www.murata-ps.com
LSM-16A W3 Models
Non-Isolated, Wide Input SMT DC/DC Converters
Non-Isolated, 3-5.5V
in
,
0.75-3.3V
out
16 Amp
DC/DC’s in SMT Packages
FEATURES
n
Step-down, wide input buck regulators for
distributed 3-5V power architectures
n
to 5V wide-input range
3V
n
0.75/1/1.2/1.5/1.8/2/2.5/3.3V
OUT
@16A
n
Non-isolated, fixed-frequency,
synchronous-rectifier topology
n
and reel SMT package
Tape
n
setpoint accuracy
±1%
n
Efficiencies to 95% @ 16 Amps
n
as low as 30mVp-p
Noise
n
Stable no-load operation
n
Remote on/off control
n
Sense pin and output voltage trim
n
derating to +65°C with no fan
No
n
Designed to meet UL/IEC/EN60950-1 safety
n
compliant
EMC
Typical unit
PRODUCT OVERVIEW
LSM Series W3 SMT’s (surface-mount
packages) are ideal building blocks for
emerging, on-board power-distribution
schemes in which isolated 3 to 5.5V buses
deliver power to any number of non-iso-
lated, step-down buck regulators. LSM 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.
LSM W3’s are ideal point-of-use/load
power processors. They typically require
no external components. 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 LSM’s best-in-class power density is
achieved with a fully synchronous, fixed-
frequency, buck topology that also delivers:
high efficiency (97%, 3.3V
OUT,
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 LSM’s feature output
overcurrent detection, continuous short-
circuit protection, over-temperature protec-
tion, a remote on/off control pin (pull low to
disable), an output-voltage trim function,
and a sense pin. High efficiency enables the
LSM 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 mul-
tiple supply voltages, check out the econom-
ics of on-board 3-5.5V distributed power. If
you don’t need to pay for multiple isolation
barriers, DATEL’s non-isolated LSM W3
SMT’s will save you money.
SIMPLIFIED SCHEMATIC
+INPUT
(2)
+OUTPUT
(4)
+SENSE
(6)
COMMON
(3)
CURRENT
SENSE
V
CC
ON/OFF
CONTROL
(1)
PWM
CONTROLLER
COMMON
(3)
REFERENCE &
ERROR AMP
V
OUT
TRIM
(5)
Typical topology is shown.
Figure 1. Simplified Schematic
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com/support
MDC_LSM-16A_W3.D02
Page 1 of 12
LSM-16A W3 Models
Performance Specifications and Ordering Guide
➀
Root Model
➄
LSM-0.75/16-W3-C
LSM-1/16-W3-C
LSM-1.2/16-W3-C
LSM-1.5/16-W3-C
LSM-1.8/16-W3-C
LSM-2/16-W3-C
LSM-2.5/16-W3-C
LSM-3.3/16-W3-C
LSM-T/16-W3-C
➅
Non-Isolated, Wide Input SMT DC/DC Converters
Regulation (Max.)
➂
V
IN
Nom.
(Volts)
Line
Load
±0.1%
±0.25%
±0.125%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.15%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
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
Output
R/N (mVp-p)
➁
Typ.
Max.
30
50
30
30
30
30
30
30
30
30
45
50
50
50
50
50
50
50
Input
Range
(Volts)
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
3-5.5
I
IN
➃
(mA/A)
70/2.98
70/3.72
70/4.36
70/5.33
70/6.30
70/6.92
70/8.56
Efficiency
Package
Full Load
½ Load (Case,
Min.
Typ.
Typ. Pinout)
80%
82%
81.5% C45, P63
85%
88%
89.5%
90.5%
91.5%
93%
93%
86%
88.8%
91.5%
92.5%
93.5%
95%
95%
86.5% C45, P63
88.0% C45, P63
90.0% C45, P63
92%
94%
95%
C45, P63
C45, P63
C45, P63
92.5% C45, P63
85.75% 86.5%
4.5-5.5➄
50/11.12
3-5.5➄
50/11.12
95.5% C45, P63
➀
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.
➁
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.
P A R T
N U M B E R
S T R U C T U R E
➂
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.
➃
Nominal line voltage, no-load/full-load conditions.
➄
V
IN
= 4.5 Volts minimum for V
OUT
= 3.3 Volts.
➅
LSM-T/16-W3 specs are given with V
OUT
= 3.3 Volts, unless noted.
M E C H A N I C A L
S P E C I F I C A T I O N S
1.30
(33.02)
Output
Configuration:
L
= Unipolar
Low Voltage
L SM
-
1.8
/
16
-
W3
-
C
RoHS-6 hazardous
substance compliant*
Input Voltage Range:
W3
= 3 to 5.5 Volts
(5V nominal)
Maximum Rated Output
Current in Amps
* Contact Murata-PS for availability.
0.062
(1.57)
TYP.
3
2
0.34
(8.64)
Non-Isolated SMT
Nominal Output Voltage:
0.75, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3
or 0.75-3.3 (T) Volts
SMT COPPER LEADS
COPLANAR 0.004
0.310
(7.87)
0.570 (14.48)
3 EQ. SP. @
0.190 (4.83)
0.085
(2.16)
4
5
6
1
1.36
(34.54)
Case C45
BOTTOM VIEW
0.53
0.48
(12.19) (13.46)
0.55
(13.97)
0.112
(2.84)
TYP.
0.05
(1.27)
0.075
(1.91)
0.048
(1.22)
1.177
(29.90)
0.570 (14.48)
3 EQ. SP. @
0.190 (4.83)
0.310
(7.87)
0.570 (14.48)
3 EQ. SP. @
0.190 (4.83)
0.010
(0.254)
0.60
(15.24)
0.297
(7.54)
0.310
(7.87)
0.375
(9.53)
0.052
(1.32)
Refer to the last page for
Tape and Reel information.
0.405
(10.29)
1
6
5
4
3
2
0.430
(10.92)
0.062
(1.57)
3
2
4
5
6
1
RECOMMENDED PAD LAYOUT
Recommended Pad Size: 0.15 x 0.10 (3.81 x 2.54)
Dimensions are in inches (mm shown for ref. only).
0.112 TYP.
(2.84)
0.049
(1.24)
0.047
(1.19)
BOTTOM VIEW
0.052
(1.32)
LSM WITH REMOVEABLE HEAT SHIELD
FOR HIGH TEMPERATURE SOLDER
CAUTION
PRESS TO REMOVE
THE HEAT SHIELD
AFTER THE SOLDER
PROCESS
NOTCH IN SHELL
INDICATES PIN ONE
DIMENSIONS IN INCHES (mm
)
I/O Connections
Pin
Function P63
1
On/Off Control
2
+Input
3
Common
4
+Output
5
V
OUT
Trim
6
+Sense
Third Angle Projection
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
Components are shown for reference only.
www.murata-ps.com/support
MDC_LSM-16A_W3.D02
Page 2 of 12
LSM-16A W3 Models
Non-Isolated, Wide Input SMT DC/DC Converters
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage, 200 lfm air flow, and full-load conditions
unless noted.
➀
➀
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.
➁
See Technical Notes and Performance Curves for details.
➂
The On/Off Control (pin 1) 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.
➃
Output noise may be further reduced with the installation of additional external output filtering. See
I/O Filtering and Noise Reduction.
➄
MTBF’s are calculated using Telcordia SR-332(Bellcore), ground fixed, T
A
= +25°C, full power,
natural convection, +67°C pcb temperature.
➅
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.
➆
LSM-0.75/16-W3 can not be trimmed down.
➇
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
➁
Input Reflected Ripple Current
➁ ➅
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
Undervoltage Shutdown
On/Off Control
➁ ➂
Input
3-5.5 Volts (5V nominal)
➇
See Ordering Guide
0.02A
2
sec
8mA
60-110mA average (model dependent)
10-70mAp-p, model dependent
Capacitive
None
None
None
On = open to +V
IN
(internal pull-up to +V
IN
)
Off = 0 to +0.4V (1mA)
Absolute Maximum Ratings
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
V
OUT
Accuracy
(50% load)
Temperature Coefficient
Minimum Loading
➀
Maximum Capacitive Load
Output
±1.5%
±0.02%/°C
No load
5000µF (electrolytic),
2000µF (0.02Ω ESR, OSCON)
±10%
➆
V
OUT
Trim Range
Ripple/Noise
(20MHz BW)
➀ ➁ ➃
See Ordering Guide
Total Accuracy
3% over line/load/temperature
Efficiency
See Ordering Guide
Overcurrent Detection and Short-Circuit Protection:
➁
Current-Limiting Detection Point
19-30 Amps (model dependent)
Short-Circuit Detection Point
98% of V
OUT
set
SC Protection Technique
Hiccup with auto recovery
Short-Circuit Current
600mA average
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.
Dynamic Characteristics
Transient Response
(50% load step) 30-70µsec to ±2% of final value
(model dependent)
Start-Up Time:
➁
V
IN
to V
OUT
and On/Off to V
OUT
7msec
Switching Frequency
300 ±50kHz
T E C H N I C A L
N O T E S
Environmental
Calculated MTBF
➄
TBD
Operating Temperature:
(Ambient)
➁
–40 to +85°C (with derating)
See Derating Curves
Maximum PC Board Temperature
Thermal Shutdown
EMI
Conducted or radiated,
FCC Part 15, EN55022
Safety
+100°C
+115°C (110 to 125°C)
Class B
Designed to meet UL/IEC/EN60950-1,
CSA-C22.2 No. 234
I/O Filtering and Noise Reduction
All models in the LSM 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 LSM’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 LSM’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
Physical
1.3" x 0.53" x 0.34" (33.03 x 13.46 x 8.64)
0.112" x 0.062" (2.84 x 1.57mm) rectangular
copper with gold plate over nickel underplate
0.28 ounces (7.8g)
UL94V-0
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MDC_LSM-16A_W3.D02
Page 3 of 12
LSM-16A W3 Models
Non-Isolated, Wide Input SMT DC/DC Converters
TO
OSCILLOSCOPE
CURRENT
PROBE
L
BUS
C
BUS
–
3
C
IN
= 2 x 100µF, ESR < 700mΩ @ 100kHz
C
BUS
= 1000µF, ESR < 100mΩ @ 100kHz
L
BUS
= 1µH
COMMON
C
IN
2
+INPUT
+
V
IN
Safety Considerations
LSM 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 spac-
ing/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
LSM 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.
Start-Up Time
The V
IN
to V
OUT
Start-Up Time is the interval between the time at which a
ramping 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 voltage 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
LSM W3 SMT Series DC/DC converters offer an output sense function on pin
6. The sense function enables point-of-use regulation for overcoming mod-
erate 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
consequently 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.
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
Power derating (output current limiting) is based upon maximum output
current 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 LSM’s specified rating. Therefore:
(V
OUT
at pins) x (I
OUT
)
≤
rated output power
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
6
4
COPPER STRIP
C1
C2
SCOPE
R
LOAD
COMMON
3
COPPER STRIP
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
The most effective combination of external I/O capacitors will be a function
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.
Input Fusing
Most applications and or safety agencies require the installation of fuses at the
inputs of power conversion components. The LSM W3 Series are not internally
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.
www.murata-ps.com/support
MDC_LSM-16A_W3.D02
Page 4 of 12
LSM-16A W3 Models
Non-Isolated, Wide Input SMT DC/DC Converters
The internal 10.5Ω 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 6) must be tied to +Output (pin 4) at the DC/DC converter pins.
On/Off Control
The On/Off Control pin may be used for remote on/off operation. LSM W3
Series DC/DC converters are designed so that they are enabled when the con-
trol pin is left open (open collector) and disabled when the control pin is pulled
low (to less than +0.4V relative to Common). As shown in Figure 4, all models
have an internal pull-up current source to V
IN
(+Input).
Dynamic control of the on/off function is best accomplished with a mechanical
relay or open-collector/open-drain drive circuit (optically isolated if appropri-
ate). The drive circuit should be able to sink appropriate current when activated
and withstand appropriate voltage when deactivated.
+INPUT
EXTERNAL
OPEN
COLLECTOR
INPUT
+INPUT
10kΩ
+V
ON/OFF
CONTROL
SIGNAL
GROUND
COMMON
SHUTDOWN
CONTROLLER
Figure 5. Inverting On/Off Control With An External CMOS Gate
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. LSM W3 SMT 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 LSM 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 LSM W3 SMT Series are ±10%.
Trimming 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.
A trimpot can be used to determine the value of a single fixed resistor which
can then be connected, as shown in Figure 7, between the Trim pin and
+Output to trim down the output voltage, or between the Trim pin and Common
to trim up the output voltage. Fixed resistors should have absolute TCR’s less
than 100ppm/°C to ensure stability.
The equations below can be starting points for selecting specific trim-resistor
values. Recall, untrimmed devices are guaranteed to be ±1% accurate.
Adjustment beyond the specified ±10% adjustment range is not recommended.
When using trim in combination with Remote Sense, the maximum rated power
must not be exceeded (see Remote Sense).
+5V
SMALL
SIGNAL
TRANSISTOR
HI = OFF
LO = ON
ON/OFF
CONTROL
SIGNAL
GROUND
COMMON
+V
SHUTDOWN
CONTROLLER
Figure 4. On/Off Control Using An External Open Collector Driver
Applying an external voltage to the On/Off Control pin when no input power is
applied to the converter can cause permanent damage to the converter. The
on/off control function, however, is designed such that the converter can be
disabled (control pin pulled low) while input voltage is ramping up and then
“released” once the input has stabilized (see also power-up sequencing).
Power-up Sequencing
If a controlled start-up of one or more LSM W3 Series DC/DC converters
is required, or if several output voltages need to be powered-up in a given
sequence, the On/Off control pin can be driven with an external open collector
device as per Figure 4.
Leaving the input of the on/off circuit closed during power-up will have the
output of the DC/DC converter disabled. When the input to the external open
collector is pulled high, the DC/DC converter’s output will be enabled.
Output Overvoltage Protection
LSM W3 SMT Series DC/DC converters do not incorporate output overvoltage
protection. 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.
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MDC_LSM-16A_W3.D02
Page 5 of 12
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