full power operation, an efficient heat sink
attached to the baseplate is required.

An inhibit is provided to allow power shut-down and start-up from a
logic input. An open circuit on the inhibit pin allows normal operation,
while a connection between the inhibit pin and input common
disables the internal oscillator and shuts down the output. In the
inhibit mode, approximately 1 mA must be sunk from pin the inhibit
pin. An open collector, active low, is required to activate the inhibit
function.

All MTW converters are characterized by close output regulation
over the entire operating range with no minimum power require-
ment. On 12 and 15 VDC output models, typical line regulation is 10
to 20 mv. The MTW2805S model uses external remote sense pins
which monitor the voltage at the load to provide typical regulation in
the 5 to 7 mV range. The voltage sensing circuitry operates in a true
four terminal voltage mode, eliminating the adverse effects of line
resistance voltage drops. The remote sense pins may be left uncon-
nected, but see cautions in on the following pages. For normal oper-
ation, remote sense pins should be connected to their respective
output pins.

The MTW Series offers low noise on both the input and output line.
in the single output converters, two-section L-C filters at both the
input and output limit output ripple voltage and minimize reflected
ripple on the input line. A small value (1000 pF, 500 V) ceramic
capacitor connected between the case and input common pin of the
single volt output models will reduce EMI on the input lines to levels
near those required by MIL-STD-461C's CE03 standard. In the dual
output converters, single-section L-C filters are used at the input
and outputs. If compliance with MIL-STD-461 is necessary, use of
Interpoint's FMA-416 EMI filter or FM-704A transient suppressor is
recommended.

DC/DC C

ONVERTERS

28 V

OLT

NPUT

MTW SERIES

30 WATT

TYPICAL CHARACTERISTICS

RECOMMENDED OPERATING CONDITIONS

ABSOLUTE MAXIMUM RATINGS

INHIBIT

Input Voltage

· 18 to 40 VDC (19 to 40 VDC MTW2805S)

Output Power

· 30 watts

Lead Soldering Temperature (10 sec per lead)

· 300°C

Storage Temperature Range (Case)

· 55°C to +125°C

B4-10

MTW SERIES
30 WATT

DC/DC C

ONVERTERS

Output Voltage Temperature Coefficient

· 100 ppm/°C, typical

Input to Output Capacitance

· 80 pF typical single output models
· 70 pF typical MTW2812D
· 60 pF typical MTW2815D

Current Limit

· 125% of full load typical

Isolation

· 100 megohm minimum at 500 V

Conversion Frequency

· 240 to 300 kHz

Inhibit Pin Voltage (unit enabled)

· 11 to 15 V single output models
· 8 to 12 V MTW2812D
· 10 to 14 V MTW2815D

Input Voltage Range

· 18 to 40 VDC continuous (19 to 40 MTW2805S)
· 50 V for 50 msec transient

Case Operating Temperature (Tc)

· 55°C to +85°C full power
· 55°C to +115°C absolute

Derating Output Power/Current

· Linearly from 100% at 85°C to 0% at 115° C

Inhibit TTL Open Collector

· Logic low (output disabled)

Inhibit pin current 1 mA typical

· Referenced to input common
· Logic high (output enabled)

Open collector

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

MTW2805S

MTW2812S

MTW2815S

PARAMETER

CONDITIONS

MIN TYP MAX

MIN

TYP

MAX

MIN

TYP

MAX

UNITS

OUTPUT VOLTAGE

4.95

5.0

5.05

11.88

12.0

12.12

14.85

15.0

15.15

VDC

OUTPUT CURRENT

6.0

2.5

2.0

OUTPUT POWER

55°C TO +85°C

30.0

OUTPUT RIPPLE

2 MHz

mV p-p

LINE REGULATION

MIN. TO MAX. V

LOAD REGULATION

NO LOAD TO FULL

INPUT VOLTAGE

NO LOAD TO FULL

VDC

55°C TO +85°C

TRANSIENT 50 ms

INPUT CURRENT

NO LOAD

FULL LOAD

1370

1400

INHIBITED

INPUT RIPPLE

CURRENT

2 MHz

mA p-p

EFFICIENCY

START-UP

DELAY

OVERSHOOT

300

400

Notes
1. For MTW2805S, with the remote sense pins connected to the load and no resistance between the output pins and load.
2. A low output impedance power source is required on the input to realize this start-up time. If less than full surge current is available, start-up time

will be longer

CAUTION
Permanent damage to the MTW2805S will result if pin 6 is shorted to ground. Damage may also result if pin 4 or pin 5 is disconnected from the load
during operation with the remote sense leads connected to the load. If remote sense pins are not connected to the load, the output voltage of the
MTW2805S will rise to approximately 6.2 VDC measured across pins 4 and 5.

PIN OUT

B4-11

MTW SERIES

30 WATT

DC/DC C

ONVERTERS

MTW2812D

MTW2815D

PARAMETER

CONDITION

MIN

TYP

MAX

MIN

TYP

MAX

UNITS

OUTPUT VOLTAGE

OUT

11.88

12.0

12.12

14.85

15.0

15.15

VDC

OUT

11.88

12.0

12.12

14.85

15.0

15.15

OUTPUT CURRENT

2.5

2.0

OUTPUT POWER

55°C to +85°C

30.0

OUTPUT RIPPLE

VOLTAGE BW

2 MHz

mV p-p

LINE REGULATION

= 18 TO 40

LOAD REGULATION

NO LOAD TO FULL

CROSS REGULATION

OUT

2.5

3.5

2.2

3.2

OUT

2.5

3.5

2.2

3.2

INPUT VOLTAGE

CONTINUOUS

VDC

55°C to +85°C

TRANSIENT 50 ms

INPUT CURRENT

NO LOAD

FULL LOAD

1350

1400

INHIBITED

INPUT RIPPLE

CURRENT

2 MHz

mA p-p

EFFICIENCY

START-UP

DELAY

OVERSHOOT

500

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

Notes
1. Up to 90% of full power is available from either output providing the total power does not exceed 30 watts.
2. The effect on the output voltage of either output (held at 3 watts) when the other output is varied from 3 to 27 watts.
3. A low output impedance power source is required on the input to realize this start-up time. If less than full surge

current is available, start-up time will be longer

Pin

MTW2805S

Single Output

Dual Output

Positive Input

Inhibit

No connection

Sense Return

No connection

Positive Output

Output Common

Positive Output

Negative Output

Positive Sense

No connection

Case Ground

No connection

Inhibit

No connection

Input Common

BOTTOM VIEW

MTW

Squared corner and dot on

top of cover indicate pin one.

See section B8, case J5, for dimensions.

IGURE

1: P

MTW 28 12 D / ES

Base Model

Voltage In

Output Voltage

Screening

Number of Outputs

(S = single, D = dual)

(Standard screening has no designator
in this position.)

B4-12

MTW SERIES
30 WATT

DC/DC C

ONVERTERS

Typical Performance Curves: 25°C Tc

IGURE

Output Power (Watts)

MTW2815D Efficiency

Efficiency (%)

18 V

40 V

28 V

Output Power (Watts)

MTW2812D and MTW2815D

Low Line Dropout

Inupt Voltage (Volts)

MTW2812D

MTW2815D

Output Power (Watts)

MTW2805S Efficiency

Efficiency (%)

28 V

19 V

40 V

IGURE

Output Power (Watts)

MTW2812S Efficiency

Efficiency (%)

28 V

18 V

40 V

IGURE

Output Power (Watts)

MTW2812S and MTW2815S

Low Line Dropout

Input Voltage (Volts)

MTW2815S

MTW2812S

IGURE

Output Power (Watts)

MTW2812D Efficiency

Efficiency (%)

28 V

18 V

40 V

MODEL NUMBERING KEY

24421-001-DTS Rev A

DQ# 1017

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. MTW Series is a trademark of Interpoint.
Copyright © 1994 - 1999 Interpoint. All rights reserved.

B8-22

CASE J

ASES

Materials
Header Case J1

Cold Rolled Steel/Nickel/Gold

Cases J2 - J5

Cold Rolled Steel/Nickel/Tin

Cover Case

Kovar/Nickel

Case J2 - J5

Cold Rolled Steel/Nickel/Tin

Pins

#52 alloy (all cases)
Case J1

MHV Series Triple compression glass seal
MTR Series Triple ceramic seal

Cases J2 - J5

compression glass 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

CASE J

BOTTOM VIEW

See Figures 36 - 40
for pin configuration

1.350 max

(34.29)

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.

Flange Thickness:

Cases J1 and J5

0.060 (1.52)

Case J2

0.073 (1.85) max

Cases J3 and J4

0.067 +0.005/-0.007 (1.70 +0.13/-0.8)

2.720 max

(69.09)

Dot on top of case indicates pin one

IGURE

35: C

ASE

J M

AXIMUM

IMENSIONS

Note: Although every effort has been made to render the case drawings at actual size, variations in the printing process may cause some distortion. Please refer

to the numerical dimensions for accuracy.

B8-25

CASE J

ASES

0.040 dia.
(1.02)

0.000

0.25 (6.4)

0.000

0.170

(4.32)

0.210

(5.33)

1.370

(34.80)

1.770

(44.96)

1.980

(50.29)

0.173

(4.39)

0.000

1.173

(29.79

0.673

(17.09)

0.162 dia

(4.11)

Flanged cases: Designator required in Case Option position of model number.
FMD28-461 EMI Filter (down-leaded): Screening Standard or ES

BOTTOM VIEW CASE J4

Solder Seal

Solder Tip-off

0.505 max

(12.83)

Squared corner and dot on top
of case indicate pin one.

IGURE

39: C

ASE

0.040 dia.
(1.02)

0.000

0.25 (6.4)

0.000

0.170

(4.32)

0.210

(5.33)

0.570

(14.48)

0.970

(24.64)

1.370

(34.80)

1.770

(44.96)

1.980

(50.29)

0.173

(4.39)

0.000

1.173

(29.79

0.673

(17.09)

0.162 dia

(4.11)

Flanged cases: Designator required in Case Option position of model number

for MHL Series and MTO Series only.

MHL Series, MTO Series, MTW Series: Screening Standard or ES
HR300 Series: no screening options

BOTTOM VIEW CASE J5

Solder Seal

Solder Tip-off

0.505 max

(12.83)

Squared corner and dot on top
of case indicate pin one.

IGURE

40: C

ASE

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: MTW2815S