+INPUT
(2)
COMMON
(3)
PWM
CONTROLLER
CURRENT
SENSE
REFERENCE &
ERROR AMP
V
CC
ON/OFF
CONTROL
(1)
V
OUT
TRIM
(5)
+OUTPUT
(4)
+SENSE
(6)
COMMON
(3)
Single Output
LSM-10A D12 Models
Features
Non-Isolated, 12V
IN
, 0.8-5V
OUT
10 Amp DC/DC's in SMT Packages
Figure 1. Simplifi ed Schematic
LSM Series D12 SMT's (surface-mount packages) are ideal building blocks for
emerging, on-board power-distribution schemes in which isolated 12V buses deliver
power to any number of non-isolated, step-down buck regulators. LSM D12 DC/DC's
accept a 12V input (10.8V to 13.2V input range) and convert it, with the highest
effi ciency in the smallest space, to a 0.8, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3 or 5 Volt output
fully rated at 10 Amps.
LSM D12'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,
fi xed-frequency, buck topology that also delivers: high effi ciency (96% for 5V
OUT
models), low noise (50mVp-p typ.), tight line/load regulation (0.1%/0.25% max.),
quick step response (100sec), stable no-load operation, and no output reverse
conduction.
The fully functional LSM's feature output overcurrent detection, continuous
short-circuit protection, over-temperature protection, a remote on/off control pin
(pull low to disable), an output-voltage trim function, and a sense pin. High
effi ciency enables the LSM D12's to deliver rated output currents of 10 Amps at
ambient temperatures to +65C with 100 lfm air fl ow.
If your new system boards call for three or more supply voltages, check out the
economics of on-board 12V distributed power. If you don't need to pay for multiple
isolation barriers, DATEL's non-isolated LSM D12 SMT's will save you money.
INNOVATION and EX C ELL E N C E
Step-down buck regulators for new
distributed 12V power architectures
12V input (10.8-13.2V range)
0.8/1/1.2/1.5/1.8/2/2.5/3.3/5V
OUT
@10A
Non-isolated, fi xed-frequency,
synchronous-rectifi er topology
Tape and reel SMT package
1.25% setpoint accuracy
Effi ciencies to 96% @ 10 Amps
Noise as low as 50mVp-p
Stable no-load operation
Remote on/off control
Sense pin and output voltage trim
No derating to +65C with 100 lfm
UL/IEC/EN60950 certifi ed
EMC compliant
DATEL, Inc., Mansfi eld, MA 02048 (USA) Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 Email: sales@datel.com Internet: www.datel.com
LSM-10A D12 Series
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
2
Pin Function
P63
1
On/Off
Control
2
+Input
3
Common
4
+Output
5
V
OUT
Trim
6
+Sense
I/O Connections
LSM-0.8/10-D12 0.8 10 45 60 0.1% 0.375% 12 10.8-13.2 30/0.84
80.5% 82.5%
85% C45, P63
LSM-1/10-D12 1 10 50 75 0.1% 0.25% 12 10.8-13.2 35/1.02
83% 85%
86% C45, P63
LSM-1.2/10-D12 1.2 10 50 75 0.1% 0.25% 12 10.8-13.2 40/1.19
85% 87%
88% C45, P63
LSM-1.5/10-D12 1.5 10 50 75 0.1% 0.25% 12 10.8-13.2 50/1.47
86.5% 88.5%
89.5% C45, P63
LSM-1.8/10-D12 1.8 10 50 75 0.1% 0.25% 12 10.8-13.2 55/1.75
88% 90%
90.5% C45, P63
LSM-2/10-D12 2 10 50 75 0.1% 0.25% 12 10.8-13.2 55/1.9
89% 91%
91.5% C45, P63
LSM-2.5/10-D12 2.5 10 50 75 0.1% 0.25% 12 10.8-13.2 60/2.3
90% 92.5%
92% C45, P63
LSM-3.3/10-D12 3.3 10 50 75 0.1% 0.25% 12 10.8-13.2 70/3
92% 94%
93.5% C45, P63
LSM-5/10-D12 5 10 75 100 0.1% 0.25% 12 10.8-13.2 85/4.5
93.5% 96%
95.5% C45, P63
Typical at T
A
= +25C under nominal line voltage and full-load conditions, unless otherwise
noted. All models are tested and specifi ed with external 22F tantalum input and output
capacitors. These capacitors are necessary to accommodate our test equipment and may
not be required to achieve specifi ed performance in your applications. See I/O Filtering and
Noise Reduction.
M E C H A N I C A L S P E C I F I C A T I O N S
Ripple/Noise (R/N) is tested/specifi ed over a 20MHz bandwidth and may be
reduced with external fi ltering. See I/O Filtering and Noise Reduction for details.
These devices have no minimum-load requirements and will regulate under no-load conditions.
Regulation specifi cations 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.
P A R T N U M B E R S T R U C T U R E
Performance Specifi cations and Ordering Guide
Package
V
OUT
I
OUT
V
IN
Nom.
Range
I
IN
(Case,
Model
(Volts)
(Amps)
Typ.
Max.
Line
Load
(Volts)
(Volts)
(mA/A)
Min.
Typ.
Typ.
Pinout)
Output
Input
R/N (mVp-p)
Regulation (Max.)
Effi ciency
Full Load
Load
Case C45
0.34
(8.64)
0.53
(13.46)
0.48
(12.19)
0.430
(10.92)
0.405
(10.29)
0.085
(2.16)
1.30
(33.02)
SMT COPPER LEADS
COPLANAR 0.004
1.177
(29.90)
0.310
(7.87)
0.048
(1.22)
0.075
(1.91)
BOTTOM VIEW
RECOMMENDED PAD LAYOUT
0.05
(1.27)
0.062
(1.57)
TYP.
0.112
(2.84)
TYP.
0.570 (14.48)
3 EQ. SP. @
0.190 (4.83)
0.310
(7.87)
Recommended Pad Size: 0.15 x 0.10 (3.81 x 2.54)
0.297
(7.54)
0.570 (14.48)
3 EQ. SP. @
0.190 (4.83)
2
2
3
4
5
6
6
5
4
3
1
1
Maximum Rated Output
Current in Amps
Non-Isolated SMT
Output
Confi guration:
L = Unipolar
Low Voltage
Nominal Output Voltage:
0.8, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3
or 5 Volts
Input Voltage Range:
D12 = 10.8 to 13.2 Volts
(12V nominal)
L SM
10
-
/
D12
-
1.8
BOTTOM VIEW
1.36
(34.54)
0.375
(9.53)
0.112 TYP.
(2.84)
0.052
(1.32)
LSM WITH REMOVEABLE HEAT SHIELD
FOR HIGH TEMPERATURE SOLDER
CAUTION
PRESS TO REMOVE
THE HEAT SHIELD
AFTER THE SOLDER
PROCESS
0.60
(15.24)
0.049
(1.24)
0.310
(7.87)
0.010
(0.254)
0.55
(13.97)
0.052
(1.32)
0.062
(1.57)
0.047
(1.19)
0.570 (14.48)
3 EQ. SP. @
0.190 (4.83)
2
3
4
5
6
1
Refer to the last page for
Tape and Reel information.
LSM-10A D12 Models
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
3
Input
Input Voltage Range 10.8-13.2 Volts (12V nominal)
Input Current:
Normal Operating Conditions See Ordering Guide
Inrush Transient 0.08A
2
sec
Standby/Off Mode 1.5mA
Output Short-Circuit Condition
12-40mA average (model dependent)
Input Refl ected Ripple Current
40mAp-p
Input Filter Type Capacitive (44F)
Overvoltage Protection None
Reverse-Polarity Protection None
Undervoltage Shutdown None
On/Off Control
On = open (internal pull-up to +V
IN
)
Off = 0 to +0.4V (1mA max.)
Output
V
OUT
Accuracy (50% load) 1.25% maximum
Minimum Loading
No load
Maximum Capacitive Load 1000F (low ESR, OSCON)
V
OUT
Trim Range
10% (0.8V not trimmable)
Ripple/Noise (20MHz BW)
See Ordering Guide
Total Accuracy 3% over line/load/temperature
Effi ciency See Ordering Guide
Overcurrent Detection and Short-Circuit Protection:
Current-Limiting Detection Point 17 (12-23.5) Amps
Short-Circuit Detection Point 98% of V
OUT
set
SC Protection Technique Hiccup with auto recovery
Short-Circuit Current 120-400mA average (model dependent)
Dynamic Characteristics
Transient Response (50% load step) 100sec to 2% of fi nal value
Start-Up Time:
V
IN
to V
OUT
and On/Off to V
OUT
75msec for V
OUT
= 1V and 0.8V
50msec for V
OUT
= 1.2V to 5V
Switching Frequency:
0.8V, 1V/1.2V Models 105/120kHz 10%
1.5V/1.8V, 2V Models 160/177kHz 10%
2.5V, 3.3V, 5V Models 195kHz 10%
Environmental
Calculated MTBF
2.3 -1.8 million hours (1V
OUT
to 5V
OUT
)
Operating Temperature: (Ambient)
Without Derating (Natural convection) 40 to +48/64C (model dependent)
With Derating See Derating Curves
Thermal Shutdown +115C (110 to 125C)
Physical
Dimensions 1.3" x 0.53" x 0.34" (33.02 x 13.46 x 8.64 mm)
Pin Dimensions/Material 0.112" x 0.062" (2.84 x 1.57mm) rectangular
copper with gold plate over nickel underplate
Weight 0.28 ounces (7.8g)
Flamability Rating UL94V-0
Performance/Functional Specifi cations
Typical @ T
A
= +25C under nominal line voltage and full-load conditions unless noted.
All models are tested and specifi ed with external 22F tantalum input and output capacitors.
These capacitors are necessary to accommodate our test equipment and may not be
required to achieve specifi ed performance in your applications. All models are stable and
regulate within spec under no-load conditions.
See Technical Notes and Performance Curves for details.
The On/Off Control (pin 1) is designed to be driven with open-collector logic or the appli-
cation 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
fi ltering. See I/O Filtering and Noise Reduction.
MTBF's are calculated using Telcordia SR-332(Bellcore), ground fi xed, T
A
= +25C, full
power, natural convection, +67C pcb temperature.
Input Ripple Current is tested/specifi ed over a 5-20MHz bandwidth with an external 33F
input capacitor and a simulated source impedance of 220F and 12H. See I/O Filtering,
Input Ripple Current and Output Noise for details.
T E C H N I C A L N O T E S
Input Voltage:
Continuous or transient 15 Volts
On/Off Control (Pin 1) +V
IN
Input Reverse-Polarity Protection None
Output Overvoltage Protection None
Output Current Current limited. Devices can
withstand sustained output short
circuits without damage.
Storage Temperature 40 to +125C
Lead Temperature See Refl ow Solder Profi le
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 Specifi cations Table is not implied.
Absolute Maximum Ratings
I/O Filtering and Noise Reduction
All models in the LSM D12 Series are tested and specifi ed with external
22F 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 D12's are designed with
high-quality, high-performance internal I/O caps, and will operate within spec
in most applications with no additional external components.
In particular, the LSM D12's input capacitors are specifi ed for low ESR
and are fully rated to handle the units' input ripple currents. Similarly, the
internal output capacitors are specifi ed for low ESR and full-range frequency
response. As shown in the Performance Curves, removal of the external 22F
tantalum output caps has minimal effect on output noise.
In critical applications, input/output ripple/noise may be further reduced using
fi ltering 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
appropriate 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 impedances can greatly affect system stability. Your specifi c system
confi guration may necessitate additional considerations.
C
IN
V
IN
C
BUS
L
BUS
C
IN
= 33F, ESR < 700m
@ 100kHz
C
BUS
= 220F, ESR < 100m
@ 100kHz
L
BUS
= 12H
2
3
+INPUT
COMMON
CURRENT
PROBE
TO
OSCILLOSCOPE
+
Figure 2. Measuring Input Ripple Current
LSM-10A D12 Series
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
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 solu-
tions and discuss the possibility of our modifying a given device's internal fi lter-
ing to meet your specifi c requirements. Contact our Applications Engineering
Group for additional details.
Input Fusing
Most applications and or safety agencies require the installation of fuses
at the inputs of power conversion components. LSM D12 Series DC/DC
converters 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 20 Amps
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 converters minimum effi ciency.
Safety Considerations
LSM D12 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 speci-
fi cations (usually UL/IEC/EN60950).
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.
4
Input Overvoltage and Reverse-Polarity Protection
LSM D12 SMT Series DC/DC's do not incorporate either input overvoltage
or input reverse-polarity protection. Input voltages in excess of the specifi ed
absolute maximum ratings and input polarity reversals of longer than "instan-
taneous" 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 specifi ed input voltage
range (10.8 Volts) and the fully loaded output voltage enters and remains
within its specifi ed accuracy band. Actual measured times will vary with input
source impedance, external input capacitance, and the slew rate and fi nal
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 specifi cation defi nes the interval between the time at which the converter
is turned on and the fully loaded output voltage enters and remains within its
specifi ed accuracy band. See Typical Performance Curves.
Figure 3. Measuring Output Ripple/Noise (PARD)
Remote Sense
LSM D12 SMT Series DC/DC converters offer an output sense function on
pin 6. 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
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 tech-
niques 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 cur-
rent and voltage at the converter's output pins. Use of trim and sense func-
tions can cause the output voltage to increase, thereby increasing output
power beyond the LSM's specifi ed 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 fl owing
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.
Output ripple/noise (also referred to as periodic and random deviations
or PARD) may be reduced below specifi ed limits with the installation of
additional external output capacitors. Output capacitors function as true fi lter
elements and should be selected for bulk capacitance, low ESR, and appro-
priate frequency 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.
C1
C1 = NA
C2 = 22F TANTALUM
LOAD 2-3 INCHES (51-76mm) FROM MODULE
C2
R
LOAD
6
4
COPPER STRIP
3
COPPER STRIP
SCOPE
+OUTPUT
COMMON
+SENSE
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.
LSM-10A D12 Models
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
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 D12 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 70% (17 Amps) or
if the output voltage drops to less than 98% of it original value, the LSM D12'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 D12 SMT Series are 10%.
Trimming is accomplished with either a trimpot or a single fi xed 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 fi xed 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 specifi c trim-resistor
values. Recall, untrimmed devices are guaranteed to be
1.25% accurate.
Adjustment beyond the specifi ed 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).
On/Off Control
The On/Off Control pin may be used for remote on/off operation. LSM D12
Series DC/DC converters are designed so that they are enabled when the
control 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 14k
pull-up resistor 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.
5
+INPUT
COMMON
ON/OFF
CONTROL
14k
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).
+INPUT
COMMON
EXTERNAL
OPEN
COLLECTOR
INPUT
14k
10k
Figure 5. Driving the External Power-Up Open Collector
ON/OFF pin open: Logic High = DC/DC converter On
ON/OFF pin <0.4V: Logic Low = DC/DC converter Off
External Input Open: On/Off pin Low = DC/DC converter Off
External Input Low:
On/Off pin High = DC/DC converter On
Power-up sequencing
If a controlled start-up of one or more LSM D12 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 5.
Leaving the input of the external circuit open during power-up will have the
output of the DC/DC converter disabled. When the input to the external open
collector is pulled low, the DC/DC converters output will be enabled.
Output Overvoltage Protection
LSM D12 SMT Series DC/DC converters do not incorporate output overvolt-
age 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.
Figure 4. Driving the On/Off Control Pin with an Open-Collector Drive Circuit
LSM-10A D12 Series
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
6
The highest temperatures in LSM D12 SMT's occur at their output inductor,
whose heat is generated primarily by I
2
R losses. The derating curves were
developed using thermocouples to monitor the inductor temperature and
varying the load to keep that temperature below +110C under the assorted
conditions of air fl ow and air temperature. Once the temperature exceeds
+115C (approx.), the thermal protection will disable the converter. Automatic
restart occurs after the temperature has dropped below +110C.
As you may deduce from the derating curves and observe in the effi ciency
curves on the following pages, LSM D12 SMT's maintain virtually constant
effi ciency from half to full load, and consequently deliver very impressive
temperature performance even if operating at full load.
Lastly, when LSM D12 SMT's are installed in system boards, they are obvi-
ously subject to numerous factors and tolerances not taken into account here.
If you are attempting to extract the most current out of these units under
demanding temperature conditions, we advise you to monitor the output-
inductor temperature to ensure it remains below +110C at all times.
Output Reverse Conduction
Many DC/DC's using synchronous rectifi cation suffer from Output Reverse
Conduction. If those devices have a voltage applied across their output before
a voltage is applied to their input (this typically occurs when another power
supply starts before them in a power-sequenced application), they will either
fail to start or self destruct. In both cases, the cause is the "freewheeling" or
"catch" FET biasing itself on and effectively becoming a short circuit.
LSM D12 SMT DC/DC converters do not suffer from Output Reverse
Conduction. They employ proprietary gate drive circuitry that makes them
immune to applied output voltages.
Thermal Considerations and Thermal Protection
The typical output-current thermal-derating curves shown below enable
designers to determine how much current they can reliably derive from each
model of the LSM D12 SMT's under known ambient-temperature and air-fl ow
conditions. Similarly, the curves indicate how much air fl ow is required to
reliably deliver a specifi c output current at known temperatures.
Figure 7. Trim Connections Using Fixed Resistors
Figure 6. Trim Connections Using a Trimpot
LOAD
20k
5-10
Turns
+INPUT
COMMON
COMMON
+OUTPUT
TRIM
Note: Install either a fi xed trim-up resistor
or a fi xed trim-down resistor depending upon
desired output voltage.
Trim
Down
Trim
Up
LOAD
+INPUT
COMMON
+OUTPUT
TRIM
COMMON
Trim Equations
Note: Resistor values are in k
. Accuracy of adjustment is subject to
tolerances of resistors and factory-adjusted, initial output accuracy.
V
O
= desired output voltage. V
O
NOM
= nominal output voltage.
Note: LSM-0.8/10-D12 is not trimmable.
UP
V
O
V
O NOM
R
T
(k) =
1.46
DOWN
V
O NOM
V
O
R
T
(k) =
X
X
1.82(V
O
0.8)
UP
V
O
V
O NOM
R
T
(k) =
3.72
DOWN
V
O NOM
V
O
R
T
(k) =
X
X
4.64(V
O
0.8)
UP
V
O
V
O NOM
R
T
(k) =
6
DOWN
V
O NOM
V
O
R
T
(k) =
X
X
7.5(V
O
0.8)
LSM-1/10-D12: X = 0.909
LSM-1.1/10-D12: X = 2.49
LSM-1.2/10-D12: X = 3.09
LSM-1.3/10-D12: X = 4.12
LSM-1.5/10-D12: X = 13.3
LSM-1.8/10-D12: X = 16.9
LSM-2/10-D12: X = 15.4
LSM-2.5/10-D12: X = 20
LSM-3.3/10-D12: X = 15
LSM-5/10-D12: X = 10
LSM-10A D12 Models
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
7
Typical Performance Curves for LSM D12 SMT Series
91
89
87
85
83
81
79
77
75
LSM-1.2/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
89
87
85
83
81
79
77
75
LSM-1/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
40 0 60 70 80 90 100
110
LSM-1/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
40 0 60 70 80 90 100
110
LSM-1.2/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
LSM-10A D12 Series
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
93
91
89
87
85
83
81
79
77
75
LSM-2/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
91
89
87
85
83
81
79
77
75
LSM-1.5/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
93
91
89
87
85
83
81
79
77
75
LSM-1.8/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
Typical Performance Curves for LSM D12 SMT Series
40 0 60 70 80 90 100
110
LSM-1.5/10-D12
Output Current vs. Ambient Temperature
(SMTmount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
40 0 60 70 80 90 100
110
LSM-1.8/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
40 0 50 60 70 80 90 100
110
LSM-2/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
8
LSM-10A D12 Models
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
95
93
91
89
87
85
83
81
79
77
75
LSM-3.3/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
98
96
94
92
90
88
86
84
82
LSM-5/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
94
92
90
88
86
84
82
80
78
76
74
LSM-2.5/10-D12
Efficiency vs. Line Voltage and Load Current
1 2 3 4 5 6 7 8 9 10
Load Current (Amps)
Efficienc
y (
%
)
V
IN
= 10.8V
V
IN
= 12V
V
IN
= 13.2V
Typical Performance Curves for LSM D12 SMT Series
40 0 50 60 70 80 90 100
110
LSM-2.5/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (
C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
40 0 50 60 70 80 90 100
110
LSM-3.3/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
40 0 40 50 60 70 80 90 100
LSM-5/10-D12
Output Current vs. Ambient Temperature
(SMT mount, air flow direction from pin 2 to pin 1)
Output Current (Amps)
Ambient Temperature (C)
12
10
8
6
4
2
0
Natural Convection
200 lfm
100 lfm
9
LSM-10A D12 Series
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
10
Typical Performance Curves for LSM D12 SMT Series
Start-Up from ON/OFF
(V
IN
= 12V, I
OUT
= 5V/10A, C
OUT
= 22F)
10msec/div
V
IN
5V/div
V
OUT
2V/div
Output Hiccup
(LSM-5/10-D12 Shorted V
OUT,
V
IN
= 12V)
20msec/div
100mV/div
Start-Up from ON/OFF
(V
IN
= 12V, I
OUT
= 0.8V/10A, C
OUT
= 22F)
10msec/div
V
IN
5V/div
V
OUT
1V/div
Start-Up from V
IN
(V
IN
= 12V, I
OUT
= 5V/10A, C
OUT
= 22F)
10msec/div
V
IN
5V/div
V
OUT
2V/div
Input Reflected Ripple Current
(Input Filter = 220F/12H/33F, V
IN
= 12V, I
OUT
= 5V/10A)
2sec/div
50mA/div
Start-Up from V
IN
(V
IN
= 12V, I
OUT
= 0.8V/10A, C
OUT
= 22F)
10msec/div
V
IN
5V/div
V
OUT
1V/div
LSM-10A D12 Models
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
11
Typical Performance Curves for LSM D12 SMT Series
Dynamic Load Response
(V
IN
= 12V, V
OUT =
5V, 5 to 10A Step, C
O
= 22F + 1000F Oscon)
100sec/div
100mV/div
Dynamic Load Response
(V
IN
= 12V, V
OUT =
5V, 0 to 10A Step, C
O
= 22F + 1000F Oscon)
100sec/div
100mV/div
Dynamic Load Response
(V
IN
= 12V, V
OUT =
0.8V, 5 to 10A Step, C
OUT
= 22F)
100sec/div
100mV/div
Dynamic Load Response
(V
IN
= 12V, V
OUT =
5V, 0 to 10A Step, C
OUT
= 22F)
100sec/div
200mV/div
Output Ripple and Noise
(V
IN
= 12V, V
OUT
= 5V/10A, C
OUT
= 22F)
2sec/div
20mV/div
Output Ripple and Noise
(V
IN
= 12V, V
OUT =
0.8V/10A, C
OUT
= 22F)
2sec/div
20mV/div
LSM-10A D12 Series
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
12
Tape & Reel Surface Mount Package
DATEL's LSM series DC/DC converters are the only higher-current (10A)
SMT DC/DC's that can be automatically "pick-and-placed" using standard
vacuum-pickup equipment (nozzle size and style, vacuum pressure and
placement speed may need to be optimized for automated pick and place)
and subsequently refl owed 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 +221C) so that you may attach them
to your board using low-temperature solder (usually Sn63/Pb37 with a melt-
ing point of +183C). Conceptually straightforward, this "stepped" solder
approach has its limitations, and it is clearly out of step with an industry
trending toward the broad use of lead-free solders. Are you to experiment
and develop refl ow profi les from other vendors that ensure the components
on those DC/DC never exceed 215-216C? If those components get too hot,
"double-refl ow" could compromise the reliability of their solder joints. Virtually
all these devices demand you "cool down" the Sn63 profi le you are likely
using today.
Figure 6. Refl ow Solder Profi le
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 LSM SMT DC/DC's
using a high-temperature (+216C), lead-free alloy (Sn96.2%, Ag2.5%,
Cu0.8%, Sb0.5%). The LSM design ensures co-planarity to within 0.004
inches (1001m) of the unit's tin-plated (150 micro-inches) copper leads. See
Mechanical Data for additional information.
The disposable heat shield (patent pending), which has a cutaway exposing
the package leads, provides thermal insulation to internal components during
refl ow and its smooth surface ideally doubles as the vacuum pick-up location
also. The insulation properties of the heat shield are so effective that tem-
perature differentials as high as 50C develop inside-to-outside the shield.
Oven temperature profi les with peaks of 250-260C and dwell times exceed-
ing 2 minutes above 221C (the melting point of Sn96.5/Ag3.5) are easily
achieved.
250
200
150
100
50
0
50sec 100sec 150sec
200sec 250sec 300sec 350sec 400sec
221
183
Sn63/Pb37 Melting Point
Sn96.5/Ag3.5 Melting Point
PCB TEMPERATURE INSIDE THE HEAT SHIELD
T
e
mperature
C
Time (Seconds)
HEAT SHIELD OUTSIDE TEMPERATURE
LSM-10A D12 Models
N O N - I S O L A T E D , 1 0 - 5 0 W S M T D C / D C C O N V E R T E R S
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. Specifi cations are subject to change without notice. The DATEL logo is a registered DATEL, Inc. trademark.
DATEL (UK) LTD. Tadley, England Tel: (01256)-880444
DATEL S.A.R.L. Montigny Le Bretonneux, France Tel: 01-34-60-01-01
DATEL GmbH Mnchen, Germany Tel: 89-544334-0
DATEL KK Tokyo, Japan Tel: 3-3779-1031, Osaka Tel: 6-6354-2025
DATEL, Inc. 11 Cabot Boulevard, Mansfi eld, 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
DS-0523 5/03
13
0.51(13.0)
7.38 (187.5)
13.0 (330.2)
2.44
(62.0)
0.158
(4)
CENTERED
PICK UP
LOCATION
2.205
(56)
2.063
(52.4)
1.370
(34.8)
1.102
(28)
0.605
(15.36)
TAPE
0.590
(14.97)
DIMENSIONS
IN INCHES (mm)
1
1
1
DATEL's new-generation LSM SMT DC/DC converters are shipped in quantities of 150 modules per tape and reel.
Figure 7. Tape Dimensions
Figure 8. Reel Dimensions
CAUTION
PRESS TO REMOVE
THE HEAT SHIELD
AFTER THE SOLDER
PROCESS
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