IMS25 25-Watt DC-DC Converter Data Sheet
Features
Wide input voltage ranges up to 75 V DC
Single output up to 15 V DC
1500 V DC I/O electric strength test voltage
• RoHS lead-solder-exempt compliant
• Industry standard pin-out
• Fixed frequency operation
• High efficiency up to 90%
10.5
0.41"
54.9
2.16"
• 2"
x
1.6" platform with 8.5 mm profile without and
10.5 mm profile with case
• Soft start
• Shut down input, output voltages adjustable
• Programmable input undervoltage lockout
• Outputs no-load, overload and short-circuit proof
• Operating ambient temperature –40...105
o
C
• Thermal protection with auto-reset (non latching)
• Basic insulation
• Immunity to IEC/EN 61000-4-2,-3,-4,-5 and -6
54.9
2.16"
Safety according to IEC/EN 60950, UL 1950
41.2
1.62"
8.2
0.32"
50.8
2."
LGA
Approvals pending
Description
The IMS25 Series of board-mountable 25 watt DC-DC con-
verters has been designed according to the latest industry
requirements and standards. The converters are particu-
larly suitable for applications in industry and telecommuni-
cation where variable input voltages or high transient volt-
ages are prevalent.
Providing two wide input voltage ranges, 14 to 36 VDC and
32 to 75 VDC, the units are available with a single output
voltage from 2.5 VDC up to 16.5 VDC externally adjust-
able. A shut down input allows remote converter on/off.
Features include efficient input and output filtering with un-
surpassed transient and surge protection, low output ripple
and noise, consistently high efficiency over the entire input
voltage range, high reliability as well as excellent dynamic
response to load and line changes.
The converters provide basic insulation with SELV outputs
as e.g., required in battery supported systems where the
bus voltage may exceed the SELV limit of
60 VDC. They are designed and built according to the in-
ternational safety standards IEC/EN 60950, UL 1950, CAN/
CSA C22.2 No.950-95.
The circuit comprises integrated planar magnetics and all
components are automatically assembled and soldered
onto a single PCB without any wire connections. The pro-
prietary magnetic feedback solution ensures maximum reli-
ability and repeatability in the control loop over all operating
conditions. Careful considerations of possible thermal
stresses ensure the absence of hot spots providing long life
in environments where temperature cycles are a reality. The
thermal design allows operation at full load up to an ambi-
ent temperature of 71 °C in free air without using any potting
material. For extremely high vibration environments the ca-
se has holes for screw mounting.
Page
Description......................................................................... 1
Type Survey and Key Data ............................................. 2
Type Key ......................................................................... 2
Functional Description .................................................... 2
Electrical Input Data ........................................................ 3
Electrical Ouput Data ...................................................... 4
MAR 04, 2002 revised to APR 17, 2006
Table of Contents
Page
Temperature Derating ..................................................... 5
Auxiliary Functions .......................................................... 6
Electromagnetic Compatibility (EMC) ............................. 7
Immunity to Environmental Conditions ........................... 8
Mechanical Data ............................................................. 9
Safety and Installation Instructions ............................... 10
Description of Option .................................................... 11
Page 1 of 11
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IMS25 25-Watt DC-DC Converter Data Sheet
Type Survey and Key Data
Table 1: Type survey
Output 1
U
o1 nom
I
o1 nom
[V DC]
[A]
2.5
3.3
5.1
12
15
6
6
5
2
1.6
Output power
P
o nom
[W]
15
19.8
25.5
24
24
Input Voltage Range and Efficiency
V
i min to
V
i max
V
i min
to
V
i max
typ
14 to 36 VDC
[%]
32 to 75 VDC
24IMS25-2.5-9G
24IMS25-03-9G
24IMS25-05-9G
24IMS25-12-9
24IMS25-15-9
82
86
87
88
88
48IMS25-2.5-9G
48IMS25-03-9G
48IMS25-05-9G
48IMS25-12-9
48IMS25-15-9
Option
typ
[%]
85
87
90
89
89
i
Z
Type Key
Model numbers highlighted in yellow or shaded are not
recommended for new designs.
24 IMS 25 - 2.5 -9 G i Z
Input voltage range
V
i
14 to 36 VDC .............................................. 24
32 to 75 VDC .............................................. 48
Series ...................................................................... IMS 25
Output voltage type output .................... 2.5, 03, 05, 12, 15
Operating ambient temperature range
T
A
(100% load @0 LFM)
–40 to 71 °C ................................................-9
Synchronous rectifier ...................................................... G
Option:
Inhibit ............................................................ i
Open frame .................................................. Z
Examples: 48 IMS 25-12-9Z: DC-DC converter, input voltage range 32 to 75 V, output 12 V, 2 A, no case.
24 IMS 25-2.5-9G: DC-DC converter, input voltage range 14 to 36 V, output 2.5 V, 6 A.
Functional Description
The IMS25 Series of DC-DC converters are magnetic feed-
back controlled forward converters using current mode
PWM (Pulse Width Modulation). The 2.5, 3.3, and 5.1 V out-
put voltage versions feature a synchronous rectifier result-
ing in very high efficiency. The output voltage of these ver-
sions can be adjusted via the Trim input. The Trim input is
referenced to the secondary side and allows for program-
ming of the output voltage in the range of approximately 90
to 110% of
V
o nom
using an external resistor.
The voltage regulation is achieved with a magnetic feed-
back circuit providing excellent line and load regulation.
Current limitation is provided by the primary circuit, thus
limiting the total output current to approx. 150%
• I
o nom
(see:
Type Survey).
The shut down input allows remote
converter on/off.
Overtemperature protection will shut down the unit in ex-
cessive overload conditions with automatic restart.
Vi+
1
03096
13
Vo+
PWM
SD
4
i
15
Vo–
Vi –
2
W
3
17
Trim
Fig. 1
Block diagram
MAR 04, 2002 revised to APR 17, 2006
Page 2 of 11
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IMS25 25-Watt DC-DC Converter Data Sheet
Electrical Input Data
General conditions:
– T
A
= 25°C, unless
T
C
is specified.
– Shut down pin left open circuit (not connected).
– Trim input not connected.
Table 2: Input Data
Input
Characteristics
U
i
U
i nom
U
i sur
t
start up
Input voltage range
1
Nominal input voltage
Repetitive input surge
voltage
Converter
Switch on
start-up time
SD h igh
Ris e time
No load input current
Input capacitance
Shut down voltage
I
o
= 0,
U
i min
...U
i max
SD high
for sur ge cal cu la tio n
Unit disabled
Unit operating
I
SD
I
inr p
I
i rr
1
24 IMS
Conditions
T
C min
...T
C max
I
o
= 0...I
o nom
max 3 s
U
i min
,
I
o
=
I
o nom 2
0.25
min
14
5
24
50
0.5
0.1
5
75
2 .0
–10
2.0
1
U
i
=
U
i nom
I
o
= 0...I
o nom
3
100
3
0.7
5.5
2
–10
2.0
150
typ
max
36
min
32
48 IMS
typ
max
75
48
100
0.25
0.5
0.1
5
40
2 .0
0.7
5.5
1
1.5
60
2
mA
A
mA
pp
80
ms
mA
F
V DC
s
Unit
V DC
t
rise
I
i NL
C
i
U
SD
Input current of SD input
Inrush peak current
4
Reflected
ripple current
U
i min
will not be as stated if
U
o
is increased above
U
o nom
by use of the Trim input. If the output voltage is set to a higher value,
U
i min
will be proportionally increased.
2
Measured with a resistive and the max. admissible capacitive load.
3
24IMS25-12/15 use a 470 uF 50Vdc electrolytic capacitor to achieve less than 30 mApp (Nichicon TVX1H100MAA or equivalent)
4
Source impedance according to prETS 300132-2, version 4.3.
5
Linear derating to 85% of
I
o nom
for
U
i
<16.8 V.
Inrush Current
The inrush current has been kept as low as possible by
choosing a very small input capacitance.
I
[A]
1.4
1.2
1
0.8
0.6
0.4
0.2
0
–2
–1
0
1
2
3
4
5
6
7
t
[ms]
8
04058
Fig. 2
Typical inrush current at U
i nom
, P
o nom
versus time
(48 IMS 25-05-9G). Source impedance according to
prETS 300132-2, version 4.3 at U
i nom
.
MAR 04, 2002 revised to APR 17, 2006
Page 3 of 11
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IMS25 25-Watt DC-DC Converter Data Sheet
Input Transient Voltage Protection
A built-in suppressor diode provides effective protection
against input transients which may be caused for example
by short-circuits accross the input lines where the network
inductance may cause high energy pulses.
Table 3: Built-in transient voltage suppressor
Type
Breakdown
voltage
V
BR nom
[V]
53
100
Peak power
at 1 ms
P
P
[W]
600
600
Peak pulse
current
I
PP
[A]
7.7
4.1
Table 4: Components for external circuitry to comply with
IEC/EN 61000-4-5, level 2 or ETR 283 (19Pfl1)
(48 IMS types).
Circuit Ref.
L
C
24 IMS 25
150 H
150 F, 63 V, 85°C
100 F, 100 V, 85°C
48 IMS 25
24 IMS 25
48 IMS 25
Reverse Polarity Protection at the Input
The built-in suppressor diode also provides for reverse po-
larity protection at the input by conducting current in the re-
verse direction. An external fuse is required to limit this cur-
rent:
24 IMS 25: 5 A (F5A)
48 IMS 25: 3.15 A (F3.15A)
For very high energy transients as for example to achieve
IEC/EN 61000-4-5 or ETR 283 (19 Pfl1) compliance (as per
table:
Electromagnetic Immunity)
an external inductor and
capacitor are required.
04009
L
V+
C
V–
+
1
Vi+
Module
2
Vi–
Fig. 3
Example for external circuitry to comply with
IEC/EN 61000-4-5 or ETR 283 (19 Pfl1) (48 IMS 25 types).
Electrical Ouput Data
General conditions:
T
A
= 25°C, unless
T
C
is specified. Shut down pin left open (not connected). Trim input not connected.
Table 5a: Output data
Output
Characteristics
U
o1
I
o nom
I
oL
U
o
u
o1
C
o ext
u
o d
t
d
Uo
2.5 V
Conditions
U
i nom
,
I
o
= 0.5
I
o nom
U
i min
...U
i max
U
i min
m i n typ max
2.47
0
9
±1
100
2200
U
i nom
I
o nom
±250
1
3.3 V
min typ max
3.26
0
9
±1
100
2200
±250
5
±0.02
approx 330
3.34
6
min
5.05
0
5.1 V
typ max
5.15
5
9
±1
120
2200
±400
2
±0.02
approx 330
%
mV
pp
F
mV
ms
%/K
kHz
Unit
V
A
Output voltage
Output current
Current limit
1
2.53
6
Line/load regulation (combined)
U
i min
...U
i max
I
= (0.01...1)
I
o nom
Output voltage noise
2
(B/W 20MHz)
o
Admissible capacitive load
Dynamic
load
regulation
3
Voltage deviation
Recovery time
/
2
I
o nom
5
±0.02
approx 330
Temperature coefficient
U
o
/
T
C
Switching frequency
U
i nom
,
I
o nom
T
C min
...T
C max
U
i nom
,
I
o nom
fs
1
2
3
The current limit is primary side controlled.
Measured with 1 F ceramic capacitor across the o/p terminals
Measured with constant resistance load
MAR 04, 2002 revised to APR 17, 2006
Page 1 of 11
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Table 5b: Output data
Output
Characteristics
U
o1
I
o nom
I
oL
U
o
u
o1
C
o ext
u
o d
t
d
Uo
12 V
Conditions
U
i nom
,
I
o
= 0.5
I
o nom
U
i min
...U
i max
U
i min
min
11.88
0
3
±1
150
650
U
i nom
I
o nom
±600
1
15 V
min typ max
14.85
0
2.4
±1
180
430
±750
1
±0.02
approx 200
%
mV
pp
F
mV
ms
%/K
kHz
15.15
1.6
Unit
V
A
typ max
12.12
2
Output voltage
Output current
Current limit
1
Line/load regulation (combined)
U
i min
...U
i max
I
= (0.01...1)
I
o nom
Output voltage noise
2
(B/W 20MHz)
o
Admissible capacitive load
Dynamic
load
regulation
3
Voltage deviation
Recovery time
/
2
I
o nom
1
±0.02
approx 200
Temperature coefficient
U
o
/
T
C
U
i nom
,
I
o nom
T
C min
...T
C max
fs
Switching frequency
U
i nom
...I
o nom
The current limit is primary side controlled.
2
Measured with 1 F ceramic capacitor across the o/p terminals
3
Measured with constant resistance load
1
Thermal Considerations
If a converter, mounted on a PCB, is located in free, quasi-
stationary air (convection cooling) at the indicated maxi-
mum ambient temperature
T
A max
(see table:
Temperature
specifications)
and is operated at its nominal input voltage
and output power, the case temperature
T
C
measured at the
Measuring point of case temperature T
C
(see:
Mechanical
Data)
will approach the indicated value
T
C max
after the
warm-up phase. However, the relationship between
T
A
and
T
C
depends heavily on the conditions of operation and inte-
gration into a system. The thermal conditions are influenced
by input voltage, output current, airflow, temperature of sur-
rounding components and surfaces and the properties of
the printed circuit board.
T
A max
is therefore only an indica-
tive value and under practical operating conditions, the ad-
missible ambient temperature
T
A
may be higher or lower
than this value.
Caution:
The case temperature
T
C
measured at the
Measuring point of case temperature T
C
(see:
Mechani-
cal Data)
must under no circumstances exceed the
specified maximum value. The installer must ensure that
under all operating conditions
T
C
remains within the lim-
its stated in the table:
Temperature specifications.
Overtemperature Protection
The converters are protected from possible overheating by
means of an internal non latching temperature monitoring
circuit. It shuts down the unit above the internal tempera-
ture limit and attempts to automatically restart in short peri-
ods. This feature prevents from excessive internal tempera-
ture excursion which could occur in heavy overload condi-
tions.
Short Circuit Behaviour
The current limit characteristic shuts down the converter
whenever a short circuit or an overload is applied to its out-
put. It acts self-protecting and automatically recovers after
removal of the overload condition (hiccup mode).
U
o
[%]
100
05162
10
O u tp u t P o w e r V s A m b i e n t T e m p . a n d A i rfl o w
0
120
100
100
t
[ms]
Fig. 5
Overload switch off (hiccup mode), typical values.
80
Output Power (%)
60
2 0 0 L F M (1 m /s )
0 L FM
40
20
0
0
10
20
30
40
50
60
70
80
90
10 0
10 5
A mb ie n t T e mp . ( d e g °C )
Fig. 4
Power derating for uncased (-Z) versions in airflow.
MAR 04, 2002 revised to APR 17, 2006
Page 5 of 11
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