鈥?/div>
14-pin SO package
General Description
PCF7991AT
The PCF7991 is a highly integrated and powerful
advanced basestation IC, ABIC, ideally suited for
vehicle immobilisation applications. The device
incorporates all necessary functions to facilitate reading
and writing of transponders.
The ABIC, PCF7991 employs a unique AM/PM
demodulation technique that extends the system
operating range compared with simple envelope
detection.
Optimised to operate with the Philips transponder family
(PCF79xx), the ABIC can be used in combination with
commonly available transponder that employ ASK
modulation. ASK modulation and receive characteristics
are widely programmable for powerful system
adaptation. The ABIC fits "Intelligent Antenna" as well
as "Active Antenna" applications.
The carrier frequency can be derived from an on-chip
oscillator or an external clock source. A wide range of
clock frequencies can be applied due to the
programmable on-chip clock divider circuitry.
The device enables system diagnostic functions by
antenna fail detection features.
Communication with the device and the transponder is
provided via the serial microcontroller interface.
Employing CMOS technology, the device features low
power operation and supports Idle and Powerdown
modes.
Minimum Application Circuitry
4.5 ... 5.5 V
VDD
XTAL1
XTAL2
PCF 7991
TX1
Modulation
Pulse Gen.
Antenna
Clk Divider
Timing
Oscillator
To microcontroller
Driver
TX2
RX
EMI
Filter
DOUT
Control
Unit
Synchron
Demodulator
SC Filter
Amplifier
CEXT
Serial
Interface
DIN
CLK
Register
VSS
QGND
May 1998
1
