1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 1 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Features
Description
The 4:1 Input Voltage 1000 Watt Single FXW DC/DC
converter provides a precisely regulated dc output. The
output voltage is fully isolated from the input, allowing the
output to be positive or negative polarity and with various
ground connections. The 1000 Watt FXW meets the
most rigorous performance standards in an industry
standard footprint for mobile (12Vin), process control
(24Vin), and military COTS (28Vin) applications.
The 4:1 Input Voltage 1000W FXW includes trim and
remote ON/OFF. Threaded through holes are provided
to allow easy mounting or addition of a heatsink for
extended temperature operation.
The converters high efficiency and high power density
are accomplished through use of high-efficiency
synchronous rectification technology, advanced
electronic circuit, packaging and thermal design thus
resulting in a high reliability product. Converter operates
at a fixed frequency and follows conservative component
de-rating guidelines.
Product is designed and manufactured in the USA.
●
4:1 Input voltage range
●
High power density
● Small size 2.5” x 4.7” x 0.52”
●
Efficiency up to 96%
●
Excellent thermal performance with metal case
●
Over-Current and Short Circuit Protection
●
Over-Temperature protection
●
Auto-restart
●
Monotonic startup into pre bias
●
Constant frequency
●
Remote ON/OFF
●
Good shock and vibration damping
●
Temperature Range -40ºC to +105ºC
Available.
●
RoHS Compliant
●
UL60950 Approved* (except 24S12.84FXW (RoHS))
Model
Input Range
VDC
Vout
VDC
Iout
ADC
Min Max
24S12.84FXW (ROHS)* 9 36 12 84
24S24.42FXW (ROHS) 9 36 24 42
24S28.36FXW (ROHS) 9 36 28 36
24S48.21FXW (ROHS) 9 36 48 21
24S53.19FXW (ROHS) 9 36 53 19
* The 24S12.84FXW is under evaluation but not currently
UL60950 Approved.
1. Negative Logic ON/OFF feature available. Add “-N” to the
part number when ordering.
i.e. 24S24.42FXW-N (ROHS)
2. Designed to meet MIL-STD-810G for functional shock and
vibration. The unit must be properly secured to the interface
medium (PCB/Chassis) by use of the threaded inserts of the unit.
3. A thermal management device, such as a heatsink, is required
to ensure proper operation of this device. The thermal
management medium is required to maintain baseplate < 105ºC for
full rated power.
4. Non-Standard output voltages are available. Please contact the
factory for additional information.
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 2 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Electrical Specifications
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 24VDC, unless otherwise specified. Specifications are subject to
change without notice.
All Models
Parameter Notes Min Typ Max Units
Absolute Maximum Ratings
Input Voltage Continuous 0
40 V
Transient (100ms)
50 V
Operating Temperature
Baseplate (100% load) -40
105 °C
Storage Temperature
-55
125 °C
Isolation Characteristics and Safety
Isolation Voltage Input to Output 2250
V
Input to Baseplate & Output to Baseplate 1500
V
Isolation Capacitance
9000
pF
Isolation Resistance
10 20
MΩ
Insulation Safety Rating
Basic
Designed to meet UL/cUL 60950, IEC/EN 60950-1
Feature Characteristics
Fixed Switching Frequency
200
kHz
Input Current and Output Voltage Ripple 400 kHz
Output Voltage Trim Range
Adjustable via TRIM (Pin 12) 60 110 %
Remote Sense Compensation Between SENSE+ and +OUT pins 1 V
Output Overvoltage Protection Non-latching 114 122 130 %
Overtemperature Shutdown (Baseplate) Non-latching (Vin=9V; 12V, 24/36V) 108 112 115 °C
Auto-Restart Period Applies to all protection features 1.7 2 2.3 s
Turn-On Delay Time from Vin Time from UVLO to
Vo=90%V
OUT
(NOM)
Resistive
load
480 517 530 ms
Turn-On Delay Time from ON/OFF Control
(From ON to 90%VOUT(NOM) Resistive load)
24S24.42FXW & 24S28.36FXW 20 27 35
ms
24S48.21FXW & 24S53.19FXW 20 35 50
ms
Rise Time (Vout from 10% to90%) 24S24.42FXW & 24S28.36FXW 4 7 11 ms
24S48.21FXW & 24S53.19FXW 7 15 25 ms
ON/OFF Control – Positive Logic
ON state Pin open = ON or 2 12 V
Control Current Leakage current
0.16 mA
OFF state 0 0.8 V
Control current Sinking 0.3 0.36 mA
ON/OFF Control – Negative Logic
ON state Pin shorted to – ON/OFF pin or 0 0.8 V
OFF state Pin open = OFF or 2 12 V
Thermal Characteristics
Thermal resistance Baseplate to Ambient Converter soldered to 5” x 3.5” x 0.07”,
4 layers/ 2Oz copper FR4 PCB. 3.3 °C/W
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 3 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Electrical Specifications (Continued):
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s) and 0.9” heatsink, Vin = 14VDC, unless otherwise specified. Specifications are
subject to change without notice.
24S12.84FXW
Parameter Notes Min Typ Max Units
Input Characteristics
Operating Input Voltage Range 9 14 36 V
Input Under Voltage
Lockout
Non
-
latching
Turn-on Threshold 8.2 8.5 8.8 V
Turn-off Threshold 7.7 8.0 8.3 V
Lockout Hysteresis Voltage 0.4 0.55 0.7 V
Maximum Input Current Vin = 9V, 80% Load 89 A
Vin = 12V, 100% Load 92 A
Vin = 14V, Output Shorted 600 mARMS
Input Stand-by Current Converter Disabled 2 4 mA
Input Current @ No Load Converter Enabled 450 550 690 mA
Minimum Input Capacitance (external)1) See Table 1 1000 µF
Inrush Transient 0.19
A
2
s
Input Terminal Ripple Current, iC 25 MHz bandwidth, 100% Load (Fig. 2) 3.65 ARMS
Output Characteristics
Output Voltage Range 11.64 12.00 12.36 V
Output Voltage Set Point Accuracy (No load) 11.90 12.00 12.10 V
Output Regulation
Over Line Vin = 9V to 36V 0.05 0.10 %
Over Load Vin = 14V, Load 0% to 100% 0.05 0.150 %
Temperature Coefficient 0.005 0.015 %/ºC
Overvoltage Protection 14 15.6 V
Output Ripple and Noise – 20 MHz bandwidth 100% Load,
See Table 1 for external components
120 mVPK-PK
40 mVrms
External Load Capacitance1) See Table 1
Output Current Range (See Fig. A) Vin = 12V – 36V 0 84 A
Vin = 9V 0 67.2 A
Current Limit Inception Vin = 12V – 36V 92.4 100.8 109.2 A
9V ≤ Vin < 12V 73.5 109.2
A
RMS Short-Circuit Current Non-latching, Continuous 7 Arms
Dynamic Response
Load Change 50%-100%-50%, di/dt =0 .5A/µs See Table 1 for external capacitors ±500 mV
Settling Time to 1% of VOUT 800 µs
Efficiency
100% Load Vin = 14V 93.0 %
Vin = 12V 92.3 %
50% Load Vin = 14V 95.4 %
Vin = 12V 95.0 %
1)
Section “Input and Output Capacitance”
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 4 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Electrical Specifications (Continued):
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 24VDC, unless otherwise specified. Specifications are subject to change
without notice.
24S24.42FXW
Parameter Notes Min Typ Max Units
Input Characteristics
Operating Input Voltage Range 9 24 36 V
Input Under Voltage
Lockout
Non
-
latching
Turn-on Threshold 8.2 8.5 8.8 V
Turn-off Threshold 7.7 8.0 8.3 V
Lockout Hysteresis Voltage 0.4 0.55 0.7 V
Maximum Input Current Vin = 9V, 80% Load 89 A
Vin = 12V, 100% Load 92 A
Vin = 24V, Output Shorted 350 mARMS
Input Stand-by Current Converter Disabled 2 4 mA
Input Current @ No Load Converter Enabled 330 420 530 mA
Minimum Input Capacitance (external)1) ESR < 0.1 Ω 1000 µF
Inrush Transient 0.19
A
2
s
Input Terminal Ripple Current, iC 25 MHz bandwidth, 100% Load (Fig. 5) 3.65 ARMS
Output Characteristics
Output Voltage Range 23.62 24.00 24.36 V
Output Voltage Set Point Accuracy (No load) 23.90 24.00 24.10 V
Output Regulation
Over Line Vin = 9V to 36V 0.05 0.10 %
Over Load Vin = 24V, Load 0% to 100% 0.05 0.10 %
Temperature Coefficient 0.005 0.015 %/ºC
Overvoltage Protection 27.36 31.2 V
Output Ripple and Noise – 20 MHz bandwidth 100% Load,
See Table 1 for external components
200 320 mVPK-PK
50 80 mVrms
External Load Capacitance1) Full Load (resistive)
C
EXT
(over operating temp range) ESR
1000 4700 µF
mΩ
10 100
Output Current Range (See Fig. A) Vin = 12V – 36V 0 42 A
Vin = 9V 0 33.5 A
Current Limit Inception Vin = 12V – 36V 46 50.2 54.6 A
9V ≤ Vin < 12V 37 49 54.6
A
RMS Short-Circuit Current Non-latching, Continuous 2.0 3.1 6.5 Arms
Dynamic Response
Load Change 50%-75%-50%, di/dt = 1A/µs Co = 2 x 470 µF/70mΩ ± 400 ± 600 mV
Load Change 50%-100%-50%, di/dt = 1A/µs Co = 2 x 470 µF/70mΩ ±700 mV
Settling Time to 1% of VOUT 500 µs
Efficiency
100% Load Vin = 24V 93.6 94.6 95.3 %
Vin = 12V 92.4 93.4 94 %
50% Load Vin = 24V 95.0 96 96.4 %
Vin = 12V 94.7 95.7 96.3 %
1)
Section “Input and Output Capacitance”
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 5 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Electrical Specifications (Continued):
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 24VDC, unless otherwise specified. Specifications are subject to change
without notice.
1)
Section “Input and Output Capacitance”
24S28.36FXW
Parameter Notes Min Typ Max
Units
Operating Input Voltage Range 9 24 36
V
Input Under Voltage
Lockout
Non
-
latching
Turn-on Threshold 8.2 8.5 8.8 V
Turn-off Threshold 7.7 8.0 8.3 V
Lockout Hysteresis Voltage 0.4 0.55 0.7 V
Maximum Input Current Vin = 9V, 80% Load 89 A
Vin = 12V, 100% Load 92 A
Vin = 24V, Output Shorted 330 mARMS
Input Stand-by Current Converter Disabled 2 4 mA
Input Current @ No Load Converter Enabled 400 480 600 mA
Minimum Input Capacitance (external)1) ESR < 0.1 Ω 1000 µF
Inrush Transient 0.19
A
2
s
Input Reflected-Ripple Current, iC
25
MHz
bandwidth, 100% Load (Fig
.
6
)
2.5 A
RMS
Output Characteristics
Nominal Output Voltage 27.56 28.00 28.42
V
Output Voltage Set Point Accuracy (No load) 27.9 28.00 28.1
V
Output Regulation
Over Line Vin = 9V to 36V
0.05 0.1
%
Over Load Vin = 24V, Load 0% to 100% 0.05 0.1
%
Temperature Coefficient 0.005
0.015
%/ºC
Overvoltage Protection 31.9 36.4 V
Output Ripple and Noise – 20 MHz bandwidth 100% Load,
See Table 1 for external components
220 360 mVPK-PK
50 80 mVRMS
External Load Capacitance1) Full Load (resistive)
CEXT
(over operating temp range) ESR
1000 4700 µF
mΩ
10 100
Output Current Range (See Fig. A) Vin = 12V – 36V 0 36 A
Vin = 9V 0 28.8 A
Current Limit Inception Vin = 12V – 36V 39.6 46.8 A
9V ≤ Vin < 12V 31.7 46.8
A
RMS Short-Circuit Current Non-latching 1.7 2.5 6.4 ARMS
Dynamic Response
Load Change 50%-75%-50%, di/dt = 1A/µs See Table 1 for external components ± 330 ± 430 mV
Load Change 50%-100%-50%, di/dt = 1A/µs See Table 1 for external components ±600 mV
Settling Time to 1% of VOUT 500 µs
Efficiency
100% Load Vin = 24V 94.5 95.5 96.2 %
Vin = 12V 93.0 93.8 94.5 %
50% Load
Vin =
24V
95.5 96.2 97
%
Vin = 12V 94.3 95.4 96.2 %
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 6 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Electrical Specifications (Continued):
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 24VDC, unless otherwise specified. Specifications are subject to change
without notice.
1)
Section “Input and Output Capacitance”
24S48.21FXW
Parameter Notes Min Typ Max
Units
Operating Input Voltage Range 9 24 36
V
Input Under Voltage
Lockout
Non
-
latching
Turn-on Threshold 8.2 8.5 8.8 V
Turn-off Threshold 7.7 8.0 8.3 V
Lockout Hysteresis Voltage 0.4 0.55 0.7 V
Maximum Input Current Vin = 9V, 80% Load 89 A
Vin = 12V, 100% Load 92 A
Vin = 24V, Output Shorted 400 mARMS
Input Stand-by Current Converter Disabled 2 4 mA
Input Current @ No Load Converter Enabled 370 470 560 mA
Minimum Input Capacitance (external)1) ESR < 0.1 Ω 1000 µF
Inrush Transient 0.19
A
2
s
Input Reflected-Ripple Current, iC
25
MHz
bandwidth, 100% Load (Fig
.
6
)
0.9 A
RMS
Output Characteristics
Nominal Output Voltage 47.28 48.00 48.92
V
Output Voltage Set Point Accuracy (No load) 47.80 48.00 48.20
V
Output Regulation
Over Line Vin = 9V to 36V
0.05 0.1
%
Over Load Vin = 24V, Load 0% to 100% 0.05 0.1
%
Temperature Coefficient 0.005
0.015
%/ºC
Overvoltage Protection 54.7 62.4 V
Output Ripple and Noise – 20 MHz bandwidth 100% Load,
See Table 1 for external components
100 150 mVPK-PK
25 50 mVRMS
External Load Capacitance1) Full Load (resistive)
CEXT
(over operating temp range) ESR
470 3000 µF
mΩ
10 100
Output Current Range (See Fig. B) Vin = 12V – 36V 0 21 A
Vin = 9V 0 16.8 A
Current Limit Inception Vin = 12V – 36V 23.1 25.2 27.3 A
9V ≤ Vin < 12V 18.48 20.16 27.3
A
RMS Short-Circuit Current Non-latching 1.0 1.6 3.3 ARMS
Dynamic Response
Load Change 50%-75%-50%, di/dt = 1A/µs See Table 1 for external components ± 480 ± 560 mV
Load Change 50%-100%-50%, di/dt = 1A/µs See Table 1 for external components ± 880 ± 1150 mV
Settling Time to 1% of VOUT 500 µs
Efficiency
100% Load Vin = 24V 94.3 95.0 95.7 %
Vin = 12V 93.2 93.9 94.6 %
50% Load Vin = 24V 95.3 96 96.7 %
Vin = 12V 94.9 95.6 96.3 %
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 7 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Electrical Specifications (Continued):
Conditions: TA = 25 ºC, Airflow = 300 LFM (1.5 m/s), Vin = 24VDC, unless otherwise specified. Specifications are subject to change
without notice.
1)
Section “Input and Output Capacitance”
24S53.19FXW
Parameter Notes Min Typ Max
Units
Operating Input Voltage Range 9 24 36
V
Input Under Voltage
Lockout
Non
-
latching
Turn-on Threshold 8.2 8.5 8.8 V
Turn-off Threshold 7.7 8.0 8.3 V
Lockout Hysteresis Voltage 0.4 0.55 0.7 V
Maximum Input Current Vin = 9V, 80% Load 89 A
Vin = 12V, 100% Load 92 A
Vin = 24V, Output Shorted 300 mARMS
Input Stand-by Current Converter Disabled 2 4 mA
Input Current @ No Load Converter Enabled 360 460 560 mA
Minimum Input Capacitance (external)1) ESR < 0.1 Ω 1000 µF
Inrush Transient 0.19
A
2
s
Input Reflected-Ripple Current, iC
25
MHz
bandwidth, 100% Load (Fig
.
6
)
0.8 A
RMS
Output Characteristics
Nominal Output Voltage 52.20 53.00 54.02
V
Output Voltage Set Point Accuracy (No load) 52.780 53.00 53.220
V
Output Regulation
Over Line Vin = 9V to 36V
0.05 0.1
%
Over Load Vin = 24V, Load 0% to 100% 0.05 0.1
%
Temperature Coefficient 0.005
0.015
%/ºC
Overvoltage Protection 60.4 64.7 69.4 V
Output Ripple and Noise – 20 MHz bandwidth 100% Load,
See Table 1 for external components
70 140 mVPK-PK
16 50 mVRMS
External Load Capacitance1) Full Load (resistive)
CEXT
(over operating temp range) ESR
470 2200 µF
mΩ
10 100
Output Current Range (See Fig. B) Vin = 12V – 36V 0 19 A
Vin = 9V 0 15.2 A
Current Limit Inception Vin = 12V – 36V 20.9 22.8 24.7 A
9V ≤ Vin < 12V 16.7 18.2 24.7
A
RMS Short-Circuit Current Non-latching 0.8 1.8 3.0 ARMS
Dynamic Response
Load Change 50%-75%-50%, di/dt = 1A/µs See Table 1 for external components ± 420 ± 510 mV
Load Change 50%-100%-50%, di/dt = 1A/µs See Table 1 for external components ± 850 ± 1100 mV
Settling Time to 1% of VOUT 500 µs
Efficiency
100% Load Vin = 24V 94.9 95.7 96.4 %
Vin = 12V 93.4 94.1 95 %
50% Load
Vin =
24V
95.3 96.2 96.9
%
Vin = 12V 95.1 95.4 96.5 %
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 8 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Environmental and Mechanical Specifications. Specifications are subject to change without notice.
Parameter Note Min Typ Max Units
Environmental
Operating Humidity
Non-condensing
95 %
Storage Humidity Non-condensing
95 %
ROHS Compliance1 See Calex Website http://www.calex.com/RoHS.html for the complete RoHS
Compliance statement
Shock and Vibration Designed to meet MIL-STD-810G for functional shock and vibration.
Water washability Not recommended for water wash process. Contact the factory for more information.
Mechanical
Weight 8.55 Ounces
242 Grams
Through Hole Pins Diameter Pins 3, 3A, 4, 4A, 5, 6, 8 and 9 0.079 0.081 0.083 Inches
2.006 2.057 2.108 mm
Pins 1, 2, 10, 11 and 12 0.038 0.04 0.042 Inches
0.965 1.016 1.667 mm
Through Hole Pins Material Pins 3, 3A, 4, 4A, 5, 6 , 8 and 9 14500 or C1100 Copper Alloy
Pins 1, 2, 10, 11 and 12 TB3 or “Eco Brass”
Through Hole Pin Finish All pins 10µ” Gold over nickel
Case Dimension 4.7 x 2.5 x 0.52 Inches
119.38 x 63.50 x 13.21 mm
Case Material Plastic: Vectra LCP FIT30: ½-16 EDM Finish
Baseplate
Material Aluminum
Flatness 0.010 Inches
0.25 mm
Reliability
MTBF Telcordia SR-332, Method I Case 1 50%
electrical stress, 40°C components 5.4 MHrs
Agency Approvals UL60950 Approved
EMI and Regulatory Compliance
Conducted Emissions MIL-STD 461F CE102 with external EMI filter network (See Figs. 57 and 58)
Additional Notes:
1 The RoHS marking is as follows
\
Figure A: Output Power as function of input voltage.
0
200
400
600
800
1000
1200
912 15 18 21 24 27 30 33 36
Output Power [W]
Input Voltage [V]
Output Power vs. Input Voltage
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 9 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Operations
Input Fusing
The FXW converters do not provide internal fusing and
therefore in some applications external input fuse may be
required. Use of external fuse is also recommended if
there is possibility for input voltage reversal. For greatest
safety, it is recommended to use fast blow fuse in the
ungrounded input supply line.
Input Reverse Polarity Protection
The FXW converters do not have input reverse polarity. If
input voltage polarity is reversed, internal diodes will
become forward biased and draw excessive current from
the power source. If the power source is not current
limited or input fuse not used, the converter could be
permanently damaged.
Input Undervoltage Protection
Input undervoltage lockout is standard with this converter.
The FXW converter will start and regulate properly if the
ramping-up input voltage exceeds Turn-on threshold of
typ. 8.5V (See Specification) and remains at or above
Turn-on Threshold.
The converter will turn off when the input voltage drops
below the Turn-off Threshold of typical 8V (See
specification) and converter enters hiccup mode and will
stay off for 2 seconds. The converter will restart after 2
seconds only if the input voltage is again above the Turn-
on Threshold.
The built-on hysteresis and 2 second hiccup time prevents
any unstable on/off operation at the low input voltage near
Turn-on Threshold.
User should take into account for IR and inductive voltage
drop in the input source and input power lines and make
sure that the input voltage to the converter is always
above the Turn-off Threshold voltage under ALL
OPERATING CONDITIONS.
Start-Up Time
The start-up time is specified under two different
scenarios: a) Startup by ON/OFF remote control (with the
input voltage above the Turn-on Threshold voltage) and b)
Start-up by applying the input voltage (with the converter
enabled via ON/OFF remote control).
The startup times are measured with maximum resistive
load as: a) the interval between the point when the
ramping input voltage crosses the Turn-on Threshold and
the output voltage reaches 90% of its nominal value and
b) the interval between the point when the converter is
enabled by ON/OFF remote control and time when the
output voltage reaches 90% of its nominal value.
When converter is started by applying the input voltage
with ON/OFF pin active there is delay of 500msec that
was intentionally provided to prevent potential startup
issues especially at low input voltages
Input Source Impedance
Because of the switching nature and negative input
impedance of DC/DC converters, the input of these
converters must be driven from the source with both low
AC impedance and DC input regulation.
The FXW converters are designed to operate without
external components as long as the source voltage has
very low impedance and reasonable voltage regulation.
However, since this is not the case in most applications an
additional input capacitor is required to provide proper
operations of the FXW converter. Specified values for
input capacitor are recommendation and need to be
adjusted for particular application. Due to large variation
between applications some experimentation may be
needed.
In many applications, the inductance associated with the
distribution from the power source to the input of the
converter can affect the stability and in some cases, if
excessive, even inhibit operation of the converter. This
becomes of great consideration for input voltage at 12V or
below.
The DC input regulation, associated with resistance
between input power source and input of the converter,
plays significant role in particular in low input voltage
applications such as 12V battery systems.
Note that input voltage at the input pins of the connector
must never degrade below Turn-off threshold under all
load operating conditions.
Note that in applications with high pulsating loads
additional input as well as output capacitors may be
needed. In addition, for EMI conducted measurement, due
to low input voltage it is recommended to use 5µH LISNs
instead of typical 50µH LISNs.
Input/ Output Filtering
Input Capacitor
Minimum required input capacitance, mounted close to the
input pins of the converter, is 1000µF with ESR < 0.1Ω.
Several criteria need to be met when choosing input
capacitor: a) type of capacitor, b) capacitance to provide
additional energy storage, c) RMS current rating, d) ESR
value that will ensure that output impedance of the input
filter is lower than input impedance of the converter and its
variation over the temperature.
Since inductance of the input power cables could have
significant voltage drop due to rate of change of input
current di(in)/dt during transient load operation, an
external capacitor on the output of the converter is
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 10 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
required to reduce di(in)/dt. Another constraint is minimum
rms current rating of the input capacitors which is
application dependent. One component of input rms
current handled by input capacitor is high frequency
component at switching frequency of the converter (typ.
400kHz) and is specified under “Input terminal ripple
current” iC. Typical values at full rated load and 24 Vin are
provided in Section “Characteristic Waveforms” for each
model and are in range of 2.5A– 3.6A . It is recommended
to use ceramic capacitors for attenuating this component
for input terminal ripple current, which is also required to
meet requirement for conducted EMI (See EMI Section).
The second component of the input ripple current is due to
pulsating load current being reflected to the input and
electrolytic capacitors usually used for this purpose need
to be selected accordingly. Using several electrolytic
capacitors in parallel on the input is recommended.
ESR of the electrolytic capacitors, need to be carefully
chosen taken into account temperature dependence.
Output Capacitor
Similar considerations apply for selecting external output
capacitor. For additional high frequency noise attenuation
use of ceramic capacitors is recommended while in order
to provide stability of the converter during high pulsating
load high value electrolytic capacitor is required. It is
recommended to use several electrolytic capacitors in
parallel in order to reduce effective ESR. Note that
external output capacitor also reduces slew rate of the
input current during pulsating load transients as discussed
above.
Table 1 shows recommend external output capacitance.
ON/OFF (Pins 1 and 2)
The ON/OFF pin is used to turn the power converter on or
off remotely via a system signal and has positive logic. A
typical connection for remote ON/OFF function is shown in
Fig. 1.
Fig. 1: Circuit configuration for ON/OFF function.
The positive logic version turns on when the ON/OFF pin
is at logic high and turns off when at logic low. The
converter is on when the ON/OFF pin is either left open or
external voltage greater than 2V and not more than 12V is
applied between ON/OFF pin and – INPUT pin. See the
Electrical Specifications for logic high/low definitions.
The negative logic version turns on when the ON/OFF pin
is at logic low and turns off when at logic high. The
converter is on when the ON/OFF pin is either shorted to –
INPUT pin or kept below 0.8V. The converter is off when
the ON/OFF pin is either left open or external voltage not
more than 12V is applied between ON/OFF pin and –
INPUT pin. See the Electrical Specifications for logic
high/low definitions.
The ON/OFF pin is internally pulled up to typically 4.5V via
resistor and connected to internal logic circuit via RC
circuit in order to filter out noise that may occur on the
ON/OFF pin. A properly de-bounced mechanical switch,
open-collector transistor, or FET can be used to drive the
input of the ON/OFF pin. The device must be capable of
sinking up to 0.36mA at a low level voltage of £ 0.8 V.
During logic high, the typical maximum voltage at ON/OFF
pin (generated by the converter) is 4.5V, and the
maximum allowable leakage current is 160µA. If not using
the remote on/off feature leave the ON/OFF pin open.
TTL Logic Level - The range between 0.81V and 2V is
considered the dead-band. Operation in the dead-band is
not recommended.
External voltage for ON/OFF control should not be applied
when there is no input power voltage applied to the
converter.
Output Overcurrent Protection (OCP)
The converter is protected against overcurrent or short
circuit conditions. Upon sensing an overcurrent condition,
the converter will switch to constant current operation
and thereby begin to reduce output voltage. When the
output voltage drops below approx. 50% of the nominal
value of output voltage, the converter will shut down.
Once the converter has shut down, it will attempt to
restart nominally every 2 seconds. The attempted restart
will continue indefinitely until the overload or short circuit
conditions are removed or the output voltage rises above
50% of its nominal value.
Once the output current is brought back into its specified
range, the converter automatically exits the hiccup mode
and continues normal operation.
During initial startup if output voltage does not exceed
typical 50% of nominal output voltage within 500 msec
after the converter is enabled, the converter will be shut
down and will attempt to restart after 2 seconds.
In case of startup into short circuit, internal logic detects
short circuit condition and shuts down converter typical 5
msec after condition is detected. The converter will
attempt to restart after 2 seconds until short circuit
condition exists.
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ECO 171214-1, (1/16/18), 180206-
2
Output Overvoltage Protection (OVP)
The converter will shut down if the output voltage across
+OUT (Pins 5 and 6) and –OUT (Pins 8 and 9) exceeds
the threshold of the OVP circuitry. The OVP circuitry
contains its own reference, independent of the output
voltage regulation loop. Once the converter has shut
down, it will attempt to restart every 2 seconds until the
OVP condition is removed.
Note that OVP threshold is set for nominal output voltage
and not trimmed output voltage value or remote sense
voltage.
Overtemperature Protection (OTP)
The FXW converters have non-latching overtemperature
protection. It will shut down and disable the output if
temperature at the center of the base plate exceeds a
threshold of typical 108ºC for 9Vin, 112 ºC for 12Vin and
115 ºC for 24Vin/36Vin. Measured with FXW converter
soldered to 5” x 3.5” x 0.07” 4 layers/ 2 Oz Cooper FR4
PCB.
The converter will automatically restart when the base
temperature has decreased by approximately 20ºC.
Safety Requirements
Basic Insulation is provided between input and the output.
The converters have no internal fuse. To comply with
safety agencies requirements, a fast-acting or time-delay
fuse is to be provided in the unearthed lead.
Recommended fuse values are:
a) 140A for 9V<Vin<18V
b) 90A for 18V<Vin<36V.
Electromagnetic Compatibility (EMC)
EMC requirements must be met at the end-product
system level, as no specific standards dedicated to EMC
characteristics of board mounted component dc-dc
converters exist.
With the addition of a two stage external filter, the FXW
converters will pass the requirements of MILSTD-461F
CE102 Base Curve for conducted emissions. Note that
5uH LISN should be used in order to enable operation of
the converter at low input voltage.
Remote Sense Pins (Pins 10 and 11)
Sense inputs compensate for output voltage inaccuracy
delivered at the load.
Fig. 2: Circuit configuration for Remote sense function.
The sense input and power Vout pins are internally
connected through 100Ω (SENSE+ to +OUT) and 10 Ω
(SENSE- to –OUT) resistors enabling the converter to
operate without external connection to the Sense. If the
Sense function is not used for remote regulation, the user
should connect SENSE- (Pin 10) to –OUT (Pins 8 and 9)
and SENSE+ (Pin 11) to +OUT (Pins 5 and 6) at the
converter pins.
Sense lines must be treated with care in PCB layouts and
should run adjacent to DC signals. If cables and discrete
wiring is used, it is recommended to use twisted pair,
shielded tubing or similar techniques.
The maximum voltage difference between Sense inputs
and corresponding power pins should be kept below 1V,
i.e.:
V(SENSE+) - V(+OUT) ≤ 1V
V(-OUT) – V(SENSE-) ≤ 1V
Note that maximum output power is determined by
maximum output current and highest output voltage at
the output pins of the converter:
[V(+OUT) – V(-OUT)]x Iout ≤ Pout rated
Output Voltage Adjust/TRIM (Pin 12)
The TRIM (Pin 12) allows user to adjust output voltage
10% up or -40% down relative to rated nominal voltage by
addition of external trim resistor. Trim resistor should be
mounted close to the converter and connected with short
leads. Internal resistor in the converter used for the TRIM
is high precision 0.1% with temperature coefficient 25
ppm/ ºC. The accuracy of the TRIM is therefore
determined by tolerance of external Trim resistor. If
trimming is not used, the TRIM pin should be left open.
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ECO 171214-1, (1/16/18), 180206-
2
Trim Down – Decrease Output Voltage
Trimming down is accomplished by connecting an
external resistor, Rtrim-down, between the TRIM (pin 12)
and the SENSE- (pin 10), with a value of:
Rtrim-down = 󰇡
∆− 9.98󰇢[kΩ]
Where,
Rtrim-down = Required value of the trim-down resistor [kΩ]
VO(NOM) = Nominal value of output voltage [V]
VO(REQ) = Required value of output voltage [V]
∆ = 󰇻()()
()󰇻[%]
Fig. 3: Circuit configuration for Trim-down function
To trim the output voltage 10% (∆=10) down, required
external trim resistance is:
Rtrim-down = 󰇡
10 − 9.98󰇢 = 39.92 kΩ
Trim Up – Increase Output Voltage
Trimming up is accomplished by connecting an external
resistor, Rtrim-up, between the TRIM (pin 12) and the
SENSE+ (pin 11), with a value of:
Rtrim-up = 4.99 ∗ 󰇥󰇣VONOM∗(100+∆)
1.25∆󰇤−(100+2∆)
∆󰇦 [kΩ]
Fig. 4: Circuit configuration for Trim-up function
To trim the output voltage up, for example 24V to 26.4V,
∆=10 and required external resistor is:
Rtrim-up = 4.99 ∗ 󰇥󰇣24∗100+10
1.25∗10 󰇤−100+2∗10
10 󰇦 = 1015 kΩ
Note that trimming output voltage more than 10% is not
recommended and OVP may be tripped.
Active Voltage Programming
In applications where output voltage need to be adjusted
actively, an external voltage source, such as for example
a Digital-to-Analog converter (DAC), capable of both
sourcing and sinking current can be used. It should be
connected across with series resistor Rg across TRIM (Pin
12) and SENSE- (Pin 10). External trim voltage should not
be applied before converter is enabled in order to provide
proper startup output voltage waveform and prevent
tripping overvoltage protection. Please contact Calex
technical representative for more details.
Thermal Consideration
The FXW converter can operate in a variety of thermal
environment. However, in order to ensure reliable
operation of the converter, sufficient cooling should be
provided. The FXW converter is encapsulated in plastic
case with metal baseplate on the top. In order to improve
thermal performance, power components inside the unit
are thermally coupled to the baseplate. In addition, thermal
design of the converter is enhanced by use of input and
output pins as heat transfer elements. Heat is removed
from the converter by conduction, convection and
radiation.
There are several factors such as ambient temperature,
airflow, converter power dissipation, converter orientation
how converter is mounted as well as the need for
increased reliability that need to be taken into account in
order to achieve required performance. It is highly
recommended to measure temperature in the middle of
the baseplate in particular application to ensure that
proper cooling of the converter is provided.
A reduction in the operating temperature of the converter
will result in an increased reliability.
Thermal Derating
There are two most common applications: 1) the FXW
converter is thermally attached to a cold plate inside
chassis without any forced internal air circulation; 2) the
FXW converter is mounted in an open chassis on system
board with forced airflow with or without an additional
heatsink attached to the base plate of the FXW converter.
The best thermal results are achieved in application 1)
since the converter is cooled entirely by conduction of heat
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ECO 171214-1, (1/16/18), 180206-
2
from the top surface of the converter to a cold plate and
temperature of the components is determined by the
temperature of the cold plate. There is also some
additional heat removal through the converter’s pins to the
metal layers in the system board. It is highly
recommended to solder pins to the system board rather
than using receptacles. Typical derating output power and
current are shown in Figs. 17–26 for various baseplate
temperatures up to 105ºC. Note that operating converter at
these limits for prolonged time will affect reliability.
Soldering Guidelines
The ROHS-compliant through-hole FXW converters use
Sn/Ag/Cu Pb-free solder and ROHS-compliant
component. They are designed to be processed through
wave soldering machines. The pins are 100% matte tin
over nickel plated and compatible with both Pb and Pb-
free wave soldering processes. It is recommended to
follow specifications below when installing and soldering
FXW converters. Exceeding these specifications may
cause damage to the FXW converter.
Wave Solder Guideline For Sn/Ag/Cu based solders
Maximum Preheat Temperature 115 ºC
Maximum Pot Temperature 270 ºC
Maximum Solder Dwell Time 7 seconds
Wave Solder Guideline For Sn/Pb based solders
Maximum Preheat Temperature 105 ºC
Maximum Pot Temperature 250 ºC
Maximum Solder Dwell Time 6 seconds
FXW converters are not recommended for water wash
process. Contact the factory for additional information if
water wash is necessary.
Test Configuration
Fig. 5: Test setup for measuring input reflected ripple currents ic .
Fig. 6: Test setup for measuring output voltage ripple, startup and
step load transient waveforms.
Ref.
Des. Manufacturing p/n 24S12.84FXW
24S24.42FXW
24S28.36FXW
24S48.21FXW
24S53.19FXW
L1 N/A 6 ft. cable, AWG 4 100nH 100nH
CIN MAL214699108E3 (Vishay) 2 x 470 µF / 72mΩ (650mΩ) 2 x 470 µF / 72mΩ (650mΩ) 2 x 470 µF / 76mΩ (650mΩ)
C1 GRM32ER72A475KA12L 10 µF / 1210 / X7R / 100v 10 µF / 1210/X7R/100V 10 µF / 1210 / X7R / 100V
C2
PCR1E471MCL1GS 3 X 470 µF/ 25V / 15 mΩ (30 mΩ) N/A N/A
PCR1J101MCL1GS (Nichicon) N/A 3 x 100 µF / 63V / 24 mΩ (48 mΩ) N/A
PCR1K680MCL1GS (Nichicon) N/A N/A 3 x 68 µF / 80V / 28 mΩ (56 mΩ)
UPS2A221MPD (Nichicon) N/A 220 µF / 100V / 100mΩ 220 µF / 100V / 100mΩ
MAL214699108E3 (Vishay) N/A 470 µF / 72mΩ (650mΩ) N/A
MAL214699606E3 (Vishay) 2 X 1500 µF / 50mΩ (450mΩ) N/A N/A
MAL214699608E3 (Vishay 2200 µF / 50mΩ (450mΩ) N/A N/A
Table 1: Component values used in test setup from Figs. 5 and 6. Resistance in ( ) represents ESR value at -40C for specified capacitor.
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Curves – Efficiency and Power Dissipation
Fig. 7: 24S12.84FXW (ROHS) Efficiency Curve
Fig. 9: 24S24.42FXW (ROHS) Efficiency Curve
Fig. 11: 24S28.36FXW (ROHS) Efficiency Curve
Fig. 8: 24S12.84FXW (ROHS) Power Dissipation
Fig. 10: 24S24.42FXW (ROHS) Power Dissipation
Fig. 12: 24S28.36FXW (ROHS) Power Dissipation
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Curves – Efficiency and Power Dissipation (Cont’d)
Fig. 13: 24S48.21FXW (ROHS) Efficiency Curve
Fig. 15: 24S53.19FXW (ROHS) Efficiency Curve
Fig. 14: 24S48.21FXW (ROHS) Power Dissipation
Fig. 16: 24S53.19FXW (ROHS) Power Dissipation
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Curves – Derating Curves
Fig. 17: 24S12.84FXW (ROHS) Derating Curve
Fig. 19: 24S24.42FXW (ROHS) Derating Curve
Fig. 21: 24S28.36FXW (ROHS) Derating Curve
Fig. 18: 24S12.84FXW (ROHS) Derating Curve
Fig. 20: 24S24.42FXW (ROHS) Derating Curve
Fig. 22: 24S28.36FXW (ROHS) Derating Curve
0
100
200
300
400
500
600
700
800
900
1000
1100
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Power [W]
Baseplate Temperature [C]
Output Power vs. Base Plate Temperature -24S24.42FXW
Vin=9V Vin=12V, 24V, 36V
0
100
200
300
400
500
600
700
800
900
1000
1100
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Power [W]
Baseplate Temperature [C]
Output Power vs. Base Plate Temperature -24S28.36 XW
Vin=9V Vin=12V, 24V, 36V
0
4
8
12
16
20
24
28
32
36
40
44
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Current [W]
Baseplate Temperature [C]
Output Current vs. Base Plate Temperature -24S24.42FXW
Vin=9V Vin=12V, 24V, 36V
0
4
8
12
16
20
24
28
32
36
40
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Current [W]
Baseplate Temperature [C]
Output Current vs. Base Plate Temperature -24S28.36FXW
Vin=9V Vin=12V, 24V, 36V
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Curves – Derating Curves (Cont’d)
Fig. 23: 24S48.21FXW (ROHS) Derating Curve
Fig. 25: 24S53.19FXW (ROHS) Derating Curve
Fig. 24: 24S48.21FXW (ROHS) Derating Curve
Fig. 26: 24S53.19FXW (ROHS) Derating Curve
0
100
200
300
400
500
600
700
800
900
1000
1100
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Power [W]
Baseplate Temperature [C]
Output Power vs. Base Plate Temperature - 24S48.21FXW
Vin=9V Vin=12V, 24V, 36V
0
100
200
300
400
500
600
700
800
900
1000
1100
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Power [W]
Baseplate Temperature [C]
Output Power vs. Base Plate Temperature - 24S53.19FXW
Vin=9V Vin=12V, 24V, 36V
0
2
4
6
8
10
12
14
16
18
20
22
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Current [W]
Baseplate Temperature [C]
Output Current vs. Base Plate Temperature -24S48.21FXW
Vin=9V Vin=12V, 24V, 36V
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Output Current [W]
Baseplate Temperature [C]
Output Current vs. Base Plate Temperature -24S53.19FXW
Vin=9V Vin=12V, 24V, 36V
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Waveforms – 24S12.84FXW
Fig. 27: Turn-on by ON/OFF transient (with Vin applied) at full rated load
current (resistive) at Vin = 14V. Top trace (C1): ON/OFF signal (5
V/div.). Bottom trace (C4): Output voltage (5 V/div.). Time: 10 ms/div.
Fig. 29: Output voltage response to load current step change 70% - 100%-
70% (58.5A–84A–58.8A) with di/dt =0.5A/µs at Vin = 14V . Top trace (C4):
Output voltage (200 mV/div.). Bottom trace (C3): Load current (50A/div.).
Time: 1ms/div.
Fig. 31: Output voltage ripple (100 mV/div.) at full rated load current into
a resistive load at Vin = 14 V. Time: 2 µs/div.
Fig. 28: Turn-on by Vin transient (ON/OFF high) at full rated load
current (resistive) at Vin = 44V. Top trace (C2): Input voltage Vin (5
V/div.). Bottom trace (C4): Output voltage (5 V/div.). Time: 100
ms/div.
Fig. 30: Output voltage response to load current step change 50% - 100%-
50% (42A–84A–42A) with di/dt =1A/µs at Vin = 14 V. Top trace (C4):
Output voltage (500 mV/div.). Bottom trace (C3): Load current (50A/div.).
Time: 1ms/div.
Fig. 32 Input reflected ripple current, ic (500mA/mV), measured at input
terminals at full rated load current at Vin = 24 V. Refer to Fig. 2 for test
setup. Time: 2 µs/div. RMS input ripple current is 7.3*0.5A = 3.65Arms.
.
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Waveforms – 24S24.42FXW
Fig. 33: Turn-on by ON/OFF transient (with Vin applied) at full rated load
current (resistive) at Vin = 24V. Top trace (C1): ON/OFF signal (5
V/div.). Bottom trace (C4): Output voltage (10 V/div.). Time: 5 ms/div.
Fig. 35: Output voltage response to load current step change 50% - 75%-
50% (21A–31.5A–21A) with di/dt =1A/µs at Vin = 24V . Top trace (C4):
Output voltage (200 mV/div.). Bottom trace (C3): Load current (20A/div.).
Co = 470µF/70mΩ. Time: 1ms/div.
Fig. 37: Output voltage ripple (100 mV/div.) at full rated load current into a
resistive load at Vin = 24 V. Co = 2 x 470 µF/70mΩ. Time: 2 µs/div.
Fig. 34: Turn-on by Vin transient (ON/OFF high) at full rated load current
(resistive) at Vin = 24V. Top trace (C2): Input voltage Vin (10 V/div.).
Bottom trace (C4): Output voltage (10 V/div.). Time: 100 ms/div.
Fig. 36: Output voltage response to load current step change 50% - 100%-
50% (21A–42A–21A) with di/dt =1A/µs at Vin = 24 V. Top trace (C4): Output
voltage (500 mV/div.). Bottom trace (C3): Load current (20A/div.). Co = 2
x 470 µF/70mΩ. Time: 1ms/div.
Fig. 38: Input reflected ripple current, ic (500mA/mV), measured at input
terminals at full rated load current at Vin = 24 V. Refer to Fig. 2 for test
setup. Time: 2 µs/div. RMS input ripple current is 7.3*0.5A = 3.65Arms.
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ECO 171214-1, (1/16/18), 180206-
2
Characteristic Waveforms – 24S28.36FXW
Fig. 39: Turn-on by ON/OFF transient (Vin applied) at full rated load current
(resistive) at Vin = 24V. Top trace (C1): ON/OFF signal (5 V/div.). Bottom
trace (C4): Output voltage (10 V/div.). Time: 5 ms/div.
Fig. 41: Output voltage response to load current step change 50% - 75%-
50% (18A–27A–18A) with di/dt =1A/µs at Vin = 24V . Top trace (C4): Output
voltage (200 mV/div.). Bottom trace (C3): Load current (10A/div.). Co =
470µF/70mΩ. Time: 1ms/div.
Fig. 43: Output voltage ripple (100 mV/div.) at full rated load current into a
resistive load at Vin = 24 V. Co = 470 µF/70mΩ. Time: 2 µs/div.
Fig. 40: Turn-on by Vin (ON/OFF high) transient at full rated load current
(resistive) at Vin = 24V. Top trace (C2): Input voltage Vin (10 V/div.).
Bottom trace (C4): Output voltage (10 V/div.). Time: 100 ms/div.
Fig. 42: Output voltage response to load current step change 50% - 100%-
50% (18A–36A–18A) with di/dt =1A/µs at Vin = 24V . Top trace (C4): Output
voltage (500 mV/div.). Bottom trace (C3): Load current (10A/div.). Co =
470 µF/70mΩ. Time: 1ms/div.
Fig. 44: Input reflected ripple current, ic (500 mA/div.), measured at input
terminals at full rated load current at Vin = 24 V. Refer to Fig. 2 for test
setup. Time: 2 µs/div. RMS input ripple current is 4.968*0.5A = 2.48Arms.
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ECO 171214-1, (1/16/18), 180206-
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Characteristic Waveforms – 24S48.21FXW
Fig. 45: Turn-on by ON/OFF transient (Vin applied) at full rated load current
(resistive) at Vin = 24V. Top trace (C1): ON/OFF signal (5 V/div.). Bottom
trace (C4): Output voltage (10 V/div.). Time: 10 ms/div.
Fig. 47: Output voltage response to load current step change 50% - 75%-
50% (10.5A–15.75A–10.5A) with di/dt =1A/µs at Vin = 24V . Top trace (C4):
Output voltage (200 mV/div.). Bottom trace (C3): Load current (10A/div.)..
Time: 1ms/div.
Fig. 49: Output voltage ripple (100 mV/div.) at full rated load current into a
resistive load at Vin = 24 V. Time: 2 µs/div.
Fig. 46: Turn-on by Vin (ON/OFF high) transient at full rated load current
(resistive) at Vin = 24V. Top trace (C2): Input voltage Vin (10 V/div.).
Bottom trace (C4): Output voltage (10 V/div.). Time: 100 ms/div.
Fig. 48: Output voltage response to load current step change 50% - 100%-
50% (10.5A–21A–10.5A) with di/dt =1A/µs at Vin = 24V . Top trace (C4):
Output voltage (500 mV/div.). Bottom trace (C3): Load current (10A/div.).
Time: 1ms/div.
Fig. 50: Input reflected ripple current, ic (500 mA/div.), measured at input
terminals at full rated load current at Vin = 24 V. Refer to Fig. 2 for test
setup. Time: 2 µs/div. RMS input ripple current is 7.3*0.5A = 3.65Arms..
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 22 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Characteristic Waveforms – 24S53.19FXW
Fig. 51: Turn-on by ON/OFF transient (Vin applied) at full rated load current
(resistive) at Vin = 24V. Top trace (C1): ON/OFF signal (5 V/div.). Bottom
trace (C4): Output voltage (10 V/div.). Time: 10 ms/div.
Fig. 53: Output voltage response to load current step change 50% - 75%-
50% (9.5A–14.25A–9.5A) with di/dt =1A/µs at Vin = 24V . Top trace (C4):
Output voltage (200 mV/div.). Bottom trace (C3): Load current (10A/div.)..
Time: 1ms/div.
Fig. 55: Output voltage ripple (100 mV/div.) at full rated load current into a
resistive load at Vin = 24 V. Time: 2 µs/div.
Fig. 52: Turn-on by Vin (ON/OFF high) transient at full rated load current
(resistive) at Vin = 24V. Top trace (C2): Input voltage Vin (10 V/div.).
Bottom trace (C4): Output voltage (10 V/div.). Time: 100 ms/div.
Fig. 54: Output voltage response to load current step change 50% - 100%-
50% (9.5A–19A–9.5A) with di/dt =1A/µs at Vin = 24V . Top trace (C4):
Output voltage (500 mV/div.). Bottom trace (C3): Load current (10A/div.).
Time: 1ms/div.
Fig. 56: Input reflected ripple current, ic (500 mA/div.), measured at input
terminals at full rated load current at Vin = 24 V. Refer to Fig. 2 for test
setup. Time: 2 µs/div. RMS input ripple current is 4.968*0.5A = 2.48Arms.
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 23 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
EMC Consideration
The filter circuit schematic for suggested input filter configuration as tested to meet the conducted emission limits of MILSTD-461F CE102 Base Curve
is shown in Fig. 57. The plots of conducted EMI spectrum measured using 5uH LISNs are shown in Fig. 58.
Note: Customer is ultimately responsible for the proper selection, component rating and verification of the suggested parts based on the end
application.
Comp. Des. Description
C1, C2, C12, C14 470µF/50V/70mΩ Electrolytic Capacitor (Vishay MAL214699108E3 or equivalent)
C3, C4, C5, C6 4.7nF/1210/X7R/1500V Ceramic Capacitor
C7, C8, C9, C10, C11, C13 10µF/1210/X7R/50V Ceramic Capacitor
L1 CM choke, 130uH, Leakage = 0.6uH (4T on toroid 22.1mm x 13.7 mm x 7.92 mm)
Fig. 57: Typical input EMI filter circuit to attenuate conducted emissions per MILSTD-461F CE102 Base Curve.
a) Without input filter from Fig. 47 (C9 = 2 x 470µF/50V/70mΩ)
b) With input filter from Fig. 47.
Fig. 58: Input conducted emissions measurement (Typ.) of 24S24.42FXW.
1000
WATT
FXW
SERIES
DC/DC CONVERTERS
2401 Stanwell Drive, Concord Ca. 94520
Ph: 925-687-4411
Page 24 of 24
Fax: 925-687-3333
www.calex.com
Email: sales@calex.com
ECO 171214-1, (1/16/18), 180206-
2
Mechanical Specification
Input/ Output Connections
Pin
Label
Function
1 +ON/OFF TTL input with internal pull up, referenced to –-
ON/OFF pin, used to turn converter on and off
2 -ON/OFF Negative input of Remote ON/OFF
3 -INPUT Negative Input Voltage
3A -INPUT Negative Input Voltage
4 +INPUT Positive Input Voltage
4A +INPUT Positive Input Voltage
5 +OUT Positive Output Voltage
6 +OUT Positive Output Voltage
8 -OUT Negative Output Voltage
9 -OUT Negative Output Voltage
10 SENSE- Negative Remote Sense
11 SENSE+ Positive Remote Sense
12 TRIM Used to trim output voltage +10/-40%
NOTES:
Unless otherwise specified:
All dimensions are in inches [millimeter]
Tolerances: x.xx in. ±0.02 in. [x.x mm ± 0.5mm]
x.xxx in. ±0.010 in. [x.xx mm ± 0.25mm]
Torque fasteners into threaded mounting inserts at 10 in.lbs. or
less. Greater torque may result in damage to unit and void the
warranty.
Note:
1) Pinout as well as pin number and pin diameter are inconsistent
between manufacturers of the full brick converters. Make sure
to follow the pin function, not the pin number as well as spec
for pin diameter when laying out your board.