PRELIMINARY
®
®
A SUBSIDIARY OF C&D TECHNOLOGIES
Single Output
LSN-16A W3 Models
Non-Isolated, 3-5.5VIN, 0.75-3.3VOUT
16 Amp DC/DC Converters
Features
■
Step-down, wide input buck regulators
for distributed 3-5V power architectures
■
3V to 5.5V wide-input range
■
0.75/1/1.2/1.5/1.8/2/2.5/3.3VOUT @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 certification pending
■
EMC compliant
LSN Series W3 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-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 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 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 overcurrent detection, continuous shortcircuit protection, over-temperature protection, a remote on/off control pin
(pull low to disable), an output-voltage trim function, and a sense pin. High efficiency
enables 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 supply 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.
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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-16A W3 Models
N O N - I S O L AT E D , W I D E I N P U T D C / D C C O N V E R T E R S
Performance/Functional Specifications
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 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, TA = +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 Setting accuracy for LSN-T/16-W3 is ±2%.
➇ Input voltage must be 4.5V minimum for 3.3V output.
Typical @ TA = +25°C under nominal line voltage and full-load conditions unless noted. ➀
Input
3-5.5 Volts (5V nominal) ➇
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
VOUT Accuracy (50% load)
See Ordering Guide
0.02A2 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 VIN max.), 1mA
Absolute Maximum Ratings
Input Voltage:
Continuous or transient
Output
±1.5% ➆
On/Off Control (Pin 1)
Temperature Coefficient
Minimum Loading ➀
Maximum Capacitive Load
±0.02%/°C
No load
5000µF (electrolytic),
2000µF (0.02Ω ESR, OSCON)
VOUT Trim Range
±10%
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
24 Amps
Short-Circuit Detection Point
98% of VOUT set
SC Protection Technique
Hiccup with auto recovery
Short-Circuit Current
600mA average
Thermal Shutdown
Dimensions
Pin Dimensions/Material
Weight
Flamability Rating
None
Output Overvoltage Protection
None
Output Current
Current limited. Devices can
withstand sustained output short
circuits without damage.
Storage Temperature
–40 to +125°C
Lead Temperature
See Reflow Solder Profile
These are stress ratings. Exposure of devices to any of these conditions may adversely
affect long-term reliability. Proper operation under conditions other than those listed in the
Performance/Functional Specifications Table is not implied.
T E C H N I C A L
N O T E S
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 highquality, high-performance internal I/O caps, and will operate within spec in
most applications with no additional external components.
300 ±50kHz
Environmental
Calculated MTBF ➄
TBD
Operating Temperature: (Ambient) ➁
Without Derating (Natural convection) –40 to +63/71°C (model dependent,
see Derating Curves)
With Derating
See Derating Curves
PC-Board Temperature
+VIN
Input Reverse-Polarity Protection
Dynamic Characteristics
Transient Response (50% load step) 30-70µsec to ±2% of final value
(model dependent)
Start-Up Time: ➁
VIN to VOUT and On/Off to VOUT
7msec
Switching Frequency
6 Volts (0.75, 1, 1.2, 1.5, 1.8, 2, 2.5 VOUT)
7 Volts (3.3VOUT and "T" models)
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.
+100°C maximum
+115°C (110 to 125°C)
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)
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.
UL94V-0
3
