Found 4 alternatives for MICRF103YM by Microchip Technology. Rf Transmitters — 8-SOIC (0.154", 3.90mm Width).
QWIKRADIO UHF ASK TRANSMITTER
RF TRANSMITTER ISM 433MHZ 8SOIC
RF TRANSMITTER ASK 315MHZ 8SOIC
RF XMITTER FSK 868/915MHZ 8SOIC