1FEATURES
• Meter-Bus Transceiver (for Slave) Meets
Standard EN1434-3
• Receiver Logic With Dynamic Level
Recognition
• Constant-Current Sink Adjustable By Resistor
• Polarity Independent
• Power-Fail Function
• Module Supply Voltage Switch
• 3.3-V Constant Voltage Source
• Up to 9600 Baud in Half Duplex for UART
Protocol
• Slave Power Support
– Supply From Meter-Bus by Output VDD
– Supply From Meter-Bus by Output VDD or
From Backup Battery
– Supply From Battery – Meter-Bus Active for
Data Transmission Only

APPLICATIONS
• E-metering
• Advanced Metering Infrastructure (AMI)
• Water Meters
• Gas Meters
• Heat Meters

DESCRIPTION
The TSS521 device is a single-chip transceiver
developed for Meter-Bus standard (EN1434-3) applications.
The TSS521 interface circuit adjusts the different
potentials between a slave system and the Meter-Bus master. The connection to the bus is polarity
independent and supports full galvanic slave isolation
with optocouplers.
The circuit is supplied by the master through the bus.
Therefore, this circuit offers no additional load for the
slave battery. A power-fail function is integrated.
The receiver has dynamic level recognition, and the
transmitter has a programmable current sink.
A 3.3-V voltage regulator with power reserve for a
delayed switch off at bus fault is integrated.