VKA50xS Rev B 4/99 Page 1
Product Data Sheet
50 WATT SINGLE OUTPUT
HIGH DENSITY DC/DC CONVERTER
VKA50xS Series
Efficiency(%)
VKA50LS03 3.3V 10.0 80 81
VKA50LS05 24VDC 5.0V 10.0 85 86
VKA50LS12 12.0V 4.2 87 88
VKA50LS15 (18-36) 15.0V 3.3 88 89
VKA50LS24 24.0V 2.1 89 90
Input VOUT IOUT Note (1)
Model Voltage (VDC) (A) Min Typ
Efficiency(%)
VKA50MS03 3.3V 10.0 81 82
VKA50MS05 48VDC 5.0V 10.0 86 87
VKA50MS12 12.0V 4.2 88 89
VKA50MS15 (33-75) 15.0V 3.3 89 90
VKA50MS24 24.0V 2.1 89 90
Input VOUT IOUT Note (1)
Model Voltage (VDC) (A) Min Typ
AGENCY APPROVALS
Internet: http://www.cdpowerelectronics.com
Power Electronics Division, United States
3400 E Britannia Drive, Tucson, Arizona 85706
Phone: 800.547.2537 Fax: 520.770.9369
Power Electronics Division, Europe
C&D Technologies (Power Electronics) Ltd.
132 Shannon Industrial Estate, Shannon, Co. Clare, Ireland
Tel: +353.61.474.133 Fax:+353.61.474.141
FEATURES
●●
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●18 - 36V & 33 - 75V INPUT RANGE
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●SMALL SIZE: 2.28" X 2.4" X 0.50"
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●HIGH EFFICIENCY: 87% TYPICAL AT 5V
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●100µµ
µµ
µS TRANSIENT RESPONSE 50-100% LOAD STEP
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●420kHZ FIXED-FREQUENCY OPERATION
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●OPERATION TO +100°C BASEPLATE TEMP.
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●PRIMARY REMOTE ON/OFF, CHOICE OF POS/NEG
LOGIC
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●ADJUSTABLE OUTPUT VOLTAGE
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●REMOTE SENSE
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●CONTINUOUS SHORT-CIRCUIT PROTECTION
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●THERMAL SHUTDOWN
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●SAFETY PER UL1950, EN 60950 AND CSA 22.2 #234
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●CASE GROUND PIN
DESCRIPTION
The VKA50xS Series DC/DC converters present an eco-
nomical and practical solution for distributed power
system architectures which require high power density
and efficiency while maintaining system modularity and
upgradeability. With the ability to operate over a wide
input voltage range of 18 to 36 and 33 to 75 volts, these
modules are ideal for use in battery backup applications
common in todays' telecommunication and electronic
data processing applications. The output is fully isolated
from the input, allowing for a variety of polarity and
grounding configurations.
The VKA50xS's proprietary control circuitry responds to
50-100% load steps in 100µSeconds to within 1% nomi-
nal Vout.
The patented fixed frequency architecture combined with
surface mount technology results in a compact, efficient
and reliable solution to DC/DC conversion requirements.
VKA50xs Rev B 4/99
Page 2
COMMON SPECIFICATIONS
Specifications typical at TCASE = +40°C, nominal input voltage, rated output current unless otherwise specified.
PARAMETER CONDITIONS MIN TYP MAX UNITS
INPUT
Voltage Range
VKA50LS 18 24 36 VDC
VKA50MS 33 48 75 VDC
Maximum Input Current
VKA50LS VIN = 16VDC 3.7 A
VKA50MS VIN = 27VDC 2.2 A
Reflected Ripple Current Peak - Peak 20 mA
Input Ripple Rejection DC to 1KHz 50 60 dB
No Load Input Current LS/MS 50/100 mA
Power Dissipation LS/MS
No Load 3.6/4.8 W
Standby, Primary On/Off Disabled LS/MS 0.18/0.4 W
Inrush Charge VIN = VINmax.
VKA50LS 0.520 mC
VKA50MS 0.360 mC
Quiescent Operating Current
Primary On/Off Disabled 812mA
OUTPUT
Rated Power 050W
Set point Accuracy 1%
Line Regulation High Line to Low Line 0.02 0.05 %
Load Regulation No Load to Rated Load 0.02 0.05 %
Output Temperature Drift ±.02 %/°C
Output Ripple, p-p DC to 20MHz BW 1% VOUT, Nom
Output Current Limit Inception 130% lOUT, Nom
Output Short-Circuit Current (2) test 110% lOUT, Nom
Output Overvoltage Limit 125% 130% V
Transient Response 50 to 100% Load Step
Peak Deviation di/dt = 1.0A/µSec 2% VOUT, Nom
Settling Time VOUT, 1% of Nominal Output 100 µSec
ISOLATION
Input to Output Peak Test for 2 Seconds 1500 VDC
Input to Baseplate 1500 VDC
Output to Baseplate 500 VDC
Resistance 10 MΩ
Capacitance 2000 pF
Leakage Current VISO = 240VAC, 60Hz 180 µA, rms
GENERAL
Efficiency, Line, Load, Temp. (3)
Switching Frequency 400 420 440 KHz
Remote Sense Compensation 0.5 V
Output Voltage Adjust Range-12V & higher(4) -50% / +25% VOUT, Nom
Remote On/Off Control Inputs
Primary Open Collector/Drain
Sink Current-Logic Low 1.0 mA
Vlow 1V
Vhigh 2V
Turn-on Time Within 1% of Rated Output 10.0 12.5 mSec
Weight 85 (3.0) g (oz.)
TEMPERATURE
Operation/Specification Case Temperature -40 +25 +100 °C
Storage Case Temperature -55 +25 +125 °C
Shutdown Temperature Case Temperature +100 +115 °C
Thermal Impedance, case-ambient 7.1 °C/W
Lead Solder Temperature 10 Seconds max +300 °C
( ) See NOTES on page 3.
VKA50xS Rev B 4/99 Page 3
NOTES:
(1) See Typical Performance Curves, page 3
(2) Continuous Mode
(3) See graphs for Efficiency vs. Output Load, VIN, TCASE
(4) 3.3V Models Limited in Trim Down Range
(5) Consult Factory for Details
TYPICAL PERFORMANCE CURVES
TA = +40°C, nominal input voltage, rated load, recommended external components applied, unless otherwise specified.
3.3V
5V
28V
020 40 60 80 100
70
75
80
85
90
95
EFFICIENCY vs OUTPUT LOAD
Efficiency (%)
Output Load (% of Rated)
15V
OUTPUT RIPPLE vs INPUT VOLTAGE
Normalized Output Ripple
Vin (VDC)
1.50
1.25
1.00
0.75
0.50
12V
Dissipated Power, P
D
(W)
Ambient Temperature (°C)
POWER DERATING WITH NO HEATSINK
Natural
Convection
0
10
25 50 75 100
400 LFM
Airflow
200 LFM
Airflow
12
2
4
6
8
Vin, min Vin, typ Vin, max
020 40 60 80 100
70
75
80
85
90
95
EFFICIENCY vs OUTPUT LOAD
Efficiency (%)
Output Load (% of Rated)
Change in Efficiency (%)
-10
-5
TYP
+5
+10
50% Load
10% Load
EFFICIENCY vs INPUT VOLTAGE
Vin (VDC)
Vin, min Vin, typ Vin, max
EFFICIENCY vs TEMPERATURE
Change in Efficiency (%)
20% Load
100% Load
-55 +25 +105
Tcase (°C)
-15 +65
+5
-5
-10
TYP
+10
100% Load
24V
REFLECTED RIPPLE CURRENT
vs TEMPERATURE
-55 +25 +105
Tcase (°C)
+100
TYP
-100
Change in Reflected Ripple Current (%)
-15 +65
-50
+50
OUTPUT RIPPLE vs TEMPERATURE
-55 +25 +105
Tcase (°C)
3.0
1.0
0.33
Normalized Output Ripple
-15 +65
0.5
2.0
14
16
24V
28V
15V
ORDERING INFORMATION
VKA50 xSzz-
Device Family
Indicates 50 Watt Regulated Unit
Model Number
Selected from Table of Electrical Characteristics
Where:
x = Input Voltage (L = 24VDC; M = 48VDC)
zz = Output Voltage (03=3.3V, 05=5V, etc.)
Lead Length
0.200" - No Number
0.145" - (6)
0.110" - (8)
Remote On-Off Logic:
Positive - No Number
Negative - (1)
25 50 75 100
0
0
2
4
6
8
10
12
14
16
18
20
22
400 LFM
200
LFM
Natural
Convection
POWER DERATING WITH NO HEATSINK
Dissipated Power, Po (W)
Ambient Temperature (°C)
VKA50xs Rev B 4/99
Page 4
OVP NOTE
Special attention should be given to the peak voltage
deviation during a dynamic load step when trimming the
output above the original set point to avoid tripping the
overvoltage protection circuit. Should an OVP condition
occur, the converter will go into a latch condition and
must be externally reset before it will return to normal
operation.
NOTES:
All dimensions are in inches (millimeters).
PIN PLACEMENT TOLERANCE: ± 0.005"
MECHANICAL TOLERANCE: ± 0.015"
Marked with: specific modeL ordered, date code, job
code.
MATERIAL: Units are encapsulated in a low thermal
resistance molding compound which has excellent
chemical resistance and electrical properties in high
humidity environments and over a wide operating
temperature range. The encapsulant and outer shell of
the unit have UL94V-0 ratings. Lead material is solder
plated to allow ease of solderability.
MECHANICAL
1.000
[25.40]
1.400
[35.56]
2.000
[50.80]
0.19 [4.8]
0.20 [5.1]
0.50 [12.7]
0.40 [10.16]
0.530 MAX
[13.46]
0.20 [5.1] .040 [1.02] DIA.
7 PLACES
.081 [2.06] DIA.
2 PLACES
1.400
[35.56]
1.000
[25.40]
0.700
[17.78]
.400 [10.16]
1.900
[48.26]
2.28
[57.91]
MAX
MOUNTING INSERTS M3 X 0.5 THRU, 4 PLACES
MAX. TORQUE, 8 IN/LBS
2.40
[61.0]
MAX
OUTPUT VOLTAGE ADJUST
This feature allows the user to accurately adjust the
module's output voltage set point to a specified level.
This is achieved by connecting a resistor or potentiometer
from the TRIM terminal to either the +Vout terminal (for
increased Vout) or the -Vout terminal (for decreased
Vout). The formulae below describe the trim resistor
value to obtain a Vout change of ∆%. VO is output
voltage prior to adjustment (3.3V, 5V, 12V, 15V, 24V or
28V).
Radj - up = ( Vo(100 + ∆%) _ (100 + 2∆%) ) kΩ
1.225∆% ∆%
Radj - down = (100 - 2) kΩ
∆%
