MODELS

VDC O

UTPUT

B4-23

EATURES

· 55°C to +85° C operation
· 9 to 16 or 16 to 36 VDC input
· Fully isolated
· Opto-coupler feedback
· Fixed frequency, 250 kHz typical
· Topology Push-Pull Forward
· 50 V for 50 ms transient protection
· Inhibit function
· Indefinite short circuit protection
· Up to 79% efficiency

TRIPLE

+5 & ±12
+5 & ±15

DESCRIPTION

Interpoint's MTO SeriesTM of DC/DC converters delivers 15 watts of
output power with three output voltages and a choice of two input
voltage ranges. The MTO Series converters are packaged in
hermetically sealed metal cases and operate at full load over a case
temperature range of -55°C to +85°C (measured at the base plate
of the converter).

ONVERTER

ESIGN

The push-pull forward topology coupled with pulse-width modulation
minimizes output noise and maintains good regulation. Nominal
switching frequency is 250 kHz. Although an internal input filter
reduces input ripple current, for applications requiring conformance
to MIL-STD-461C, CE03, use the MTO in conjunction with
Interpoint's FM-461 EMI filter.

Operating at maximum ratings may require removing self-generated
heat. To increase heat dissipation, heat conducting material can be
used in contact with the converter's base plate. Interpoint's Thermal
Mounting Pad (TMP), model TMP-002, is designed for use with the
MTO converter.

EATURES

An inhibit terminal, pin 8, provides shut-down and start-up control.
Applying a logic low (<0.8 V) will disable the output of the converter
reducing input current to 8 mA, typical. Leaving the terminal uncon-
nected or connecting it to Vin will enable the converter. The inhibit
pin has an open circuit voltage of approximately 10 volts.

Soft-start provides a controlled 20 milliseconds turn-on to minimize
inrush current and reduce overshoot at initial start-up or when inhibit
is released.

Internal current limiting circuitry protects all three outputs against
short circuits. When output power exceeds approximately 125% of
maximum output power, the output currents are limited. In addition,
separate current limiting circuitry protects each output individually.

ACKAGING

MTO converters are packaged in hermetically sealed metal cases.
The cases are constructed of cold-rolled steel with a fused tin finish.
MTO converters can be purchased in a flanged or non-flanged case.
The flanged option provides increased heat dissipation and also
provides greater stability when mechanically secured.

DC/DC C

ONVERTERS

12 & 28 V

OLT

NPUT

MTO SERIES

15 WATT

Size (max.): Non-flanged, case F4, 1.950 x 1.350 x 0.505 inches (49.53 x 34.29 x 12.83 mm)

Flanged, case J5, 2.720 x 1.350 x 0.505 inches (69.09 x 34.29 x 12.83 mm)
See Section B8, cases F4 and J5, for dimensions.

Weight:

53 grams typical

Screening: Standard or ES. See Section C2 for screening options, see Section A5 for

ordering information.

TYPICAL CHARACTERISTICS

INHIBIT

RECOMMENDED OPERATING CONDITIONS

ABSOLUTE MAXIMUM RATINGS

Inhibit TTL Open Collector

· Logic low (output disabled)

V = <0.8 V
Inhibit pin current < 2.0 mA

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

Unconnected or connected to Vin

Output Power

· 15 watts

Lead Soldering Temperature (10 sec per lead)

· 300°C

Storage Temperature Range (Case)

· 65°C to +125°C

B4-24

MTO SERIES
15 WATT

DC/DC C

ONVERTERS

Output Voltage Temperature Coefficient

· 150 ppm/°C typical

Input to Output Capacitance

· 80 pF typical

Current Limit

· 125% of full load typical

Isolation

· 100 megohm minimum at 500 V

Conversion Frequency

· 250 kHz typical

Inhibit Pin Voltage (unit enabled)

· 10 V typical

Input Voltage Range

· MTO12XXT 9 to 16 VDC continuous
· MTO28XXT 16 to 36 VDC continuous
· MTO12XXT 25 V for 50 msec transient
· MTO28XXT 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

Note

1. Minimum load required for full output capability on auxiliary outputs. Minimum current can be reduced when dual outputs are used at reduced loads.

MTO1212T

MTO1215T

MTO2812T

MTO2815T

PARAMETER

CONDITION

MIN TYP MAX

MIN

TYP

MAX

MIN

TYP

MAX

MIN

TYP

MAX

UNITS

MAIN

4.95

5.0

5.05

4.95

5.0

5.05

4.95

5.0

5.05

4.95

5.0

5.05

OUTPUT VOLTAGE

+ AUXILIARY

11.88

12.0

12.12

14.85

15.0

15.15

11.88

12.0

12.12

14.85

15.0

15.15

VDC

AUXILIARY

11.88

12.0

12.12

14.85

15.0

15.15

11.88

12.0

12.12

14.85

15.0

15.15

OUTPUT CURRENT

MAIN

100

2000

100

2000

100

2000

100

2000

AUXILIARY

±208

±167

±208

±167

MAIN

10.0

OUTPUT POWER

+ AUXILIARY

2.5

AUXILIARY

2.5

TOTAL

OUTPUT RIPPLE

MAIN

VOLTAGE, BW = 1 MHZ

± AUXILIARY

mV p-p

LINE REGULATION

MAIN

= MIN. TO MAX.

±AUXILIARY

LOAD REGULATION

MAIN

NO LOAD TO FULL

± AUXILIARY

INPUT VOLTAGE

CONTINUOUS

VDC

TRANSIENT 50 ms

NO LOAD

INPUT CURRENT

FULL LOAD

1670

700

INHIBITED

INPUT RIPPLE

CURRENT

100

mA p-p

EFFICIENCY

Electrical Characteristics: 25°C Tc, 28 VDC Vin (12 VDC for 12V models), 100% load, unless otherwise specified.

B4-26

MTO SERIES
15 WATT

DC/DC C

ONVERTERS

IGURE

MTO2815T Efficiency

Representative of all models

EFFICIENCY (%)

18 VIN

28 VIN

36 VIN

Output Power (Watts)

Typical Performance Curve: 25°C Tc

PIN OUT

Pin

Designation

Positive Input

+5 VDC Output

Output Common

Negative Aux. Output

Positive Aux. Output

No Connection

Case Ground

Inhibit

No Connection

Input Common

BOTTOM VIEW

MTO

Squared corner and dot on

top of cover indicate pin one.

Dotted line outlines flanged package option.

See Section B8, Cases F4 and J5, for dimensions

IGURE

3: P

MTO 12 12 T F / ES

Base Model

Input Voltage

Output Voltage

Number of Outputs

(T = triple)

(Aux. Vout)

Screening

Case Option
(Non-flanged case has no designator in
this position)

(Standard screening has no designator
in this position.)

MODEL NUMBERING KEY

24223-001-DTS Rev A

DQ# 1021

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. MTO Series is a trademark of Interpoint.
Copyright © 1990 - 1999 Interpoint. All rights reserved.

B8-12

CASE F

ASES

Materials
Header Case F1

Cold Rolled Steel/Nickel/Gold

Cases F2 - F4

Cold Rolled Steel/Nickel/Tin

Cover Case

Kovar/Nickel

Cases F2 - F4

Cold Rolled Steel/Nickel/Tin

Pins

#52 alloy (all cases)

MHV Series Triple compression glass seal
MTR Series Triple, case F1 ceramic seal
MTR Series Triple, case F2 compression glass seal
HUM40 compression glass seal or ceramic seal
Case F3 compression glass seal
Case F4 compression glass seal or 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

CASE F

BOTTOM VIEW

See Figures 20 - 23 for pin configuration

1.350 max

(34.29)

1.950 max

(49.53)

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.

Dot on top of case indicates pin one

0.000

0.170

(4.32)

1.170

(29.72)

0.000

0.170

(4.32)

0.570

(14.48)

0.970

(24.64)

1.370

(34.80)

1.770

(44.96)

0.040 dia.
(1.02)

0.000

0.25 (6.4)

MTR

Series

MHV

Series

0.405 max

(10.29)

0.000

0.405 max

(10.29)

Bathtub

Platform

MTR Series Triple and MHV Series Triple: Screening Standard, ES, or 883

BOTTOM VIEW CASE F1

Seam Seal

0.25 (6.4)

Dot on top of case indicates pin one

IGURE

20: C

ASE

IGURE

19: C

ASE

F 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.

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