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date 01/03/2014
page 1 of 6
SERIES: VFK400W │ DESCRIPTION: DC-DC CONVERTER
date 01/03/2014
page 1 of 6
FEATURES
• up to 400 W isolated output
• rugged metal enclosure with integrated heat sink
• 4:1 input range (10~36 Vdc, 18~75 Vdc)
• single output from 12~48 Vdc
• 1,500 Vdc isolation
• over current, over temperature, over voltage,
and short circuit protection
• remote on/off
• efficiency up to 87%
PART NUMBER KEY
VFK400W - QXX - SXX
Input Voltage Output Voltage
Base Number
MODEL input
voltage
output
voltage
output
current
output
power
ripple
and noise1
effi ciency
range
(Vdc) (Vdc)
max
(A)
max
(W)
max
(mVp-p)
max
(%)
VFK400W-Q24-S12 10~36 12 33.3 400 200 87
VFK400W-Q24-S24 10~36 24 16.7 400 240 86
VFK400W-Q24-S48 10~36 48 8.3 398 480 86
VFK400W-Q48-S12220~75 12 33.3 400 200 87
VFK400W-Q48-S24 18~75 24 16.7 400 240 86
VFK400W-Q48-S48 18~75 48 8.3 398 480 86.5
Note: 1. Ripple and noise are measured at full load, 20 MHz BW with 10F tantalum capacitor and 1F ceramic capacitor across the output. The 48 Vdc output models require a
22uF aluminum capacitor and a 1uF ceramic capacitor across the output.
2. An external input capacitor of 470uF is recommended to reduce input ripple voltage.
For more information, please visit the product page.
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CUI Inc │ SERIES: VFK400W │ DESCRIPTION: DC-DC CONVERTER date 01/03/2014 │ page 2 of 6
INPUT
parameter conditions/description min typ max units
operating input voltage
24 Vdc input 10 24 36 Vdc
48 Vdc input 12 Vdc output model
24/48 Vdc output models
20
18
48
48
75
75
Vdc
Vdc
under voltage shutdown
24 Vdc input power up
power down
9.5
8.5
Vdc
Vdc
48 Vdc input power up
power down
17.8
15.5
Vdc
Vdc
CTRL1positive logic models ON (>3.5 Vdc or open circuit)
models OFF (0~1.2 Vdc)
fi lter pi fi lter
Note: 1. Open collector refer to -Vin
OUTPUT
parameter conditions/description min typ max units
maximum output capacitance for all models 2,200 F
line regulation measured from high line to low line ±1 %
load regulation measured from full load to zero load ±1 %
voltage accuracy ±1.5 %
adjustability 90 105 %
switching frequency 250 kHz
transient response 25% step load change 500 s
temperature coeffi cient ±0.03 %/°C
PROTECTIONS
parameter conditions/description min typ max units
short circuit protection continuous
over current protection % nominal output current 110 150 %
over voltage protection 115 140 %
over temperature protection shutdown 110 °C
SAFETY AND COMPLIANCE
parameter conditions/description min typ max units
isolation voltage for 1 minute: input to output; input to case;
output to case 1,500 Vdc
isolation resistance 10 M
RoHS 2011/65/EU (CE)
ENVIRONMENTAL
parameter conditions/description min typ max units
operating temperature see derating curves -40 85 °C
storage temperature -55 105 °C
For more information, please visit the product page.
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CUI Inc │ SERIES: VFK400W │ DESCRIPTION: DC-DC CONVERTER date 01/03/2014 │ page 3 of 6
38.93 1.533
111.29 4.382
11
1
2
4
5
6
3
7
8
9
10
12
13
116.92 4.603
7.831198.90
5.118130.00
4.50 0.177
(4 PLCS)
127.00 5.000
MECHANICAL
parameter conditions/description min typ max units
dimensions 198.90 x 127.00 x 38.93 (7.831 x 5.000 x 1.533 inch) mm
case material steel and aluminum extrusion
weight 1.18 kg
MECHANICAL DRAWING
PIN CONNECTIONS
PIN FUNCTION
1, 2 +Vin
3, 4 -Vin
5 on/off
6 case
7, 8 +Vout
9+S
10 trim
11 -S
12, 13 -Vout
units: mm[inch]
tolerance: X.X = ±0.5[±0.02]
X.XX = ±0.25[±0.010]
wire range: 22~12 AWG
screw size: #6-32
For more information, please visit the product page.
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CUI Inc │ SERIES: VFK400W │ DESCRIPTION: DC-DC CONVERTER date 01/03/2014 │ page 4 of 6
DERATING CURVES
80%
100%
120%
f
nominal output
Natural
Convection
0.5 m/S
(100LFM)
1.0 m/S
(200LFM)
1.5 m/S
(300LFM)
0%
20%
40%
60%
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
Relative Output Power - % o
f
(300LFM)
2.0 m/S
(400LFM)
2.5 m/S
(500LFM)
3.0 m/S
(600LFM)
3.5 m/S
(700LFM)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
Ambient Temperature - degrees C
80%
100%
120%
f
nominal output
Natural
Convection
0.5 m/S
(100LFM)
1.0 m/S
(200LFM)
1.5 m/S
(300LFM)
0%
20%
40%
60%
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
Relative Output Power - % o
f
(300LFM)
2.0 m/S
(400LFM)
2.5 m/S
(500LFM)
3.0 m/S
(600LFM)
3.5 m/S
(700LFM)
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
Ambient Temperature - degrees C
VFK400W Power Derating Curves At Nominal Input
(Includes VFK400W-Q24-S12 and all 48 Vdc input models)
VFK400W Power Derating Curves At Nominal Input
(Includes VFK400W-Q24-S24 and VFK400W-Q24-S48)
For more information, please visit the product page.
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CUI Inc │ SERIES: VFK400W │ DESCRIPTION: DC-DC CONVERTER date 01/03/2014 │ page 5 of 6
1. Output Voltage Trimming
Leave open if not used.
101% 102% 103% 104% 105%
12 2.2 1.6 1.2 0.82 0.68
24 4.3 3.3 2.2 1.6 1.5
48 10 6.8 4.8 3.9 3.5
90% 92% 94% 96% 98%
12 9 12 22 51 100
24 12 22 51 100 300
48 22 32 49 100 300
Note: All specifi cations measured at 25°C, nominal input voltage, and full load unless otherwise noted.
Note: 1. VFK400W-Q48-S12 model requires minimum input voltage of 21.6 Vdc in order to trim between 100~105%.
APPLICATION NOTES
+Vin
R trim-down
R-Load
Trim
+Vo
+Sense
+Sense
-Sense
-Sense
-Vin -Vo
Trim up
+Vin
-Vin -Vo
+Vo
R trim-up
R-Load
Trim
Trim down
Figure 1
Table 1 Table 2
Application Circuit for Trim pin
Trim Up Resistor Values (M)1Trim Down Resistor Values (K)
Desired Vout
(%Vout)
Desired Vout
(%Vout)
Nom. Vout
(Vdc)
Nom. Vout
(Vdc)
For more information, please visit the product page.
CUI Inc │ SERIES: VFK400W │ DESCRIPTION: DC-DC CONVERTER date 01/03/2014 │ page 6 of 6
CUI offers a two (2) year limited warranty. Complete warranty information is listed on our website.
CUI reserves the right to make changes to the product at any time without notice. Information provided by CUI is believed to be accurate and reliable. However, no responsibility is
assumed by CUI for its use, nor for any infringements of patents or other rights of third parties which may result from its use.
CUI products are not authorized or warranted for use as critical components in equipment that requires an extremely high level of reliability. A critical component is any component of a
life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
Headquarters
20050 SW 112th Ave.
Tualatin, OR 97062
800.275.4899
Fax 503.612.2383
cui.com
techsupport@cui.com
rev. description date
1.0 initial release 03/13/2012
1.01 updated adjustability range 09/20/2012
1.02 corrected weight 12/18/2012
1.03 updated spec 04/01/2013
1.04 added trimming information 01/03/2014
The revision history provided is for informational purposes only and is believed to be accurate.
REVISION HISTORY
For more information, please visit the product page.
