Rugged Environment
DC-DC Converters <40 W
IMX 7-Family
7 W DC-DC Converters
Input/output isolation test voltage up to 1500 V
rms
Single, double outputs of 3.3, 5, 12, 15 and 24 V DC
Input voltage ranges: 8.4...36 V DC, 16.8...75 V DC
and 40...121 V DC
•
Extremely wide input voltage ranges
•
Galvanic isolation, single and double output units
•
High efficiency (typ. >84%)
•
Inhibit input, output voltage adjustable
•
No load and short-circuit proof
•
High reliability and no derating
•
Operating ambient temperature ranges from
–25...+71
°C
up to –40...+85
°C
•
Emissions below EN 55 022 level B.
•
Immunity to IEC 1000- 4 -2, -3, -4, -5 and -6
•
2"
×
1" case with 10.5 mm profile
Safety according to IEC 950
C
IMX 7-Family
new
1
For 70 IMX types
Table of Contents
Page
Electromagnetic Compatibility EMC .......................... 6 - 24
Supplementary Data ................................................. 6 - 25
Immunity to Environmental Conditions ...................... 6 - 27
Mechanical Data ....................................................... 6 - 28
Type Key and Product Marking ................................. 6 - 29
Type Survey .............................................................. 6 - 17
Description ................................................................ 6 - 17
Functional Description ............................................... 6 - 18
Safety and Installation Instructions ........................... 6 - 19
Electrical Input and Output Data ............................... 6 - 20
Description of Options ............................................... 6 - 22
Type Survey
Table 1: Type survey
Output 1
Output 2
2
Input Voltage Range and Efficiency
2
Option
U
o nom
[V DC]
3.3
5.1
5
12
15
24
1
2
I
o nom
[A]
1
U
o nom
[V DC]
I
o nom
[A]
1
U
i min
...
U
i max
8.4...36 V DC
20 IMX 7-03-7
20 IMX 7-05-7
η
typ
[%]
77
80
82
84
84
84
3
U
i min
...
U
i max
16.8...75 V DC
40 IMX 7-03-7
40 IMX 7-05-7
40 IMX 7-05-05-7
40 IMX 7-12-12-7
40 IMX 7-15-15-7
40 IMX 7-24-24-7
η
typ
[%]
78
81
83
84
84
84
U
i min
...U
i max
40...121 V DC
70 IMX 7-03-7
70 IMX 7-05-7
70 IMX 7-05-05-7
70 IMX 7-12-12-7
70 IMX 7-15-15-7
70 IMX 7-24-24-7
η
typ
[%]
77
81
82
83
83
83
3
1.5
1.2
1.5
1.2
5
12
15
24
0.6 0.7
0.25 0.3
0.2 0.24
0.13 0.15
0.6 0.7
0.25 0.3
0.2 0.24
0.13 0.15
20 IMX 7-05-05-7
20 IMX 7-12-12-7
20 IMX 7-15-15-7
20 IMX 7-24-24-7
-8
-9
D
X
M
C
Values for 20 IMX 7 types (output power approx. 6 W)
Values for 40 IMX 7 and 70 IMX 7 types
See table 8: "Survey of options"
Description
The IMX 7 series has been designed according to the latest
industry requirements and standards (1995) and is particu-
larly suitable for industrial and telecom applications. The
converters are ideal for use in applications where variable
input voltages or high input transients are prevalent, e.g.
mobile applications. They feature consistently high effi-
ciency over the entire input voltage range, high reliability
and good dynamic response to line and load changes.
Edition 2/96 - © Melcher AG
A special feature is their small case size, 2"
×
1" with 10.5
mm height. Generous design margins have been applied.
The circuit is mounted on a single PCB, all components
solidly soldered without any wire connections and no pot-
ting material is applied. The thermal design allows opera-
tion at nominal load up to an ambient temperature of 85
°C
in free air. For extremely high vibration environments the
case has holes allowing screw mounting.
6 - 17
MELCHER
The Power Partners.
6.1
LGA
1
IMX 7-Family
Functional Description
DC-DC Converters <40 W
Rugged Environment
The IMX 7 DC-DC modules are feedback controlled flyback
converters using current mode PWM (Pulse Width Modula-
tion). See block diagram for single and double output types.
In the case of the single output units the output is directly
monitored and fed back to the primary control circuit via a
pulse transformer, resulting in tight regulation of the output
voltage. The R-input is referenced to the secondary side
and allows for programming of the output voltages in the
range 75 to 105 % of
U
o nom
using either an external resistor
or an external voltage source.
In the case of the double output units the output voltage is
monitored by a separate transformer winding close to the
secondary windings and fed back to the control circuit. The
R-input is referenced to the primary side and allows pro-
gramming of the output voltage in the range 100 to 105 % of
U
o nom
by an external resistor or within 75 to 105 % of
U
o nom
using an external voltage source.
Current limitation is provided by the primary circuit, thus
limiting the total output current (I
o nom
for the single and
I
o1 nom
+
I
o2 nom
for the double output types).
The inhibit input allows remote converter shut down.
1
11
1
11
PWM
3
10
4
10
PWM
3
10 nF, 200V
13
2
×
2200 pF
1500 V
2
12
6.1
13
4
14
2
12
2
×
2200 pF, 1500 V
14
Fig. 1
Block diagram, single output types, standard pinout
Table 2: Pin allocation, standard pinout see fig. 16 and 17
Pin
1
2
3
4
10
11
12
13
14
1
Fig. 2
Block diagram, double output types, standard pinout
Table 3: Pin allocation for C-pinout (option C) see fig. 3
and 18
Pin
1
2
3
4
5
Single output units
Vi+
Vi–
Vo+
n.c.
Vo–
Dual output units
Vi+
Vi–
Vo+
Go
Vo–
Single output units
Vi+
Vi–
i
n.c.
Vo–
Vo +
Vo–
R
n.c./D
1
Double output units
Vi+
Vi–
i
R
Vo1–
Vo1+
Vo2–
Vo2+
n.c.
Option D
3
1
2
4
5
Fig. 3
C-pinout
6 - 18
MELCHER
The Power Partners.
Edition 2/96 - © Melcher AG
Rugged Environment
DC-DC Converters <40 W
IMX 7-Family
Safety and Installation Instructions
The converters comply with IEC 950, EN 60950 and
UL 1950 and are designed to meet EN 41003. The unit
should be connected to a secondary circuit.
Isolation
Input to output electric strength tests in accordance with the
safety standards IEC 950, EN 60950, VDE 0805 and
EN 41003 respectively are performed as factory tests and
should not be repeated in the field.
Important Advice
Melcher will not honour any guarantee/warranty claims
resulting from high voltage tests.
Cleaning Agents
In order to avoid possible damage, any penetration of
cleaning fluids is to be prevented, since the power supplies
are not hermetically sealed.
Table 4: Electric strength test voltages and creepage dis-
tances
Characteristics
Electric strength
test voltage
Creepage
distances
Input/Output
20/40 IMX 70 IMX
1.2
1.5
1.6
2.0
1.5
Output/Output Unit
0.1
0.15
0.4
kV
rms
kV DC
mm
Table 5: Insulation concept for SELV circuits
Nominal
mains
supply
voltage
(AC)
≤150
V
Minimum required grade
of isolation, to be
provided by the AC-DC
front end, including mains
supplied battery charger
Basic
Maximum
output
voltage
from the
front end
≤60
V
≤121
V
≤250
V
Basic
Double or reinforced
≤60
V
≤60
V
≤121
V
Minimum required
safety status of the
front end output circuit
Minimum required grade of
isolation between the input
and the output of the DC-DC
converter, provided by
the converter
Operational
Supplementary, based on
AC 150 V
Operational
Operational
Resulting safety
status of the
DC-DC converter
output circuit
SELV circuit
Earthed SELV circuit
1
Unearthed hazardous
voltage secondary circuit
2
Earthed SELV circuit
1
SELV circuit
Double or reinforced insu- Supplementary. based on
lated unearthed hazardous DC 121 V
voltage secondary circuit,
supplying an SELV circuit
2
1
2
The earth connection has to be provided by the installer according to the relevant safety standard, e.g. IEC 950.
Has to be insulated from earth by at least basic insulation according to the relevant safety standard, based on the maximum input
voltage of the DC-DC converter.
Edition 2/96 - © Melcher AG
MELCHER
The Power Partners.
6 - 19
6.1
Safety
If the output circuit of an IMX-family DC-DC converter is
operator-accessible according to the IEC 950 related safety
standards, it shall be an SELV circuit (Safety Extra Low Volt-
age circuit, i.e. a circuit, separated from mains by at least
basic insulation, that is so designed and protected that un-
der normal and single fault conditions, the voltage between
any two conductors and between any conductor and earth
does not exceed 60 V DC).
In the following table an interpretation is provided of the
IEC 950 safety standard with respect to the safety status of
the output circuit. However, it is the sole responsibility of the
installer or user to assure the compliance with the relevant
and applicable safety standards.
If the table below is observed, the output of any IMX-family
DC-DC converter is considered to be an SELV circuit up to
a nominal output voltage of 30 V (2 x 15 V in series).
IMX 7-Family
DC-DC Converters <40 W
Rugged Environment
Electrical Input and Output Data
General conditions:
T
A
= 25°C, unless
T
C
is specified.
Table 6: Input Data
Input
Characteristics
Conditions
20 IMX 7
min typ max
8.4
20
36
40 IMX 7
min typ max
16.8
40
100
45
0.25
0.5
5
5
70 IMX 7
min
40
70
typ max
121
Unit
V DC
U
i
U
i nom
U
i sur
Input voltage range
1
Input voltage (nominal)
Repetitive surge
voltage
Converter
2
start-up time
Rise time
2
T
A min
...T
A max
I
o
= 0...
I
o nom
max. 3 s
max. 10 ms
Worst case condition at
U
i min
and full load
75
t
start up
t
ris
0.25 0.5
0.25 0.5
s
U
i nom
,
I
o nom
resistive load
capacitive load
5
12
15
30
30
B
1.2
–10...0.8
open, 2.4...U
i max
–0.5
1
<3.0
approx. 400
B
0.5
–10 ...0.8
open, 2.4...U
i max
–0.5
1
<3.0
approx. 400
5
12
8
15
30
B
0.5
–10 ...0.8
open, 2.4...U
i max
–0.5
1
<3.0
approx. 400
kHz
mA
µF
V DC
5
12
8
15
30
mA
mA
pp
ms
I
io
I
i rr
U
i RFI
C
i
No load input current
Reflected
ripple current
I
o
= 0,
U
i min
...U
i max
I
o
= 0...
I
o nom
Input RFI level
EN 55022
4
conducted and radiated
Input capacitance
Inhibit voltage
3
for surge calculations
Converter operating
Converter inhibited
6.1
U
ih
I
ih
I
i ih
f
s
1
2
3
4
5
Inhibit current
Converter operating
Converter inhibited
Input current
if unit inhibited
Switching frequency
U
i
min
...U
i max
U
i min
...U
i max
,
I
o
= 0...
I
o min
U
i min
will not be as stated if
U
o
is increased above
U
o nom
by use of the R input pin. If the output voltage is set to a higher value,
U
i min
will be proportionally increased.
Measured with a resistive or max. admissable capacitive load. (See fig. below)
Switching times are typically 10 ms for transition from one state to another.
Measured with a lead lenght of 0.1 m, leads twisted. Double output units with both outputs in parallel.
See 19 Pfl 1, "Electromagnetic Immunity".
U
o
U
o nom
t
rise
t
t
start up
Fig. 4
Converter start-up and rise time
6 - 20
MELCHER
The Power Partners.
Edition 2/96 - © Melcher AG
Rugged Environment
DC-DC Converters <40 W
IMX 7-Family
Table 7a: Output data for single output units
Output
Characteristics
U
o nom
Conditions
min
3.28
3.3 V
typ max
3.32
1.5
3.0
±1
70
min
5.07
5.1 V
typ max
5.13
1.2
2.4
±1
70
%
mV
pp
Unit
V DC
A
U
o
I
o nom
I
CL
∆
U
o U
Output voltage
Output current
Current limit
1
Line and
load regulation
Output voltage
ripple and noise
Output overvoltage
clamping
Temperature coeff.
Admissable
capacitive load
U
i nom
I
o
= 0.5
I
o nom
U
i min
...U
i max
U
i nom
,
T
C
= 25°C
U
i min
...U
i max
I
o
= (0.01...1)
I
o nom
U
i min
...U
i max
I
o
=
I
o nom
(BW = 20 MHz)
u
o
U
o clp
α
Uo
115
∆
U
o
/∆ TC
±0.02
130
115
±0.02
130
%
%/K
µF
ms
mV
C
o ext
t
d
∆
U
o td
≤2500
1
±150
1
≤2000
Dynamic load tran-
U
i nom
sient response time
I
o
= (1...
1
/
4
...1)
I
o nom
Transient output
voltage deviation
±150
Table 7b: Output data for double output units
Output
Characteristics
U
o nom
Conditions
min
2
×
5V
typ max
5.03
5.05
2
×
12 V
min
11.93
11.88
typ max
2
×
15 V
min
typ max
2
×
24 V
min
typ max
24.15
24.25
Unit
VDC
A
U
o1
U
o2
I
o nom
I
CL
∆
U
o U
∆
U
o l
Output voltage
Output
current
1
Current
limit
1, 2
U
i nom
I
o
= 0.5
I
o nom
4.97
4.95
12.07 14.90
12.12 14.85
15.10 23.85
15.15 23.75
20 IMX
U
i min
...
U
i max
40/70 IMX
20 IMX
U
i nom
,
T
C
= 25°C
40/70 IMX
2
×
0.60
2
×
0.70
2.4
2.8
±1
±3
80
2
×
0.25
2
×
0.30
1.0
1.2
±1
±3
120
2
×
0.20
2
×
0.24
0.95
1.1
±1
±3
150
2
×
0.12
2
×
0.15
0.5
0.6
±1
±3
240
Line regulation
Load regulation
3
Output voltage
ripple and noise
Output overvoltage
clamping
4
Temperature coeff.
Admissable
capacitive load
2
U
i min
...
U
i max
I
o nom
U
i nom
I
o
= (0,1...1)
I
o nom
U
i min
...
U
i max
I
o
=
I
o nom
(BW = 20 MHz)
Applies to both
V
o1
and V
o2
∆
U
o
/∆ TC
115
±0.02
%
u
o1/2
mV
pp
U
o clp
α
Uo
130
115
±0.02
130
115
±0.02
130
115
±0.02
130
%
%/K
C
o ext
t
d
∆
U
o td
1
2
≤2000
1
±150
1
±330
≤300
1
±350
≤200
1
±600
≤100
µF
ms
mV
Dynamic load tran-
2
U
i nom
sient response time
I
o
= (1...
1
/
4
...1)
I
o nom
Transient output
voltage deviation
The current limit is primary side controlled.
Measured with both outputs connected in parallel.
3
Conditions for specified output. Other output loaded with constant current
I
= 0.5
I
o
o nom
.
4
The overvoltage protection device is a zener diode whose breakdown region is typically 120...125% of the nominal output voltage. The
zener diode protects the converter only against internally generated overvoltages.
Edition 2/96 - © Melcher AG
MELCHER
The Power Partners.
6 - 21
6.1
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