®
®
INNOVATION and EXCELLENCE
Single Output
LSM-10A D5 Models
Non-Isolated, 5VIN, 0.8-3.3VOUT
10 Amp DC/DC’s in SMT Packages
Features
■
Step-down buck regulators with
industry-standard SMT footprint
■
5V input (4.5-5.5V range)
■
0.8/1/1.2/1.5/1.8/2/2.5/3.3VOUT @10A
■
Non-isolated, fixed-frequency,
synchronous-rectifier topology
■
Tape and reel SMT package
■
±1% setpoint accuracy
■
Efficiencies to 95% @ 10 Amps
■
Noise as low as 30mVp-p
■
Stable no-load operation
■
Remote on/off control
■
Sense pin and output voltage trim
■
Thermal shutdown
■
No derating to +71°C, natural convection
■
UL/IEC/EN60950 certified
■
EMC compliant
DATEL's LSM D5 Series for SMT (surface-mount) are non-isolated DC/DC converters that accept a 5V input (4.5V to 5.5V input range) and deliver 0.8V, 1V, 1.2V,
1.5V, 1.8V, 2V, 2.5V, or 3.3V outputs at 10 Amps. LSM D5 SMT's are designed to take
on-board 5V power and convert it, with the highest efficiency in the smallest space, to
any lower voltage required by today's current-hungry DSP's, ASIC's and CPLD's.
The LSM D5's miniature size makes them ideal for true point-of-use/load power
processing. They occupy a mere 0.7 square inches (4.5 cm2) and are only 0.34 inches
(8.64 mm) high. The SMT package is designed for pick and place including lead free
reflow soldering, and they typically require no additional external components.
The LSM's best-in-class power density is achieved with a fully synchronous,
fixed-frequency (300kHz), buck topology that also delivers: high efficiency (95% for
3.3VOUT models), low noise (30mVp-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 LSM's feature output overcurrent detection, continuous shortcircuit and over-temperature protection, an output-voltage trim function, a remote
on/off control pin (pull low to disable), and a sense pin. High efficiency enables the
LSM D5's to deliver rated output currents of 10 Amps at ambient temperatures to
+71°C with no air flow (natural convection).
If your low-voltage, high-current requirements have made the use of inefficient
linear regulators impractical, take a look at one of DATEL's easy-to-use, low-cost
LSM SMT's (or equivalent LSN SIP's). All devices are UL/IEC/EN60950 certified and
EMC compliant. UL, CB, HALT and EMC reports are available upon request.
+OUTPUT
(4)
+INPUT
(2)
+SENSE
(6)
COMMON
(3)
COMMON
(3)
CURRENT
SENSE
ON/OFF
CONTROL
(1)
VCC
PWM
CONTROLLER
REFERENCE &
ERROR AMP
VOUT
TRIM
(5)
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
LSM-10A D5 Models
N O N - I S O L AT E D , 8 - 3 3 W S M T D C / D C C O N V E R T E R S
Performance/Functional Specifications
Absolute Maximum Ratings
Typical @ TA = +25°C under nominal line voltage and full-load conditions unless noted. ➀
Input Voltage:
Continuous or transient
7 Volts
On/Off Control (Pin 1)
Input
+VIN
Input Voltage Range
4.5 to 5.5 Volts (5V nominal)
Input Current:
Normal Operating Conditions
Inrush Transient
Standby/Off Mode
Output Short-Circuit Condition ➁
See Ordering Guide
0.02A2sec
5mA
60mA average
Input Reflected Ripple Current ➁
20mAp-p
Input Filter Type
Capacitive (44µF)
Storage Temperature
–40 to +125°C
Overvoltage Protection
None
Lead Temperature (soldering, 10 sec.)
See Reflow Solder Profile
Reverse-Polarity Protection
None
Undervoltage Shutdown
None
On/Off Control ➁ ➂
On = open (internal pull-up to +VIN)
Off = 0 to +0.8V (1ma max.)
Input Reverse-Polarity Protection
None
Output Overvoltage Protection
None
Output Current
Current limited. Devices can
withstand sustained output short
circuits without damage.
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.
Output
VOUT Accuracy (50% load)
±1% maximum
Minimum Loading ➀
No load
Maximum Capacitive Load
1000µF (low ESR, OSCON)
VOUT Trim Range ➁
±10% (0.8V not trimmable)
Ripple/Noise (20MHz BW) ➀ ➁ ➃
See Ordering Guide
Total Accuracy
3% over line/load temperature
Efficiency ➁
T E C H N I C A L
See Ordering Guide
I/O Filtering and Noise Reduction
All models in the LSM D5 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 D5'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.
Overcurrent Detection and Short-Circuit Protection: ➁
Current-Limiting Detection Point
17 (13-23.5) Amps
Short-Circuit Detection Point
98% of VOUT set
SC Protection Technique
Hiccup with auto recovery
Short-Circuit Current
600mA average
In particular, the LSM D5'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.
Dynamic Characteristics
Transient Response (50% load step)
100µsec to ±2% of final value
Start-Up Time: ➁
VIN to VOUT
On/Off to VOUT
7msec
6msec
Switching Frequency:
300kHz (+40/–50kHz)
In critical applications, input/output ripple/noise may be further reduced using
filtering techniques, the simplest being the installation of external I/O caps.
Environmental
Calculated MTBF ➄
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.
2.3 -1.8 million hours (1VOUT to 5VOUT)
Operating Temperature: (Ambient) ➁
Without Derating (Natural convection) –40 to +63/71°C (model dependent)
With Derating
See Derating Curves
Thermal Shutdown
+115°C (110 to 125°C)
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
N O T E S
UL94V-0
TO
OSCILLOSCOPE
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.
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, TA = +25°C, full
power, natural convection, +67°C pcb temperature.
2
+INPUT
LBUS
+
VIN
CURRENT
PROBE
CBUS
CIN
–
3
COMMON
CIN = 33µF, ESR < 700mΩ @ 100kHz
CBUS = 220µF, ESR < 100mΩ @ 100kHz
LBUS = 12µH
Figure 2. Measuring Input Ripple Current
3
