POWER ELECTRONICS DIVISION
UHE Series
Isolated, High Efficiency, .6" x 2" 2-0 Amp, 2-30 Watt DC/DC's
Housed in smaller, .6" x 2" x 0.40" (4 x 5 x 0.2mm) packages
carrying the standard 2" x 2" pinout, C&D's new UHE Series DC/
DC Converters deliver more current/power (up to 0A/30W) than
currently available from either package size.
FEATURES
n
most I
OUT
/P
OUT
in this format
The
n
Lower priced than bricks
n
Small .6" x 2" x 0.4" plastic package with
standard 2" x 2" pinout
n
Output configurations:
.2/.5/.8/2.5V
OUT
@ 0 Amps
3.3/5V
OUT
@ 25 Watts
5/2/5V
OUT
@ 30 Watts
n
input ranges from 9-75 Volts
Five
n
Efficiencies as high as 9.5%
n
Stable no-load operation
n
Optional Sense pins for low V
OUT
n
Thermal shutdown, I/O protected
n
Vdc I/O BASIC Insulation
500
n
UL/EN60950 certified; CE marked for Q48
models
n
compliant
RoHS
PRODUCT OVERVIEW
The UHE 2-30W Series of high-efficiency, isolated
DC/DC's provide output power ranging from 0
Amps @ .2V to 2 Amps @ 5V. Offering both
2: and 4: input voltage ranges, UHE's meet V
IN
requirements from 9 to 75 Volts.
Taking full advantage of the synchronous-recti-
fier, forward topology, UHE's boast outstanding
efficiency (some models exceed 9%) enabling
full-power operation to ambient temperatures as
high as +60°C, without air flow. Assembled using
fully automated, SMT-on-pcb techniques, UHE's
provide stable no-load operation, excellent line
(±0.%) and load (±0.5%) regulation, quick step
response (200µsec), and low output ripple/noise
(50-00mVp-p). Additionally, the UHE's unique
output design eliminates one of the topology's few
SIMPLIFIED SCHEMATIC
+INPUT
(1)
+OUTPUT
(6)
shortcomings–output reverse conduction.
All devices feature full I/O fault protection including:
input overvoltage and undervoltage shutdown,
precise output overvoltage protection (a rarity on
low-voltage outputs), output current limiting, short-
circuit protection, and thermal shutdown.
All UHE models incorporate a V
OUT
Trim function and
an On/Off Control pin (positive or negative polarity).
Low-voltage models (.2V to 5V) offer optional
sense pins facilitating either remote load regula-
tion or current sharing for true N+ redundancy.
All models are certified to the BASIC insulation
requirements of UL/EN60950, and 48V
IN
(75V max.)
models carry the CE mark. Selected models are
RoHS compliant (Reduction of Hazardous Sub-
stances).
SWITCH
CONTROL
+SENSE
(5)
–OUTPUT
(7)
–INPUT
(2)
THERMAL
SHUTDOWN
OPTO
ISOLATION
OVERVOLTAGE
COMPARATOR
*
–SENSE
(8)
PWM
CONTROLLER
UVLO & OVLO
COMPARATORS
ON/OFF
CONTROL
(4)
OPTO
ISOLATION
REFERENCE &
ERROR AMP
V
OUT
TRIM
(9)
*One phase of two is shown.
Optional comparator feedback. Contact DATEL.
Sense pins are optional on .2-5V
OUT
models ("R" suffix).
Typical topography is shown.
For full details go to
www.cd4power.com/rohs
DC/DC CONVERTERS
MDC_UHE_A01
Page of 4
www.cd4power.com
POWER ELECTRONICS DIVISION
UHE Series
Isolated, High Efficiency, .6" x 2" 2-0 Amp, 2-30 Watt DC/DC's
Output
R/N (mVp-p)
Typ.
Max.
80
80
80
55
55
55
55
55
50
50
50
50
50
60
60
80
50
60
50
80
80
90
00
65
65
00
60
70
70
70
00
70
20
20
20
80
80
80
80
80
75
75
75
75
70
90
90
00
70
90
70
00
00
25
20
00
00
20
00
00
00
00
50
00
PERFORMANCE SPECIFICATIONS AND ORDERING GUIDE
Model Family
(See model numbering
on page 3)
Input
Regulation (Max.)
Line
Load
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.05%
±0.075%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.625%
±0.5/0.5%
±0.5/0.5%
±0.5/0.5%
±0.5/0.3%
±0.5/0.3%
±0.5/0.3%
±0.25%
±0.5/0.3%
±0.5/0.3%
±0.5%
±0.25/0.5%
±0.25%
±0.45%
±0.3%
±0.3%
±0.3%
±0.3%
±0.3%
±0.3%
±0.5%
±0.3%
±0.3%
±0.3%
V
OUT
(Volts)
.2
.2
.2
.5
.5
.5
.8
.8
.8
2.5
2.5
2.5
3.3
3.3
3.3
3.3
5
5
5
5
5
5
2
2
2
2
2
5
5
5
5
5
I
OUT
(Amps)
0
0
0
0
0
0
0
0
0
0
0
0
7.5
7.5
7.5
7.5
5
5
6
6
6
6
2.5
2.5
2.5
2.5
2.5
2
2
2
2
2
V
IN
Nom.
(Volts)
2
24
48
2
24
48
2
24
48
2
24
48
24
48
48
48
24
48
24
48
48
48
24
2
24
48
48
2
24
24
48
48
Range
(Volts)
9-8
8-36
36-75
9-8
8-36
36-75
9-8
8-36
36-75
9-8
8-36
36-75
9-36
8-75
36-75
36-75
9-36
8-75
9-36
36-75
36-75
8-75
9-36
9-8
8-36
8-75
36-75
9-8
9-36
8-36
8-75
36-75
I
IN
(mA/A)
35/.27
35/0.63
35/0.3
35/.56
35/0.76
35/0.38
35/.8
35/0.89
35/0.46
35/2.48
35/.23
35/0.6
50/.2
38/0.6
35/0.6
35/0.58
50/.22
35/0.6
50/.44
45/0.73
45/0.7
38/0.7
45/.5
90/2.92
55/.44
45/0.72
30/0.7
0/2.92
50/.42
70/.44
45/0.72
35/0.7
Efficiency
80%
8%
8%
8%
84%
82%
84%
85.5%
83.5%
85%
86%
86%
86.5%
87.5%
88.5%
87%
86%
87.5%
86.5%
87.5%
87.5%
86%
85%
87%
88%
88%
90%
87%
86%
88%
88%
90%
82%
83%
83%
83%
86%
84%
85.5%
87%
85%
87%
88%
88%
88%
89.5%
9%
88.5%
87.5%
90%
87%
89%
89%
87.5%
87.5%
89%
90%
90.5%
92%
89%
88%
90%
90.5%
92%
Package
(Case/
Pinout)
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5/52
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
C32, P5
UHE-1.2/10000-D12
UHE-1.2/10000-D24
UHE-1.2/10000-D48
UHE-1.5/10000-D12
UHE-1.5/10000-D24
UHE-1.5/10000-D48
UHE-1.8/10000-D12
UHE-1.8/10000-D24
UHE-1.8/10000-D48
UHE-2.5/10000-D12
UHE-2.5/10000-D24
UHE-2.5/10000-D48
UHE-3.3/7500-Q12
UHE-3.3/7500-Q48
UHE-3.3/7500-D48
UHE-3.3/7500-D48T
UHE-5/5000-Q12
UHE-5/5000-Q48
UHE-5/6000-Q12
UHE-5/6000-D48
UHE-5/6000-D48T
UHE-5/6000-Q48T
UHE-12/2500-Q12
UHE-12/2500-D12
UHE-12/2500-D24
UHE-12/2500-Q48
UHE-12/2500-D48
UHE-15/2000-D12
UHE-15/2000-Q12
UHE-15/2000-D24
UHE-15/2000-Q48
UHE-15/2000-D48
Typical at T
A
= +25°C under nominal line voltage and full-load conditions, unless noted.
Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth. All models are specified with
an external 0.47µF multi-layer ceramic capacitor installed across their output pins.
Nominal line voltage, no-load/full-load conditions.
Devices have no minimum-load requirements and will regulate under no-load conditions.
Regulation specifications describe the output voltage deviation as the line voltage or load
(with/without sense option) is varied from its nominal/midpoint value to either extreme.
Contact C&D for availability.
MECHANICAL SPECIFICATIONS
INPUT/OUTPUT CONNECTIONS
Pin
Function P51
2
3
4
5
6
7
8
9
+Input
–Input
No Pin
On/Off Control
No Pin
+Output
–Output
No Pin
Trim
Function P52
+Input
–Input
No Pin
On/Off Control
Sense*
+Output
–Output
–Sense*
Trim
* Pins 5 and 8 are installed for optional R-suffix versions of
.2-5V
OUT
models.
See page 4 for complete Part Number structure & ordering details.
DC/DC CONVERTERS
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MDC_UHE_A01
Page 2 of 4
POWER ELECTRONICS DIVISION
UHE Series
Isolated, High Efficiency, .6" x 2" 2-0 Amp, 2-30 Watt DC/DC's
() (2)
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage and full-load conditions, unless noted.
Input
Input Voltage Range:
D2 Models (start up at 0V max.)
Q2 Models (start up at 0V max.)
D24 Models
Q48 Models
D48 Models
Overvoltage Shutdown:
D2 Models
Q2/D24 Models
D48/Q48 Models
Start-Up Threshold:
D2/Q2 Models
D24/Q48 Models
D48 Models
(2)
Output
9-8 Volts (2V nominal)
9-36 Volts (24V nominal)
8-36 Volts (24V nominal)
8-75 Volts (48V nominal)
36-75 Volts (48V nominal)
8.5-23 Volts
37-42 Volts
Not applicable
9.4-0 Volts
5.5-8 Volts
33.5-36 Volts
(2)
Overvoltage Protection:
.2V Outputs
.5V Outputs
.8V Outputs
2.5V Outputs
3.3V Outputs
5V Outputs
2V Outputs
5V Outputs
Maximum Capacitive Loading:
(Low ESR capacitor)
Magnetic feedback
.5-2. Volts
.8-2.4 Volts
2.2-2.8 Volts
2.8 to 3.2 Volts
4 to 4.8 Volts
6.-7.5 Volts
2.7-3.5 Volts
5.8-6.2 Volts
0,000µF (.2-5V
OUT
)
2,000µF (2-5V
OUT
)
Dynamic Characteristics
Dynamic Load Response:
(50-00% load step to ±3% V
OUT
)
Start-Up Time:
(8)
V
IN
to V
OUT
and On/Off to V
OUT
UHE-5/2000-Q2
Switching Frequency
Environmental
MTBF
(9)
Operating Temperature (Ambient):
Without Derating
With Derating
Thermal Shutdown
Storage Temperature
Flammability
Physical
Dimensions
Case Material
Pin Material
Weight
Primary to Secondary Insulation Level
(0)
Undervoltage Shutdown:
D2/Q2 Models
D24/Q48 Models
D48 Models
200µsec maximum
(8)
8msec typical
5msec maximum
30mS typ., 50mS max.
50-350kHz (model dependent)
TBC million hours
–40 to +65°C (model dependent)
To +00°C (see Derating Curves)
+5°C
–55 to +25°C
94V-Ø
.6" x 2" x 0.40" (40.64 x 50.8 x
0.6mm)
Diallyl Phthalate
Gold-plated copper alloy
.5 ounces (46.9 grams)
Basic
7.0-8.8 Volts
5-7 Volts
32-35.5 Volts
See Ordering Guide
5mA
0mAp-p
LC or Pi type
Brief duration, 5A maximum
On = open, open collector, or
+3V to V
IN
applied. I
IN
= 2.6mA max.
Off = pulled low to 0-0.8V. I
IN
= 2mA
max.
On = pulled low to 0-0.8V. I
IN
= 6mA
max.
Off = open, open collector or
+3.5V to V
IN
applied. I
IN
= mA max.
Input Current:
Normal Operating Conditions
Standby Mode (Off, OV, UV)
Input Reflected Ripple Current
Input Filter Type
Reverse-Polarity Protection
Remote On/Off Control (Pin 4):
(4)
Positive Logic (Standard)
(3)
Negative Logic ("N" Suffix Models)
Output
V
OUT
Accuracy (50% load):
Initial
Temperatue Coefficient
Extreme
(5)
Minimum Loading for Specification:
(2)
Ripple/Noise (20MHz BW)
Line/Load Regulation
Efficiency
V
OUT
Trim Range
(6)
()
±.5%
±0.02% per °C
±3%
No load
See Ordering Guide
See Ordering Guide
See Ordering Guide
±5% minimum (±0% for T models)
±5%
500Vdc minimum (BASIC)
650pF
00MΩ
(7)
Remote Sense Compensation
(2)
Isolation Voltage:
Input-to-Output
Isolation Capacitance
Isolation Resistance
Current Limit Inception (@98%V
OUT
):
0 Amp Models
7.5 Amp Models
5/6 Amp Models
2.5 Amp Models
2.0 Amp Models
Short Circuit Current (Hiccup)
2-5 Amps
8.2-.5 Amps
6.5-8.5 Amps
2.6-3.75 Amps
2.-3 Amps
.5-2.3 Amps
() All models are tested and specified with a single, external, 0.47µF, multi-layer ceramic
output capacitor and no external input capacitors, unless otherwise noted. All models
will effectively regulate under no-load conditions (with perhaps a slight increase in output
ripple/noise).
(2) See Technical Notes/Performance Curves for additional explanations and details.
(3) Input Ripple Current is tested/specified over a 5-20MHz bandwidth with an external 33µF
input capacitor and a simulated source impedance of 220µF and 2µH. See I/O Filtering,
Input Ripple Current and Output Noise for details.
(4) The On/Off Control is designed to be driven with open-collector (or equivalent) logic or the
application of appropriate voltages (referenced to –Input (pin 2)). Applying a voltage to the
On/Off Control pin when no input voltage is applied to the converter can cause permanent
damage. See Remote On/Off Control for more details.
(5) Extreme Accuracy refers to the accuracy of either trimmed or untrimmed output voltages
over all normal operating ranges and combinations of input voltage, output load and tem-
perature.
(6) Tie the Output Trim pin (pin 9) to +Output (pin 6) for maximum trim down or to –Output
(Output Return/Common, pin 7) for maximum trim up. See Output Trimming for detailed trim
equations.
(7) The Current-Limit-Inception point is the output current level at which the converter's power-
limiting circuitry drops the output voltage 2% from its initial value. See Output Current Limit-
ing and Short-Circuit Protection for more details.
(8) For Start-Up-Time specifications, output settling time is defined as the output voltage having
reached ±% of its final value at maximum load current.
(9) MTBF’s are calculated using TELCORDIA SR-332 Method Case, ground fixed, +25°C ambi-
ent air and full-load conditions. Contact C&D for demonstrated life-test data.
(0) All models are fully operational and meet all published specifications, including "cold start,"
at –40°C.
DC/DC CONVERTERS
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MDC_UHE_A01
Page 3 of 4
POWER ELECTRONICS DIVISION
UHE Series
Isolated, High Efficiency, .6" x 2" 2-0 Amp, 2-30 Watt DC/DC's
Input Undervoltage Shutdown and Start-Up Threshold
Under normal start-up conditions, devices will not begin to regulate until
the ramping-up input voltage exceeds the Start-Up Threshold Voltage. Once
operating, devices will not turn off until the input voltage drops below the
Undervoltage Shutdown limit. Subsequent re-start will not occur until the
input is brought back up to the Start-Up Threshold. This built in hysteresis
prevents any unstable on/off situations from occurring at a single input
voltage.
Start-Up Time
The V
IN
to V
OUT
Start-Up Time is the interval of time between the point at
which the ramping input voltage crosses the Start-Up Threshold and the
fully loaded output voltage enters and remains within its specified accuracy
band. Actual measured times will vary with input source impedance,
external input/output capacitance, and load. The UHE Series implements a
soft start circuit that limits the duty cycle of its PWM controller at power up,
thereby limiting the input inrush current.
The On/Off Control to V
OUT
start-up time assumes the converter has its
nominal input voltage applied but is turned off via the On/Off Control pin.
The specification defines the interval between the point at which the con-
verter is turned on and the fully loaded output voltage enters and remains
within its specified accuracy band. Similar to the V
IN
to V
OUT
start-up, the
On/Off Control to V
OUT
start-up time is also governed by the internal soft
start circuitry and external load capacitance.
The difference in start up time from V
IN
to V
OUT
and from On/Off Control to
V
OUT
is therefore insignificant.
Absolute Maximum Ratings
Input Voltage:
Continuous:
D2 Models
D24/Q2 Models
D48/Q48 Models
Transient (00msec):
D2 Models
D24/Q2 Models
D48/Q48 Models
On/Off Control (pin 4) Max. Voltages
Referenced to –Input (pin 2)
No Suffix
"N" Suffix
Input Reverse-Polarity Protection
Output Current
23 Volts
42 Volts
8 Volts
25 Volts
50 Volts
00 Volts
+V
IN
+7 Volts
Current must be <5 Amps. Brief
duration only. Fusing recommended.
Current limited. Devices can
withstand sustained output short
circuits without damage.
+00°C
–55 to +25°C
+300°C
Case Temperature
Storage Temperature
Lead Temperature (soldering, 0 sec.)
These are stress ratings. Exposure of devices to any of these conditions may adversely
affect long-term reliability. Proper operation under conditions other than those listed in
the Performance/Functional Specifications Table is not implied.
T E C H N I C A L
N O T E S
Input Overvoltage Shutdown
All D2/Q2 and D24 Models of the UHE DC/DC converters are equipped
with Input Overvoltage Protection. Input voltages exceeding the input
overvoltage shutdown specification listed in the Performance/Functional
Specifications will cause the device to shutdown. A built-in hysteresis for
all models will not allow the converter to restart until the input voltage is
sufficiently reduced.
All 48V
IN
models have this overvoltage shutdown function disabled because
of requirements for withstanding brief input surges to 00V for up to
00msec without output voltage interruption.
Please contact DATEL to have input overvoltage shutdown for D48/Q48
models enabled.
Input Source Impedance
UHE converters must be driven from a low ac-impedance input source.
The DC/DC's performance and stability can be compromised by the use of
highly inductive source impedances. The input circuit shown in Figure 2
is a practical solution that can be used to minimize the effects of induct-
ance in the input traces. For optimum performance, components should
be mounted close to the DC/DC converter. If the application has a high
source impedance, low V
IN
models can benefit of increased external input
capacitance.
Input Fusing
Certain applications and/or safety agencies may require the installation of
fuses at the inputs of power conversion components. Fuses should also
be used if the possibility of sustained, non-current-limited, input-voltage
polarity reversals exists. For DATEL UHE 2-30 Watt DC/DC Converters, you
should use slow-blow type fuses, installed in the ungrounded input supply
line, with values no greater than the following.
Model
Output/Input
.2 V
OUT
.5 V
OUT
.8 V
OUT
2.5 V
OUT
3.3 V
OUT
5 V
OUT
2 V
OUT
5 V
OUT
D12
3
4
5
5
--
--
6
6
Fuse Values in Amps
Q12
D24
Q48
--
2
--
--
2
--
--
2.5
--
--
2.5
--
7.5
-
3
5
-
3
3
3
5
3
3
5
D48
.5
2
2
2
All relevant national and international safety standards and regulations
must be observed by the installer. For system safety agency approvals, the
converters must be installed in compliance with the requirements of the
end-use safety standard, e.g. IEC/EN/UL60950.
DC/DC CONVERTERS
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MDC_UHE_A01
Page 4 of 4
POWER ELECTRONICS DIVISION
UHE Series
Isolated, High Efficiency, .6" x 2" 2-0 Amp, 2-30 Watt DC/DC's
I/O Filtering, Input Ripple Current, and Output Noise
All models in the UHE 2-30 Watt DC/DC Converters are tested/specified for
input reflected ripple current and output noise using the specified external
input/output components/circuits and layout as shown in the following two
figures.
External input capacitors (C
IN
in Figure 2) serve primarily as energy-storage
elements, minimizing line voltage variations caused by transient IR drops
in conductors from backplane to the DC/DC. Input caps should be selected
for bulk capacitance (at appropriate frequencies), low ESR, and high rms-
ripple-current ratings. The switching nature of DC/DC converters requires
that dc voltage sources have low ac impedance as highly inductive source
impedance can affect system stability. In Figure 2, C
BUS
and L
BUS
simulate a
typical dc voltage bus. Your specific system configuration may necessitate
additional considerations.
TO
OSCILLOSCOPE
+SENSE
+OUTPUT
COPPER STRIP
C1
C2
SCOPE
R
LOAD
–OUTPUT
–SENSE
COPPER STRIP
C1 = 0.47µF CERAMIC
C2 = NA
LOAD 2-3 INCHES (51-76mm) FROM MODULE
Figure 3. Measuring Output Ripple/Noise (PARD)
Minimum Output Loading Requirements
CURRENT
PROBE
L
BUS
C
BUS
–
–INPUT
C
IN
= 33µF, ESR < 700m @ 100kHz
C
BUS
= 220µF, ESR < 100m @ 100kHz
L
BUS
= 12µH
C
IN
+INPUT
+
V
IN
UHE converters employ a synchronous-rectifier design topology and all
models regulate within spec and are stable under no-load to full load con-
ditions. Operation under no-load conditions however might slightly increase
the output ripple and noise.
Thermal Shutdown
These UHE converters are equipped with thermal-shutdown circuitry. If
environmental conditions cause the internal temperature of the DC/DC
converter to rise above the designed operating temperature, a precision
temperature sensor will power down the unit. When the internal tempera-
ture decreases below the threshold of the temperature sensor, the unit will
self start. See Performance/Functional Specifications.
Output Overvoltage Protection
UHE output voltages are monitored for an overvoltage condition via mag-
netic feedback. The signal is coupled to the primary side and if the output
voltage rises to a level which could be damaging to the load, the sensing
circuitry will power down the PWM controller causing the output voltages
to decrease. Following a time-out period the PWM will restart, causing the
output voltages to ramp to their appropriate values. If the fault condi-
tion persists, and the output voltages again climb to excessive levels, the
overvoltage circuitry will initiate another shutdown cycle. This on/off cycling
is referred to as "hiccup" mode.
Contact DATEL for an optional output overvoltage monitor circuit using a
comparator which is optically coupled to the primary side thus allowing
tighter and more precise control.
Current Limiting
As soon as the output current increases to 0% to 50% above its rated
value, the DC/DC converter will go into a current-limiting mode. In this
condition, the output voltage will decrease proportionately with increases in
output current, thereby maintaining somewhat constant power dissipation.
This is commonly referred to as power limiting. Current limit inception is
defined as the point at which the full-power output voltage falls below the
specified tolerance. See Performance/Functional Specifications. If the load
current, being drawn from the converter, is significant enough, the unit will
go into a short circuit condition as specified under "Performance."
Figure 2. Measuring Input Ripple Current
In critical applications, output ripple/noise (also referred to as periodic and
random deviations or PARD) may be reduced below specified limits using
filtering techniques, the simplest of which is the installation of additional
external output capacitors. These output caps function as true filter ele-
ments and should be selected for bulk capacitance, low ESR and appropri-
ate frequency response. All external capacitors should have appropriate
voltage ratings and be located as close to the converter as possible.
Temperature variations for all relevant parameters should also be taken
carefully into consideration.
The most effective combination of external I/O capacitors will be a function
of line voltage and source impedance, as well as particular load and layout
conditions. Our Applications Engineers can recommend potential solutions
and discuss the possibility of our modifying a given device's internal filter-
ing to meet your specific requirements. Contact our Applications Engineer-
ing Group for additional details.
In Figure 3, the two copper strips simulate real-world pcb impedances
between the power supply and its load. In order to minimize measurement
errors, scope measurements should be made using BNC connectors, or
the probe ground should be less than ½ inch and soldered directly to the
fixture.
Floating Outputs
Since these are isolated DC/DC converters, their outputs are "floating" with
respect to their input. Designers will normally use the –Output (pin 7) as the
ground/return of the load circuit. You can, however, use the +Output (pin 6)
as ground/return to effectively reverse the output polarity.
DC/DC CONVERTERS
www.cd4power.com
MDC_UHE_A01
Page 5 of 4
DIY/Open Source Hardware
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