The TRF4900 single-chip solution is an integrated circuit intended for use as a low cost FSK transmitter to establish a frequency-agile RF link. The device is available in a 24-lead TSSOP package and is designed to provide a fully-functional multichannel transmitter. The chip is intended for linear (FM) or digital (FSK) modulated applications in the new 868-MHz European band and the North American 915-MHz ISM band. The single chip transmitter operates down to 2.2 V and is expressly designed for low power consumption. The synthesizer has a typical channel spacing of approximately 230 Hz to allow narrow-band as well as wide-band applications. Due to the narrow channel spacing of the direct digital synthesizer (DDS), the DDS can be used to adjust the TX frequency and allows the use of inexpensive reference crystals. Two fully-programmable operation modes, Mode0 and Mode1, allow extremely fast switching between two preprogrammed settings (e.g., TX_frequency_0/TX_frequency_1) without reprogramming the device. Each functional block of the transmitter can be specifically enabled or disabled via the serial interface. These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.