PRELIMINARY
®
®
INNOVATION and EXCELLENCE
Single Output
LSN-15A D12 Models
Non-Isolated, 12V
IN
, 0.8-5V
OUT
15 Amp DC/DC’s in SIP Packages
Features
■
Step-down buck regulators for new
distributed 12V power architectures
12V input (10-14V range)
0.8/1/1.2/1.5/1.8/2/2.5/3.3/5V
OUT
@15A
Non-isolated, fixed-frequency,
synchronous-rectifier topology
Outstanding performance:
•
±1.25% setpoint accuracy
•
Efficiencies to 96% @ 15 Amps
•
Noise as low as 30mVp-p
•
Stable no-load operation
•
Trimmable output voltage
Remote on/off control and sense
Thermal shutdown
No derating to +68°C with 200 lfm
UL/IEC/EN60950 certified
EMC compliant
■
■
■
■
■
■
■
■
■
LSN Series D12 SIP's (single-in-line 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. LSN D12 DC/DC's
accept a 12V input (10V to 14V input range) and convert it, with the highest
efficiency 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 15 Amps.
LSN D12's are ideal point-of-use/load power processors. They typically require
no external components. Their vertical-mount packages occupy a mere 0.72 square
inches (4.6 sq. cm), and reversed pin vertical mount allows mounting to meet
competitor's keep out area. Horizontal-mount packages ("H" suffix) are only 0.37
inches (9.4mm) high.
The LSN's best-in-class power density is achieved with a fully synchronous,
fixed-frequency, buck topology that also delivers: high efficiency (96% for 5V
OUT
models), low noise (30 to 50mVp-p typ.), tight line/load regulation (±0.1%/±0.25%
max.), quick step response (100µsec), stable no-load operation, and no output
reverse conduction.
The fully functional LSN’s feature output overcurrent detection, continuous
short-circuit protection, an output-voltage trim function, a remote on/off control pin
(pull high to disable), thermal shutdown and a sense pin. High efficiency enables
the LSN D12's to deliver rated output currents of 15 Amps at ambient temperatures
to +68°C with 200 lfm air flow.
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 LSN D12 SIP's will save you money.
+INPUT
(7,8)
10.5Ω
+OUTPUT
(1,2,4)
66µF
100µF
330µF
+SENSE
(3)
COMMON
(5)
COMMON
(6)
CURRENT
SENSE
V
CC
ON/OFF
CONTROL
(11)
PWM
CONTROLLER
REFERENCE &
ERROR AMP
V
OUT
TRIM
(10)
Figure 1. Simplified Schematic
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
LSN-15A D12 Series
Performance Specifications and Ordering Guide
Output
Model
LSN-0.8/15-D12
➄
LSN-1/15-D12
LSN-1.2/15-D12
LSN-1.5/15-D12
LSN-1.8/15-D12
LSN-2/15-D12
LSN-2.5/15-D12
LSN-3.3/15-D12
LSN-5/15-D12
N O N - I S O L AT E D , 1 2 - 7 5 W S I P D C / D C C O N V E R T E R S
➀
Input
Efficiency
Full Load
½ Load
Min.
80%
83%
85%
86%
87%
88.5%
90.5%
92.5%
94%
V
OUT
(Volts)
0.8
1
1.2
1.5
1.8
2
2.5
3.3
5
I
OUT
(Amps)
15
15
15
15
15
15
15
15
15
R/N (mVp-p)
➁
Typ.
Max.
45
45
45
30
30
30
35
40
50
65
65
60
45
45
45
50
55
75
Regulation (Max.)
➂
Line
Load
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.1%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
V
IN
Nom.
(Volts)
12
12
12
12
12
12
12
12
12
Range
(Volts)
10-14
10-14
10-14
10-14
10-14
10-14
10-14
10-14
10-14
I
IN
➃
(mA/A)
39/1.21
39/1.45
45/1.70
54/2.09
53/2.49
59/2.74
60/3.38
69/4.37
75/6.52
Typ.
82.5%
86%
88%
89.5%
90.5%
91.2%
92.5%
94.5%
96%
Typ.
86%
86%
90%
91%
92%
93%
94%
96%
95.5%
Package
(Case,
Pinout)
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
B5/B5x, P59
➀
Typical at T
A
= +25°C under nominal line voltage and full-load conditions, unless otherwise
noted. All models 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 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
Contact DATEL for availablilty.
M E C H A N I C A L
S P E C I F I C A T I O N S
L SN
-
1.8
/
15
-
D12 H J
Output
Configuration:
L
= Unipolar
Low Voltage
Non-Isolated SIP
Nominal Output Voltage:
0.8, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3
or 5 Volts
Maximum Rated Output
Current in Amps
See page 12 for Part Number
Structure and ordering details.
J Suffix:
Reversed Pin
Vertical Mount
H Suffix:
Horizontal Mount
Input Voltage Range:
D12
= 10-14 Volts
(12V nominal)
Case B8
Vertical Mounting
(Standard)
0.37
(9.4)
0.20
(5.08)
0.50
(12.7)
1 2 3 4 5
6 7 8 9 10 11
0.37
(9.4)
2.00
(50.80)
0.05
(1.27)
1 2 3 4 5
6 7 8 9 10 11
0.21
(5.33)
0.50
(12.7)
ISOLATING
PAD
0.17
(4.32)
2.00
(50.80)
0.030 ±0.001 DIA.
(0.762 ±0.025)
0.400
(10.16)
4 EQ. SP. @
0.100 (2.54)
0.56
(14.22)
1.000
(25.40)
0.500
(12.70)
5 EQ. SP. @
0.100 (2.54)
0.05
(1.27)
0.360
(9.14)
0.16
(4.06)
0.030 ±0.001 DIA.
(0.762 ±0.025)
0.400
(10.16)
4 EQ. SP. @
0.100 (2.54)
1.000
(25.40)
0.500
(12.70)
5 EQ. SP. @
0.100 (2.54)
0.05
(1.27)
0.07
(1.8)
0.13
(3.3)
0.53
(13.46)
Case B8A
Horizontal Mounting
0.50
(12.7)
0.32
(8.13)
LAYOUT PATTERN
TOP VIEW
0.37
(9.4)
0.45
(11.43)
LAYOUT PATTERN
TOP VIEW
Case B8B
Reverse Pin
Vertical Mounting
(Tyco-compatible)
RECOMMENDED
COPPER PAD
ON PCB (0.55 SQ. IN.)
Dimensions in inches (mm)
Pin
1
2
3
4
Function P59
+Output
+Output
+Sense
+Output
I/O Connections
Pin
Function P59
5
Common
6
Common
7
+Input
8
+Input
Pin
9
10
11
Function P59
No Pin
V
OUT
Trim
On/Off Control
2
N O N - I S O L AT E D , 1 2 - 7 5 W S I P D C / D C C O N V E R T E R S
LSN-15A D12 Models
Performance/Functional Specifications
Typical @ T
A
= +25°C under nominal line voltage and full-load conditions unless noted.
➀
Physical
Outline Dimensions
Pin Dimensions/Material
Weight
See Mechanical Specifications
0.03" (0.76mm) round copper with tin-lead
plate over nickel underplate
0.3 ounces (9g)
UL94V-0
Not rated
UL/cUL 60950, CSA-C22.2 No.234
IEC/EN 60950
Input
Input Voltage Range
Input Current:
Normal Operating Conditions
Standby/Off Mode
Output Short-Circuit Condition
Input Reflected Ripple Current
➁
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
Undervoltage Shutdown
No-load Input Current
Remote On/Off Control
➄
–Negative Logic
10-14 Volts (12V nominal)
See Ordering Guide
5.7mA
30mA
100mAp-p
Capacitive
None
None
None
60mA
ON = no connection or open
(internal pull down), 0 to +0.4V
OFF = +2.8V to +V
IN
or pulled high
3mA maximum
±10% of V
OUT
Flammability Rating
Electromagnetic Interference
Safety
➀
All models 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 specified performance in your applications. All models are stable and regulate within
spec under no-load conditions.
Input Ripple Current is tested and specified over a 5-20MHz bandwidth. Input filtering is
C
IN
= 200µF, C
BUS
= 1000µF, L
BUS
= 1µH.
Current limit inception is given at either cold start-up or after warm-up.
Mean Time Before Failure is calculated using the Telecordia (Bellcore) SR-332 Method 1,
Case 3, ground fixed conditions, T
CASE
= +25°C, full load, natural convection, +67°C max. PC
board temp.
The On/Off Control (pin 11) may be driven with open-collector logic or by applying appropriate
external voltages which are referenced to Common, pins 5 and 6.
Short circuit shutdown begins when the output voltage degrades approximately 2% from the
selected setting.
➁
➂
➃
➄
➅
Remote Control On/Off Current
Sense Input Range
Voltage Output Accuracy
(50% load)
Minimum Loading
➀
Maximum Output Power
Maximum Capacitive Loading
V
OUT
Trim Range
Ripple/Noise
(20 MHz bandwidth)
Total Accuracy
Efficiency
Overcurrent Detection and
Short Circuit Protection
Current-limiting Detection
Short Circuit Detection
Short Circuit Protection Method
Short Circuit Current
Short Circuit Duration
Temperature Coefficient
Output
±1.25% maximum
No minimum load
See Ordering Guide
V
OUT
x I
OUT
must not exceed max. power
2,000µF (low ESR, OSCON)
±10%
See Ordering Guide
±3% over line, load and temperature
See Ordering Guide
Storage Temperature
Lead Temperature
(soldering, 10 sec.)
Absolute Maximum Ratings
Input Voltage:
Continuous or transient
On/Off Control
(Pin 11)
Input Reverse-Polarity Protection
Output Overvoltage Protection
Output Current
14Vdc maximum
+V
IN
None
None
Current limited. Devices can
withstand sustained output short
circuits without damage.
–40 to +120°C
+300°C, 10 seconds maximum.
Refer to solder profile.
21.5 Amps (18.5-26.5A, after warmup)
98% of V
OUT
setting
➅
Hiccup with autorecovery
See Technical Notes
400mA average (integrates hiccup pulses)
Continuous, output shorted to ground
±0.02% per °C
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 to 100% load step to ±2% of Vout)
LSN-0.8:
135µsec typical, 165µsec maximum
LSN-1:
50µsec typical, 100µsec maximum
LSN-1.2 to LSN-5
100µsec typical, 150µsec maximum
Start-Up Time
On/Off to V
OUT
Switching Frequency
Calculated MTBF
➃
Operating Temperature:
(Ambient)
No derating
With derating
Storage Temperature Range
Thermal Protection/Shutdown
Altitude
Relative Humidity
70µsec for V
OUT
= nominal
220 ±20 KHz
T E C H N I C A L
N O T E S
Return Current Paths
The LSN D12 SIP’s are non-isolated DC/DC converters. Their two Common
pins (pins 5 and 6) are connected to each other internally (see Figure 1). To
the extent possible (with the intent of minimizing ground loops), input return
current should be directed through pin 6 (also referred to as –Input or
Input Return), and output return current should be directed through pin 5
(also referred to as –Output or Output Return). Any on/off control signals
applied to pin 11 (On/Off Control) should be referenced to Common
(specifically pin 6).
I/O Filtering and Noise Reduction
All models in the LSN D12 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 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.
Environmental
TBD Hours
–40 to +58°C, natural convection
See derating curves
–40 to +120°C
115°C
0 to 10,000 feet
10% to 90%, non-condensing
3
LSN-15A D12 Series
N O N - I S O L AT E D , 1 2 - 7 5 W S I P D C / D C C O N V E R T E R S
In particular, the LSN D12'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. As shown in the Performance Curves, removal of the external 22µF
tantalum output caps has minimal effect on output noise.
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
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 specific system
configuration may necessitate additional considerations.
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 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.
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 solu-
tions and discuss the possibility of our modifying a given device’s internal filter-
ing to meet your specific 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. LSN D12 Series DC/DC
converters are not internally fused. Therefore, if input fusing is mandatory,
either a normal-blow or a slow-blow fuse with a value no greater than 9 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 efficiency.
Safety Considerations
LSN D12 SIP'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-
fications (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.
Input Overvoltage and Reverse-Polarity Protection
LSN D12 SIP Series DC/DC's do not incorporate either input overvoltage
or input reverse-polarity protection. Input voltages in excess of the specified
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 specified input voltage
range (10 Volts) 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
LSN D12 SIP 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
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 differ-
ences 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 LSN's specified rating. Therefore:
(V
OUT
at pins) x (I
OUT
)
≤
rated output power
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: Connect the +Sense pin (pin 3) to +Output (pin 4) at the DC/DC
converter pins, if the sense function is not used for remote regulation.
4
N O N - I S O L AT E D , 1 2 - 7 5 W S I P D C / D C C O N V E R T E R S
LSN-15A D12 Models
On/Off Control and Power-up Sequencing
The On/Off Control pin may be used for remote on/off operation. LSN D12 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 (+2.8V to +V
IN
), as shown in Figure 2 and 2a.
Dynamic control of the on/off function is best accomplished with a mechanical
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.
+INPUT
Output Overcurrent Detection
Overloading the output of a power converter for an extended period of
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 D12 SIP Series DC/DC converters incorporate an output overcur-
rent 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 60% (24 Amps) or
if the output voltage drops to less than 98% of it original value, the LSN 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 LSN D12 SIP 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 3 below.
A trimpot can be used to determine the value of a single fixed resistor
which can then be connected, as shown in Figure 4, 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 used as 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.
SHUTDOWN
4.12kΩ
ON/OFF
CONTROL
SIGNAL
GROUND
CONTROLLER
15.4kΩ
POWER
COMMON
Figure 2. Driving the On/Off Control Pin with an External
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.
For a controlled start-up of one or more LSN-D12's, or if several output
voltages 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.
+INPUT
CMOS
LOGIC
ON/OFF
CONTROL
SHUTDOWN
4.12kΩ
SIGNAL
GROUND
CONTROLLER
COMMON
+INPUT
+OUTPUT
15.4kΩ
POWER
COMMON
TRIM
20kΩ
5-10
Turns
LOAD
COMMON
Figure 2a. Inverting On/Off Control Pin with an External CMOS Gate
Figure 3. Trim Connections Using a Trimpot
Output Overvoltage Protection
LSN D12 SIP 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.
+OUTPUT
+INPUT
TRIM
COMMON
COMMON
Trim
Up
Trim
Down
LOAD
Note:
Install either a fixed
trim-up resistor
or a fixed trim-down
resistor depending upon
desired output voltage.
Figure 4. Trim Connections Using Fixed Resistors
5
Analog electronics
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