CC2550RST (Texas Instruments) is a low-power 2.4 GHz RF transmitter controlled via SPI in a QFN-16 (4 × 4 mm) package.

• 2400 to 2483.5 MHz band · 1.2 to 500 kBaud data rate
• Programmable output power up to +1 dBm
• OOK, 2-FSK, GFSK and MSK modulation · 64-byte TX FIFO
• 200 nA in SLEEP mode · 240 us startup to TX

Minimum order: 2 pieces.

Data per TI CC2550 datasheet.