–VIN
(1)
+VIN
(3)
OPTO
ISOLATION
PWM
CONTROLLER
REFERENCE &
ERROR AMP
INPUT UNDERVOLTAGE, INPUT
OVERVOLTAGE, AND OUTPUT
OVERVOLTAGE COMPARATORS * Can be ordered with positive ("P" suffix) or negative ("N" suffix) polarity.
REMOTE
ON/OFF
CONTROL*
(2)
+SENSE
(7)
–SENSE
(5)
+VOUT
(8)
VOUT
TRIM
(6)
–VOUT
(4)
SWITCH
CONTROL
DATEL, Inc., Mansfield, MA 02048 (USA) · Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 · Email: sales@datel.com · Internet: www.datel.com
INNOVATION and EX C ELL E N C E
®®
Single Output
ULE 20A Models
Isolated, High-Density, Eighth-Brick
5-20 Amp, DC/DC Converters
Figure 1. Simplified Schematic
Features DATEL's new ULE Series "Eighth-Brick" DC/DC Converters are high-current
isolated power converters designed for use in high-density system boards. Measuring
just 0.89 x 2.22 x 0.36 inches ( 22.6 x 56.4 x 9.1mm), these open-frame, low-profile
E-bricks fit the industry-standard quarter-brick footprint. Now you can "cut-and-paste"
the layout from your last Q-brick design to save time and save 44% board space
(1.86 square inches versus 3.3) in the process.
From an 18-36V or 36-75V input, ULE's deliver 1.2, 1.5, 1.8, 2.5, or 3.3 Volt outputs
fully rated at 20 Amps (5V @ 12A and 12V @ 5A). They employ an interleaved,
synchronous-rectifier topology that exploits 100% of their duty cycle. They simultane-
ously achieve high efficiency (to 92%), low noise (50-70mVp-p), tight line/load regula-
tion (±0.25%), and quick step response (150µsec).
An open-frame design, high efficiency, low-on-resistance FET's, and planar mag-
netics embedded in heavy-copper pc boards all contribute to impressive thermal
derating. All ULE's deliver full power to +70°C with a mere 100lfm (0.5m/s) air flow.
The ULE's feature set includes high isolation (2250Vdc, 48V models), input pi
filters, input undervoltage shutdown, output overvoltage protection, current limiting,
short-circuit protection, and thermal shutdown. The standard footprint carries VOUT
trim, on/off control, and sense pins.
All ULE E-Bricks are designed to meet the BASIC-insulation requirements of
UL/EN/IEC60950, and all "D48" models (36-75V input ranges) will carry the CE mark.
Safety certifications, EMC compliance testing and qualification testing (including
HALT) are currently in progress. Contact DATEL for latest updates.
New 1/8-brick package, 1/4-brick pinout
in through-hole or SMT version
0.89 x 2.22 x 0.36 in. (22.6 x 56.4 x 9.1mm)
Output current: 5-20 Amps
Output voltages: 1.2/1.5/1.8/2.5/3.3/5/12V
Input voltage: 24V and 48V nominal
Interleaved, synchronous-rectifier
topology delivers:
• Outstanding efficiency (to 92%)
• Low noise (50-70mVp-p)
• Stable no-load operation
• No output reverse conduction
Excellent thermal performance
On/off control, trim and sense pins
Fully isolated (2250Vdc BASIC)
Fully I/O protected; Thermal shutdown
UL/EN/IEC60950 certification requested
ULE Series
U LE
1.8 20
D48 N
-/ -
Remote On/Off Control Polarity:
Add "P" for positive polarity
(pin 2 open = converter on)
Add "N" for negative polarity
(pin 2 open = converter off)
Eighth-Brick Package
Output Configuration:
U = Unipolar/Single
Nominal Output Voltage:
1.2/1.5/1.8/2.5/3.3/5/12 Volts
Maximum Rated Output
Current in Amps
Input Voltage Range:
D12 = 10-18 Volts (12V nominal)
D24 = 18-36 Volts (24V nominal)
D48 = 36-75 Volts (48V nominal)
Performance Specifications and Ordering Guide ➀
2
➀ Typical at TA = +25°C under nominal line voltage and full-load conditions, unless otherwise
noted. All models are tested and specified with external output capacitors (1µF multi-layer
ceramic in parallel with 10µF tantalum).
➁ Add "N" or "P" to the part number for Remote Control Polarity. See Part Number Structure.
➂ Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth.
I/O Connections
Pin Function P32
1 –Input
2 On/Off Control *
3 +Input
4 –Output
5 –Sense
6 Output Trim
7 +Sense
8 +Output
* The Remote On/Off
can be provided with
either positive (P suffix)
or negative (N suffix)
polarity.
➃ 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%.)
➄ Nominal line voltage, no load/full load conditions.
➅ Contact DATEL for availability.
➆ Half load output is 18VIN minimum. Full load output is 20VIN minimum.
ULE-1.2/20-D48 ➅ 1.2 20 50 100 ±0.25% ±0.25% 48 36-75 50/0.6 84% 86% C56, C52, P32
ULE-1.5/20-D48 ➅ 1.5 20 50 100 ±0.25% ±0.25% 48 36-75 50/0.7 85% 87% C56, C52, P32
ULE-1.8/20-D48 1.8 20 40 80 ±0.25% ±0.25% 48 36-75 40/0.9 84.5% 86% C56, C52, P32
ULE-2/20-D48 ➅ 2 20 50 100 ±0.25% ±0.25% 48 36-75 50/1 85% 87% C56, C52,P32
ULE-2.5/20-D24 2.5 20 50 100 ±0.25% ±0.25% 24 18-36 55/2.5 TBD 87% C56, C52, P32
ULE-2.5/20-D48 2.5 20 50 100 ±0.25% ±0.25% 48 36-75 50/1.2 86.5% 88% C56, C52, P32
ULE-3.3/20-D12 ➅ 3.3 20 50 100 ±0.25% ±0.25% 12 10-18 TBD TBD 88% C56, C52, P32
ULE-3.3/20-D24 ➅ 3.3 20 50 100 ±0.25% ±0.25% 24 18-36 50/3.1 87% 89% C56, C52, P32
ULE-3.3/20-D48 3.3 20 50 100 ±0.25% ±0.25% 48 36-75 50/1.6 87% 89% C56, C52, P32
ULE-5/10-D12 ➅ 5 10 50 100 ±0.25% ±0.25% 12 10-18 TBD TBD 89% C56, C52, P32
ULE-5/12-D24 5 10 50 100 ±0.25% ±0.25% 24 18-36 ➆ 50/2.3 87.5% 90% C56, C52, P32
ULE-5/12-D48 5 12 50 100 ±0.25% ±0.25% 48 36-75 50/1.4 88.5% 90.5% C56, C52, P32
ULE-12/4.2-D24 ➅ 12 4.2 50 100 ±0.1% ±0.1% 24 18-36 ➆ 55/2.81 86.5% 89% C56, C52, P32
ULE-12/5-D48 ➅ 12 5 70 140 ±0.25% ±0.25% 48 36-75 60/1.4 90% 92% C56, C52, P32
Output Input
Surface-Mount Package
Contact DATEL for availability
M Lx
Pin Length Option: Through-hole packages only
(100 pcs. minimum quantity)
L1 Pin length 0.110 ±0.010 inches (2.79 ±0.25mm)
L2 Pin length 0.145 ±0.010 inches (3.68 ±0.25mm)
Package
VOUT IOUT VIN Nom. Range IIN ➄ (Case,
Model ➁ (Volts) (Amps) Typ. Max. Line Load ➃ (Volts) (Volts) (mA/A) Min. Typ. Pinout)
R/N (mVp-p) ➂ Regulation (Max.) Efficiency
TOLERANCES: 3 decimal places = ±0.005 inches
2 decimal places = ±0.01 inches
Unless otherwise stated.
MECHANICAL SPECIFICATIONS
PART NUMBER STRUCTURE
Case C56 Through-Hole Package Case C52 Surface-Mount Package
Note:
Not all model number
combinations are available.
Contact DATEL.
2 4 - 6 0 W , 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
ULE Models
Performance/Functional Specifications
Typical @ TA = +25°C under nominal line voltage and full-load conditions, unless noted. ➀
3
Input
Input Voltage Range:
D12 Models 10-18 Volts (12V nominal)
D24 Models 18-36 Volts (24V nominal)
D48 Models 36-75 Volts (48V nominal)
Start-Up Threshold:
D12 Models 9-10 Volts (9.6V typical)
D24 Models 18-20 Volts (19V typical)
D48 Models 31-36 Volts (35V typical)
Undervoltage Shutdown:
D12 Models 8.5-9.5 Volts (9V typical)
D24 Models 16.5-18.5 Volts (17.5V typical)
D48 Models 32.5-34.5 Volts (33.5V typical)
Input Current:
Normal Operating Conditions See Ordering Guide
Standby Mode (Off, Under Voltage) 1-8mA (model dependent)
Output Short-Circuit Condition 40-250mA (model dependent)
Low Line Voltage (VIN = VMIN):
ULE-1.8/20-D48 1.08 Amps
ULE-2.5/20-D48 1.50 Amps
ULE-3.3/20-D48 2.05 Amps
ULE-5/12-D24 3.31 Amps
ULE-5/12-D48 1.82 Amps
Input Reflected Ripple Current ➁ 15-25mAp-p (model dependent)
Input Filter Type LC type
Overvoltage Protection None
Reverse-Polarity Protection ➇ 5A max., 10sec max. via external fuse
No-load Input Current 16-90mA (model dependent)
Remote On/Off Control: ➄
Positive Logic ("P" suffix models) OFF = ground pin or +0.8 V max.
ON = open pin or +VIN max.
Negative Logic ("N" suffix models) ON = ground pin or +0.8 V max.
OFF = open pin or +VIN max.
Remote Control On/Off Current 1mA pulldown
Sense Input Range +10% of VOUT
Output
Total Output Power (VOUT x IOUT must not exceed maximum power): ➆
ULE-1.8/20-D48 36.36 Watts
ULE-2.5/12-D48 50.50 Watts
ULE-3.3/20-D48 66.83 Watts
ULE-5/12-D24 60.60 Watts
ULE-5/12-D48 60.75 Watts
Voltage Output Accuracy (50% load):
Initial ±1.25% (except ±1.5% 1.8V)
Temperature Coefficient 0.02% of VOUT per °C
Minimum Loading ➀ No minimum load
Ripple/Noise (20MHz bandwidth) See Ordering Guide
Line/Load Regulation See Ordering Guide
Efficiency See Ordering Guide
VOUT Trim Range –15% to +10%
Isolation Voltage, input/ouput:
D12 and D24 models 1500 Vdc min.
D48 models 2250 Vdc min.
Isolation Safety Rating Basic
Isolation Resistance 100MΩ
Isolation Capacitance 470-1750pF (model dependent)
Current Limit Inception (98% of VOUT):
ULE-5/12-D24 16A (cold start), 15A (warmed up)
ULE-5/12-D48 18A (cold start), 16A (warmed up)
20 Amp models 26A (cold start), 24A (warmed up)
Short Circuit Detection See Note 6
Short Circuit Protection Method Hiccup with autorecovery, See Tech Notes
Short Circuit Current 2-5 Amps (model dependent)
Short Circuit Duration Continuous, output shorted to ground
Overvoltage Protection: Method: magnetic feedback
ULE-1.8/20-D48 3Vdc
ULE-2.5/20-D48 3Vdc
ULE-3.3/20-D48 3.96Vdc
ULE-5/12-D24 6Vdc
ULE-5/12-D48 6.4Vdc
Capacitive Load 10,000µF typical
(ESR = 0.02Ω maximum) 15,000µF maximum
Dynamic Characteristics
Dynamic Load Response:
(50-75-50% load step to ±2% of VOUT) 200-250µSec, model dependent.
Start-Up Time:
On/Off or VIN on to VOUT 90mSec for VOUT = nominal
Switching Frequency:
ULE-1.8/20-D48 340kHz ±10%
ULE-2.5/20-D48 400kHz ±10%
ULE-3.3/20-D48 365kHz ±10%
ULE-5/12-D24 485kHz ±10%
ULE-5/12-D48 450kHz ±10%
Environmental
Calculated MTBF ➃ TBD Hours
Operating Temperature Range (Ambient)
No derating, natural convection
(50-100 lfm self-cooling) +60 to +75°C, model dependent, see
derating curves
With derating See derating curves
Storage Temperature Range –40 to +125°C
Thermal Protection/Shutdown 120°C
Altitude 0 to 10,000 feet
Relative Humidity 10% to 90%, non-condensing
Physical
Outline Dimensions See Mechanical Specifications
Pin Material (Through-hole model) Round copper with tin-lead plate
over nickel underplate
Weight TBD ounces
Flammability Rating UL94V-0
Electromagnetic Interference FCC Part 15, EN55022, (conducted or
radiated) Class B
Safety UL/cUL 60950 CSA-C22.2 No.234
IEC/EN 60950
➀ All models are tested and specified with external 22µF tantalum input capacitor and 10µF/
1µF tantalum/ceramic output capacitors. 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. Standard airflow is
300 lfm for extended operation.
➁ Input Ripple Current is tested and specified over a 5-20MHz bandwidth. Input filtering is
CIN = 33µF, CBUS = 220µF, LBUS = 12µH.
➂ Current limit inception is given at either cold start-up or after warm-up.
➃ Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case 3,
ground fixed conditions, TCASE = +25°C, full load, natural air convection.
➄ The On/Off Control may be driven with open-collector logic or by applying appropriate
external voltages referenced to Common. The On/Off Control Input should use either an open
collector/open drain transistor or logic gate which does not exceed +VIN.
➅ Short circuit shutdown begins when the output voltage degrades approximately 2% from the
selected setting.
➆ 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 shorter
full current outputs if the total RMS current over time does not exceed the Derating curve.
➇ The user must install an external fuse in series with the input to protect against reverse polarity.
See Input Fusing.
2 4 - 6 0 W , 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
ULE Series
TECHNICAL NOTES
Input Voltage:
Continuous:
12 Volt input models 18 Volts
24 Volt input models 36 Volts
48 Volt input models 75 Volts
Transient (100 mSec. Max.)
12 Volt input models 25 Volts
24 Volt input models 50 Volts
48 Volt input models 100 Volts
On/Off Control (pin 2) +VIN
Input Reverse Polarity Protection 5 Amps, 10 sec. max.
Output Overvoltage Protection Magnetic feedback. See note (7).
Output Current * Current-limited. Devices can withstand
sustained short circuit without
damage.
Storage Temperature –40 to +125°C.
Lead Temperature +300°C, 10 seconds max.
Refer to solder profile.
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.
Absolute Maximum Ratings
4
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 exist. For DATEL ULE 24-60 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 Fuse Values
12 Volt Input 10 Amps
24 Volt input 5 Amps
48 Volt Input 4 Amps
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, e.g. IEC/EN/UL60950.
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.
All D12 models will start-up at 9.6V typically and will then work within specifi-
cations from 10-18V.
Start-Up Time
The VIN to VOUT 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 ULE 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 VOUT 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 and the fully loaded output voltage enters and remains within its
specified accuracy band. Similar to the VIN to VOUT start-up, the On/Off Con-
trol to VOUT start-up time is also governed by the internal soft start circuitry
and external load capacitance.
The difference in start up time from VIN to VOUT and from On/Off Control to
VOUT is therefore insignificant.
Input Source Impedance
ULE 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 inductance in
the input traces. For optimum performance, components should be mounted
close to the DC/DC converter. If the application has a high source imped-
ance, low VIN models can benefit of increased external input capacitance.
I/O Filtering, Input Ripple Current, and Output Noise
All models in the ULE 24-60 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 (CIN 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, CBUS and LBUS simulate a typical
dc voltage bus. Your specific system configuration may necessitate additional
considerations.
* The outputs are not intended to sink appreciable current. If the outputs are forced to sink
excessive current, damage may result.
2 4 - 6 0 W , 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
ULE Models
5
Figure 3. Measuring Output Ripple/Noise (PARD)
Figure 2. Measuring Input Ripple Current
CIN
VIN CBUS
LBUS
CIN = 33µF, ESR < 700mΩ @ 100kHz
CBUS = 220µF, ESR < 100mΩ @ 100kHz
LBUS = 12µH
+INPUT
–INPUT
CURRENT
PROBE
TO
OSCILLOSCOPE
+
–
C1
C1 = 0.47µF CERAMIC
C2 = NA
LOAD 2-3 INCHES (51-76mm) FROM MODULE
C2 RLOAD
COPPER STRIP
COPPER STRIP
SCOPE
+OUTPUT
–OUTPUT
+SENSE
–SENSE
In critical applications, output ripple/noise (also referred to as periodic and
random deviations or PARD) may be reduced below specified limits using fil-
tering techniques, the simplest of which is the installation of additional exter-
nal output capacitors. These output caps 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 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
ULE 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
These ULE converters are equipped with thermal-shutdown circuitry. If envi-
ronmental 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 temperature decreases
below the threshold of the temperature sensor, the unit will self start. See
Performance/Functional Specifications.
Output Overvoltage Protection
ULE output voltages are monitored for an overvoltage condition via magnetic
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 condition 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 10% 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 condi-
tion as specified under "Performance."
2 4 - 6 0 W , 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
ULE Series
�
Figure 6. Trim Connections Using A Trimpot
Figure 7. Trim Connections To Increase Output Voltages Using a Fixed Resistor
6
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 voltages to begin ramping to their
appropriate values. 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
internal temperatures from rising to excessive levels. The ULE is capable of
enduring an indefinite short circuit output condition.
FEATURES AND OPTIONS
On/Off Control
The input-side, remote On/Off Control function can be ordered to operate
with either polarity:
Standard models are equipped with Positive-polarity ("P" part-number suffix)
and these devices are enabled when the On/Off Control is left open (or is
pulled high, applying +13V to +VIN with respect to –Input) as per Figure 4.
Positive-polarity devices are disabled when the On/Off Control is pulled low
(0 to 0.8V with respect to –Input).
Optional Negative-polarity devices ("N" suffix) are off when the On/Off Con-
trol is open (or pulled high, applying +3.5V to +VIN), and on when the On/Off
Control is pulled low (0 to 0.8V) with respect to –VIN as shown in Figure 5.
Figure 4. Driving the Positive Polarity On/Off Control Pin
Figure 5. Driving the Negative Polarity On/Off Control Pin
Dynamic control of the remote on/off function is facilitated with a
mechanical relay or an open-collector/open-drain drive circuit (optically iso-
lated if appropriate). The drive circuit should be able to sink appropriate current
(see Performance Specs) when activated and withstand appropriate voltage
when deactivated. Applying an external voltage to the On/Off Control when
no input power is applied to the converter can cause permanent damage to
the converter.
Trimming Output Voltage
ULE converters have a trim capability that allows users to adjust the output
voltages ±5% of VOUT. Adjustments to the output voltages can be accom-
plished via a trim pot (Figure 6) or a single fixed resistor as shown in Figures
7 and 8. A single fixed resistor can increase or decrease the output voltage
depending on its connection. The resistor should be located close to the
converter and have a TCR less than 100ppm/°C to minimize sensitivity to
changes in temperature. If the trim function is not used, leave the trim pin
floating.
A single resistor connected from the Trim to the +Output, or +Sense where
applicable, will increase the output voltage in this configuration. A resistor
connected from the Trim to the –Output, or –Sense where applicable, will
decrease the output voltage in this configuration.
Trim adjustments greater than the specified ±5% can have an adverse affect
on the converter's performance and are not recommended. Excessive volt-
age differences between VOUT and Sense, in conjunction with trim adjustment
of the output voltage, can cause the overvoltage protection circuitry to acti-
vate (see Performance Specifications for overvoltage limits). Power derating
is based on maximum output current and voltage at the converter's output
pins. Use of trim and sense functions can cause output voltages to increase,
thereby increasing output power beyond the converter's specified rating or
cause output voltages to climb into the output overvoltage region. Therefore:
(VOUT at pins) x (IOUT) <= rated output power
2 4 - 6 0 W , 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
ULE Models
Remote Sense Note: The Sense and VOUT lines are internally connected
through low value resistors. Nevertheless, if the sense function is not used for
remote regulation the user should connect the +Sense to +VOUT and –Sense
to –VOUT at the DC/DC converter pins.
ULE series converters have a sense feature to provide point of use regula-
tion, thereby overcoming moderate IR drops in pcb conductors or cabling.
The remote sense lines carry very little current and therefore require minimal
cross-sectional-area conductors. The sense lines are used by the feedback
control-loop to regulate the output. As such, they are not low impedance
points and must be treated with care in layouts and cabling. Sense lines
on a pcb should be run adjacent to dc signals, preferably ground. In cables
and discrete wiring applications, twisted pair or other techniques should be
implemented.
ULE series converters will compensate for drops between the output
voltage at the DC/DC and the sense voltage at the DC/DC provided that:
[VOUT(+) –VOUT(–)] –[Sense(+) –Sense (–)] ≤ 5% VOUT
Output overvoltage protection is monitored at the output voltage pin, not
the Sense pin. Therefore, excessive voltage differences between VOUT and
Sense in conjunction with trim adjustment of the output voltage can cause
the overvoltage protection circuitry to activate (see Performance Specifica-
Figure 9. Remote Sense Circuit Configuration
Figure 8. Trim Connections To Decrease Output Voltages
7
tions for overvoltage limits). Power derating is based on maximum output
current and voltage at the converter’s output pins. Use of trim and sense
functions can cause output voltages to increase thereby increasing output
power beyond the ULE’s specified rating or cause output voltages to climb
into the output overvoltage region. Also, the use of Trim Up and Sense com-
bined may not exceed +10% of VOUT. Therefore, the designer must ensure:
(VOUT at pins) x (IOUT) ≤ rated output power
Trim Equations
Note: Resistor values are in kΩ. Adjustment accuracy is subject to resistor
tolerances and factory-adjusted output accuracy. VO = desired output voltage.
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Trim Up Trim Down
2 4 - 6 0 W , 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
ULE Series
8
Typical Performance Curves
92.5
90
87.5
85
82.5
80
77.5
75
72.5
70
ULE-3.3/20-D48
Efficiency vs. Line Voltage and Load Current @ +25°C
2 4 6 8 10 12 14 16 18 20
Load Current (Amps)
Efficiency (%)
V
IN
= 36V
V
IN
= 48V
V
IN
= 75V
95
90
85
80
75
70
65
60
55
50
ULE-1.8/20-D48
Efficiency vs. Line Voltage and Load Current @ +25°C
1 3 5 7 9 11 13 15
Load Current (Amps)
Efficiency (%)
V
IN
= 36V
V
IN
= 48V
V
IN
= 75V
–40 0 25 35 45 55 65 75 85
30 40 50 60 70 80
ULE-3.3/20-D48 Maximum Current Temperature Derating
(VIN = 48V, air flow direction is transverse)
Output Current (Amps)
Ambient Temperature (°C)
25
20
15
10
5
0
100 lfm
400 lfm
200 lfm
300 lfm
2 4 - 6 0 W , 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
ULE Models
9
Typical Performance Curves
92
90
88
86
84
82
80
ULE-5/12-D24
Efficiency vs. Line Voltage and Load Current @ +25°C
2 3 4 5 6 7 8 9 10 11 12
Load Current (Amps)
Efficiency (%)
V
IN
= 18V
V
IN
= 24V
V
IN
= 36V
92
90
88
86
84
82
80
ULE-5/12-D48
Efficiency vs. Line Voltage and Load Current @ +25°C
2 3 4 5 6 7 8 9 10 11 12
Load Current (Amps)
Efficiency (%)
V
IN
= 36V
V
IN
= 48V
V
IN
= 75V
–40 0 25 35 45 55 65 75 85
30 40 50 60 70 80
ULE-5/12-D24 Maximum Current Temperature Derating
(VIN = 24V, air flow direction from input to output)
Output Current (Amps)
Ambient Temperature (°C)
12.5
12
11.5
11
10.5
10
9.5
9
8.5
8
100 lfm
200 lfm
300 lfm
–40 0 30 40 50 60 70 80 90 35 45 55 65 75 85
ULE-5/12-D48 Maximum Current Temperature Derating
(VIN = 48V, air flow direction from input to output)
Output Current (Amps)
Ambient Temperature (°C)
12.5
12
11.5
11
10.5
10
9.5
9
8.5
8
100 lfm
200 lfm
300 lfm
2 4 - 6 0 W , 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
ULE SeriesULE Series 2 4 - 6 0 W , 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
Surface-Mount Package ("M" suffix)
DATEL's ULE series SMT DC/DC converters are the only higher-power
DC/DC's that can be automatically "pick-and-placed" using standard vacuum-
pickup equipment and subsequently reflowed using high-temperature,
lead-free solder.
Virtually all SMT DC/DC's today are unprotected "open-frame" devices
assembled by their vendors with high-temperature solder (usually Sn96.5/
Ag3.5 with a melting point +221°C) so that you may attach them to your
board using low-temperature solder (usually Sn63/Pb37 with a melting point
of +183°C). Conceptually straightforward, this "stepped" solder approach has
its limitations . . . and is clearly out of step with an industry trending toward
the broad use of lead-free solders. No need to experiment and develop reflow
profiles that ensure the components on their DC/DC never exceed 215-
216°C. If those components get too hot, "double-reflow" could compromise
the reliability of their solder joints. Virtually all these devices demand you
"cool down" the Sn63 profile you are likely using today.
Figure 11. Recommended Solder Profile
(When The Heat-shield Temperature Exceeds +250°C, The Air Within Is 50°C Cooler)
DATEL is not exempted from the Laws of Physics. And we do not have magic
solders no one else has. Nevertheless, we have a simple and practical,
straightforward approach that works. We assemble our SMT DC/DC's on
a hightemperature, plastic lead-frame (nylon 46, UL94V-0 rated) using a
high-temperature (+216°C), lead-free alloy (Sn96.2%, Ag2.5%, Cu0.8%,
Sb0.5%). The lead-frame ensures coplanarity (to within 0.004 in.) of the unit's
tin-plated (150 microinches) copper leads and also supports a removable
heat shield.
The disposable heat shield, which has a cutaway exposing the package
leads, provides thermal insulation to internal components during reflow and
also doubles as the vacuum pick-up location. The insulation properties of the
heat shield are so effective that temperature differentials as high as 50°C
develop inside-to-outside the shield. Oven temperature profiles with peaks of
250-260°C and dwell times exceeding 2 minutes above 221°C (the melting
point of Sn96.5/Ag3.5) are easily achieved. DATEL's new-generation SMT
units are shipped in stackable, JEDEC-style plastic.
Z1 Z2 Z3 Z4 Z5 Z6 Z7
100
Seconds
Degrees Celsius
250
200
150
100
50
200 300 400 500 600
Heat Shield
Test Board
Air Under Shield
Figure 10. ULE SMT DC/DC
With Disposable Heat Shield
10
2 4 - 6 0 W , 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
ULE Models
Automated Assembly Production Notes
DATEL’s new high-efficiency DC/DC converters are designed for modern
surface-mount technology (SMT) automated assembly using screened solder
paste, "pick and place" component positioning and forced hot air reflow oven
soldering. If you are new to SMT techniques and have a volume applica-
tion, these features save time, cost and improve manufacturing efficiency.
DATEL’s DC/DC assembly operations themselves make extensive use of
such techniques.
Even if you have previous SMT experience, you should read the sections
below on solder reflow profiles and heat shields. This information is not
intended to replace the documentation for your SMT system. We assume that
you are already experienced with all the components of your SMT system.
This section will discuss several SMT issues, including:
I/O Mechanical Configuration
Part Handling and Supply
Printed Circuit Board (pcb) Mounting
Soldering using Reflow Technology
Temperature Profiling
Heat Shields and Removal
Mechanical Configuration of Input/Output Connections
These new converters are supplied either using traditional through-hole pins
or SMT leads. (Note that some models are offered only with lead mounting).
The pin options insert into plated-through holes in the host pcb. Be aware
that some heat dissipation is carried off by either the pins or leads. The
Derating Curves assume that some additional pad area is available on your
host pcb to absorb the heat.
The lead option uses either short tabs in "gullwing" style or standoff leads
under the converter. The gullwing leads typically are copper alloy with 150
microinches of tin plating. Solder paste (typically 0.008" to 0.009" thick) is
applied to the host pcb using a solder mask pressure screening technique
and the board is heated and cooled long enough for the solder to reflow and
adhere to both the host pads and the converter’s mounting leads.
After such mounting, the entire mechanical mounting load is carried by the
solder. Obviously the converters must be accurately positioned all during the
solder reflow period. Where solder surface tension is sufficient to force tiny
components into position, these larger converters may not move and must be
accurately positioned by your SMT system.
Part Handling and Supply
SMT eighth- and quarter-brick DC/DC converters (plus installed heat shields
if used) are supplied in JEDEC-standard 5.35" by 12.4" waffle trays which are
compatible with the feeders on industry-standard pick-and-place machines.
Since the converters are larger and heavier than many other components,
make sure your system can reliably remove the units from their trays, move
them to the host pcb and accurately position them. The plastic heat shield
(see below) doubles as a vacuum pickup area.
Heatsinks
If you are using the preinstalled heatsink from DATEL, proceed normally
with surface mounting per the information in this section (the heat shield
fits completely over the heatsink). However, if you wish to add the heatsink
after receiving the converters and heatsink separately, you must install the
heatsink before solder reflow. Essentially, install the heatsink then place the
assembled converters back in the tray for surface mount positioning. Please
observe the torquing and assembly procedure discussed earlier for the
heatsink.
Pick and Place pcb Mounting
The main issues here are pad area, orientation, positioning accuracy,
vacuum pickup and coplanarity. DATEL recommends that pcb pads to
interface with the DC/DC converter should be sized as shown in the diagram
below. The pads footprint accommodates the positioning accuracy of your
SMT equipment and manufactured tolerances of the DC/DC mounting leads.
Orientation: When loaded into JEDEC trays, these converters are all
oriented in the same direction. See the diagram below. For the ULE series,
a notch is placed on the top of the case (on the removal tabs) to indicate the
pin 1 position. You should visually inspect the tray to be sure of this orienta-
tion.
On the bottom of the converter, the ULE series include optical fiducial marks
viewable by your SMT imaging system. See the attached diagram. Observ-
ing from the bottom, your SMT imaging camera should find these marks
to identify the converter and verify pin 1. On most pick-and-place systems,
during head transit, the imaging system will automatically fine tune the end
mounting position of the converter using image comparisons from these
fiducials or other reference marks you have chosen.
The fiducial marks are placed fairly close together because most imaging
systems have a one inch or less observing area since most SMT parts are
considerably smaller than these converters. You may prefer to train your
imaging system to use a corner of the converter or an I/O lead.
In the drawing below, these dimensions are intended for initial search for
these marks by your camera. There will be tiny variations in absolute position
from unit to unit.
Figure 12. Recommended SMT Mounting Pad Dimensions
11
2 4 - 6 0 W , 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
ULE Series
If you use a camera above the pcb after placement on the solder paste, do
not rely on the inkjet marking on the heat shield to verify proper orientation.
Use the pin 1 notch instead.
Coplanarity: DATEL manufactures these converters with very flat mounting
leads (see coplanarity specs) however your host pcb must also be flat for a
successful mounting. Be aware of possible warping of the pcb under heat
gradients and/or humidity conditions. The solder paste will tolerate a small
amount of mismatch and will tend to “wet” the entire pad area by capillary
action if the temperatures are correct.
Vacuum Pickup: Select the vacuum collet on your SMT placement system
for the weight and size of the DC/DC converter. Note that units with heatsinks
are slightly heavier. Tests at DATEL have shown that excellent acceleration
and transit head speed are available for these converters if the collet size is
proper and the vacuum is sufficient. When positioning the vacuum collet, use
the geometric center of the heat shield as the pickup area since the center of
gravity is very close.
Soldering
Reflow technology works well for small parts. However, larger components
such as these DC/DC’s with higher thermal mass may require additional
reflow time (but not enough to disturb smaller parts also being reflowed con-
currently with the DC/DC). When this is combined with higher temperature
lead-free solders (or solders with reduced heavy metals), there is increased
risk of reheating components inside the DC/DC enough so that they either
change positions (and possibly stop functioning) or the components are
damaged by the heat.
For these reasons, DATEL developed disposable heat shields using high
temperature plastic. The DC/DC is installed and reflowed with the shield in
place. After successful reflow and cooling, and before washing, the heat
shield should be removed.
Temperature Profiling
We wish to ramp the temperature up and down to successfully reflow the
solder without heat damage. Each reflow oven, humidity conditions, solder
paste type, oven feed rate, and the number of heat zones all require a differ-
ent profile. Therefore you may have to experiment.
Since these converters are constructed using high temperature solders, there
will be no heat problems on your host pcb using traditional solder with 63%
lead and 37% tin with a melting point of +183°C. Device lead temperature
must remain below 230°C for less than 75 seconds, assuming that the heat
shield is in place. DATEL uses a 216°C melt lead-free tin/silver/copper alloy
to assemble these converters.
There are several lead-free solders suitable for your host pcb depending on
your SMT system and whatever local certification and environmental regula-
tions you must observe. Contact DATEL if you need specific advice.
Heat Shield
Careful thermocouple testing has shown that the interior of the DC/DC under
the heat shield is tens of degrees cooler than the outside ambient tempera-
ture for typical reflow profiles. This protects internal components and limits
the amount of reflow where it is not desired. The heat shield also includes
marking for product identification and a date/lot code.
On ULE models, the heat shield is attached to the converter using molded
plastic pins on the heat shield interior which insert into recessed dimples
in the pinframe. An extra molded pin on the heat shield at the pin 1 location
(and corresponding notch on the pcb) can only be installed one way properly
on the pinframe. If the shield accidentally comes loose, it may be reinstalled
by aligning the pins and dimples.
To remove the shield from the converter, after successful mounting and cool-
ing, squeeze the heat shield ears inward toward the converter body and pull
the shield upwards. Discard or recycle the shield. If you are using a flux wash
cycle, remove the heat shield before washing to avoid coming loose inside
the washer.
Figure 13. Fiducial Mark Location
TO COME
12
2 4 - 6 0 W , 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
Figure 14. Shipping Tray
DS-0515 4/04
DATEL makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein
do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
Internet: www.datel-europe.com E-mail: datel.ltd@datel.com
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01
Internet: www.datel-europe.com E-mail: datel.sarl@datel.com
DATEL GmbH München, Germany Tel: 89-544334-0
Internet: www.datel-europe.com E-mail: datel.gmbh@datel.com
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025
Internet: www.datel.co.jp Email: salestko@datel.co.jp, salesosa@datel.co.jp
DATEL China Shanghai, China Tel: 011-86-51317131
E-mail: davidx@datel.com
DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151
Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356
Internet: www.datel.com Email: sales@datel.com
ISO 9001 REGISTERED
INNOVATION and EX C ELL E N C E
®®
ULE Models
2 4 - 6 0 W , 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
13
