The CC2540 USB dongle reference design shows how to make a compact USB dongle with the CC2540 System-on-Chip, using a PCB antenna and single sided components mounting. The reference design contains schematics and layout files for the CC2540 USB dongle. The reference design demonstrates good techniques for CC2540 decoupling and RF layout. For optimum RF performance, these parts should be copied accurately. This is a 4-layer reference design with a discrete balun and a compact meandered inverted F PCB antenna. This antenna is the recommended small PCB antenna for the 2.4 GHz frequency band.