Single Output LSN-W3 Models
Non-Isolated, 3-5.5V
IN
, 0.75-3.3V
OUT
16 Amp DC/DC Converters
For full details go to
www.murata-ps.com/rohs
Typical unit
FEATURES
Step-down, wide input buck regulators
for distributed 3-5V power architectures
3V to 5.5V wide-input range
0.75/1/1.2/1.5/1.8/2/2.5/3.3V
OUT
@16A
Non-isolated, fixed-frequency,
synchronous-rectifier topology
±1% setpoint accuracy
Efficiencies to 95% @ 16 Amps
Noise as low as 30mVp-p
Stable no-load operation
Remote on/off control
Sense pin and output voltage trim
No derating to +65°C with no fan
UL/IEC/EN60950-1 certification pending
EMC compliant
PRODUCT OVERVIEW
LSN Series W3 are ideal building blocks for emerg-
ing, on-board power-distribution schemes in which
isolated 3 to 5.5V buses deliver power to any num-
ber of non-isolated, step-down buck regulators.
LSN W3 DC/DC’s accept 3 to 5.5 Volts and convert
it, with the highest efficiency in the smallest space,
to a 0.75, 1, 1.2, 1.5, 1.8, 2, 2.5, or 3.3 Volt output
fully rated at 16 Amps.
LSN W3’s are ideal point-of-use/load power
processors. They typically require no external com-
ponents. Their surface-mount packages occupy a
mere 1.3" x 0.53" (33.0 x 13.5mm), and are only
0.34 inches (8.6mm) high.
The LSN’s best-in-class power density
is achieved with a fully synchronous, fixed-
frequency, buck topology that also delivers:
high efficiency (97%, 3.3Vout, 8A), low noise
(30mVp-p typ.), tight line/load regulation
(±0.1%/±0.25% max.), quick step response
(30μsec), stable no-load operation, and no
output reverse conduction.
The fully functional LSN’s feature output over-
current detection, continuous short-circuit protec-
tion, over-temperature protection, a remote on/off
control pin (pull low to disable), an output-voltage
trim function, and a sense pin. High efficiency en-
ables the LSN W3’s to deliver rated output currents
of 16 Amps at ambient temperatures to +65°C
with natural convection.
If your new system boards call for multiple sup-
ply voltages, check out the economics of on-board
3-5.5V distributed power. If you don’t need to pay
for multiple isolation barriers, DATEL’s non-isolated
LSN W3 SMT’s will save you money.
Typical topology is shown.
Figure 1. Simplified Schematic
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MDC_LSN W3 Models.A01 Page 1 of 8
Single Output LSN-W3 Models
Performance Specifications and Ordering Guide
ORDERING GUIDE
Output
V
OUT
(Volts)
0.75
1
1.2
1.5
1.8
2
2.5
3.3
0.75-3.3
I
OUT
(Amps)
16
16
16
16
16
16
16
16
16
R/N (mVp-p)
Typ.
30
30
30
30
30
30
30
30
30
Max.
50
50
50
50
50
50
50
50
50
Regulation (Max.)
Line
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.05%
Load
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.15%
V
IN
Nom.
(Volts)
5
5
5
5
5
5
5
5
5
Input
Range
(Volts)
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
I
IN
(mA/A)
70/2.79
70/3.72
70/4.36
70/5.33
70/6.30
70/6.92
70/8.56
50/11.12
50/11.12
Efficiency (Full Load)
V
IN
= nom.
Min.
84%
84%
86%
88%
89.5%
90.5%
91.5%
93%
93%
Typ.
86%
86%
88%
90%
91.5%
92.5%
93.5%
95%
95%
V
IN
= min
Typ.
86.5%
86.5%
88.5%
90.5%
92%
92.5%
94%
95%
95%
Package
(Case,
Pinout)
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
B8/B8x, P59
Non-Isolated, 3-5.5V
IN
, 0.75-3.3V
OUT
16 Amp DC/DC Converters
Preliminary
Models
LSN-0.75/16-W3
LSN-1/16-W3
LSN-1.2/16-W3
LSN-1.5/16-W3
LSN-1.8/16-W3
LSN-2/16-W3
LSN-2.5/16-W3
LSN-3.3/16-W3
LSN-T/16-W3
Typical at T
A
= +25°C under nominal line voltage and full-load conditions, unless noted. All models
are tested/specified with external 22μF tantalum input and output capacitors. These capacitors
are necessary to accommodate our test equipment and may not be required to achieve specified
performance in your applications. See I/O Filtering and Noise Reduction.
Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth and may be reduced with external
filtering. See I/O Filtering and Noise Reduction for details.
These 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.
Nominal line voltage, no-load/full-load conditions.
V
IN
= 4.5 Volts minimum for V
OUT
= 3.3 Volts.
Unless noted, LSN-T/16-W3 specifications are at 3.3V
OUT
.
PART NUMBER STRUCTURE
P A R T
N U M B E R
MECHANICAL SPECIFICATIONS
L SN
-
1.8
/
16
-
W3 H
-
C
RoHS-6 compliant*
Blank =
Vertical Mount
H =
Horizontal Mount
J =
Reversed Pin
Vertical Mount
Input Voltage Range:
W3
= 3-5.5 Volts
(5V nominal)
Note:
Not all model number
combinations are available.
Contact MPS.
S T R U C T U R E
Output
Configuration:
L
= Unipolar
Low Voltage
Non-Isolated SIP
Nominal Output Voltage:
0.75, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3
or 0.75-3.3 Volts
Maximum Rated Output
Current in Amps
* Contact MPS for availability.
Case B8
Vertical Mounting
(Standard)
Case B8A
Horizontal Mounting
Case B8B
Reverse Pin
Vertical Mounting
(Tyco-compatible)
I/O Connections
Pin
Function P59
5
Common
6
Common
7
+Input
8
+Input
Dimensions in inches (mm)
Pin
1
2
3
4
Function P59
+Output
+Output
+Sense
+Output
Pin
9
10
11
Function P59
No Pin
V
OUT
Trim
On/Off Control
Component locations are
typical and may vary.
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MDC_LSN W3 Models.A01 Page 2 of 8
Single Output LSN-W3 Models
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage and full-load conditions unless noted.
Input
Non-Isolated, 3-5.5V
IN
, 0.75-3.3V
OUT
16 Amp DC/DC Converters
See Technical Notes and Performance Curves for details.
The On/Off Control is designed to be driven with open-collector logic or the application of appropriate
voltages (referenced to Common, pin 3). Applying a voltage to On/Off Control when no input voltage is
applied to the converter may cause permanent damage.
Output noise may be further reduced with the installation of additional external output filtering. See
I/O Filtering and Noise Reduction.
MTBF’s are calculated using Telcordia SR-332(Bellcore), ground fixed, T
A
= +25°C, full power,
natural convection, +67°C pcb temperature.
Input Ripple Current is tested/specified over a 5-20MHz bandwidth with an external 2 x 100μF input
capacitor and a simulated source impedance of 1000μF and 1μH. See I/O Filtering, Input Ripple
Current, and Output Noise for details.
Setting accuracy for LSN-T/16-W3 is ±2%.
Input voltage must be 4.5V minimum for 3.3V output.
Input Voltage Range
Input Current:
Normal Operating Conditions
Inrush Transient
Standby/Off Mode
Output Short-Circuit Condition
Input Reflected Ripple Current
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
Undervoltage Shutdown
On/Off Control
3-5.5 Volts (5V nominal)
See Ordering Guide
0.02A
2
sec
8mA
60-110mA average (model dependent)
10-20mAp-p, model dependent
Capacitive
None
None
None
On = open or low (<0.4V max.)
Off = high (>2.5V to V
IN
max.), 1mA
Output
Absolute Maximum Ratings
V
OUT
Accuracy
(50% load)
Temperature Coefficient
Minimum Loading
Maximum Capacitive Load
±1.5%
Input Voltage:
Continuous or transient
On/Off Control
(Pin 1)
Input Reverse-Polarity Protection
Output Overvoltage Protection
Output Current
6 Volts (0.75, 1, 1.2, 1.5, 1.8, 2, 2.5 V
OUT)
7 Volts (3.3V
OUT
and "T" models)
+V
IN
None
None
Current limited. Devices can withstand
sustained output short circuits without
damage.
–40 to +125°C
See Reflow Solder Profile
±0.02%/°C
No load
5000μF (electrolytic),
2000μF (0.02 ESR, OSCON)
±10%
V
OUT
Trim Range
See Ordering Guide
Ripple/Noise
(20MHz BW)
Total Accuracy
3% over line/load/temperature
Efficiency
See Ordering Guide
Overcurrent Detection and Short-Circuit Protection:
Current-Limiting Detection Point
20-36 Amps (model dependent)
Short-Circuit Detection Point
98% of V
OUT
set
SC Protection Technique
Hiccup with auto recovery
Short-Circuit Current
600mA average
Dynamic Characteristics
Storage Temperature
Lead Temperature
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.
Transient Response
(50% load step)
Start-Up Time:
V
IN
to V
OUT
and On/Off to V
OUT
Switching Frequency
30-70μsec to ±2% of final value
(model dependent)
7msec
300 ±50kHz
TECHNICAL NOTES
Environmental
Calculated MTBF
TBD
Operating Temperature:
(Ambient)
Without Derating (Natural convection) –40 to +63/71°C (model dependent,
see Derating Curves)
With Derating
See Derating Curves
PC-Board Temperature
Thermal Shutdown
+100°C maximum
+115°C (110 to 125°C)
Physical
I/O Filtering and Noise Reduction
All models in the LSN W3 Series are tested and specified with external 22μF
tantalum input and output capacitors. These capacitors are necessary to
accommodate our test equipment and may not be required to achieve desired
performance in your application. The LSN’s are designed with high-quality,
high-performance
internal
I/O caps, and will operate within spec in most appli-
cations with
no additional external
components.
In particular, the LSN’s input capacitors are specified for low ESR and are
fully rated to handle the units’ input ripple currents. Similarly, the internal
output capacitors are specified for low ESR and full-range frequency response.
In critical applications, input/output ripple/noise may be further reduced using
filtering techniques, the simplest being the installation of external I/O caps.
External input capacitors serve primarily as energy-storage devices. They
minimize high-frequency variations in input voltage (usually caused by IR drops
in conductors leading to the DC/DC) as the switching converter draws pulses of
current. Input capacitors should be selected for bulk capacitance (at appropri-
ate frequencies), low ESR, and high rms-ripple-current ratings. The switching
nature of modern DC/DC’s requires that the dc input voltage source have low
ac impedance at the frequencies of interest. Highly inductive source imped-
ances can greatly affect system stability. Your specific system configuration
may necessitate additional considerations.
Dimensions
Pin Dimensions/Material
Weight
Flamability Rating
EMI
Conducted and Radiated
Safety
See Mechanical Specifications
0.112" x 0.062" (2.84 x 1.57mm) rectangular
tellurium copper alloy with 100-300
microinches of tin electroplate over
100 microinches of nickel underplate
0.28 ounces (7.8g)
UL94V-0
FCC Part 15, EN55022 Class B may
require external filter
UL/cUL/IEC/EN 60950-1, CSA-C22.2 No.234
All models are tested/specified with external 22μF tantalum input and 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.
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Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDC_LSN W3 Models.A01 Page 3 of 8
Single Output LSN-W3 Models
Non-Isolated, 3-5.5V
IN
, 0.75-3.3V
OUT
16 Amp DC/DC Converters
TO
OSCILLOSCOPE
CURRENT
PROBE
+INPUT
+
V
IN
–
COMMON
C
IN
= 2 x 100μF, ESR < 700m @ 100kHz
C
BUS
= 1000μF, ESR < 100m @ 100kHz
L
BUS
= 1μH
C
BUS
L
BUS
C
IN
Input Fusing
Most applications and or safety agencies require the installation of fuses at the
inputs of power conversion components. The LSN W3 Series are not inter-
nally fused. Therefore, if input fusing is mandatory, either a normal-blow or a
fast-blow fuse with a value no greater than twice the maximum input current
should be installed within the ungrounded input path to the converter.
As a rule of thumb however, we recommend to use a normal-blow or
slow-blow fuse with a typical value of about twice the maximum input current,
calculated at low line with the converter’s minimum efficiency.
Safety Considerations
LSN W3 SMT’s are non-isolated DC/DC converters. In general, all DC/DC’s must
be installed, including considerations for I/O voltages and spacing/separation
requirements, in compliance with relevant safety-agency specifications (usually
UL/IEC/EN60950-1).
In particular, for a non-isolated converter’s output voltage to meet SELV
(safety extra low voltage) requirements, its input must be SELV compliant. If the
output needs to be ELV (extra low voltage), the input must be ELV.
Input Overvoltage and Reverse-Polarity Protection
LSN W3 SMT Series DC/DC’s do not incorporate either input overvoltage
or input reverse-polarity protection. Input voltages in excess of the speci-
fied absolute maximum ratings and input polarity reversals of longer than
“instantaneous” duration can cause permanent damage to these devices.
Figure 2. Measuring Input Ripple Current
Output ripple/noise (also referred to as periodic and random deviations or
PARD) may be reduced below specified limits with the installation of additional
external output capacitors. Output capacitors function as true filter elements
and should be selected for bulk capacitance, low ESR, and appropriate fre-
quency response. Any scope measurements of PARD should be made directly
at the DC/DC output pins with scope probe ground less than 0.5" in length
+SENSE
+OUTPUT
COPPER STRIP
C1
C2
SCOPE
R
LOAD
COMMON
COPPER STRIP
Start-Up Time
The V
IN
to V
OUT
Start-Up Time is the interval between the time at which a ramp-
ing input voltage crosses the lower limit of the specified input voltage range
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 volt-
age as it appears to the converter.
The On/Off to V
OUT
Start-Up Time assumes the converter is turned off via the
On/Off Control with the nominal input voltage already applied to the converter.
The specification defines the interval between the time at which the converter
is turned on and the fully loaded output voltage enters and remains within its
specified accuracy band. See Typical Performance Curves.
Remote Sense
LSN W3 SMT Series DC/DC converters offer an output sense function on pin 3.
The sense function enables point-of-use regulation for overcoming moderate
IR drops in conductors and/or cabling. Since these are non-isolated devices
whose inputs and outputs usually share the same ground plane, sense is
provided only for the +Output.
The remote sense line is part of the feedback control loop regulating the
DC/DC converter’s output. The sense line carries very little current and conse-
quently requires a minimal cross-sectional-area conductor. As such, it is not
a low-impedance point and must be treated with care in layout and cabling.
Sense lines should be run adjacent to signals (preferably ground), and in cable
and/or discrete-wiring applications, twisted-pair or similar techniques should
be used. To prevent high frequency voltage differences between V
OUT
and
Sense, we recommend installation of a 1000pF capacitor close to the converter.
C1 = NA
C2 = 22μF TANTALUM
LOAD 2-3 INCHES (51-76mm) FROM MODULE
Figure 3. Measuring Output Ripple/Noise (PARD)
All external capacitors should have appropriate voltage ratings and be
located as close to the converters as possible. Temperature variations for all
relevant parameters should be taken into consideration.
You should add only enough output capacitance to attenuate the noise to
your desired level. Large amounts of output capacitance cause poor dynamic
response (step load changes, etc.). Too great an output capacitor can make the
converter oscillate (actually increasing the noise!) while substantial capaci-
tance which is less than the oscillation threshold can still cause ringing and
overshoot. Finally, you must use less output capacitance if the cap is a low
ESR type (OSCON, etc.).
The most effective combination of external I/O capacitors will be a func-
tion of your line voltage and source impedance, as well as your 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 Engineer-
ing Group for additional details.
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Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDC_LSN W3 Models.A01 Page 4 of 8
Single Output LSN-W3 Models
Non-Isolated, 3-5.5V
IN
, 0.75-3.3V
OUT
16 Amp DC/DC Converters
The sense function is capable of compensating for voltage drops between
the +Output and +Sense pins that do not exceed 10% of V
OUT
.
[V
OUT
(+) – Common] – [Sense(+) – Common]
10%V
OUT
For a controlled start-up of one or more LSN-W3’s, or if several output volt-
ages need to be powered-up in a given sequence, the On/Off Control pin can be
pulled high (external pull-up resistor, converter disabled) and then driven low
with an external open collector device to enable the converter.
Output Overvoltage Protection
LSN W3 Series DC/DC converters do not incorporate output overvoltage protec-
tion. In the extremely rare situation in which the device’s feedback loop is
broken, the output voltage may run to excessively high levels (V
OUT
= V
IN
). If it
is absolutely imperative that you protect your load against any and all possible
overvoltage situations, voltage limiting circuitry must be provided external to
the power converter.
Output Overcurrent Detection
Overloading the power converter’s output for an extended time will invariably
cause internal component temperatures to exceed their maximum ratings and
eventually lead to component failure. High-current-carrying components such
as inductors, FET’s and diodes are at the highest risk. LSN W3 Series DC/DC
converters incorporate an output overcurrent detection and shutdown function
that serves to protect both the power converter and its load.
If the output current exceeds it maximum rating by typically 50% (24 Amps)
or if the output voltage drops to less than 98% of it original value, the LSN W3’s
internal overcurrent-detection circuitry immediately turns off the converter,
which then goes into a "hiccup" mode. While hiccupping, the converter will
continuously attempt to restart itself, go into overcurrent, and then shut down.
Under these conditions, the average output current will be approximately
400mA, and the average input current will be approximately 40mA. Once the
output short is removed, the converter will automatically restart itself.
Output Voltage Trimming
Allowable trim ranges for each model in the LSN W3 Series are ±10%. Trim-
ming is accomplished with either a trimpot or a single fixed resistor. The trimpot
should be connected between +Output and Common with its wiper connected
to the Trim pin as shown in Figure 6 below.
Power derating (output current limiting) is based upon maximum output cur-
rent and voltage at the converter’s output pins. Use of trim and sense functions
can cause the output voltage to increase, thereby increasing output power
beyond the LSN’s specified rating. Therefore:
(V
OUT
at pins) x (I
OUT
)
rated output power
The internal 10.5 resistor between +Sense and +Output (see Figure 1)
serves to protect the sense function by limiting the output current flowing
through the sense line if the main output is disconnected. It also prevents
output voltage runaway if the sense connection is disconnected.
Note: If the sense function is not used for remote regulation, +Sense (pin 3)
must be tied to +Output (pin 4) at the DC/DC converter pins.
On/Off Control and Power-up Sequencing
The On/Off Control pin may be used for remote on/off operation. LSN W3 SIP
Series DC/DC’s are designed so they are enabled when the control pin is left
open (internal pull-down to Common) and disabled when the control pin is
pulled high (+2.5V to +V
IN
), as shown in Figures 4 and 5.
Dynamic control of the on/off function is best accomplished with a mechani-
cal relay or open-collector/open-drain drive circuit. The drive circuit should
be able to sink appropriate current when activated and withstand appropriate
voltage when deactivated.
Figure 4. Driving the On/Off Control Pin with an Open-Collector Drive Circuit
The on/off control function, however, can be externally inverted so that
the converter will be disabled while the input voltage is ramping up and then
“released” once the input has stabilized.
Figure 6. Trim Connections Using a Trimpot
Figure 5. Inverting On/Off Control Pin Signal and Power-Up Sequencing
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MDC_LSN W3 Models.A01 Page 5 of 8
Analogue and Mixed Signal
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