PRELIMINARY
Single Output
UCQ Models
Low-Profile, Quarter-Brick
20-35 Amp Isolated
DC/DC Converters
Features
■
■
■
■
■
Standard quarter-brick package/pinout
Low cost; Low profile, 0.4" (10.2mm)
24V or 48V nominal input
Outputs: 3.3V/30-35A or 5V/20A
Interleaved synchronous-rectifier topology
·
Ultra high efficiency
·
No output reverse conduction
Outstanding thermal performance
On/off control, trim & sense functions
Fully isolated, 2250Vdc (BASIC)
Output overvoltage protection
Fully I/O protected; Thermal shutdown
UL/EN/IEC60950 safety approvals
Qual/HALT/EMI tested
■
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For applications requiring improved electrical and thermal performance at
reduced cost, consider DATEL’s new UCQ series “quarter brick” DC/DC power
converters. These compact units measure just 1.45" x 2.3" x 0.4" (36.8 x 60.9 x 10.2
mm) and fit the industry-standard footprint.
Available outputs are 3.3Vdc at 30-35 Amps or 5Vdc at 20 Amps and accept
a wide input range. The UCQ’s interleaved, synchronous-rectifier topology offers
high efficiency (up to 93%), tight line and load regulation, low noise and fast step
response. A single-board optimized open-frame design contributes to impressive
thermal operation. UCQ’s will operate up to +70°C and 100 LFM airflow with no
derating.
The UCQ’s feature full isolation to 2250Vdc meeting BASIC insulation require-
ments of UL/EN/IEC 60950. Input Pi filters reduce propagated switching noise back
to input sources. Also included is a remote On/Off switch control (with positive or
negative polarity), output trim adjustable from –20% to +10% over nominal and
output sense functions to reduce power lead losses. Extensive protection items
avoid damage from out of limit voltages, currents and temperatures. Protection faults
automatically recover using the hiccup technique. Besides safety testing to 60950,
certifications for the UCQ include application for EMC compliance (to FCC class B),
qualification testing (including HALT) and CE marking.
+SENSE
(7)
+V
OUT
(8)
+V
IN
(3)
SWITCH
CONTROL
–V
OUT
(4)
–V
IN
(1)
–SENSE
(5)
PWM
CONTROLLER
OPTO
ISOLATION
REFERENCE &
ERROR AMP
V
OUT
TRIM
(6)
INPUT UNDERVOLTAGE, INPUT
OVERVOLTAGE, AND OUTPUT
OVERVOLTAGE COMPARATORS
REMOTE
ON/OFF
CONTROL*
(2)
* Can be ordered with positive (standard) or negative (optional) polarity.
Figure 1. Simplified Schematic
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UCQ Series
2 0 - 3 5 A M P, S I N G L E O U T P U T D C / D C C O N V E R T E R S
0
Performance Specifications and Ordering Guide
Output
Model
UCQ-3.3/35-D24
UCQ-3.3/30-D48
UCQ-5/20-D48
V
OUT
(Volts)
3.3
3.3
5
I
OUT
(Amps)
35
30
20
R/N (mVp-p)
➁
Typ.
50
35
35
Max.
80
50
55
➀
Input
Regulation
Line
±0.2%
±0.2%
±0.125%
Load
➂
±0.25%
±0.2%
±0.25%
V
IN
Nom.
(Volts)
24
48
48
Range
(Volts)
18-36
36-75
36-75
I
IN
➃
(mA/A)
120/5.5
50/2.3
80/2.24
Efficiency
Min.
87%
91%
89%
Typ.
89%
92%
93%
Package
(Case/
Pinout)
C67, P32
C67, P32
C67, P32
➀
Typical at T
A
= +25°C under nominal line voltage and full-load conditions. All models are
specified with an external 1µF multi-layer ceramic and 10µF capacitors across their output pins.
➁
Ripple/Noise (R/N) measured over a 20MHz bandwidth.
➂
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
is varied from its nominal/midpoint value to either extreme. (Load step = 50%.)
➃
Nominal line voltage, no load/full load condition.
PA R T N U M B E R S T R U C T U R E
U CQ
-
3.3
/
30
-
D48 N B
-
C
Output
Configuration:
U = Unipolar
Quarter-Brick Package
Nominal Output Voltage:
3.3 and 5 Volts
Maximum Rated Output :
Current in Amps
Input Voltage Range:
D24 - 18-36 Volts (24V nominal)
D48 = 36-75 Volts (48V nominal)
RoHS-6 compliant*
Optional Functions:
Blank
N
B
Positive polarity on/off control (pin 2)
Negative polarity on/off control (pin 2)
Add baseplate
Optional Functions
* Contact C&D Technologies (DATEL)
for availability.
M E C H A N I C A L S P E C I F I C AT I O N S
UCQ WITH OPTIONAL BASEPLATE
Case C67
ALL DIMENSIONS ARE IN INCHES (MM)
I/O Connections
Pin Function P32
1
–Input
2 Remote On/Off*
3
+Input
4
–Output
Pin
5
6
7
8
Function P32
–Sense
Output Trim
+Sense
+Output
* The Remote On/Off can be provided with either
positive (no suffix) or negative ("N" suffix) polarity.
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2
2 0 - 3 5 A M P, S I N G L E O U T P U T C O N V E R T E R S
UCQ Models
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage, nominal output voltage, natural air convection,
external caps and full-load conditions unless noted. (1)
Input
Input Voltage Range
See Ordering Guide
Start-Up Threshold
(17)
UCQ-3.3/35-D24
17 Volts
UCQ-3.3/30-D48
36 Volts
UCQ-5/20-D48
36 Volts
Undervoltage Shutdown
(17)
UCQ-3.3/35-D24
14 Volts
UCQ-3.3/30-D48
33 Volts
UCQ-5/20-D48
33 Volts
Overvoltage Shutdown
None
(12)
Reflected (Back) Ripple Current
(2)
UCQ-3.3/35-D24
18mAp-p
UCQ-3.3/30-D48
10mAp-p
UCQ-5/20-D48
10mAp-p
Input Current:
Full Load Conditions
See Ordering Guide
Inrush Transient
UCQ-3.3/35-D24
0.2A
2
/sec
UCQ-3.3/30-D48
0.05A
2
/sec
UCQ-5/20-D48
0.05A
2
/sec
Output Short Circuit
UCQ-3.3/35-D24
200mA
UCQ-3.3/30-D48
50mA
UCQ-5/20-D48
50mA
No Load
UCQ-3.3/35-D24
120mA
UCQ-3.3/30-D48
50mA
UCQ-5/20-D48
80mA
Low Line (V
IN
= V
MIN
)
UCQ-3.3/35-D24
9.5 Amps max.
UCQ-3.3/30-D48
3.05 Amps
UCQ-5/20-D48
3.02 Amps
Standby Mode (Off, UV, OT shutdown)
UCQ-3.3/35-D24
10mA
UCQ-3.3/30-D48
4mA
UCQ-5/20-D48
1mA
Internal Input Filter Type
Pi-type
Recommended External Fuse
UCQ-3.3/35-D24
20 Amps
UCQ-3.3/30-D48
7.5 Amps
UCQ-5/20-D48
7.5 Amps
Reverse Polarity Protection
See fuse information
(5)
Remote On/Off Control
Positive Logic (no model suffix)
OFF = ground to +1V max.
ON = open or +3.5V min. to +13.5V max.
Negative Logic (“N” model suffix)
OFF = open or +3.5V min. to +13.5V max.
ON = ground to +1V max.
Current
2 mA max.
Output
Total Output Power
UCQ-3.3/35-D24
UCQ-3.3/30-D48
UCQ-5/20-D48
Voltage Output Range
Voltage Output Accuracy,
50% load
Extreme Accuracy
(18)
Voltage Adjustment Range
(Note 13)
Temperature Coefficient
Minimum Loading
Remote Sense Compensation
(“R” suffix)
Ripple/Noise
(20MHz bandwidth)
Line/Load Regulation
Efficiency
Maximum Capacitive Loading
(Low ESR <0.02Ω max., resistive load)
Isolation Voltage
- Input to Output
115 Watts
99.9 Watts
101 Watts
See Ordering Guide
±1% of V
NOM
±3%
–10% to +10% of V
NOM
±0.02% of V
OUT
range per °C
No minimum load
+10%
See Ordering Guide
(8)
See Ordering Guide
(10)
See Ordering Guide
10,000µF
2250Vdc min. (no baseplate)
1500Vdc min. (with baseplate)
Isolation Resistance
10MΩ
Isolation Capacitance
UCQ-3.3/30-D48
1500pF
UCQ-3.3/35-D24
1000pF
UCQ-5/20-D48
1000pF
Isolation Safety Rating
Basic insulation
Current Limit Inception
(Percent of V
OUT
setting, after warmup)
38 Amps
UCQ-3.3/35-D24 (98% of V
OUT
)
33 Amps
UCQ-3.3/30-D48 (97% of V
OUT
)
24 Amps
UCQ-5/20-D48 (98% of V
OUT
)
Short Circuit Protection Method
(6)
Current limiting with hiccup
autorestart. Remove overload
for recovery
Short Circuit Current
Narrow pulse, less than 1 Amp rms
Short Circuit Duration
Continuous, output shorted to ground
(no damage)
Overvoltage Protection
Via optocoupled hiccup loop
UCQ-3.3/35-D24
4 Volts
UCQ-3.3/30-D48
3.96 Volts, min.
UCQ-5/20-D48
6.2 Volts static
Dynamic Characteristics
Dynamic Load Response
UCQ-3.3/35-D24 (50-100% load step)
UCQ-3.3/30-D48 (50-75% load step)
UCQ-5/20-D48 (50-100% load step)
Start-Up Time
V
IN
on to V
OUT
regulated
On/Off to V
OUT
regulated
Switching Frequency
UCQ-3.3/35-D24
UCQ-3.3/30-D48
UCQ-5/20-D48
200µsec to ±2% of final value
150µsec to ±1% of final value
200µsec to ±2% of final value
Less than10msec
Less than10msec
350kHz
330kHz
315kHz
Environmental
Calculated MTBF
(4)
1.4 million hours
Operating Temperature Range
(Ambient)
No baseplate, 100 LFM airflow,
vertical mount
No derating
–40 to +70°C
With derating
See Derating Curves
Operating Case Temperature
–40 to +100°C max.
No derating required
(3) (14)
Storage Temperature Range
–55 to +125°C
Thermal Protection/Shutdown
+115°C
Relative Humidity
to 85%/+85°C, non-condensing
Physical
Outline Dimensions
Baseplate Material
(if installed)
Pin Material
Pin Diameter
(11)
Weight
Electromagnetic Interference
(conducted and radiated)
Safety
See the mechanical drawings
Aluminum
Brass alloy
See the mechanical drawings
1.2 ounce (35 grams)
FCC part 15, class B, EN55022
(may need external filter)
UL/cUL 60950
CSA-C22.2 No.234
IEC/EN 60950
ULV94-0
Flammability
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3
UCQ Series
2 0 - 3 5 A M P, S I N G L E O U T P U T D C / D C C O N V E R T E R S
Input Voltage
Continuous
Transient (100msec)
Absolute Maximum Ratings
24V Models
0 to +36 Volts
+50 Volts
Input Fusing
48V Models
0 to +75 Volts
+100 Volts
On/Off Control
Input Reverse Polarity Protection
Output Overvoltage
Output Current
(7)
Operating Temperature
Storage Temperature
Lead Temperature
(soldering 10 sec. max.)
0V min. to +13.5V max.
See Fuse section
TBD
Current-limited. Devices can
withstand sustained short circuit
without damage.
–40 to +100°C
–55 to +125°C
+280°C
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 UCQ series DC/DC converters, we recommend
the use of a time delay fuse, installed in the ungrounded input supply line.
As a rule of thumb however, we recommend the use of a normal-blow or
slow-blow fuse with a typical value about twice the maximum input current,
calculated at low line with the converter’s minimum efficiency.
All relevant national and international safety standards and regulations must
be observed by the installer. For system safety agency approvals, the con-
verters must be installed in compliance with the requirements of the end- use
safety standard, i.e. IEC/EN/UL60950.
Input Reverse-Polarity Protection
If the input voltage polarity is accidentally reversed, an internal diode will
become forward biased and likely draw excessive current from the power
source. If this source is not current limited or the circuit appropriately fused, it
could cause permanent damage to the converter.
Input Under-Voltage 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 Under-Voltage Shutdown limit. Subsequent re-start will not occur until
the input is brought back up to the Start-Up Threshold. This built in hyster-
esis 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 time interval 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 capacitance, and the slew rate and final value of the input voltage as
it appears at the converter. The UCQ Series implements a soft start circuit
to limit 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 Source Impedance
The input of UCQ 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 induc-
tance in the input traces. For optimum performance, components should be
mounted close to the DC/DC converter.
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.
Specification Notes:
(1) All models are tested and specified with natural convection airflow, external 1 || 10µF ceramic/
tantalum output capacitors and no 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.
(2) Input Ripple Current is tested and specified over a 5Hz to 20MHz bandwidth. Input filtering
is C
IN
= 33µF/100V tantalum, C
BUS
= 220µF/100V electrolytic, L
BUS
= 12µH. Output loading is
100% resistive.
(3) 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. All
Derating curves are presented at sea level altitude. Be aware of reduced power dissipation
with increasing density altitude.
(4) Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case
3, ground fixed conditions, T
PCBOARD
= +25°C, full output load, natural air convection.
(5) The On/Off Control may be driven with external logic or by applying appropriate external volt-
ages which are referenced to Input Common. The On/Off Control Input should use either an
open collector/open drain transistor or logic gate which does not exceed +13.5V.
(6) Short circuit shutdown begins when the output voltage degrades approximately 2% from the
selected setting.
(7) The outputs are not intended to sink appreciable reverse current. Output damage is possible
with excessive reverse current.
(8) Output noise may be further reduced by adding an external filter. See I/O Filtering and Noise
Reduction.
(9) All 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) Alternate pin length and/or other output voltages are available under special quantity order.
(12) Overvoltage shutdown on 48V input models is normally eliminated to comply with certain
telecom reliability requirements which attempt continued operation despite significant input
overvoltage.
(13) Do not exceed maximum power specifications when adjusting the output trim.
(14) Note that the converter may operate over +100°C with the baseplate installed. However, ther-
mal self-protection occurs near +115°C. Therefore, +100°C is recommended to avoid thermal
shutdown.
(15) If reverse polarity is accidentally applied to the input, a body diode will become forward biased
and will accept considerable current. To ensure reverse input protection with full output load,
always connect an external input fuse in series with the +V
IN
input. Use approximately twice
the full input current rating with nominal input voltage.
(16) For On/Off Control on negative-polarity models, the maximum OFF mode control voltage is
+13.5 Volts. For the ON mode, the range is pin grounded to +1 Volt max.
(17) The converter is guaranteed to start up at the maximum startup voltage. The converter is
guaranteed to shut down at the minimum undervoltage.
(18) “Extreme accuracy” includes all combinations of temperature drift, output load and calibration
setting over the operating temperature range.
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2 0 - 3 5 A M P, S I N G L E O U T P U T C O N V E R T E R S
UCQ Models
I /O Filtering, Input Ripple Current, and Output Noise
All models in the UCQ Series are tested/specified for input reflected ripple
current and output noise using the specified external input/output compo-
nents/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 conduc-
tors from backplane to the DC/DC. Input caps should be selected for bulk
capacitance (at appropriate frequencies), low ESR, and high rms-ripple-cur-
rent ratings. The switching nature of DC/DC converters requires that dc volt-
age 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.
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 4) as the
ground/return of the load circuit. You can however, use the +Output (pin 8) as
ground/return to effectively reverse the output polarity.
Minimum Output Loading Requirements
UCQ 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 UCQ converters are equipped with thermal-shutdown circuitry. If environ-
mental 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 Over-Voltage Protection
TO
OSCILLOSCOPE
CURRENT
PROBE
L
BUS
3
+INPUT
+
V
IN
–
C
BUS
C
IN
1
–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.
The UCQ output voltage is monitored for an over-voltage 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 over-voltage
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 130% 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.
Short Circuit Condition
When a converter is in current-limit mode, the output voltage will drop as
the output current demand increases. If the output voltage drops too low, the
magnetically coupled voltage used to develop primary side voltages will also
drop, thereby shutting down the PWM controller. Following a time-out period,
the PWM will restart causing the output voltage to begin ramping to their
appropriate value. If the short-circuit condition persists, another shutdown
cycle will be initiated. This on/off cycling is referred to as “hiccup” mode. The
hiccup cycling reduces the average output current, thereby preventing inter-
nal temperatures from rising to excessive levels. The UCQ Series is capable
of enduring an indefinite short circuit output condition.
+SENSE
+OUTPUT
7
8
COPPER STRIP
C1
4
–OUTPUT
5
–SENSE
C2
SCOPE
R
LOAD
COPPER STRIP
C1 = 1µF CERAMIC
C2 = 10µF TANTALUM
LOAD 2-3 INCHES (51-76mm) FROM MODULE
Figure 3. Measuring Output Ripple/Noise (PARD)
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