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2401 Stanwell Drive, Concord Ca. 94520 Ph: 925-687-4411 Fax: 925-687-3333 www.calex.com Email: sales@calex.com
ECO# 101028-1, 151005-3
100 WATT HEW SINGLE SERIES
DC/DC CONVERTERS
Output Parameters
Model 24S3.25HEW
48S3.25HEW
24S5.20HEW
48S5.20HEW
24S12.8HEW
48S12.8HEW
24S15.7HEW
48S15.7HEW
24S24.4HEW
48S24.4HEW
Units
Output Voltage 3.3 5 12 15 24 V
Output Voltage
Setpoint Accuracy MAX ±1 %
Turn On Overshoot Min-Max Load TYP 0 %
Temperature Coefcient TYP
MAX
0.005
0.01
0.003
0.005
0.003
0.005
0.003
0.005
0.003
0.005 %/ºC
Noise (8) TYP
TYP
75
20
75
20
150
60
150
60
250
100
mV p-p
mV rms
Load Current (4) MIN
MAX
2.5
25
2
20
0.833
8.33
0.667
6.67
0.413
4.13 A
Load Transient Overshoot (7) TYP 3 %
Load Transient Recovery Time (6) TYP 200 µs
Load Regulation (5)
Min-Max Load
TYP
MAX
0.02
0.2 %
Line Regulation
Vin = Min-Max
TYP
MAX
0.01
0.1 %
Overvoltage Protection (OVP)
Threshhold
OVP Type - Non-latching
Open Loop Overvoltage Clamp
MIN
MAX
115
135 %
Output Current Limit
Vout = 90% of Vout-nom TYP 120 %
Output Short Circuit Current
Vout = 0.25V
TYP
MAX
140
150 %
Notes:
(1) Refer to the CALEX Application Notes for the denition of terms,
measurement circuits, and other information.
(2) Refer to the CALEX Application Notes for information of fusing.
For inrush current, refer to the specications above.
(3) 33µF capacitor connected between the two “Input” pins. Then
insert current sensor in series with 1.0µH inductor between
100µF and the source. The reected ripple current is measured
over a 5 Hz to 20 MHz bandwidth. (current sensor is located
between the converter input pin and the 1.0 µH inductor)
(4) Optimum performance is obtained when this power supply is
operated within the minimum to maximum load specications.
No damage to the module will occur when the output is operated
at less than minimum load, however, below minimum load the
dynamic response will degrade. Operation below minimum load
is not recommended.
(5) Load regulation is dened as the output voltage change when
changing load current from a maximum to minimum.
(6) Load Transient Recovery Time is dened as the time for the
output to settle from a 50% to 75% step load change to a 1%
error band (rise time of step = 2µs).
(7) Load Transient Overshoot is dened as the peak overshoot
during a transient as dened in the Note 6 above.
(8) Noise is measured per the CALEX Application Notes. Output
noise is measured with a 10µF tantalum capacitor in parallel with
a 0.1µF ceramic capacitor connected across the output pins.
Measurement bandwidth is 0-20MHz.
(9) When an external ON/OFF switch is used, such as open collector
switch, logic high requires the switch to be high-impedance.
Switch leakage currents greater than 10µA may be sufcient to
trigger the ON/OFF to the logic-low state.
(10) Most switches would be suitable for the logic ON/OFF control. In
case there is a problem you can make the following estimations and
then leave some margin.
When open collector is used for logic high, “Open Circuit Voltage at
ON/OFF Pin”, “Output Resistance” and “External Leakage Current
Allowed for Logic High” are used to estimate the high impedance
requirement of open collector.
When switch is used for logic low, “Open Circuit Voltage at ON/
OFF Pin”, “Output Resistance” and “LOW Logic Level” are used to
estimate the low impedance requirement of the switch.
(11) Thermal impedance is tested with the converter mounted vertically
and facing another printed circuit board 1/2 inch away. If converter
is mounted horizontally with no obstruction, thermal impedance is
approximately 8°C/W.
(12) Water Washability - Calex DC/DC converters are designed to
withstand most solder/wash processes. Careful attention should be
used when assessing the applicability in your specic manufacturing
process. Converters are not hermetically sealed.
(13) Torque fasteners into threaded mounting inserts at 12 in.lbs. or less.
Greater torque may result in damage to unit and void the warranty.
(14) Input impedance on these units needs to be kept to a minimum. The
9-36Vdc DC units need a maximum input impedance of 0.2 Ohms
and the 18-75Vdc DC units need a maximum input impedance of 0.8
Ohms. In order to support this requirement, the 9-36Vdc DC units
need 25 µF of capacitance (low ESR) for every 1.0 µH of inductance
between the power source and the DC/DC converter. The 18-75Vdc
DC units need 1.7µF of capacitance (low ESR) for every 1.0 µH of
inductance between the power source and the DC/DC converter.
Inductance includes all sources and should take into account input
power lines.
(15) RoHS Compliance:
See Calex Website www.calex.com/RoHS.html for the complete
RoHS Compliance statement.
The RoHS marking is as follows.