General Description

The AS8218 / AS8228 are highly integrated CMOS single-phase energy metering devices for fully electronic LCD meter systems. The AS8218 / AS8228 have been designed to ensure the meters full compliance with the international Standards IEC62052 and ANSI.

Key Features

- Precision single-phase, one or two current input energy measurement front-end including SigmaDelta modulators for A/D-conversion and digital signal processor (DSP).

- Low current consumption of 5mA, depending on MCU activity.

- Digital phase correction and selectable gain on both current channels for use with two current transformers (CT) or one CT and one shunt.

- Power-supply monitor (PSM) for power-on reset and reset when the supply voltage falls below a defined threshold.

- Customer programmable 8-bit 8051 compatible microcontroller (MCU).

- Programmable MCU clock with optional low power operating conditions.

- 2 x Universal Asynchronous Receiver / Transmitters (UART) for external communications such as programme download and debugging.

- Programmable watchdog timer (WDT) and external system reset pin.

- Real-time clock/calendar (RTC) with on-chip digital calibration and separate battery supply pin.

- On-chip voltage reference (VREF) with small temperature coefficient.

- Low power 3.0 – 4.0MHz crystal oscillator.

- SPI compatible interface for external EEPROM memory.

- Standard on-chip LCD driver (LCDD) interface.

- Programmable multi-purpose I/Os (MPIO) with selectable data direction, pull-up or pull-down resistors and drive strength.

- Mains current lead/lag status indication for reactive energy measurement.

- Low power battery operating mode for meter reading when Mains voltage is not present.

- The AS8218 and AS8228 ICs offer the following options:

AS8218: 20 x 4 segment LCDD 9 x multi-purpose I/O (MPIO)

AS8228: 24 x 4 segment LCDD 12 x multi-purpose I/O (MPIO)