IMX35 Series
35 Watt Quad-Output DC-DC Converter
Features
63.5
2.5"
76.2
3"
10.5
0.41"
• Extremely wide input voltage ranges up to 150 VDC
• 4 outputs up to 60 V
• RoHS lead-free-solder and lead-solder-exempted
products available
• 5 year warranty for RoHS lead-free-solder products
• 1500 to 1800 VAC i/o electric strength test
• Electrical isolation between outputs
• Programmable input undervoltage lockout
• Shutdown/inhibit input
• Adjustable output voltages with flexible load distribution
• Frequency synchronization
• Outputs no-load, overload, and short-circuit proof
• Operating ambient temperature from –40 to 85 °C
• Thermal protection
• Low profile: 10.5 mm or 8.9 mm with open frame
• Basic insulation
• Flexible output possibilities between 5 V and 60 V
• Safety-approved to the latest edition of IEC/EN 62368-1,
UL/CSA 60950-1
1
1
47.8
1.88"
72.8
2.87"
8.9
0.35"
70/110IMX35 models
Table of Contents
Description............................................................................2
Model Selection.....................................................................2
Functional Description...........................................................3
Electrical Input Data..............................................................4
Electrical Output Data...........................................................6
Auxiliary Functions..............................................................10
Electromagnetic Compatibility (EMC)..................................12
Immunity to Environmental Conditions................................13
Mechanical Data..................................................................14
Safety and Installation Instructions......................................14
Description of Options.........................................................16
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BCD20009-G Rev G, 11 Nov. 2021
IMX35 Series
35 Watt Quad-Output DC-DC Converter
Description
The IMX35 Series of board-mountable, 35 Watt DC-DC converters has been designed according to the latest industry requirements
and standards. The converters are particularly suitable for use in mobile or stationary applications in transport, railways, industry,
or telecommunication, where variable input voltages or high transient voltages are prevalent.
Covering a total input voltage range from 9 V up to 150 V with 4 different models, the converters are available with up to four
electrically isolated outputs from 5 V to 60 V, externally adjustable and with flexible load distribution. A shutdown input allows
remote converter on/off. Features include consistently high efficiency over the entire input voltage range, high reliability, and
excellent dynamic response to load and line changes.
The converters are designed and built according to the international safety standards IEC/EN 62368-1 3rd edition, and approved
by Nemko. The converters provide basic insulation.
The circuit is comprised of 2 planar magnetics devices, and all components are automatically assembled and securely soldered
onto a single PCB board without any wire connection. Magnetic feedback ensures maximum reliability 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 present. The thermal design without using any potting material
allows operation at full load up to an ambient temperature of 71 °C in free air and operation up to 105 °C with airflow. For extremely
high vibration environments the case has holes for screw mounting.
Model Selection
Table 1: Model Selection
Output 1
Output 2
Output 3
Output 4
Input voltage
Efficiency 1
Model
Vo nom
[VDC]
Io nom
[mA]
Vo nom
[VDC]
Io nom
[mA]
Vo nom
[VDC]
Io nom
[mA]
Vo nom
[VDC]
Io nom
[mA]
Vi min to Vi max
[VDC]
η min
[%]
η max
[%]
5
5
5
5
1.35
1.4
1.4
1.4
5
5
5
5
1.35
1.4
1.4
1.4
5
5
5
5
1.35
1.4
1.4
1.4
5
5
5
5
1.35
1.4
1.4
1.4
9 to 36
18 to75
40 to 121
60 to 150 2
82.5
82
83
82
84.5
84
85
84
20IMX35D05D05-8G
40IMX35D05D05-8G
70IMX35D05D05-8G
110IMX35D05D05-8G
12
12
12
12
0.65
0.7
0.7
0.7
12
12
12
12
0.65
0.7
0.7
0.7
12
12
12
12
0.65
0.7
0.7
0.7
12
12
12
12
0.65
0.7
0.7
0.7
9 to 36
18 to75
40 to 121
60 to 150 2
83.5
83.5
84.5
84
85.5
85.5
86.5
86
20IMX35D12D12-8G
40IMX35D12D12-8G
70IMX35D12D12-8G
110IMX35D12D12-8G
15
15
15
15
0.55
0.6
0.6
0.6
15
15
15
15
0.55
0.6
0.6
0.6
15
15
15
15
0.55
0.6
0.6
0.6
15
15
15
15
0.55
0.6
0.6
0.6
9 to 36
18 to75
40 to 121
60 to 150 2
84
83.5
84
83
86
85.5
86
85
20IMX35D15D15-8G
40IMX35D15D15-8G
70IMX35D15D15-8G
110IMX35D15D15-8G
5
5
5
5
1.35
1.4
1.4
1.4
12
12
12
12
0.65
0.7
0.7
0.7
12
12
12
12
0.65
0.7
0.7
0.7
5
5
5
5
1.35
1.4
1.4
1.4
9 to 36
18 to75
40 to 121
60 to 150 2
84
84
84
83.5
86
86
86
85.5
20IMX35D05D12-8G
40IMX35D05D12-8G
70IMX35D05D12-8G
110IMX35D05D12-8G
5
5
5
5
1.35
1.4
1.4
1.4
15
15
15
15
0.55
0.6
0.6
0.6
15
15
15
15
0.55
0.6
0.6
0.6
5
5
5
5
1.35
1.4
1.4
1.4
9 to 36
18 to75
40 to 121
60 to 150 2
83.5
83.5
84
84
85.5
85.5
86
86
20IMX35D05D15-8G
40IMX35D05D15-8G
70IMX35D05D15-8G
110IMX35D05D15-8G
Options 2
i,
Z,
non-G
Efficiency at TA = 25 °C, Vo nom, Io nom
154 V for 2 s.
1
2
Product Marking
Converters without option Z are marked with type designation, input and output voltages and currents, applicable safety approval
and recognition marks, company logo, production date, and serial no.
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Page 2 of 16
IMX35 Series
35 Watt Quad-Output DC-DC Converter
Part Number Description
40 IMX35 - D05 D05 -8 i Z G
Input voltage range Vi
9 to 36 VDC............................................. 20
18 to 75 VDC............................................. 40
40 to 121 VDC............................................. 70
60 to 150 VDC............................................110
Series........................................................................ IMX35
Outputs 1 and 4 (1st power train)..................D05, D12, D15
Outputs 2 and 3 (2nd power train).................D05, D12, D15
Operating ambient temperature range
TA = – 40 to 85 °C ......................................- 8
Options:
Inhibit.............................................................-i
Open frame................................................... Z
RoHS compliant for all six substances........ G
Note: The sequence of options must follow the order above !
NFND: Not for new designs.
Preferred for new designs.
Functional Description
The IMX35 converters are comprised of 2 feedback-controlled interleaved-switching flyback powertrains using current mode control.
Each converter consists of 4 electrically isolated outputs deriving from the 2 power trains. Vo1, Vo4 derive from the first powertrain
and Vo2, Vo3 from the second one. Thus each pair of outputs is independent from the other one.
Voltage regulation for each pair of outputs is achieved with passive transformer feedback from the main transformer of the powertrain.
Each pair of outputs has the same output voltage (i.e. D05, D12, etc.). If both powertrains have the same nominal output voltage (e.g.
D12D12), all outputs may be simultaneously adjusted by the Trim input (pin 5). In case of different output voltages (e.g. D05D15), the
Trim1 input influences only Vo1 and Vo4.
Current limitation is provided on the primary side for each powertrain and limits the possible output power for each pair of outputs. In
the case of an overload on either of the power trains, which causes the output voltage to fall to less than typically 70% of Vo nom, the
entire converter shuts down and automatically restart in short intervals (hiccup mode).
The incorporated overtemperature protection shuts down the hole converter in the case of overtemperature and resumes automatically
after cooling down.
03098b
Vi+ 4
16 Vo1+
PUL 1
15 Vo1–
Trim/Trim1 5
W 6
PWM
17 Vo4+
Ref 7
SD 8
18 Vo4–
Vi– 2
n.c. 3
13 Vo2+
14 Vo2–
12 Vo3+
11 Vo3–
19 n.c.
Fig. 1
Block diagram of quad-output models
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Electrical Input Data
General conditions:
TA = 25 °C, unless specified
Pins 8 (shutdown or i), 6 (W), 5 (Trim or Trim1), and 1 (PUL) left open-circuit (not connected), unless specified.
Table 2: Input Data
Model
20IMX35
Characteristics
Conditions
min
Vi
Input voltage range
Vi nom
Nominal input voltage
Io = 0 to Io nom
Vi sur
Repetitive surge voltage
Abs. max input (3 s)
1
Switch on
TA min to TA max,
9
typ
2
40IMX35
max
min
36
18
typ
40
40
0.25
V
100
0.5
0.25
0.5
tstart-up
Converter
start-up time 2
trise
Rise time 3
Ii o
No-load input current
Io = 0, Vi min to Vi max
70
50
mA
Ii rr
Reflected ripple current
Io = 0 to I o nom
30
30
mApp
Ii inr p
Inrush peak current 4
Vi = Vi nom
8
9
A
Ci
Input capacitance
For surge calculation
SD high
Worst case condition at Vi min,
and full load
max
75
2
20
Unit
0.1
Vi nom, resistive load
3
I o nom, capacitive load
6
3
12
6
2
1.3
-10 to +0.7
-10 to +0.7
Converter operating
open circuit or 2 to 20
open circuit or 2 to 20
approx. 10
approx. 10
Shutdown voltage
RSD
Shutdown input resistance
ISD
Input current during shutdown
Vi min to Vi max
fs
Switching frequency
Vi min to Vi max, Io = 0 to I o nom
12
220
Model
240
220
70IMX35
Characteristics
Conditions
min
40 2
typ
ms
12
Converter disabled
VSD
s
0.1
µF
V
kΩ
6
mA
240
kHz
110IMX35
max
min
121
60 2
typ
Unit
max
Vi
Input voltage range 1
TA min to TA max,
Vi nom
Nominal input voltage
Io = 0 to Io nom
Vi sur
Repetitive surge voltage
Abs. max input (3 s)
tstart-up
Converter
start-up time 2
trise
Rise time 3
Ii o
No-load input current
Io = 0, Vi min to Vi max
30
20
mA
Ii rr
Reflected ripple current
Io = 0 to I o nom
30
30
mApp
Ii inr p
Inrush peak current 4
Vi = Vi nom
Ci
Input capacitance
For surge calculation
VSD
Shutdown voltage
RSD
Shutdown input resistance
ISD
Input current during shutdown
Vi min to Vi max
fs
Switching frequency
Vi min to Vi max, Io = 0 to I o nom
Switch on
SD high
70
Worst case condition at Vi min,
and full load
150 5
110
150
0.25
0.5
0.4
0.1
Vi nom, resistive load
3
I o nom, capacitive load
6
V
170
0.7
3
12
6
7
ms
12
7
0.5
A
0.5
µF
Converter disabled
-10 to +0.7
-10 to +0.7
Converter operating
open circuit or 2 to 20
open circuit or 2 to 20
approx. 10
approx. 10
220
s
0.1
V
kΩ
5
5
mA
240
225 6
kHz
Vi min will not be as stated, if Vo is increased above Vo nom by use of Trim input. If the output voltage is set to a higher value, Vi min will be
proportionately increased.
2
Input undervoltage lockout at typ. 85% of Vi min.
3
Measured with resistive and max. admissible capacitive load.
4
Source impedance according to ETS 300132-2, version 4.3.
5
154 V during 2 s
6
Revision BA or later. Older converters had fs ≤ 240 kHz.
1
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Inrush Current
The inrush current has been made as low as possible by choosing a very small input capacitance. A series resistor may be installed
in the input line to further reduce this current.
A
Vo
04022b
4
trise
Vo nom
3
04008b
2
1
0
20
60
40
80
t
100 µs
Fig. 2
Typical inrush current at Vi nom, Po nom versus time (40IMX35).
Source impedance according to ETS 300132-2 at Vi nom.
t
tstartup
Fig. 3
Converter start-up and rise time (see table 2)
Reverse Polarity Protection
The built-in suppressor diode also provides for reverse polarity protection at the input by conducting current in the reverse
direction. An external fuse is required to limit this current.
Table 3: Recommended external fuses in the non-earthed input line
Model
Fuse type
20IMX35
F 8.0 A
40IMX35
F 4.0 A
70IMX35
F 2.0 A
110IMX35
F 1.5 A
Input Transient Voltage Protection
A built-in suppressor diode provides effective protection against input transients, which may be generated for example by shortcircuits across the input lines, where the network inductance may cause high energy pulses.
Table 4: Built-in transient voltage suppressor
Model
Breakdown voltage
VBR nom [V]
Peak power at 1 ms
P P [Ω]
Peak pulse current
IPP [A]
20IMX35
39
1500
22
40IMX35
100
1500
9.7
70IMX35
151
600
2.9
110IMX35
176
600
2.5
For very high energy transients as for example to achieve IEC/EN 61000-4-5 compliance (as per table Electromagnetic Immunity)
an external inductor and capacitor are required. The components should have similar characteristics as listed in table below.
Table 5:
Components for external circuitry for IEC/EN 61000-4-5, level 2
Model
Inductor (L)
Capacitor (C1 , C2)
Diode (D)
20IMX35
1.45 mH / 5 A
C1, C2: 220 μF / 50 V
1.5 k E47A
40IMX35
4 mH / 3 A
C1, C2: 100 μF / 100 V
---
70IMX35
4 mH / 1.5 A
C1: 120 μF / 160 V
C2: 240 μF / 160 V
---
110IMX35
4.5 mH / 1.5 A
C1: 120 μF / 200 V
C2: 240 μF / 200 V
---
Vi+
L
C1
+
C2
+
D
IMX35
Vi–
Fig. 4
Example for external circuitry to comply with IEC/EN 61000-4-5;
the diode D is only necessary for 20IMX35 models.
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Electrical Out put Data
We recommend connecting an external 1 µF ceramic capacitor across the output pins.
General conditions:
– TA = 25 °C, unless TC is specified
– Pins 8 (shutdown or i), 6 (W), 5 (Trim or Trim1), and 1 (PUL) left open-circuit (not connected), unless specified.
Table 6: Output data per double-output powertrain (Vo1/Vo4 or Vo2/Vo3; each power train has 2 outputs)
Output
2x5V
Characteristics
V o1
V o2
Io nom
Output voltage
Output current
Conditions
min
Vi nom, I o = 0.5 I o nom
4.95
4.94
max
min
typ
5.05
5.06
11.88
11.86
2 x 15 V
max
min
12.12
12.14
14.85
14.82
typ
2 x 1.35
2 x 0.65
2 x 0.55
40IMX
2 x 1.40
2 x 0.70
2 x 0.60
70IMX
Vi min to Vi max
2 x 1.40
2 x 0.70
2 x 0.60
110IMX
2 x 1.40
2 x 0.70
2 x 0.60
20IMX
3.5
1.8
1.5
40IMX
Vi nom, TC = 25 °C,
3.8
2.0
1.7
70IMX
Vo = 93% Vo nom
3.8
2.0
1.7
Current limit 1
∆Vo
Line regulation
Vi min to Vi max , I o nom
∆Vo l
Load regulation
Vi nom, I o = (0.1 to 1) I o nom
110IMX
3.8
±3
±3
120
150
I o = I o nom
3
40
60
70
Min. load 1%
Co ext
Admissible capacitive load
per power train 6
produced after 2011
produced until 2011
αVo
Temperature coefficient ∆Vo / ∆TC
Recovery time
±1
±3
Output overvoltage limit 4
Voltage deviation
1.7
±1
80
Vo L
115
Vi nom, I o nom ↔ 1/2 I o nom
Vi min to Vi max , I o = (0.1 to 1) I o nom
0
0
115
6000
4000
115
0
0
V
A
2
Output voltage noise 5
Dynamic load
regulation
max
Vi min to Vi max
Vo1/2
td
2.0
±1
Unit
15.15
15.18
20IMX
Io L
Vo d
typ
2 x 12 V
680
470
0
0
%
mVpp
%
470
330
µF
±250
±480
±520
mV
0.75
0.75
0.75
ms
±0.02
±0.02
±0.02
%/K
Both outputs of each powertrain connected in parallel. The current limit is primary side controlled. In the case of an overload condition, the
thermal protection may cause the converter to shut down (automatic restart on cool-down).
2
BW = 20 MHz, measured with an external capacitor of 1 µF across the output pins.
3
Measured with a probe according to EN 61204
4
The output overvoltage protection is located on the primary side. It is not tracking the Trim/Trim1 control.
5
Both outputs of each powertrain connected in parallel.
6
Sum of capacities on the outputs of each powertrain.
1
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Thermal Considerations
If a converter, mounted on a PCB, is located in free, quasi-stationary air (convection cooling) at the indicated maximum ambient
temperature TA max (see table Temperature specifications) and is operated at its nominal input voltage and output power, the case
temperature TC (TC Z with option Z) measured at the measuring point of case temperature (see Mechanical Data) will approach the
indicated value TC max after the warm-up phase. However, the relationship between TA and TC depends heavily on the conditions of
operation and integration into a system. The thermal conditions are influenced by input voltage, output current, airflow, temperature
of surrounding components and the surfaces and properties of the printed circuit board. TA max is therefore only an indicative value,
and under practical operating conditions, the ambient temperature TA may be higher or lower than this value.
Caution: The case temperature TC (or TC Z) measured at the measuring point of case temperature (see Mechanical Data) may under no
circumstances exceed the specified maximum value. The installer must ensure that under all operating conditions TC (or TC Z) remains within
the limits stated in the table Temperature specifications.
The converters provide the specified output power with free air convection cooling. In the upper temperature range the output
power derating below should be observed.
Po /Po max
11047-X35a
1.0
0.8
0.5 m/s = 100 LFM
0.6
natural cooling
0.4
0.2
0
20
40
60
80
100
°C
TA
Fig. 5
Maximum allowed output power versus ambient temperature (models with and without option Z)
Overtemperature Protection
The converter is protected against possible overheating by means of an internal temperature monitoring circuit located on the
primary side. It shuts down the converter above the internal temperature limit and attempts to restart automatically. This feature
prevents excessive internal temperature building up which could occur under overload conditions.
Short Circuit Behavior
The current limit characteristic shuts down the converter whenever a short circuit is applied to an output. It acts self-protecting and
automatically recovers after removal of the overload condition (hiccup mode).
Vo [%]
100
70
0
overload short-circuit condition
switch-off
05041b
0.3 s
t
Fig. 6
Overload switch off (hiccup mode), typical values.
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Series and Parallel Connection
The outputs of one or several double-output powertrains may be connected in series respecting the current limitation.
Both outputs of the same powertrain can always be connected in parallel in will behave like a single output.
Several outputs of the same converter with equal output voltage (e.g. 5 V / 5 V) can be connected in parallel and will share their
output currents almost equally.
If outputs of the same converter are being parallel and series-connected, it is recommended that outputs from the same powertrains
are parallel-connected first. This applies for instance, if 24 V shall be generated by a converter with four 12 V outputs; see fig. 7.
JM138a
Vi+ 4
IMX35D12D12
PUL 1
Vo1–
15
Trim 5
W 6
Vo1+
16
Vo4+
17
PWM
Ref 7
Vo4–
–24V
Vo2+
+24V
18
SD 8
Vi– 2
13
n.c. 3
14
12
11
Vo2–
Vo3+
Vo3–
19 n.c.
Fig. 7
Generating 24 V with an IMX35D12D12-8
Note: Parallel operation of several converters may cause start-up problems. This becomes noticeable in applications, where one converter is
not able to deliver the full resistive and capacitive load current alone, as it is required in true redundant systems.
Typical Performance Curves
General conditions:
– TA = 25°C, unless TC is specified.
– Shut down and Trim pin left open-circuit.
Vo [V]
Vo4 [V]
05020-X35
13
05164b
13.5
12
13
11
12.5
10
9
12
8
11.5
0
0.5
1
1.5
2
A
Io total
Fig. 8
Vo versus Io (typ.) of a double-output power train, with both
outputs in parallel (e.g., Vo1/4 of a 40IMX35D12D12)
Io4 = 0.035 A
Io4 = 0.35 A
Io1
0.06 0.1
0.2
0.3
0.4
0.5
0.6
0.7 A
Fig. 9
Cross load regulation (typ.) on powertrain 1. Vo4 versus Io1
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Vo1, Vo4 [V]
05039b
14
13
Vo4
12
Vo1
11
10
0
0.25
0.5
0.75
1
1.25
1.5
Io1/Io1 nom
Fig. 10
Flexible load distribution (typ.) on power train 1 of a
40IMX35D12D12-8:
Vo1 versus Io1, Io4 = 0.5 Io4 nom
η [%]
η [%]
90
05153a
90
Vi min
80
Vi nom
80
Vi nom
70
60
25
05152a
Vi min
70
50
75
Po
100 % Po total
Fig. 11
Efficiency versus input voltage and load. Typical values
(20IMX35D12D12-8)
60
25
50
75
Po
100 % Po total
Fig. 12
Efficiency versus input voltage and load. Typical values
(40IMX35D12D12-8)
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IMX35 Series
35 Watt Quad-Output DC-DC Converter
Auxiliary Functions
Adjustable Output Voltage
As a standard feature, the IMX35 offer adjustable output voltages in the range of 85 to 105% of Vo nom. Fig. 13 shows the schematic
diagram for the adjustment of quad-output models.
All models with equal output voltages have a Trim input at pin 5 referenced to the primary side, influencing all outputs simultaneously.
Models with different output voltages exhibit a Trim1 input, influencing only the first power train (Vo1 and Vo4).
Adjustment by means of an external resistor Rext:
06137c
Vi+
Trim
+
–
Vext
4
16
5
15
Control
circuit
Vref = 2.5 V
Rext
Vi–
2
13
14
Vo1+
Vo1–
Vo2+
Vo2–
Fig. 13
Output voltage control by means of the Trim input
Table 7: Rext for Vo > Vo nom;
approximate values (Vi nom, Io = 0.5 Io nom)
Vo [%Vo nom]
105 to 108 (107 typically)
105
102
100
Table 8: Vo versus Vext for Vo = 85 to 105% Vo nom;
typical values (Vi nom, Io = 0.5 Io nom)
Rext [kΩ]
Trim
Trim 1
0
10
62
∞
0
17
110
∞
Vo [%Vo nom]
Vext [V]
> 105
102
100
95
90
85
Trim [V]
Trim 1 [V]
0
1.8
2.5
4.3
6.2
8
0
1.5
2.5
4.25
6.2
8
Adjustment of the output voltage by means of an external resistor Rext is possible within the range of 100 to 105% of Vo nom. Rext
should be connected between Trim (pin 5) and Vi– (pin 2). The following table indicates suitable resistor values for typical output
voltages under nominal conditions (Vi nom, Io = 0.5 Io nom).
Note: Connection of Rext to Vi+ may damage the converter.
Adjustment by means of an external voltage source Vext
For external output voltage adjustment in the range 85 to 105% of Vo nom a voltage source Vext (0 to 20 V) is required, connected to
Trim or Trim1 (pin 5) and Vi–. The table below indicates typical values Vo versus Vext. Applying a control voltage of 15 to 20 V will
set the converter into the hiccup mode. Direct paralleling of the Trim pins of converters of the same type connected in parallel is
feasible.
Synchronization (W)
It is possible to synchronize the switching frequency of one or more converters to an external clock signal.
This logic input W can be used to synchronize the oscillator to an external frequency source. This signal is edge-triggered with TTL
thresholds and requires a source frequency of 440 to 480 kHz (duty cycle 10 to 90%). The external source frequency is internally
divided by 2 to define the switching frequency of the converter. If unused, this pin can be connected to V1– (pin 2) or left open-circuit.
Reference Output (Ref)
The converter provides a stable 5 V (±0.1 V) reference signal on pin 7 (Ref). The output is protected by a 1 kΩ resistor. The signal
may be used also in conjunction with the Trim input (pin 5) as a limited external voltage reference.
It is recommended to connect a filter capacitor (0 .1 µF) between Ref and Vi–, if Ref is used.
tech.support@psbel.com
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BCD20009-G Rev G, 11 Nov. 2021
© 2021 Bel Power Solutions & Protection
Page 10 of 16
IMX35 Series
35 Watt Quad-Output DC-DC Converter
Shutdown
The outputs of the converters may be enabled or disabled by means of a logic signal (TTL, CMOS, etc.) applied to shutdown (pin 8).
If the shutdown function is not required, pin 8 should be left open-circuit:
Converter operating:
Converter disabled:
2.0 to 20 V
–10 to +0 .7 V
Progr. Input Undervoltage Lockout PUL
A special feature of the converter (with Rev. BA or later) is the adjustable undervoltage lockout protection, which protects the
converter (and the system) from high current caused by operation at low input voltages. This ensures easier start-up in distributed
power systems.
The table below shows the band of switch on/off and the hysteresis.
Table 9: Trigger level and hysteresis (pin 1 left open)
Model
Trigger level
Hysteresis
20IMX35
7 to 8
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