Echelon LONWORKS PLT-22, User Manual

Page: 81 / 128

To 50ž
measuring
equipment
50ž coax
450ž
1 µF
To PLT-22 SIP
Power Supply
pins
50 cm
max
Figure 5.15 10x Power Supply Noise Probe
Options
The following switching power supply options are available: pre-designed, off-
the-shelf, and custom.
Pre-designed Switching Supplies
This option is highly recommended if a small, low-cost power supply is desired and
significant application current is required. Power Integrations has developed a
power supply based on their TOP210 chip to specifically meet all of the design
requirements for PLT-22 based nodes. This TOP210 design can supply a total of
400 mA at 12V and thus can support the PLT-22 transceiver operating in 7Vp-p
mode, a Neuron Chip plus about 100mA of application electronics. Detailed design
information, including schematic and parts list, is available from Power
Integrations in design note DN-15, TOPSwitch ® Power Supply for Echelon PLT-21
Power Line Transceiver . This design note is available on the Power Integrations
web site at http://www.powerint.com, or it can be ordered from Power Integrations
at the following address:
Power Integrations, Inc.
477 North Mathilda Avenue
Sunnyvale, CA 94086
Phone: +1-408-523-9200 or 1-800-552-3155
Fax: +1-408-523-9300
Building a power supply using DN-15 greatly simplifies the task of developing a
switching supply-based PLT-22 node since an instance of this design has been
verified to meet all of the impedance and noise requirements documented in this
chapter. Even though it is necessary to re-verify noise performance (due to
variations in PCB layout), using a predesigned/preverified supply significantly
reduces development time relative to a custom switching supply.
L
ON
W
ORKS
PLT-22 Transceiver's User Guide 5-21