Hi-Rel DC/DC CONVERTER
MGDM-75 : 75W POWER
Hi-Rel
Grade
5:1 Ultra Wide Input
Single Output
Metallic case - 1.500 VDC Isolation
• 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°C/+ 105° baseplate
• High efficiency (typ. 86%-90%)
• Soft start
• Galvanic isolation 1.500 VDC
• Integrated LC EMI filter
• Synchronizable
• Fully protected by independant security
• Under & overvoltage lock-out
• Overvoltage protection
• Current limitation protection
• Overtemperature protection
• No optocoupler for high reliability
1-General
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.
4
2-Product Selection
Single output model
: MGDS-75-
(/T) and/or (/S)
(/T) : option for -55°C start up operating temperature
(/S) : option for screening and serialization
Input Voltage Range
Permanent
H : 9-45 VDC
O : 16-80 VDC
B
C
E
F
I
J
Output
:
:
:
:
:
:
3.3 VDC
5 VDC
12 VDC
15 VDC
24 VDC
28 VDC
REDEFINING THE SOURCE OF POWER
©
Gaia Converter FC03-032.03/06 Revision G
For locations, phone, fax, E-Mail see back cover
MGDM-75 Series
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).
Hi-Rel
Grade
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.
Vin
LC input
filter
POWER STAGE
LC output
filter
Vo
4
UVLO
Current
Sense
Mosfet
Driver
OVP
On/Off
Auxilliary
supply
Control circuit
Feed-back
function
Sense
Trim
Sync
Thermal
Shutdown
Isolation Barrier
©
Gaia Converter FC03-032.03/06 Revision G
3
For locations, phone, fax, E-Mail see back cover
MGDM-75 Series
4- Electrical Specifications
Data are valid at +25°C, unless otherwise specified.
Parameter
Input
Nominal input voltage
Permanent input
voltage range (Ui)
Undervoltage lock-out
(UVLO)
Start up time
Reflected ripple current
Input current in short circuit
mode (Average)
No load input current
Input current in inhibit mode
Output
Nominal
Nominal
Nominal
Nominal
Nominal
Nominal
Maximum
Maximum
Maximum
Maximum
Maximum
Maximum
Maximum
Maximum
Typical
Typical
Typical
Typical
Maximum
Minimum
Maximum
Typical
VDC
VDC
VDC
VDC
VDC
VDC
%
W
A
A
A
A
A
A
mVpp
mVpp
mVpp
mVpp
%
%
%
%
3,3
5
12
15
24
28
+/- 2
50 to 75
15
12,5
6,25
5
3,125
2,7
50
100
150
250
+/- 1
90 **
110
Conditions
Limit or
typical
Nominal
Min. - Max.
Nominal
Nominal
Maximum
Maximum
Typical
Maximum
Maximum
Units
Hi-Rel
Grade
Single Output MGDS-75
75 - H
24
9 - 45
8,5
7,5
30
500
1
30
10
75 - O
28
16 - 80
15,5
14,5
30
500
0,2
30
10
Full temperature range
Full temperature range
Turn-on voltage
Turn-off voltage
Ui nominal
Nominal output
Full load : resistive
Ui nominal, full load
BW = 20MHz
Ui nominal
Short-circuit
Ui nominal
No load
Ui nominal
Inhibit
VDC
VDC
VDC
VDC
ms
mApp
A
mA
mA
Output voltage *
Ui min. to max.
3,3
5
12
15
24
28
+/- 2
50 to 75
15
15
6,25
5
3,125
2,7
50
100
150
250
+/- 1
90 **
110
4
Set Point accuracy *
Output power
Output current
3,3V output
5V output
12V output
15V output
24V output
28V output
Ripple output voltage
3,3V and 5V output
12V output
15V output
24V and 28V output
Output regulation *
(Line + load + thermal)
Output Voltage Trim
Efficiency
Ambient temperature : +25°c
Ui nominal, 75% load
At 105°c baseplate
Ui min. to max.
Full temperature range
Ui min. to max.
Ui nominal
Full load
BW = 20MHz
Ui min. to max.
0% to full load
As function of output voltage
Ui nominal
Full load
Please consult factory
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.
©
Gaia Converter FC03-032.03/06 Revision G
4
For locations, phone, fax, E-Mail see back cover