PCF7991AT

Product Profile

Advanced Basestation IC, ABIC

Features

• Extended system operating range due to powerfulAM/PM demodulation technique

• Ideally suited for \"Intelligent Antenna\" and \"ActiveAntenna\" architectures

• High antenna drive capabilities, CW: 200mAp• Low antenna driver output resistance, 3.5 Ω• Excellent receiver sensitivity, 2mVpp• Large receiver dynamic range

• Programmable clock divider, modulator, receivergain and filter characteristics

• Fast \"read after write\" receiver settlingcharacteristics

• On-chip receive EMI filter

• Antenna failure mode detection• Few external components

• Operating supply voltage: 4.5 to 5.5 V• Power down mode: 7µA @ 5.5 V• 14-pin SO package

General Description

PCF7991AT

The PCF7991 is a highly integrated and powerfuladvanced basestation IC, ABIC, ideally suited forvehicle immobilisation applications. The device

incorporates all necessary functions to facilitate readingand writing of transponders.

The ABIC, PCF7991 employs a unique AM/PMdemodulation technique that extends the systemoperating range compared with simple envelopedetection.

Optimised to operate with the Philips transponder family(PCF79xx), the ABIC can be used in combination withcommonly available transponder that employ ASK

modulation. ASK modulation and receive characteristicsare widely programmable for powerful system

adaptation. The ABIC fits \"Intelligent Antenna\" as wellas \"Active Antenna\" applications.

The carrier frequency can be derived from an on-chiposcillator or an external clock source. A wide range ofclock frequencies can be applied due to theprogrammable on-chip clock divider circuitry.The device enables system diagnostic functions byantenna fail detection features.

Communication with the device and the transponder isprovided via the serial microcontroller interface.Employing CMOS technology, the device features lowpower operation and supports Idle and Powerdownmodes.

Minimum Application Circuitry

4.5 ... 5.5 VVDDTX1AntennaXTAL1XTAL2PCF 7991ModulationPulse Gen.Clk DividerTimingOscillatorTo microcontrollerDriverTX2RXEMIFilterControlUnitSynchronDemodulatorQGNDSC FilterAmplifierCEXTSerialInterfaceDOUTDINCLKRegisterVSSMay 1998