Mother Board with ADF7242 Low Power IEEE 802.15.4/Proprietary GFSK/FSK Zero-IF 2.4 GHz Transceiver IC
The ADF7242 is a highly integrated, low power, and high performance transceiver for operation in the global 2.4 GHz ISM band. It is designed with emphasis on flexibility, robustness, ease of use, and low current consumption. The IC supports the IEEE 802.15.4-2006 2.4 GHz PHY requirements as well as proprietary GFSK/ FSK/GMSK/MSK modulation schemes in both packet and data streaming modes. With a minimum number of external components, it achieves compliance with the FCC CFR47 Part 15, ETSI EN 300 440 (Equipment Class 2), ETSI EN 300 328 (FHSS, DR > 250 kbps), and ARIB STD T-66 standards.
The ADF7242 complies with the IEEE 802.15.4-2006 2.4 GHz PHY requirements with a fixed data rate of 250 kbps and DSSS-OQPSK modulation. With its support of GFSK/FSK/GMSK/MSK modulation schemes, the IC can operate over a wide range of data rates from 50 kbps to 2 Mbps and is, therefore, equally suitable for proprietary applications in the areas of smart metering, industrial control, home and building automation, and consumer electronics. In addition, the agile frequency synthesizer of the ADF7242, together with short turnaround times, facilitates the implementation of FHSS systems.
The transmitter path of the ADF7242 is based on a direct closed-loop VCO modulation scheme using a low noise fractional-N RF frequency synthesizer. The automatically calibrated VCO operates at twice the fundamental frequency to reduce spurious emissions and avoid PA pulling effects. The bandwidth of the RF frequency synthesizer is automatically optimized for transmit and receive operations to achieve optimum phase noise, modulation quality, and synthesizer settling time performance. The transmitter output power is programmable from −20 dBm to +4 dBm with automatic PA ramping to meet transient spurious specifications. An integrated biasing and control circuit is available in the IC to significantly simplify the interface to external PAs.
The receive path is based on a zero-IF architecture enabling very high blocking resilience and selectivity performance, which are critical performance metrics in interference dominated environments such as the 2.4 GHz band. In addition, the architecture does not suffer from any degradation of blocker rejection in the image channel, which is typically found in low IF receivers. In GFSK/FSK modes, the receiver features a high speed automatic frequency control (AFC) loop, which allows the frequency synthesizer to find and correct any frequency errors in the received packet.
The IC can operate with a supply voltage between 1.8 V and 3.6 V with very low power consumption in receive and transmit modes while maintaining its excellent RF performance, making it especially suitable for battery-powered systems.
The ADF7242 features a flexible dual-port RF interface that can be used with an external LNA and/or PA in addition to supporting switched antenna diversity.
The ADF7242 incorporates a very low power custom 8-bit processor that supports a number of transceiver management functions. These functions are handled by the two main modules of the processor; the radio controller and the packet manager.Applications
- Wireless sensor networks
- Automatic meter reading/Smart metering
- Industrial wireless control
- Wireless audio / video
- Consumer electronics