Narrowband transceiver IC for operation in multiple frequency bands between 80 and 940MHz

"The new ADF7021 fortifies our portfolio of sub-GHz RF transceivers for high range, low-power, and low-cost wireless connectivity applications," said Christian Kermarrec, vice president, RF and wireless systems, Analog Devices, Inc. "Our commitment to innovation is evident in the ADF7021 as it
includes several features that address the core concerns of our customers, namely performance, robustness, cost and component count reduction."

The ADF7021 is the latest addition to ADI's successful ADF702x family of sub-GHz transceiver ICs, which offer low power and minimal external components for applications including low-rate connectivity, security systems and wireless AMR. In addition, to help speed wireless product
development, ADI offers its ADIismLINK development tool.

Utilizing the ADIismLINK tool, wireless product designers can transfer data between multiple units (slave node) and a master node (another ADF702x device) without having to spend time developing their own protocol software, resulting in more streamlined designs and faster time to market for
customers.

The ADF7021 is a low power, highly integrated 2FSK/3FSK/4FSK transceiver. It is designed to operate from 80 MHz to 940MHz. It has both Gaussian and raised cosine 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. The transmit section contains a voltage controlled oscillator (VCO) and a low noise fractional-N PLL with output resolution of less than 1 ppm. This frequency-agile PLL allows the ADF7021 to be used in frequency hopping spread spectrum (FHSS) systems. The VCO operates at twice the fundamental frequency to reduce spurious emissions and frequency pulling problems. The transmitter output power is programmable in 63 steps from -16 dBm to +13 dBm and has an automatic power ramp control to prevent spectral splatter and help meet regulatory standards. The transceiver RF frequency, channel spacing, and modulation are programmable using a simple 3-wire interface. The device operates with a power supply range of 2.3 V to 3.6 V and can be powered down when not in use.

A low IF architecture is used in the receiver (100 kHz), minimizing power consumption and the external component count while avoiding interference problems at low frequencies. The IF filter has programmable bandwidths of 12.5 kHz, 18.75 kHz, and 25 kHz. The ADF7021 supports a wide variety of
programmable features including Rx linearity, sensitivity, and IF bandwidth, allowing the user to trade off receiver sensitivity and selectivity against current consumption, depending on the application.

The receiver also features a patent-pending automatic frequency control (AFC) loop with programmable pull-in range, allowing the PLL to track out the frequency error in the incoming signal. An on-chip ADC provides readback of an integrated temperature sensor, an external analog input, the battery voltage, and the RSSI signal, which can provide cost savings.