[Melexis]

General Description
The TH71101 receiver IC consists of the following building blocks
◾ PLL synthesizer (PLL SYNTH) for generation of the local oscillator signal LO
◾ Parts of the PLL SYNTH are the high-frequency VCO1, the feedback divider DIV_16, a phase-frequency detector (PFD) with charge pump (CP) and a crystal-based reference oscillator (RO)
◾ Low-noise amplifier (LNA) for high-sensitivity RF signal reception
◾ First mixer (MIX1) for down-conversion of the RF signal to the IF
◾ IF pre amplifier which is a mixer cell (MIX2) that operates as an amplifier
◾ IF amplifier (IFA) to amplify and limit the IF signal and for RSSI generation
◾ Phase coincidence demodulator (DEMOD) with third mixer (MIX3) to demodulate the IF signal
◾ Operational amplifier (OA) for data slicing, filtering and ASK detection
◾ Bias circuitry for bandgap biasing and circuit shutdown

Features
❐ Single superhet architecture for low external component count
❐ FSK for digital data and FM reception for analog signal transmission
❐ FM/FSK demodulation with phase-coincidence demodulator
❐ Low current consumption in active mode and very low standby current
❐ Switchable LNA gain for improved dynamic range
❐ RSSI allows signal strength indication and ASK detection
❐ Surface mount package LQFP32

Application Examples
❐ General digital and analog 315 MHz or 433 MHz ISM band usage
❐ Low-power telemetry
❐ Alarm and security systems
❐ Keyless car and central locking
❐ Pagers