Classic CC2430 hardware application circuit

The RF card terminal uses TI's CC2430 as the wireless RF chip, which is the first RF system-on-chip produced by Chipcon that complies with 802.15.14/Zigbee technology. It is suitable for various ZigBee or ZigBee-like wireless network nodes, including tuners, routers and terminal devices. It has very significant advantages such as low cost, low power consumption, multiple network nodes, and long transmission distance. It has the following main features: integrated RF radio transceiver that complies with the IEEE802.15.4 standard; excellent wireless receiving sensitivity and strong anti-interference; hardware supports CSMA/CA function; digital RSSI/LQI support.

　　The hardware application circuit of CC2430 is shown in the figure below. Considering that every employee needs to wear a wireless RF terminal, a simple and typical design method is adopted from the perspective of cost saving. The circuit uses an unbalanced antenna, and connecting an unbalanced transformer can make the antenna performance better.

　　Figure 1 CC2430 circuit application diagram

　　The unbalanced transformer in the circuit is composed of capacitor C341 and inductors L341, L321, L331 and a PCB microwave transmission line. The entire structure meets the requirements of RF input/output matching resistance (50Ω). The internal T/R switching circuit completes the switching between LNA and PA. R221 and R261 are bias resistors. Resistor R221 is mainly used to provide a suitable operating current for the 32 MHz crystal oscillator. A 32 MHz crystal oscillator circuit is formed by a 32 MHz quartz resonator (XTAL1) and two capacitors (C191 and C211). A 32.768 kHz crystal oscillator circuit is formed by a 32.768 kHz quartz resonator (XTAL2) and two capacitors (C441 and C431). The voltage regulator provides power for all pins requiring 1.8V voltage and the internal power supply. Capacitors C241 and C421 are decoupling capacitors used for power supply filtering to improve the stability of chip operation.