MGDS-75-H-I/T-L - GAIA Converter - Datasheet.Directory

Hi-Rel DC/DC CONVERTER

MGDM-75 : 75W POWER

• Ultra wide input range 16-80 Vdc, 9-45 Vdc

• 28Vdc input compliant with MIL-STD-704A/D/F

• Industry standard quarter brick package

• Power up to 75 W

• Wide temperature range : -40/+105°C baseplate

• High efficiency (typ. 86%-90%)

• Soft start

• Galvanic isolation 1 500 VDC

• Integrated LC EMI filter

• Synchronizable

• Fully protected by independant security

• Under voltage lock-out

• Overvoltage protection

• Current limitation protection

• Overtemperature protection

• No optocoupler for high reliability

• Leaded process

Gaia Converter FC03-032.12/13 Revision L

REDEFINING THE SOURCE OF POWER

1-General

5:1 Low Input Voltage 9-45 & 16-80 VDC

Single Output

Metallic case - 1 500 VDC Isolation

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2-Product Selection

Input Voltage Range

B : 3.3 VDC

C : 5 VDC

E : 12 VDC

F : 15 VDC

I : 24 VDC

J : 28 VDC

Permanent

H : 9-45 VDC

O : 16-80 VDC

Output

The MGDM-75 series is a complete line of high

density wide input range DC/DC power modules

designed for aerospace, military and high-end

industrial applications. These modules use a

patented fixed switching topology at 420 KHz

providing ultra wide input range, low noise

characteristics and high power density. Standard

models are available with ultra wide input vol-

tage range of 9-45, 16-80 volts. The series

include single output voltage choices of 3.3, 5,

12, 15, 24, 28 volts.

The MGDM-75 series include synchronization, trim

and sense functions.

The synchronization function allows to synchronize

more than one converter to one frequency or an

external source frequency.

All the modules are designed with LC network

filters to minimize reflected input current ripple

and output voltage ripple.

The modules have totally independant security

functions including input undervoltage lock-out,

output overvoltage protection, output current

limitation protection, and temperature protec-

tion. Additionnally a soft-start function allows

current limitation and eliminates inrush current

during start-up.

The design has been carried out with surface

mount components, planar transformer and is

manufactured in a fully automated process to

guarantee high quality. The modules are potted

with a bi-component thermal conductive

compound and used an insulated metallic subs-

trat to ensure optimum power dissipation under

harsh environmental conditions.

Single output model : MGDS - 75 - input output option suffix

Options : Suffix :

/T : option for -55°C start up operating temperature

/S : option for screening and serialization -L : leaded process

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MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

2- Product Selection (continued)

Current

15 A

6,25 A

5 A

3,125 A

2,7 A

15 A

6,25 A

5 A

3,125 A

2,7 A

Reference

MGDS-75-H-B

MGDS-75-H-C

MGDS-75-H-E

MGDS-75-H-F

MGDS-75-H-I

MGDS-75-H-J

MGDS-75-O-B

MGDS-75-O-C

MGDS-75-O-E

MGDS-75-O-F

MGDS-75-O-I

MGDS-75-O-J

Output

3.3 VDC

5 VDC

12 VDC

15 VDC

24 VDC

28 VDC

3.3 VDC

5 VDC

12 VDC

15 VDC

24 VDC

28 VDC

Options

/T , /S

Input range

9-45 VDC

16-80 VDC

Converter Selection Chart

MGDS - 75 - O - C / T - L

Number of Outputs :

S : single output

Input voltage range :

H : 9-45 VDC

O : 16-80 VDC

Output voltage :

See table page 1

Option :

/T : -55°C start up operation

/S : screening & serialization

(consult application note

«screening grades»)

Suffix :

-L : Leaded process

Suffix

-L

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MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

3- Block Diagram

The MGDM-75 DC/DC converter is based on a cons-

tant 420KHz pulse-width modulated forward topology

designed for ultra large input range.

The output voltage is monitored on the secondary

side avoiding the use of optocoupler to optimize

long-term reliability and provide good immunity

against radiations.

An auxilliary supply is implemented to feed

independently all security functions such as the input

undervoltage lock-out (UVLO), the output overload

protection (OCP), the ouput overvoltage protection

(OVP) and the thermal protection (OTP).

As this auxilliary power is independent from the main

power supply, the module features a wide trim

windows from 90% to 110% of the nominal output

voltage.

The main power transformer designed for more than

75W power is a multi-layer planar transformer which

allows 100% reproductibility for optimized module

efficiencies.

The controlled feedback regulation is located at the

secondary side allowing a high regulation bandwidth

and a very fast response to load changes.

UVLO

Thermal 

Shutdown

OVP

LC output 

filter

LC input 

filter

Mosfet 

Driver

Current 

Sense

POWER STAGE

Auxilliary 

supply Feed-back

function

Vin

On/Off

Sync 

Vo

Trim

Isolation Barrier

Control circuit Sense

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MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

Note * : These performances are measured with the sense line connected..

Note ** : It is recommended to mount the converter on a heatsink for this test, see section 10-3 and 10-9 for further details.

Note *** : The ripple output voltage is the periodic AC component imposed on the output voltage, an aperiodic and random component (noise) has also to be considered.

This noise can be reduced by adding 4 external decoupling capacitors connected between inputs and case and between outputs and case. These capacitance should

be layed-out as close as possible from the converter. Please refer to page 8 for more details.

4- Electrical Specifications

Data are valid at +25°C, unless otherwise specified.

Parameter Conditions Limit or

typical Units Single Output MGDS-75

75 - H 75 - O

Input

Nominal input voltage Full temperature range Nominal VDC 24 28

Permanent input

voltage range (Ui) Full temperature range Min. - Max. VDC 9 - 45 16 - 80

Undervoltage lock-out (UVLO) Turn-on voltage

Turn-off voltage

Nominal

VDC

10,2

8,3

15,2

13,8

Start up time

Ui nominal

Nominal output

Full load : resistive

Maximum ms 30 30

Reflected ripple current Ui nominal, full load

BW = 20MHz Maximum mApp 500 500

Input current in short circuit

mode (Average)

Ui nominal

Short-circuit Typical A 1 0,2

No load input current Ui nominal

No load Maximum mA 30 30

Input current in inhibit mode Ui nominal

Inhibit Maximum mA 10 10

Output

Output voltage * Ui min. to max.

Nominal

VDC

3,3

Set Point accuracy * Ambient temperature : +25°c

Ui nominal, 75% load Maximum % +/- 2 +/- 2

Output power At 105°c baseplate

Ui min. to max. Maximum W 50 to 75 50 to 75

Output current

3,3V output

5V output

12V output

15V output

24V output

28V output

Full temperature range

Ui min. to max.

Maximum

6,25

3,125

2,7

6,25

3,125

2,7

Ripple output voltage

3,3V and 5V output

12V output

15V output

24V and 28V output

Ui nominal

Full load

BW = 20MHz

Typical

mVpp

100

150

250

100

150

250

Output regulation *

(Line + load + thermal)

Ui min. to max.

0% to full load Maximum % +/- 1 +/- 1

Output Voltage Trim As function of output voltage Minimum

Maximum

90 **

110

90 **

110

Efficiency Ui nominal

Full load Typical % See curves page 5 & 6

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5 10 15 20 25 30 35 40 45

58%

60%

63%

65%

68%

70%

73%

75%

78%

80%

83%

85%

88%

Typical efficiency MGDS75HJ at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

5 10 15 20 25 30 35 40 45

73%

74%

75%

76%

77%

78%

79%

80%

81%

82%

83%

84%

85%

86%

87%

88%

89%

Typical efficiency MGDS75HF at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

5 10 15 20 25 30 35 40 45

68%

70%

72%

74%

76%

78%

80%

82%

84%

86%

88%

Typical efficiency MGDS75HE at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

5 10 15 20 25 30 35 40 45

60%

63%

65%

68%

70%

73%

75%

78%

80%

83%

Typical efficiency MGDS75HC at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

5 10 15 20 25 30 35 40 45

60%

63%

65%

68%

70%

73%

75%

78%

80%

83%

Typical efficiency MGDS75HB at 25°C

10W

20W

30W

40W

50W

Input voltage Vin (Vdc)

4- Electrical Characteristics (continued)

5 10 15 20 25 30 35 40 45

60%

63%

65%

68%

70%

73%

75%

78%

80%

83%

85%

88%

90%

Typical efficiency MGDS75HI at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

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10 20 30 40 50 60 70 80

68%

70%

73%

75%

78%

80%

83%

85%

88%

90%

Typical efficiency MGDS75OJ at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

10 20 30 40 50 60 70 80

68%

70%

72%

74%

76%

78%

80%

82%

84%

86%

88%

Typical efficiency MGDS75OE at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

10 20 30 40 50 60 70 80

71%

72%

73%

74%

75%

76%

77%

78%

79%

80%

81%

82%

83%

84%

85%

86%

Typical efficiency MGDS75OC at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

4- Electrical Characteristics (continued)

10 20 30 40 50 60 70 80

60%

63%

65%

68%

70%

73%

75%

78%

80%

83%

85%

88%

90%

Typical efficiency MGDS75OI at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

10 20 30 40 50 60 70 80

70%

71%

72%

73%

74%

75%

76%

77%

78%

79%

80%

81%

82%

83%

84%

Typical efficiency MGDS75OB at 25°C

10W

20W

30W

40W

50W

Input voltage Vin (Vdc)

10 20 30 40 50 60 70 80

70%

72%

74%

76%

78%

80%

82%

84%

86%

88%

90%

Typical efficiency MGDS75OF at 25°C

15W

30W

45W

60W

75W

Input voltage Vin (Vdc)

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5- Switching Frequency

7- Protection Functions

Characteristics Protection Device Recovery Limit or typical Specifications

Input undervoltage lock-out (UVLO)

Turn-on, turn-off

circuit with hysteresis

cycle

Automatic

recovery

Turn-on nominal

Turn-off nominal see section 4

Output current limitation protection

(OCP)

Straight line current

limitation

Automatic

recovery Nominal 120% of

output current

Output overvoltage protection (OVP) Overvoltage protection

device with latch-up

Automatic

recovery Nominal 120% of

output voltage

Over temperature protection (OTP) Thermal device with

hysteresis cycle

Automatic

recovery Nominal 115°C

8- Reliability Data

Parameter Conditions Limit or typical Specifications

Switching frequency

Full temperature range

Ui min. to max.

No load to full load

Nominal, fixed 420 KHz

6- Isolation

Characteristics Conditions Temperature Specifications

Mean Time Between Failure (MTBF)

According to MIL-HDBK-217F

Ground fixed (Gf) Case at 40°C

Case at 85°C

700 000 Hrs

190 000 Hrs

Airborne, Inhabited,

Cargo (AIC)

Case at 40°C

Case at 85°C

390 000 Hrs

125 000 Hrs

Mean Time Between Failure (MTBF)

According to IEC-62380-TR

Civilian avionics,

calculators

Ambient at 55°C

100% time on 570 000 Hrs

Parameter Conditions

Limit or

typical Specifications

Electric strength test voltage

Input to output

Input to case

Output to case

Minimum

1 500 VDC / 1 min

Isolation resistance 500 VDC Minimum 100 MOhm

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MGDM-75 Series

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9- Electromagnetic Interference

Electromagnetic Interference requirements according to MIL-STD-461C/D/E standards can be easily achieved as indicated in

the following section. The following table resumes the different sections covered by these standards.

9-1 Module Compliance with MIL-STD-461C/D/E Standards

To meet the latest US military standards MIL-STD-461D/E (and also the MIL-STD-461C) requirements and in particular the

conducted noise emission CE102 (and also CE03) requirements, Gaïa Converter can propose a stand-alone ready-to-use EMI

filter module. This EMI filter module has to be used together with 4 external decoupling capacitance Cc (10nF/rated

voltage depending on isolation requirement) connected between input and case and output and case.

EMI filter module reference : FGDS-10A-50V or FGDS-20A-50V.

Please consult EMI filter datasheet for further details.

Standard Requirements MIL-STD-461C

Standard

MIL-STD-461D/E

Standard

Compliance with GAIA Converter

Module & common mode capacitance

Conducted emission (CE) :

Low frequency

High frequency

CE 01

CE 03

CE 101

CE 102

compliant module stand-alone

compliant with additionnal filter

Conducted susceptibility (CS) :

Low frequency

High frequency

CS 01

CS 02

CS 101

CS114

compliant with additionnal filter

Radiated emission (RE) :

Magnetic field

Electrical field

RE 01

RE 02

RE 101

RE 102

compliant module stand-alone

Radiated susceptibility (RS) :

Magnetic field

Electrical field

RS 01

RS 03

RS 101

RS 103

compliant module stand-alone

MGDM-series

VI Vo

BP: Base Plate

EMI input Filter

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10- Thermal Characteristics

Characteristics Conditions Limit or typical Performances

Operating ambient temperature range

at full load Ambient temperature * Minimum

Maximum

- 40°C

see below

Baseplate temperature Base plate temperature Minimum

Maximum

- 40°C

+ 105°C

Storage temperature range Non functionning Minimum

Maximum

- 55°C

+ 125°C

Thermal resistance Baseplate to ambient

Rth(b-a) free air Typical 11°C/W

Note * : The upper temperature range depends on configuration, the user must ensure a max. baseplate temperature of + 105°C.

The following discussion will help designer to determine

the thermal characteristics and the operating temperature.

The MGDM-75 series maximum baseplate temperature at

full load must not exceed 105°C. Heat can be removed

from the baseplate via three basic mechanisms :

• Radiation transfert : radiation is counting for less

than 5% of total heat transfert in majority of case, for

this reason the presence of radient cooling is used as

a safety margin and is not considered.

• Conduction transfert : in most of the applications,

heat will be conducted from the baseplate into an

attached heatsink or heat conducting member; heat is

conducted thru the interface.

• Convection transfert : convecting heat transfer

into air refers to still air or forced air cooling.

In majority of the applications, heat will be removed from

the baseplate either with :

• heatsink,

• forced air cooling,

• both heatsink and forced air cooling.

To calculate a maximum admissible ambient temperature

the following method can be used.

Knowing the maximum baseplate temparature Tbase =

105°C of the module, the power used Pout and the

efficiency η :

• determine the power dissipated by the module Pdiss

that should be evacuated :

Pdiss = Pout(1/ηη

ηη

η - 1) (A)

• determine the maximum ambient temperature :

Ta = 105°C - Rth(b-a) x Pdiss (B)

where Rth(b-a) is the thermal resistance from the

baseplate to ambient.

This thermal Rth(b-a) resistance is the summ of :

• the thermal resistance of baseplate to heatsink

(Rth(b-h)). The interface between baseplate and

heatsink can be nothing or a conducting member, a

thermal compound, a thermal pad.... The value of

Rth(b-h) can range from 0.4°C/W for no interface down

to 0.1°C/W for a thermal conductive member inter-

face.

• the thermal resistance of heatsink to ambient air

(Rth(h-a)), which is depending of air flow and given

by heatsink supplier.

The table hereafter gives some example of thermal resistance for different heat transfert configurations.

Radian and Thermaflo are heasink manufacturers. «Silpad» © is a registered trademark of Bergquist.

Note* : Silpad performance are for Silpad 400 with pressure conditions of 50 Psi. Surface of MGDS-75 series is 3,3 inch2.

Heat transfert Thermal resistance heatsink to air Rth(h-a) Thermal resistance baseplate to

heatsink

Global

resistance

Free air cooling

only

No Heatsink baseplate only : 11°C/W No need of thermal pad 11°C/W

Heatsink Thermaflo 4245OOBOOOO : 7,64°C/W Bergquist Silpad* : 0,21°C/W 7,85°C/W

Heatsink Thermaflo 4248OOBOOOO : 3,5°C/W Bergquist Silpad* : 0,21°C/W 3,71°C/W

Forced air cooling

200 LFM

No Heatsink baseplate only : 6,9°C/W No need of thermal pad 6,9°C/W

Heatsink Radian HS1568EX : 3,5°C/W Bergquist Silpad* : 0,21°C/W 3,71°C/W

Heatsink Thermaflo 4248OOBOOOO : 2,8°C/W Bergquist Silpad* : 0,21°C/W 3,01°C/W

Forced air cooling

400 LFM

No Heatsink baseplate only : 4,8°C/W No need of thermal pad 4,8°C/W

Heatsink Radian HS1568EX : 2°C/W Bergquist Silpad* : 0,21°C/W 2,21°C/W

Heatsink Thermaflo 4248OOBOOOO : 1,8°C/W Bergquist Silpad* : 0,21°C/W 2,01°C/W

Forced air cooling

1000 LFM

No Heatsink baseplate only : 2,8°C/W No need of thermal pad 2,8°C/W

Heatsink Thermaflo 4248OOBOOOO : 1°C/W Bergquist Silpad* : 0,21°C/W 1,21°C/W

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The module case is built with a copper IMS (isolated metalic

substrate ) crimped on an aluminum frame that provides

case rigidity. The IMS surface is the module base plate

that need to be reported to heat sink to achieve proper

cooling. If for some reasons like poor module report, the

IMS base plate is subject to mechanical overstress, module's

electrical characteristics may be definitely affected.

A typical example of damageable report is the use of

thick thermal interface with usual screwing torque applied

on mounting screws. This combination causes a high pres-

sure on baseplate center due to thermal interface material

compression. The final consequence is a slight IMS bending

that can conduct for the module to fail high voltage isola-

tion leading to heavy electrical damage on internal cir-

cuit.

screw

PCB

Thermal Pad

Heatsink

screw

PCB

Too ThickThermal Pad

Heatsink

Base plate overstress

9- Thermal Characteristics (continued) : Heatsink Mounting

- do not exceed recommended screwing torque of

0,7 N.m (6 lbs.in)

- prefer thin thermal pad with thickness lower

than 0,34 mm (0.015").

GAIA Converter recommends to use thin thermal

pads instead of thermal compound like grease.

- take care to reflow module leads only when all

assembly operations are completed.

- do not report module on surfaces with poor

flatness characteristics. GAIA Converter recommends

not to overflow 0,1mm/m for the surface flatness.

Poor report not recommended

Example of banned thermal interface : Bergquist Gap Pad VO Ultra Soft

1. Choice of the thermal gap pad : its shape must be the same

as the module. The dimensions of the gap pad can be a little

larger than the module.

2. Screw the converter to the heatsink and/or to the board.

The four screws have to be screwed in a "X" sequence.

• Lightly finger-tighten all screws and run several «X» sequences

before achieving final torque to get homogeneous tightening.

• Torque screws from 0,35 N.m (3 lbs.in) to 0,7 N.m (6 lbs.in).

3. Screw the heatsink to the board.

4. Solder the pins of the converters on the board.

This sequence avoids mechanical stresses on the converters

that could lead to stress internal components or assemblies

and cause their failures.

To mount properly the module to heatsink, some important recommendations need to be taken into account in order to avoid

overstressing conditions that might lead to premature failures.

The good practice is to respect the 4 following recommendations:

Example of recommended thermal interface : Bergquist Silpad 400

Gaia converter suggests to follow the procedure hereunder for the mechanical assembly procedure in order to avoid any stress on the

pins of the converters. It is good practice to be sure to mount the converters first mechanically, then solder the units in place.

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11- Environmental Qualifications

The modules have been subjected to the following environmental qualifications.

Characteristics Conditions Severity Test procedure

Climatic Qualifications

Life at high

temperature

Duration

Temperature / status of unit

Test D : 1 000 Hrs

@ 105°C case, unit operating

@ 125°C ambient, unit not operating

MIL-STD-202G

Method 108A

Altitude

Altitude level C

Duration

Climb up

Stabilization

Status of unit

40 000 ft@-55°C

30 min.

1.000 ft/min to 70 000 ft@-55°C,

30 min.

unit operating

MIL-STD-810E

Method 500.3

Humidity cyclic

Number of cycle

Cycle duration

Relative humidity variation

Temperature variation

Status of unit

Cycle I : 24 Hrs

60 % to 88 %

31°C to 41°C

unit not operating

MIL-STD-810E

Method 507.3

Humidity steady

Damp heat

Temperature

Duration

Status of unit

93 % relative humidity

40°C

56 days

unit not operating

MIL-STD-202G

Method 103B

Salt atmosphere

Temperature

Concentration NaCl

Duration

Status of unit

35°C

5 %

48 Hrs

unit not operating

MIL-STD-810E

Method 509.3

Temperature

cycling

Number of cycles

Temperature change

Transfert time

Steady state time

Status of unit

200

-40°C / +85°C

40 min.

20 min.

unit operating

MIL-STD-202A

Method 102A

Temperature

shock

Number of shocks

Temperature change

Transfert time

Steady state time

Status of unit

100

-55°C / +105°C

10 sec.

20 min.

unit not operating

MIL-STD-202G

Method 107G

Mechanical Qualifications

Vibration

(Sinusoidal)

Number of cycles

Frequency / amplitude

Frequency / acceleration

Duration

Status of unit

10 cycles in each axis

10 to 60 Hz / 0.7 mm

60 to 2 000 Hz / 10 g

2h 30 min. per axis

unit not operating

MIL-STD-810D

Method 514.3

Shock

(Half sinus)

Number of shocks

Peak acceleration

Duration

Shock form

Status of unit

3 shocks in each axis

100 g

6 ms

1/2 sinusoidal

unit not operating

MIL-STD-810D

Method 516.3

Bump

(Half sinus)

Number of bumps

Peak acceleration

Duration

Status of unit

2 000 Bumps in each axis

40 g

6 ms

unit not operating

MIL-STD-810D

Method 516.3

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12- Description of Protections

12-2 Output Over Current Protection (OCP)

The MGDM-75 Series incorporates a current limit and protec-

tion circuit. When the output current reaches 110%-140% of

it’s full-rated current (Icurrent limit), the output voltage falls

and output current falls along the line as described in the

figure herein. The module restart automatically to normal

operation when overcurrent is removed.

12-3 Output Overvoltage Protection (OVP)

Each circuit has an internal overvoltage protection circuit that

monitors the voltage accross the output power terminals.

It is designed to turn the converter off at 120%

(+/-5%) of output voltage.

Once in OVP protection, the module will restart automatically

when overvoltage is removed.

The MGDM-75 series include 3 types of protection devices that

are powered and controlled by a fully independant side power

stage.

12-4 Over Temperature Protection (OTP)

A thermal protection device adjusted at 115°C (+/-5%) internal

temperature with 10°C hysteresis cycle will inhibit the mo-

dule as long as the overheat is present and restores to nor-

mal operation automatically when overheat is removed. The

efficiency of the OTP function is warranty with the module

mounted on a heatsink.

Baseplate

Temperature

115˚c

Off

10˚c

12-1 Input Undervoltage Lockout (UVLO)

12-1-1 Undervoltage Lockout (UVLO)

An undervoltage protection will inhibit the module when input

voltage drops below the lockout turn-off threshold (see sec-

tion 4 for value) and restores to normal operation automatically

when the input voltage rises the lockout turn-on threshold.

Vin

Off

UVLO

Turn-on

1,5V

Vout

110% of full

Rated current

Iout

Icurrent limit

170% of full

Rated current

140% of full

Rated current

Vout

2% Vnom

For locations, phone, fax, E-Mail see back cover

Hi-Rel

Grade

MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

13- Description of Functions

13-1 Trim Function

The output voltage Vo may be trimmed in a range of

90%/110% of the nominal output voltage via a single external

trimpot or fixed resistor.

Trim Up Function

Do not attempt to trim the module higher than 110% of

nominal output voltage as the overvoltage protection may

occur.

Also do not exceed the maximum rated output power when

the module is trimmed up.

The trim up resistor must be connected to S+ pin.

The trim up resistance must be calculated with the following

formula :

Ru = R1 (V0-Vref)V0nom - R1 - R2

(V0-V0nom)Vref

Trim Down Function

Do not trim down more than -10% of nominal output vol-

tage.

The available output power is reduced by the same

percentage that output voltage is trimmed down.

The trim down resistor must be connected to S- pin.

The trim down resistance must be calculated with the

following formula :

Rd = (R2 + R1)V0- R2V0nom

V0nom - V0

Trim via a voltage

The output voltage is given by the following formula :

V0 = 1 + R1 (Vtrim - 1)

(R1 + R2) Vref

Parameter Unit Min. Typ. Max.

Trim reference Vdc 2,45 2,5 2,55

Resistor R1 Ohm / 3 600 for H input

3 900 for O input /

Resistor R2 Ohm / 270 /

Trim capacitor µF / 1 /

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

Load

R1 R2

1µF

Vref=

2.5V

Error amp.

Vcontrol

100nF

BAT54

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

Load

R1 R2

1µF

Vref=

2.5V

Error amp.

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

Load

R1 R2

1µF

Vref=

2.5V

Error amp.

For locations, phone, fax, E-Mail see back cover

Hi-Rel

Grade

MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

13- Description of Functions (continued)

13-3 On/Off Function

The control pin 3 (On/Off) can be used for applications requiring

On/Off operation. This may be done with an open collector

transistor, a switch, a relay or an optocoupler. Several

converters may be disabled with a single switch by connecting

all

On/Off pins together.

• The converter is disabled by pulling low the pin 3.

• No connection or high impedance on pin 4 enables the

converter.

By releasing the On/Off function, the converter will restart

within the start up time specifications given in table section

3. For further details please consult ‘’Logic On/Off’’ application note.

13-4 Synchronization Function

An external clock with rectangular «Pull Up» signals can be

used to lock one or more converters. The external clock si-

gnal should have a frequency range from 420KHz to 480KHz,

a low level below 0,5V a high level of 4V (+/-0.5V), a rise

time of 30 ns max. and a drop time of 100ns max..

Parameter Unit Min. Typ. Max. Notes, conditions

On/Off module enable voltage Vdc 2 / 4,5 Open, the switch must not sink more than 100µA

On/Off module disable voltage Vdc 0 / 0.5 The switch must be able to sink 1mA

On/Off module enable delay ms / / 30 The module restarts with the same delay after alarm mode removed

On/Off module disable delay µs / / 100 Vi nominal, full load

Vin

4V

+/- 0,5

T/2

Vsync

100ns

max

30ns

max

T

( 420Khz < F < 480Khz )

13-2 Sense Function

If the load is separated from the output by any line lenght,

some of these performance characteristics will be degraded

at the load terminals by an amount proportional to the

impedance of the load leads. Sense connections enable to

compensate the line drop at a maximum of 10% of output

voltage. The overvoltage protection will be activated if remote

sense tries to boost output voltage above 110% of nominal

output voltage. Connection is described in figure herein.

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

Load

Totem pole

output

100pF

1N4148 4.7k

Ext. clock MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

Load

On/Off

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

For locations, phone, fax, E-Mail see back cover

Hi-Rel

Grade

MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

14- Application Notes

14-1 Synchronization of Modules

The MGDM-75 series provides a synchronization function

trough the pin 2 (Synchro) to enable automatic synchroni-

sation between several converters.

If several converters are used, they lock themselves into

the highest switching frequency.

The synchronization signal available on pin 2 is referenced

to ground in (Gi). It is a rectangular signal with 4 Vp (+/-

0.5V) amplitude with an input impedance of 4,7 KOhm.

14-2 Connection of Modules in Series

The output of single output units can be connected in

series without any precautions to provide higher output

voltage level.

Nevertheless, GAIA Converter recommends to protect each

individual output by a low power shottky diode rated with

the maximum current of the converter to avoid reverse

polarity at any output.

Reverse polarity may occur at start up if the output volta-

ges do not rise at the same time.

10nF

(*)

BP: Base Plate

10nF

100µF

(*)

100µF

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

10nF

(*)

BP: Base Plate

10nF

(*)

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

MGDM75

S-

Gin

Vin Vo

On/Off

Trim

S+

Sync

On/Off

For locations, phone, fax, E-Mail see back cover

Hi-Rel

Grade

MGDM-75 Series

Gaia Converter FC03-032.12/13 Revision L

11- Dimensions

Dimensions are given in mm (inches). Tolerance : +/- 0,2 mm (+/- 0.01 “) unless otherwise indicated.

Weight : 70 grams (1.95 Ozs) max.

14- Connections

Use this side 

for heat sinking

5.6 min

(0,22)

6.8 max

(0,267)

12.7 Max

(0,5)

0.5 (0,019)

Mouting Hole

0 3,1 (0.122)

3,81 (0.15)

10,795

(0.425)

9,894

(0.39)

26,16 (1.03)

36,83 (1.45)

R2,4 (0.1)

CH 2x2

57,912 (2.28)

9,589

(0.38)

3,81 (0.15)

47,24 (1.86)

50,8 (2.00)

3,56 (0.14)

Pin dimensions : 

Pins : 1, 2, 3, 4, 7, 8 : Ø 1 mm (0.04”)

Pins : 5, 9 : Ø 1,5 mm (0.059”)

2 431

8569 7

Bottom view

Pin Single Output

1 - Input (Gi)

2 Synchro (Sync)

3 On/Off

4 + Input (Vi)

5 + Output (Vo)

6 Sense + (S+)

7 Trim (Trim)

8 Sense - (S-)

9 - Output (Go)

12- Materials

Frame : Aluminium alodined coating.

Baseplate : Copper with tin finishing.

Pins : Plated with pure matte tin over nickel underplate.

13- Product Marking

Side face : Company logo, location of manufacturing.

: Module reference : MGDx-75-»X»-»Y».

Date code : year and week of manufacturing, suffix, /option.

Information given in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed for the consequence of its use nor for any infringement of patents or other rights of third parties which may result from its use.

These products are sold only according to GAIA Converter general conditions of sale, unless otherwise confirmed by writing. Specifications subject to change without notice.

Printed in France by Gaia Converter FC03-032.12/13 Revision L Graphisme : Philippe Clicq

Represented by :

For more detailed specifications and applications information, contact :

International Headquarters

GAÏA Converter - France

ZI de la Morandière

33185 LE HAILLAN - FRANCE

Tel. : + (33)-5-57-92-12-80

Fax : + (33)-5-57-92-12-89

North American Headquarters

GAÏA Converter Canada, Inc

4038 Le Corbusier Blvd

LAVAL, QUEBEC - CANADA H7L 5R2

Tel. : (514)-333-3169

Fax : (514)-333-4519