GENERAL DESCRIPTION

The ADF7021 is a high performance, low power, highly integrated 2FSK/3FSK/4FSK transceiver. It is designed to operate in the narrow-band, license-free ISM bands, and in the licensed bands with frequency ranges of 80 MHz to 650 MHz and 862 MHz to 950 MHz. The part has both Gaussian and raised cosine transmit data filtering options to improve spectral efficiency for narrow band applications. It is suitable for circuit applications targeted at European ETSI EN 300 220, the Japanese ARIB STD-T67, the Chinese short range device regulations, and the North American FCC Part 15, Part 90, and Part 95 regulatory standards. A complete transceiver can be built using a small number of external discrete components, making the ADF7021 very suitable for price sensitive and area sensitive applications.

The range of on-chip FSK modulation and data filtering options allows users greater flexibility in their choice of modulation schemes while meeting tight spectral efficiency requirements. The ADF7021 also supports protocols that dynamically switch between 2FSK/3FSK/4FSK to maximize communication range and data throughput.

The transmit section contains dual voltage controlled oscillators (VCOs) and a low noise fractional-N PLL with an output resolution of <1 ppm. The ADF7021 has a VCO using an internal LC tank (431 MHz to 475 MHz, 862 MHz to 950 MHz) and a VCO using an external inductor as part of its tank circuit (80 MHz to 650 MHz). The dual VCO design allows dual-band operation where the user can transmit and/or receive at any frequency supported by the internal inductor VCO and can also transmit and/or receive at a particular frequency band supported by the external inductor VCO.

The frequency agile PLL allows the ADF7021 to be used in frequency hopping spread spectrum (FHSS) systems.

Both VCOs operate at twice the fundamental frequency to reduce spurious emissions and frequency pulling problems.

FEATURES

  Low power, narrow-band transceiver

  Frequency bands using dual VCO

     80 MHz to 650 MHz

     862 MHz to 950 MHz

  Modulation schemes

     2FSK, 3FSK, 4FSK, MSK

  Spectral shaping

     Gaussian and raised cosine filtering

  Data rates supported

     0.05 kbps to 32.8 kbps

  2.3 V to 3.6 V power supply

  Programmable output power

     −16 dBm to +13 dBm in 63 steps

  Automatic PA ramp control

  Receiver sensitivity

     −130 dBm at 100 bps, 2FSK

     −122 dBm at 1 kbps, 2FSK

     −113 dBm at 25 kbps, raised cosine 2FSK

  Patent pending, on-chip image rejection calibration

  On-chip VCO and fractional-N PLL

  On-chip, 7-bit ADC and temperature sensor

  Fully automatic frequency control loop (AFC)

  Digital received signal strength indication (RSSI)

  Integrated Tx/Rx switch

  0.1 µA leakage current in power-down mode

APPLICATIONS

  Narrow-band standards

     ETSI EN 300 220, FCC Part 15, FCC Part 90, FCC Part 95,

     ARIB STD-T67

  Low cost, wireless data transfer

  Remote control/security systems

  Wireless metering

  Private mobile radio

  Wireless medical telemetry service (WMTS)

  Keyless entry

  Home automation

  Process and building control

  Pagers