B4-27

MODELS

VDC O

UTPUT

EATURES

· 55°C to +85°C operation
· 16 to 32 VDC input
· Fully isolated
· Opto-coupler feedback
· Switching frequency

Single and dual outputs

typical 80 kHz, variable freq.

Triple output - 200 kHz, fixed

· Topology Flyback
· 40 V for 50 ms transient protection
· Inhibit function
· Indefinite short circuit protection
· Up to 70% efficiency
· External capacitors required

SINGLE

DUAL

±12
±15

TRIPLE

+5 & ±12
+5 & ±15

DESCRIPTION

The MSR SeriesTM DC/DC converters provide the high efficiencies
associated with switching regulators, yet have full isolation between
input and output. Interpoint builds the MSR converters using thick-
film hybrid technology and seals them in metal packages for military,
aerospace, and other high-reliability applications. The solder sealed
packages of the standard models pass a dip gross leak hermeticity
test. Environmentally screened models pass a fine leak hermeticity
test. See Section C2 for a complete list of screening options.

ONVERTER

ESIGN

A footprint of just over one square inch makes the MSR Series
DC/DC converters one of Interpoint's smallest converters. These
converters incorporate a flyback topology which requires a minimum
of components resulting in small package size. Single and dual
models self-oscillate at an operating frequency which is an approx-
imate inverse function of the load. At full load, the frequency is typi-
cally 80 kHz for single and dual output models. Triple output models
operate at a fixed frequency of approximately 200 kHz. A trans-
former in the forward power circuit and an opto-coupler in the feed-
back/control loop maintain input to output isolation.

ONVERTER

PERATION

MSR Series DC/DC converters feature an input voltage range of 16
to 32 VDC and can withstand a transient of up to 40 V for up to 50
msec. They offer a choice of five different output voltage (VDC)
configurations: +5 , ±12 , ±15, +5 main with ±12 auxiliaries, and +5
main with ±15 auxiliaries. Dual output models deliver up to 4 watts
for either balanced or unbalanced loads, however, at least 25% of
the total load should be on the positive output. The single output
model supplies up to 3.5 watts of output power while the triple output
models supply up to 3.2 watts. The high efficiency remains almost
constant over the entire input voltage range and from approximately
25% of full load to full load. This makes the MSR Series converters
ideal for either battery or aircraft power applications.

NHIBIT

UNCTION

The open collector TTL compatible inhibit terminal is referenced to
input common. Inhibiting the converter by pulling the inhibit terminal
(pin 15) low results in an input current as low as 2 mA for the
MSR2805S. The inhibit terminal has an open circuit voltage of 12
to 28 V.

HORT

IRCUIT

ROTECTION

Each output has current limiting circuitry for indefinite short circuit
protection providing that the case temperature does not exceed the
specified limits. Under short circuit conditions the input current is
reduced to less than full load input current and the output short
circuit current remains higher than full load output current.

INIMAL

EAT

INKING

The MSR Series converters' high efficiency minimizes heat sinking
requirements, but care should be taken to remove self-generated
heat to prevent exceeding the maximum case temperature. Heat
conducting material (PCB, copper sheet, heat sink, etc.) in contact
with the converter's baseplate can help to increase heat dissipation.
The converter can be operated at full load at a case temperature of
85°C, with the output power derated linearly to zero at 115°C.

ARNING

: E

XTERNAL

APACITORS

EQUIRED

External capacitors are required on the outputs. Operating the unit
without external capacitors will result in damage to the internal
circuitry. Minimum recommended capacitor values are given in
Tables 1 and 2. For optimum performance, low ESR (Equivalent
Series Resistance) solid tantalum capacitors are required. The
specifications on the following pages are based on the use of high-
quality solid tantalums. Operation with different types of capacitors
will seriously affect performance.

DC/DC C

ONVERTERS

28 V

OLT

NPUT

MSR SERIES

4 WATT

Size (max.): 1.075 x 1.075 x 0.370 inches (27.31 x 27.31 x 9.40 mm).

See Section B8, case C2, for dimensions.

Weight:

20 grams maximum.

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

see Section A5 for ordering information.

INHIBIT

TYPICAL CHARACTERISTICS

RECOMMENDED OPERATING CONDITIONS

SINGLE AND DUAL OUTPUT MODELS

MSR2805S

MSR2812D

MSR2815D

PARAMETER

CONDITIONS

MIN TYP MAX

MIN

TYP

MAX

MIN

TYP

MAX

UNITS

OUTPUT VOLTAGE

4.90

5.0

5.10

±11.88

±12

±12.12

±14.85

±15

±15.15

VDC

OUTPUT CURRENT

16 TO 32 V

700

±167

±133

OUTPUT POWER

Tc = 55°C TO +85°C

3.5

4.0

OUTPUT RIPPLE

BW = DC TO 1 MHz

150

mV p-p

LINE REGULATION

16 TO 32 V

LOAD REGULATION

NO LOAD TO FULL

INPUT VOLTAGE

Tc = 55°C TO +85°C

VDC

TRANSIENT 50 ms

INPUT CURRENT

NO LOAD

FULL LOAD

192

213

INHIBITED

EFFICIENCY

B4-28

MSR SERIES
4 WATT

DC/DC C

ONVERTERS

ABSOLUTE MAXIMUM RATINGS

Input Voltage Range

· 16 to 32 VDC continuous
· 40 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)

0.8 V

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

12 V

Open collector

Required Minimum

Model

Connection

Capacitor Value

Single Output

Positive Output (12 & 13) to

MSR2805S

Output Common (8 & 9)

220 µF, 10 V

Positive Output (10) to

Dual Outputs

Output Common (8)

100 µF, 25 V

MSR2812D

External Capacitor (14) to

100 µF, 25 V

and

Output Common (8)

MSR2815D

Negative Output (12) to

10 µF, 25 V

Output Common (8)

FEEDBACK

LOGIC

TIMING

CONTROL

SWITCH

POSITIVE

OUTPUT

1, 2

POSITIVE

INPUT

INHIBIT

17, 18

INPUT

COMMON

NEGATIVE

OUTPUT

COMMON

EXTERNAL

CAPACITOR

TERMINAL

100

EXTERNAL

CAPACITORS

VOLTAGE

REGULATOR

IGURE

1: D

UAL

UTPUT

XTERNAL

APACITOR

ONNECTIONS

Notes Table 1
1. Capacitors should be high quality, low ESR components --

solid tantalum is recommended.

2. See Figure 1 for connection diagram
3. Place positive side of capacitor toward pin 8.

TABLE 1: EXTERNAL CAPACITOR REQUIREMENTS

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

Input Voltage

· 16 to 32 VDC

Output Power

· 3.2 to 4 watts depending on model

Lead Soldering Temperature (10 sec per lead)

· 300°C

Storage Temperature Range (Case)

· -65°C to +150°C

Output Voltage Temperature Coefficient

· MSR2805S 100 ppm/°C typ, 200 max.
· MSR28XXD 50 ppm/°C typ
· MSR285XXT 100 ppm/°C typ

Input to Output Capacitance

· 60 pF typical

Isolation

· 100 megohm minimum at 500 V

Conversion Frequency

· Single and dual output models, 80 kHz at

full load typical, variable frequency

· Triple output models, 200 kHz typical

fixed frequency

Inhibit Pin Voltage (unit enabled)

· 12 to 28 V

ARNING

: E

XTERNAL

APACITORS

EQUIRED

Notes
1. External capacitors required to prevent damage to internal circuitry (see

Table 1 for specifications).

2. Dual output models deliver up to 4 watts total for balanced or unbalanced

loads, however, the positive output should carry at least 25% of the total load.

SINGLE AND DUAL OUTPUT EXTERNAL CAPACITORS

PERATION WITHOUT EXTERNAL CAPACITORS WILL RESULT IN DAMAGE TO THE INTERNAL CIRCUITRY

TRIPLE OUTPUT EXTERNAL CAPACITOR

PERATION WITHOUT EXTERNAL CAPACITORS WILL RESULT IN DAMAGE TO THE INTERNAL CIRCUITRY

B4-29

MSR SERIES

4 WATT

DC/DC C

ONVERTERS

FEEDBACK

LOGIC

TIMING

CONTROL

SWITCH

REF. &

COMP

DUAL

TRACKING

REGULATOR

+5 OUTPUT

6, 7

POSITIVE

AUXILIARY

OUTPUT

NEGATIVE

AUXILIARY

OUTPUT

COMMON

1, 2

POSITIVE

INPUT

INHIBIT

17, 18

INPUT

COMMON

220

EXTERNAL

CAPACITOR

Required Minimum

Model

Connection

Capacitor Value

MSR28512T

Positive 5 VDC Output (9) to

and

Output Common (6 or 7)

220 µF, 10 V

MSR28515T

IGURE

RIPLE

UTPUT

XTERNAL

APACITOR

ONNECTIONS

Notes Table 2
1. See Figure 2 for connection diagram.
2. Capacitors should be high quality, low ESR components --

solid tantalum is recommended.

TABLE 2: EXTERNAL CAPACITOR REQUIREMENTS

TRIPLE OUTPUT MODELS

MSR28512T

MSR28515T

PARAMETER

CONDITIONS

MIN

TYP

MAX MIN

TYP

MAX

UNITS

OUTPUT VOLTAGE

16 TO 32 V

MAIN

4.9

5.0

5.1

4.9

5.0

5.1

VDC

BALANCED LOAD

AUX

±11.5

±12.0

±12.5

±14.5

±15.0

±15.5

OUTPUT CURRENT

MAIN

10.0

400

10.0

400

AUX

±50.0

±40.0

OUTPUT POWER

Tc = 55°C TO +85°C

3.2

OUTPUT RIPPLE

BW DC TO 1 MHz

MAIN

100

mV p-p

± AUX

100

LINE REGULATION

16 TO 32 V

MAIN

± AUX

7.5

LOAD REGULATION

NO LOAD TO FULL

MAIN

± AUX

INPUT VOLTAGE

Tc = 55°C TO +85°C

VDC

TRANSIENT 50 ms

NO LOAD

INPUT CURRENT

FULL LOAD

176

INHIBITED

EFFICIENCY

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

ARNING

: E

XTERNAL

APACITORS

EQUIRED

Notes
1. External capacitors required (see Table 2 for specifications).
2. Minimum load required on main output for full power auxiliary operation.

PIN OUT

B4-30

MSR SERIES
4 WATT

DC/DC C

ONVERTERS

MODEL NUMBERING KEY

MSR 28 512 T / ES

Base Model

Input Voltage

Output Voltage

Screening

Number of Outputs

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

(Main and aux. Vout for triple models)

(Standard screening has no designator
in this position.)

Dot on top of cover
indicates pin one.

BOTTOM VIEW

MSR

1 2

See section B8, case C2, for dimensions.

IGURE

3: P

Pin

Single Output

Dual Output

Triple Output

1, 2

Positive Input

No connection

Case

No connection

Negative Aux. Output

No connection

No Connection

Output Common Main

No connection

Output Common Aux.

Output Common

Positive Aux. Output

Output Common

No connection

+5 VDC Output

No connection

Positive Output

No connection

Positive Output

Negative Output

No connection

Positive Output

No connection

Ext. Capacitor

No connection

Inhibit

No connection

17, 18

Input Common

Pin Out Notes
1. Make external connection to both pins on all models.

Pins 1 and 2 positive input
Pins 17 and 18 input common

2. Pins 6 and 7 on triple output models are connected internally.
3. On the HR41-2805:

Make external connections to both output common pins (8 and 9).
Make external connections to both positive output pins (12 and 13).

ARNING

: E

XTERNAL

APACITORS

EQUIRED

PERATION WITHOUT EXTERNAL CAPACITORS WILL RESULT IN DAMAGE TO THE INTERNAL CIRCUITRY

24021-001-DTS Rev A

DQ# 1022

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. MSR Series is a trademark of Interpoint.
Copyright © 1992 - 1999 Interpoint. All rights reserved.

B8-8

CASE C

ASES

CASE C

BOTTOM VIEW

See Figures 9 - 11

for pin configurations.

1.075 max

(27.31)

Materials
Header Case C1

Cold Rolled Steel/Nickel/Gold

Cases C2 and C3

Kovar/Nickel/Tin

Cover Case

Cold Rolled Steel/Nickel

Cases C2 and C3

Kovar/Nickel/Tin

Pins Case

Copper/Nickel/Gold

Cases C2 and C3

Kovar/Nickel/Gold,
matched glass seal

Case dimensions in inches (mm)
Tolerance

0.005 (0.13) for three decimal places

0.01 (0.3) for two decimal places

unless otherwise specified

1.075 max

(27.31)

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

0.132

(3.35)

0.932

(23.67)

0.000

0.132 (3.35)

0.332 (8.43)

0.532 (13.51)

0.732 (18.59)

0.932 (23.67)

0.025

(0.64)

dia.

0.000

0.270 max.

(6.86)

MSA Series: Screening Standard, ES, or 883
SMSA Series: Screening Space Standard, H, or K

BOTTOM VIEW CASE C1

0.205

0.010

(5.21

0.25)

0.000

0.270 max.

(6.86)

0.205

0.010

(5.21

0.25)

Projection Weld

Seam Seal

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

1 2

0.018

0.002 dia.

(0.46

0.05)

0.350 (8.89)

0.000

Pins equally

spaced

Marker bead
on pin 18

MSR Series: Screening Standard or ES
HR40 Series: No screening options

BOTTOM VIEW CASE C2

0.205

0.010

(5.21

0.25)

Dot on top of case
indicates pin one

0.100 (2.54)

0.370 max.

(9.40)

0.800 (20.32)

0.800 (20.32

1 2

0.018

0.002 dia.

(0.46

0.05)

MSF EMI Filter: Screening Standard or ES

BOTTOM VIEW CASE C3

0.350 (8.89)

0.000

0.370 max.

(9.40)

0.205

0.010

(5.21

0.25)

Dot on top of case
indicates pin one

0.100 (2.54)

0.800

(20.32)

0.800 (20.32

0.600

(15.24)

0.300

(7.62)

0.000

0.365 max.

(9.27)

0.205

0.010

(5.21

0.25)

Seam Seal

IGURE

ASE

IGURE

10:

ASE

IGURE

11:

ASE

IGURE

8: C

ASE

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 dimen-
sions for accuracy.

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