[Melexis]

General Description

The TH71102 receiver IC consists of the following building blocks:

◾ PLL synthesizer (PLL SYNTH) for generation of the first and second local oscillator signals LO1 and LO2

◾ Parts of the PLL SYNTH are the high-frequency VCO1, the feedback dividers DIV_8 and DIV_2, 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 first IF (IF1)

◾ second mixer (MIX2) for down-conversion of the IF1 to the second IF (IF2)

◾ IF amplifier (IFA) to amplify and limit the IF2 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

❐ Double superhet architecture for high degree of image rejection

❐ 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