The Melexis TH72035 FSK/ASK transmitter IC is designed for applications in the European 868 MHz industrial-scientific-medical (ISM) band, according to the EN 300 220 telecommunications standard. It can also be used for any other system with carrier frequencies ranging from 850 to 930 MHz (for example for applications in the US 902 to 928 MHz ISM band). The transmitter's carrier frequency is determined by the frequency of the reference crystal fref. The integrated phase-locked loop (PLL) synthesizer ensures that carrier frequencies, ranging from 850 to 930 MHz, can be achieved. This is done by using a crystal with a reference frequency according to fref = fc/N, where N = 32 is the PLL feedback divider ratio.
Features
Application examples
Fully integrated PLL-stabilized VCO
Frequency range from 850MHz to 930MHz
Single-ended RF output
FSK through crystal pulling allows modulation from DC to 40kbit/s
High FSK deviation possible for wideband data transmission
ASK achieved by on/off keying of internal power amplifier up to 40kbit/s
Wide power supply range from 1.95V to 5.5V
Operating temp. range from -40°C to +125°C
Very low standby current
On-chip low voltage detector
High over-all frequency accuracy
FSK deviation and center frequency independently adjustable
Adjustable output power range from -10dBm to max. +9.5dBm
Adjustable current consumption from 5.1mA to 13.4mA
The Melexis TH72035 FSK/ASK transmitter IC is designed for applications in the European 868 MHz 
