Data Sheet AS3977

Revision 1.2, 20.09.2007

Page 1 of 2

General Description

The AS3990 UHF reader chip is an integrated

analogue front end and data framing system for a

900MHz RFID reader system. Built in programming

options make it suitable for a wide range of

applications in UHF RFID systems. Designed to

simplify the design and implementation of an EPC

Class 1Gen2 reader, this IC requires only a standard

8Bit microcontroller with minimal other components.

The AS3990 comprises the EPC Class 1- Gen2

protocol (ISO 18000-6c) with digital high speed logic

up to the framing level and supports the ISO 18000-

6a and ISO 18000-6b Protocol with direct data mode.

The Interface to the microcontroller can be either a 4

pin serial date Interface (SDI) or alternatively in case

of high data rates are necessary an eight Bit parallel.

The frame management will be done using a 12 Byte

FIFO in order to decrease processor workload and

ensure a smooth data stream and correct protocol

handling. All low level transmission codec’s and CRC

generation is done internally.

An on chip level shifter with a special supply pin can

be used to adapt microcontroller supply voltages in

the range of 1.8- 3.3V for optimized power usage. In

order to reduce the BOM, an integrated LDO with

driver strength of 20mA can be used to supply the

microcontroller. Additional regulators for the RF

section suppress disturbances and thus allow noisy

main supply.

A 20MHz crystal is used for the reference oscillator.

Using this reference, an additional programmable

glitch free clock output can be used to clock the

microcontroller thus saving costs and current. In

addition, by using the integrated power management

features modes power-down, standby and active it is

possible to shut down or reduce the microcontroller

clock and hence save additional power.

Applications

•

Barcode label printers

•

Add-on module for handheld computers, PDA

•

Point of sales

•

Currency reader

•

UHF RFID reader systems

•

Hand-held UHF RFID readers

•

Toll systems

•

mobile phones

Key Features

•

Fully compliant with ISO 18000 6a, 6b, 6c and

EPC Class 1- Gen2 protocol using external MCU

•

EPC Class 1 -Gen2 framing support using low

cost 8 Bit microcontroller

•

Direct data mode in the frequency range of 860 to

960 MHz enables propriety Protocol support

•

Internal power amplifier with level controlled

20dBm for short range applications

•

Modulator using ASK or PR-ASK modulation

•

Adjustable ASK modulation index

•

Automatic selection between I and Q Signal

ensuring no “communication holes”

•

Built-in reception low-pass and high-pass filters

having selectable corner frequencies.

•

On chip VCO and PLL covering complete RFID

frequency range and frequency hopping support

•

Selectable receiver gain with AGC

•

Supported link frequencies from 40 up to 640kHz

Package

•

64 pin QFN 9*9

UHF RFID single chip reader EPC Class1 Gen2 compatible

AS3990

Preliminary Information

PRELIMINARY INFORMATION: SUBJECT TO CHANGE WITHOUT ANY NOTICE