HD688ADR

HD688ADR is a single-chip transceiver compliant with the Meter Bus standard (EN1434-3). The internal interface circuit accommodates the different voltage levels between master and slave devices in the M-Bus architecture. The bus connection is non-polarized and supports full galvanic isolation between the slave device via optocoupler. The chip can be powered directly from the bus without imposing additional power demands on slave devices, and features a built-in bus voltage fault indicator. The receiver incorporates dynamic level detection, and the transmitter features a programmable current sink. An on-chip 3.3 V voltage regulator is integrated, which shuts down with a delay upon bus fault occurrence. This device is widely used in M-Bus remote meter reading, security systems, smart home, and related applications.

Applications

• M-BUS remote meter reading
• Security
• Smart home

Key features

• Compliant with EN1434-3 communication standard
• Dynamic level recognition for receiver
• Modulation current adjustable via external resistor
• Polarity reversal protection
• Undervoltage indication
• Module power supply switching
• Integrated 3.3 V regulated power supply
• Remote bus powering
• Half-duplex UART communication up to 9600 baud
• Multiple slave powering modes supported: bus-powered via VDD pin; bus-powered via VDD pin with battery backup; battery-powered with bus for data transmission only