®
UHP-12/21-D48
Isolated, 21 Amp Half Brick, 48V
IN
/12V
OUT
DC/DC Converter
ORDERING GUIDE SUMMARY
Model
UHP-12/21-D48
V
OUT
Range
12V
I
OUT
Range
0-21A
V
IN
Range
36-75V
Ripple/Noise
125mVp-p
Efficiency
91%
INPUT CHARACTERISTICS
Parameter
Voltage Range
Current, full power
Undervoltage Shutdown
Short Circuit Current
Remote On/Off Control
OUTPUT CHARACTERISTICS
Parameter
Typ. @ 25°C, full load
36-75 Volts
5.77 Amps
33 Volts
20mA
0 to +V
IN
Notes
48V nominal
V
IN
= 48V
V
IN
= 48V
Positive or negative logic
Typ. @ 25°C, full load
12 Volts ±10%
0 to 21 Amps
255 Watts max.
±1.25%
125mVp-p
±0.05%/±0.25%
30 Amps
+125°C
90%
91%
Notes
Trim range shown
No minimum load
Maximum baseplate = +110°C
@ 255W
20MHz bandwidth
With hiccup auto-restart
FEATURES
■
■
■
■
■
■
■
■
■
■
■
Voltage
Current
Power Output
Accuracy
Ripple & Noise
Line and Load Regulation
Overcurrent Protection
Overtemperature Protection
Efficiency
(minimum)
Efficiency
(typical)
GENERAL SPECIFICATIONS
Parameter
Dynamic Load Response
Operating Temperature Range
Operating Temperature Range
Safety
Wide 36-75V input range
12V output @ 21 Amps. max.
Very high efficiency of 91%
Operates to +110°C baseplate w/derating
Conduction-cooled baseplate, no fans
Industry-standard mounting and pinout
Remote sense, trim and On/Off control
Isolated to 2250Vdc (Basic insulation)
Multiple I/O protection features
UL/EN60950 safety approvals, CE mark
Start up into pre-biased load
Typ. @ 25°C, full load
150μsec
–40 to +110°C
–40 to +32°C
UL/IEC/EN 60950
Notes
50-75-50% step to ±1.5% of final value
With baseplate, see derating curve
Without baseplate
And CSA C22.2-No.60950
DESCRIPTION
For “distributed architecture” power applications,
DATEL’s UHP-12/21-D48 DC/DC converter offers a
wide input range of 36-75 Volts DC, delivering up
to 21 Amps with 12 Volts DC output. This DC/DC
converter is an ideal precision intermediate bus
power unit with tight regulation and 2250 Volt
isolation. It is manufactured on a 2.3" x 2.4"
open-frame package with industry-standard “half
brick” pinout and mounting.
UHP converters use a interleaved forward, fixed-
frequency topology with synchronous output recti-
fication to achieve high efficiency. UHP-12/21-D48
can be operated using conduction cooling
attached to a housing wall or system heat sink.
No forced air-flow is needed to +110°C base-
MECHANICAL CHARACTERISTICS
With baseplate
Without baseplate
2.30 x 2.40 x 0.502 inches (58.42 x 60.96 x 12.75 mm)
2.30 x 2.40 x 0.452 inches (58.42 x 60.96 x 11.48 mm)
plate temperature. Multiple protection features
avoid damage to outside equipment and to the
converter itself. The converter will shut down on
sustained input undervoltage, output overcurrent,
output short circuit and overvoltage and thermal
shutdown. Overload currents less than a short
circuit limit the output current so that operation
is not interrupted. Upon short circuit shutdown,
the converter will automatically attempt to restart
(“hiccup” mode) when the overload is removed.
The overall unit is designed to be as “lead-free”
as practical in construction and attachment
method (no lead added in assembly). Standard
features also include Sense and Trim pins and
On/Off Control.
Pb
Lead-free
construction/attach
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UHP-12/21-D48
Page 1 of 12
®
UHP-12/21-D48
Isolated, 21 Amp Half Brick, 48V
IN
/12V
OUT
DC/DC Converter
PERFORMANCE SPECIFICATIONS AND ORDERING GUIDE
➀
Output
Model
UHP-12/21-D48
➀
➁
➂
➃
Input
Regulation (max.)
Line
±0.05%
Load
➂
±0.15%
Max.
175
V
IN
Nom.
(Volts)
48
Range
(Volts)
36-75
I
IN
➃
(mA/A)
195/5.77
Efficiency
Min.
90%
Typ.
91%
Package
(Case/
Pinout)
C66, P17
V
OUT
(Volts)
12
I
OUT
(Amps)
21
R/N (mVp-p)
➁
Typ.
125
Typical at T
A
= +25°C under nominal line voltage and full-load conditions, unless noted.
Ripple/Noise (R/N) is measured over a 20MHz bandwidth and input filter.
Regulation is tested no load to 100% load.
Nominal line voltage, no-load/full-load conditions.
PART NUMBER STRUCTURE
Optional
Functions
UHP
-
12
/
21
-
D48 N B Lx
-
C
RoHS-6 compliant *
Unipolar High-Power
Nominal Output Voltage:
12 Volts
Alternate Pin Length:
Blank
= Standard pin length
L1
= 0.110 in. (2.79mm) ±0.010
L2
= 0.145 in. (3.68mm) ±0.010
Maximum Output Current:
21
Amps
Input Voltage Range:
D48 = 36-75 Volts (48V nominal)
On/Off Control Polarity:
P
= Positive
N
= Negative
Baseplate:
Blank
= not installed
B
= Installed
* Contact C&D Technologies (DATEL) for availability
Figure 1. Simplified Schematic
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UHP-12/21-D48
Page 2 of 12
®
UHP-12/21-D48
Isolated, 21 Amp Half Brick, 48V
IN
/12V
OUT
DC/DC Converter
Dynamic Characteristics
(1)
Performance/Functional Specifications
Typical @ TA = +25°C under nominal line voltage, full-load conditions, unless noted.
Dynamic Load Response
(50-75-50%step) 150μsec to ±1.25% of final value
Load Step Peak Deviation
±700mV
280msec for V
OUT
= nominal
2msec
290kHz
Start-Up Time
Remote On/Off to V
OUT
Regulated
Switching Frequency
Input
Input Voltage Range
Start-Up Threshold
Undervoltage Shutdown
Voltage Transients
(100msec, no damage)
Overvoltage Shutdown
Reflected
(Back)
Ripple Current
(2)
Input Current:
Full Load Conditions
Inrush Transient
Output Short Circuit
No Load
Low Line (V
IN
= V
MIN
)
Standby Mode
(Off, UV, OT, OC shutdown)
Internal Input Filter
Recommended External Fuse
Reverse Polarity Protection
Remote On/Off Control:
Positive Logic ("P" model suffix)
Negative Logic ("N" model suffix)
(5)
See Ordering Guide
33/35 Volts (min./max.)
32/34 Volts (min./max.)
+100 Volts max.
None
(7)
15mAp-p
See Ordering Guide
0.5A
2
sec
20mA
195mA
7.65 Amps
8mA
Pi-type
15 Amps slow blow
See fuse information
ON = open or +3.5V min. to +V
IN
max.
OFF = –0.5V
min.
to +0.8V
max.
ON = ground pin to +0.8V max.
OFF = +3.5V min. to +V
IN
max.
255 Watts max.
See Ordering Guide
±1.25 % of V
NOMINAL
±3 % max. of V
NOMINAL
(15)
+14.5 Volts
Magnetic feedback and comparator
±10% of V
NOMINAL
±0.02% of V
OUT
range per °C
No minimum load
+5% max.
See Ordering Guide
(8)
See Ordering Guide and note
(10)
See Ordering Guide
3300μF (Low ESR <0.02Ω max.)
2250Vdc min.
1500Vdc min.
750Vdc min.
100MΩ
2000 pF
Basic insulation
30 Amps, cold condition
28 Amps, after warmup
Current limiting with hiccup autorestart
1 Amp
Continuous, output shorted to ground
(2)
Environmental
Calculated MTBF
(4)
945,162 Hours
Operating Temperature Range
(Ambient, with unmounted baseplate):
No derating, 400 lfm
–40 to +32°C
(9)
With derating
See Derating Curves
Operating Temperature with Baseplate
(Mounted to heat sink)
–40 to +110°C max.
(No derating required)
(3) (13)
Storage Temperature Range
Thermal Protection/Shutdown
(13)
Density Altitude
Relative Humidity
–55 to +125°C
+125°C (hotspot)
0 to 10,000 feet
10% to 90%, non-condensing
Physical
Outline Dimensions
Baseplate Material
Pin Material
Weight
Electromagnetic Interference
Conducted and radiated
Safety
Flammability
See Mechanical Specifications
Aluminum
Solder-coated brass
3.3 ounces (94 grams)
FCC part 15, class B, EN55022
(external filter may be required)
UL/cUL 60950 CSA-C22.2 No.234
IEC/EN 60950
ULV94-0
Output
Total Output Power
Voltage Output Range
Voltage Output Accuracy
Extreme Accuracy
Overvoltage Protection
(14)
Method
Voltage Adjustment Range
(12)
Temperature Coefficient
Minimum Loading
Remote Sense Compensation
Ripple/Noise
(20 MHz bandwidth)
Line/Load Regulation
Efficiency
Maximum Capacitive Loading
Isolation Voltage:
Input to Output
Input to Baseplate
Baseplate to Output
Isolation Resistance
Isolation Capacitance
Isolation Safety Rating
Current Limit Inception
(98% of V
OUT
)
Short Circuit
(6)
Protection Method
Short Circuit Current
Short Circuit Duration
(no damage)
Absolute Maximum Ratings
Input Voltage
Continuous
Transient (100 msec max.)
On/Off Control
Input Reverse Polarity Protection
Output Overvoltage
Output Current
(7)
to +75V
to +100V
–0.3 V min to +V
IN
max.
See Fuse section
(11)
V
OUT
+20% max.
Current-limited. Devices can
withstand sustained short circuit
without damage.
–55 to +125°C
+280°C
Storage Temperature
Lead Temperature
(soldering 10 sec. max.)
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, nor recommended.
Performance/Functional Specification Notes:
(1)
The UHP-12/21-D48 is tested and specified with natural convection airflow, external 1 || 10μF
ceramic/tantalum output capacitors and a 22μF external input capacitor. All capacitors are
low ESR types. These capacitors are necessary to accommodate our test equipment and may
not be required to achieve specified performance in your applications. All models are stable
and regulate within spec under no-load conditions.
General conditions for Specifications are +25°C, V
IN
= nominal, V
OUT
= nominal, full load.
Input Ripple Current is tested and specified over a 5Hz to 20MHz bandwidth. Input filtering is
C
IN
= 33μF tantalum, C
BUS
= 220μF electrolytic, L
BUS
= 12μH.
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UHP-12/21-D48
Page 3 of 12
®
UHP-12/21-D48
Isolated, 21 Amp Half Brick, 48V
IN
/12V
OUT
DC/DC Converter
TECHNICAL NOTES
Performance/Functional Specification Notes:
Note that Maximum Power Derating curves indicate an average current at nominal input voltage.
At higher temperatures and/or lower airflow, the DC/DC converter will tolerate brief full current
outputs if the total RMS current over time does not exceed the Derating curve.
(4)
Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case 3,
ground fixed conditions, operating temperature = 55°C, full output load, natural air convection.
(5)
The On/Off Control may be driven with external logic or by applying appropriate external voltages
which are referenced to Input Common. The On/Off Control Input should use either an open col-
lector/open drain transistor or logic gate which does not exceed +V
IN
max.
(6)
Short circuit shutdown begins when the output voltage degrades approximately 2% from the
selected setting. Remove overload for recovery.
(7)
Input overvoltage shutdown is explicitly not included to improve system reliability in datacom and
telecom applications. These requirements attempt continued operation despite significant input
overvoltage.
(8)
Output noise may be further reduced by adding an external filter. See I/O Filtering and Noise
Reduction.
(9)
Models are fully operational and meet published specifications, including “cold start” at –40°C.
(10)
Regulation specifications describe the deviation as the line input voltage or output load current is
varied from a nominal midpoint value to either extreme.
(11)
If the input voltage is reversed, a normally back-biased bulk substrate diode will become forward
biased and draw current. An external fuse is recommended to avoid damage from reverse input
current.
(12)
Do not exceed maximum power specifications when adjusting the output trim.
(13)
Note that the converter may operate up to +110°C with the baseplate installed. However, thermal
self-protection occurs near +125°C on the circuit hotspot. And there is a thermal gradient
between the baseplate and the hotspot. Therefore, +110°C maximum baseplate temperature is
recommended to avoid thermal shutdown.
(14)
If the output exceeds the Overvoltage specification, the output will shut down in auto recovery
mode.
(15)
Extreme accuracy includes all combinations of temperature coefficient and line/load regulation.
(3)
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 UHP Series DC/DC Converters, we recommend the
use of slow-blow type fuses, installed in the ungrounded input supply line,
with values no greater than the following.
Output
12 V
OUT
Fuse Value
15 Amp
All relevant national and international safety standards and regulations must
be observed by the installer. For system safety agency approvals, the convert-
ers must be installed in compliance with the requirements of the end-use
safety standard, i.e. IEC/EN/UL60950.
Input Undervoltage Shutdown and Start-Up Threshold
Under normal start-up conditions, devices will not begin to regulate properly
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 pre-
vents 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 90% of V
OUT
. Actual measured times
will vary with input source impedance, external input capacitance, and the
slew rate and final value of the input voltage as it appears at the converter.
The UHP 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 converter is
turned on (released) 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.
Input Overvoltage Shutdown
The UHP Series does not feature input overvoltage shutdown. The converters
do withstand and fully operate during input transients to 100V for 100msec
without interruption; consequently, this function has been disabled.
Input Source Impedance
The input of UHP converters must be driven from a low ac-impedance 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 inductance in the
input traces. For optimum performance, components should be mounted as
close as possible to the DC/DC converter.
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UHP-12/21-D48
Page 4 of 12
®
UHP-12/21-D48
Isolated, 21 Amp Half Brick, 48V
IN
/12V
OUT
DC/DC Converter
I/O Filtering, Input Ripple Current, and Output Noise
All models in the UHP Series are tested/specified for input reflected ripple cur-
rent 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 imped-
ance 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.
+SENSE
+OUTPUT
6
5
COPPER STRIP
C1
9
–OUTPUT
8
–SENSE
C2
SCOPE
R
LOAD
COPPER STRIP
C1 = 0.1µF CERAMIC
C2 = 10µF TANTALUM
LOAD 2-3 INCHES (51-76mm) FROM MODULE
TO
OSCILLOSCOPE
CURRENT
PROBE
L
BUS
Figure 3. Measuring Output Ripple/Noise (PARD)
4
+INPUT
+
V
IN
–
C
BUS
C
IN
1
Minimum Output Loading Requirements
UHP converters employ a synchronous-rectifier design topology and all
models regulate within spec and are stable under no-load to full load condi-
tions. Operation under no-load conditions however might slightly increase the
output ripple and noise.
Thermal Shutdown
The UHP converters are equipped with thermal-shutdown circuitry. If envi-
ronmental conditions cause the 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 temperature decreases below the
threshold of the temperature sensor, the unit will self start. See Performance/
Functional Specifications.
Output Overvoltage Protection
The UHP output voltage is monitored for an overvoltage condition using a
comparator. The signal is optically coupled to the primary side and if the
output voltage rises to a level which could be damaging to the load, the sens-
ing circuitry will power down the PWM controller causing the output voltage to
decrease. Following a time-out period the PWM will restart, causing the output
voltage to ramp to its appropriate value. If the fault condition persists, and the
output voltage again climbs to excessive levels, the overvoltage circuitry will
initiate another shutdown cycle. This on/off cycling is referred to as "hiccup"
mode.
Current Limiting
As soon as the output current increases to approximately 120% of its rated
value, the DC/DC converter will go into a current-limiting mode. In this condi-
tion, 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 toler-
ance. 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 described below.
–INPUT
C
IN
= 33µF, ESR < 700mΩ @ 100kHz
C
BUS
= 220µF, ESR < 100mΩ @ 100kHz
L
BUS
= 12µH
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. They function as true filter elements and should be
selected for bulk capacitance, low ESR and appropriate 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 filtering to
meet your specific requirements. Contact our Applications Engineering 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 as short as possible (i.e. 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 9) as the
ground/return of the load circuit. You can however, use the +Output (pin 5) as
ground/return to effectively reverse the output polarity.
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UHP-12/21-D48
Page 5 of 12
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