INTEGRATED CIRCUITS
DATA SHEET
PCF7991AT
Advanced Basestation IC
Product Specification (Rev. 1998 Apr 20)
printed 1998 Apr 20
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
PCF7991AT
CONTENTS
1
FEATURES
2
GENERAL DESCRIPTION
3
ORDERING INFORMATION
4
BLOCK DIAGRAM
5
QUICK REFERENCE DATA
6
PINNING INFORMATION
6.1
6.2
Pinning Diagram
Pin Description
7
MINIMUM APPLICATION CIRCUITRY
8
FUNCTIONAL DESCRIPTION
8.1
8.2
8.3
8.4
8.5
8.5.1
8.5.2
8.5.3
8.5.4
8.5.5
8.5.6
8.6
8.7
8.8
8.8.1
Power Supply
Antenna driver
Modulator
Oscillator
Receiver
Synchron Demodulator
Bandpass Filter, Amplifier and Digitizer
Phase Measurement
Determining the Sampling Time
Data Amplitude Comparison
System Diagnostics
Power-on reset
Power-down modes
Serial Interface
Serial Interface Mode
9
COMMAND SET
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
READ_TAG
WRITE_TAG_N
WRITE_TAG
READ_PHASE
SET_SAMPLING_TIME
GET_SAMPLING_TIME
SET_CONFIG_PAGE
GET_CONFIG_PAGE
10
LIMITING VALUES
11
DC CHARACTERISTICS
12
AC CHARACTERISTICS
13
PACKAGE
14
DEFINITIONS
15
LIFE SUPPORT APPLICATIONS
printed 1998 Apr 20
2
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
1
PCF7991AT
identification transponder. The device is intended for use
with the Philips transponder family (PCF79xx) as well as
other transponder types operating at 125 kHz and
employing ASK, Amplitude Shift Keying for write and
AM/PM for the read operation. The receiver characteristics
(amplifier gain, filter cutoff frequencies) can be optimized
to system and transponder requirements. The
PCF7991AT IC is designed for easy integration into
immobilizer read/write and read-only systems featuring a
high degree of integration and very low external
component count. The device integrates a powerful
antenna driver/modulator, a low-noise adaptive sampling
time demodulator, programmable filters/amplifier and
digitizer, required to design high-performance
basestations. A three wire microcontroller interface is
provided for programming the PCF7991AT as well as for
the bidirectional communication with the transponder. The
three-wire interface can be configured for two wire
operation by connecting the data input and the data
output.
FEATURES
• Fully integrated single chip basestation
• Compatible with PCF79xx transponder family
• Robust antenna coil power driver stage with modulator
• High performance adaptive sampling time AM/PM
demodulator (patent pending)
• Read and write function
• Programmable modulator/demodulator characteristics
• On-chip clock oscillator and divider in the case of
external clock reference
• Antenna rupture and short circuit detection
• Low power consumption
• Very low power stand-by mode
• Low external component count
• Small package (SO14).
2
GENERAL DESCRIPTION
The device employs a unique Adaptive Sampling Time
(AST) demodulation technique, that extends the system
operation range and eliminates the effect of a zero
amplitude modulation response from the transponder, as a
result of resonance frequency tolerances.
The PCF7991AT is a fully integrated Advanced
Basestation IC, ABIC, designed for car immobilizer
systems providing read and write access to an
3
ORDERING INFORMATION
PACKAGE
EXTENDED
TYPE NUMBER
NAME
PCF7991AT/1081
SO14
printed 1998 Apr 20
DESCRIPTION
plastic small outline package; 14 leads
3
VERSION
TEMPERATURE
RANGE (°C)
SOT108-1
−40 to +85
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
4
PCF7991AT
BLOCK DIAGRAM
VDD
XTAL1
TX1
Antenna Drivers
Modulator
Oscillator
XTAL2
TX2
Control
Unit
DIN
Bandpass Filter
Amplifier
Synchron
Demodulator
RX
Serial Interface
DOUT
SCLK
Dynamic Control
Digitizer
Phase
Measurement
Control Register
QGND
CEXT
VSS
MODE
Fig.1 Blockdiagram advanced basestation PCF7991AT.
5
QUICK REFERENCE DATA
VALUE
PARAMETER
Supply voltage
MIN.
MAX.
4.5
5.5
V
20
µA
16
MHz
Power-down current
Clock/Oscillator frequency
(antenna carrier frequency 125 kHz)
4
Antenna driver current
Receiver sensitivity
400
2
Serial interface
SO14
−40 °C to +85 °C
Operation temperature range
printed 1998 Apr 20
4
mAp
mVpp
CMOS compatible
Package
UNIT
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
6
PCF7991AT
PINNING INFORMATION
6.1
Pinning Diagram
Pin 1 ID
VSS
1
14
RX
TX2
2
13
QGND
3
12
CEXT
11
N.C.
VDD
TX1
4
PCF7991AT
MODE
5
10
DOUT
XTAL1
6
9
DIN
XTAL2
7
8
SCLK
Fig.2 Pinning diagram for PCF7991AT.
6.2
Pin Description
Table 1
Pin description for PCF7991AT
SYMBOL PIN
DESCRIPTION
VSS
1
Common ground, GND.
TX2
2
Antenna driver output.
VDD
3
Supply voltage input, stabilized.
TX1
4
Antenna driver output.
MODE
5
Microcontroller interface mode select.
XTAL1
6
Oscillator interface, external clock reference input.
XTAL2
7
Oscillator interface.
SCLK
8
Microcontroller interface: serial clock input.
DIN
9
Microcontroller interface: serial data in.
DOUT
10
Microcontroller interface: serial data out.
N.C.
11
Not connected.
CEXT
12
High pass filter decoupling.
QGND
13
Analog ground bias.
RX
14
Receiver input.
printed 1998 Apr 20
5
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
7
PCF7991AT
MINIMUM APPLICATION CIRCUITRY
The following figure shows a minimal application circuitry for the PCF7991AT. The antenna coil La together with the
capacitor Ca form a series resonant LC circuit (f = 125 kHz). The antenna tap voltage is attenuated by RV and the input
impedance of the RX-pin. The capacitors at XTAL1 and XTAL2 are selected according to the crystal or ceramic resonator
specification. In the case of an external clock reference they may be omitted. The capacitors at QGND and CEXT are for
device internal biasing and decoupling purposes.
VDD
+
10 µF
100nF
VDD
TX1
XTAL1
La
Ca
XTAL2
TX2
DIN
Rv
DOUT
RX
SCLK
QGND
100nF
CEXT
VSS
MODE
100nF
Fig.3 Minimum application circuitry
printed 1998 Apr 20
6
TO
MICROPROCESSOR
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
8
8.1
PCF7991AT
order to match the receiver input voltage specification. The
receive signal passes an on-chip second order low pass
filter and is further attenuated before it is fed to the
synchron demodulator and phase measurement circuitry.
FUNCTIONAL DESCRIPTION
Power Supply
The PCF7991AT operates from an external 5 V power
supply. For optimum performance a stabilized supply
voltage should be applied.
8.2
8.5.1
The antenna current and therefore the tap voltage is
modulated by the transponder in amplitude and/or phase
depending on various system parameters. By employing a
unique Adaptive Sampling Time (AST) demodulation
technique, amplitude and phase modulation of the receive
signal is detected featuring an extended system operation
range. The receive sampling time is set by the
SET_SAMPLING_TIME command (see Table 2). The
appropriate sampling time can be derived from an on-chip
phase measurement and an offset that accounts for the
external antenna interface component values.
Antenna driver
The antenna drivers are configured as a full bridge capable
to deliver a square wave shaped voltage to the series
resonant antenna circuit, which is connected between TX1
and TX2. The full bridge drivers are characterized by a low
output impedance featuring a large drive voltage to the
resonant antenna circuit. The antenna carrier frequency is
125 kHz typically.
8.3
Modulator
Receive signal sampling is inhibited when a WRITE_TAG
or WRITE_TAG_N command is issued in order to avoid
that write pulses de-sensitize the amplifier and digitizer
circuitry. Signal sampling is resumed when the
WRITE_TAG mode is terminated. For better receiver
setting a short delay after the last write pulse has to be
provided before the WRITE_TAG mode is terminated.
The modulator enables ASK (Amplitude Shift Keying)
modulation of the antenna RF signal after switching the
device into transparent mode (WRITE_TAG mode) by a
WRITE_TAG or WRITE_TAG_N command (see Table 2).
ASK modulation is achieved by blanking the antenna drive
signal under control of the data input (DIN). The modulator
features a timer circuitry that supports carrier blanking with
a programmable duration (see Table 2).
8.5.2
8.4
Oscillator
For fast receiver settling after device power-up, sampling
time shift or when switching from WRITE_TAG mode to
READ_TAG mode the bandpass filter, amplifier and
digitizer circuit biasing condition can be initialized and
restored by a set of control bits accessible via the
SET_CONFIG_PAGE commands.
Receiver
The receiver senses and demodulates the absorption
modulation applied by a transponder that is inside the
antenna RF field. The demodulated and digitized signal is
available at the data output (DOUT) after switching the
device into transparent mode (READ_TAG mode) by a
READ_TAG command (see Table 2).
8.5.3
PHASE MEASUREMENT
The optimum receive signal sampling time depends on the
actual tuning condition of the resonant antenna circuitry.
The actual tuning condition of the resonance antenna is
determined by measuring the phase relationship between
the exciting signal at the antenna driver output and the
antenna tap voltage applied to the receiver input. In case
of perfect tuning, the phase should be 90 degree plus an
offset that accounts for the receiver input attenuation and
The receiver features a high sensitivity and an extended
input voltage range to ensure a large receiver dynamic
range. The antenna tap signal is fed to the receiver input
(RX) after attenuation by means of an external series
resistor (RV) and the receiver input impedance (RIRX) in
printed 1998 Apr 20
BANDPASS FILTER, AMPLIFIER AND DIGITIZER
After demodulation the receive signal passes a baseband
filter and amplifier prior to digitization. The amplifier gain
and bandpass filter cutoff frequencies are adjustable by
the SET_CONFIG_PAGE 0 command, in order to adapt
the receiver path to the system coupling factor and
transponder data rate.
The on-chip oscillator operates either with a crystal or
ceramic resonator connected to XTAL1/2. Alternatively, an
external clock source (CMOS compatible) may be applied
at XTAL1. The oscillator frequency feeds a programmable
divider in order to derive the system clock and the antenna
carrier frequency of 125 kHz. The programmable divider
supports an oscillator frequency of 4, 8, 12 and 16 MHz
(see Table 11).
8.5
SYNCHRON DEMODULATOR
7
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
PCF7991AT
time and when the antenna drivers are disabled.
Advanced system diagnostics are feasible by considering
the phase measurement information also.
low pass filter. Miss-tuning of the resonance antenna
circuit by component spreads or due to ambient
temperature changes results in a change of the phase
relationship. The actual phase relationship is determined
by a READ_PHASE command (see Table 6) and used to
calculate the optimum receive signal sampling time with
support of an external microcontroller.
8.5.4
8.6
The device generates an internal power-on reset to
initialize the chip after power-on or power fail condition. As
a result the control register is initialized according to
Table 11.
DETERMINING THE SAMPLING TIME
Measurement, calculation and setting of the sampling time
is typically implemented during system power-up
initialization when the transponder is also in its power-up
sequence not sending any data. As soon as the oscillator
and resonance antenna circuit are settled a phase
measurement is initiated and the sampling time
determined according to the following relation:
8.7
Receive signal sampling time
TANT
Actual phase measurement
TOFFSET
Offset that accounts for the phase shift due
to the antenna tap voltage attenuation and
low pass filtering
In Idle mode only the oscillator and a minimum of other
circuitry is active. In Power-down mode the device is in
OFF state completely. The serial interface is operational in
any case in order to provide access to the control register.
8.8
DATA AMPLITUDE COMPARISON
For advanced receiver sampling time optimization the
demodulated data signal strength can be weighted by
amplitude comparison and the result reported in the status
bit AMPCOMP (see Table 13).
The interface is operated by the following signals:
When the ACQAMP control bit (see Table 10) is set by a
SET_CONFIG_PAGE command, the actual demodulated
data signal amplitude is stored as reference. After
resetting the ACQAMP control bit the status bit
AMPCOMP is set, when the actual data signal amplitude
is larger than the stored reference otherwise it is cleared.
8.5.6
SCLK
Clock
DIN
Data Input
DOUT
Data Output
SCLK and DIN are realized as Schmitt-Trigger inputs.
DOUT is an open drain output with internal pullup resistor.
Any communication between the PCF7991AT and the
microcontroller begins with an initialization of the serial
interface before the desired command can be issued. The
interface initialization condition is a low-to-high transition
of the signal DIN while SCLK is high (see Fig.4).
SYSTEM DIAGNOSTICS
In order to detect an antenna short or open condition the
receiver input voltage at the RX-pin is monitored and an
antenna fail condition is reported in the status bit ANTFAIL,
(see Table 13). If the receiver input voltage does not
exceed the diagnostic threshold level VDTH (see
Chapter 11), the status bit ANTFAIL is set, otherwise it is
cleared. The status bit is updated once per antenna carrier
period and can be read by a GET_CONFIG_Page 2 or 3
command (see Table 13). The status bit is undefined in
Power-down or Idle mode, during the oscillator start-up
printed 1998 Apr 20
Serial Interface
The communication between the PCF7991AT and the
microcontroller is done via a three wire digital interface.
The interface is used to issue commands for writing and
reading of device configuration data and for writing and
reading to the transponder in one of the transparent
modes (READ_TAG, WRITE_TAG). Device configuration
is stored in a control register with read back feature.
After setting the sampling time the receiver has to settle
before data can be demodulated and digitized properly.
8.5.5
Power-down modes
After a power-on reset condition the device operates in
ACTIVE mode. The PCF7991AT supports an Idle and
Power-down mode for power saving means. The mode of
operation is determined by control bits addressed by an
SET_CONFIG_PAGE 1 command (see Table 10).
TS = 2 * TANT + TOFFSET
TS
Power-on reset
All commands are transmitted to the PCF7991AT serial
interface starting with Most Significant Bit (MSB). DIN is
latched with a high state at SCLK. DOUT is valid during the
high state of SCLK (MODE pin connected to VSS).
DOUT and DIN may be connected to each other in order to
form a two wire communication link with the
microcontroller.
8
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
8.8.1
PCF7991AT
internal state of these signals is updated only, if two
successive samples are equal. Due to the sampling
operation a state change at the SCLK or DIN input is
delayed at least by 16 µs before it is recognized by the
internal circuitry. If DIN and DOUT are connected to each
other to form a two wire communication link, the filtering
delay between DIN and DOUT must be considered. Due to
the digital filtering, the maximum serial interface data rate
is limited to approximately 30 kbit/sec.
SERIAL INTERFACE MODE
The serial interfaces supports two modes of operation,
filtered and non-filtered communication.
If MODE is connected to VSS no filtering is applied and the
state of the interface signals is directly available at the
internal circuitry. The maximum data rate of the serial
interface is limited by the set-up and hold time as specified
(see Chapter 12).
If digital filtering of SCLK and DIN is enabled and the device
has been forced into Power-down mode, this mode can be
terminated by setting SCLK to LOW and DIN unequal to the
status bit TXDIS (see Table 10). As a result the XTAL
oscillator is restarted and the configuration bit PD_MODE
is cleared, which causes the device to enter Idle mode.
If MODE is connected to VDD, digital filtering of SCLK and
DIN is performed offering improved immunity against
glitches on these interface signals. This mode of operation
is intended for use for so called ‘Active Antenna
Applications’, where the PCF7991AT and the
microcontroller have to communicate via long interface
wires. The digital filtering is provided by sampling the
SCLK and DIN inputs at a rate of 1/fTX, 8 µs typically. The
TS
TH
SCLK
DIN
D7
D6
D5
D4
D3
D2
D1
D0
initialization
DOUT
D7
D6
D5
Fig.4 Serial Interface Timing.
printed 1998 Apr 20
9
D4
D3
D2
D1
D0
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
9
PCF7991AT
COMMAND SET
Table 2
Command set summary
MSB
BIT NO.
LSB
COMMAND NAME
RESPONSE
7
6
5
4
3
2
1
0
GET_SAMPLING_TIME
0
0
0
0
0
0
1
0
GET_CONFIG_PAGE
0
0
0
0
0
1
P1
P0
READ_PHASE
0
0
0
0
1
0
0
0
8 bit (0 0 D5 - D0)
READ_TAG
1
1
1
−
−
−
−
−
enter READ_TAG-mode
WRITE_TAG_N
0
0
0
1
N3
N2
N1
N0
WRITE_TAG
1
1
0
−
−
−
−
−
SET_CONFIG_PAGE
0
1
P1
P0
D3
D2
D1
D0
4 bit per config page addressed
SET_SAMPLING_TIME
1
0
D5
D4
D3
D2
D1
D0
8 bit (00 D5 - D0)
9.1
8 bit (0 0 D5-D0)
8 bit (X3 X2 X1 X0 D3-D0)
enter WRITE_TAG-mode with pulse
width programming
enter WRITE_TAG-mode
READ_TAG
This command is used to read the demodulated bit stream from a transponder: After the assertion of the three command
bits the PCF7991AT instantaneously switches to READ_TAG-mode and the demodulated, filtered and digitized data
from the transponder is available at the data output DOUT for decoding by the microcontroller.
READ_TAG-mode is terminated immediately by a low to high transition at SCLK.
Table 3
READ_TAG command sequence
BIT NO.
Command
9.2
7
6
5
4
3
2
1
0
1
1
1
−
−
−
−
−
REMARK
received data available at DOUT
WRITE_TAG_N
This command is used to write data to a transponder and to set the modulator blanking characteristics.
If N3-N0 are set to zero, the signal from DIN is transparently switched to the drivers. A high level at DIN corresponds to
antenna drivers switched off, a low level corresponds to antenna drivers switched on.
If any binary number between 1 and 1111 is loaded into N3-N0, the drivers are switched off at the next positive transition
of DIN. The driver off state is maintained for a time interval equal to N * T0 (T0=8 µs) regardless the state of DIN. This
method relaxes the timing resolution requirements to the microcontroller and to the software implementation while
providing an exact, selectable write pulse timing.
WRITE_TAG-mode is terminated immediately by a low to high transition at SCLK. As a result, the driver resume their
initial state, regardless the actual state of the modulation pulse timer.
Table 4
WRITE_TAG_N command sequence
BIT NO.
Command
printed 1998 Apr 20
7
6
5
4
3
2
1
0
0
0
0
1
N3
N2
N1
N0
10
REMARK
no response
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
9.3
PCF7991AT
WRITE_TAG
This is the 3 bit short form of the command WRITE_TAG_N. It allows to switch into WRITE_TAG-mode with a minimum
communication time.
The behaviour of the WRITE_TAG command is identical to WRITE_TAG_N with two exceptions:
WRITE_TAG-mode is entered after assertion of the 3rd command bit.
No N parameter is specified with this command; instead the N value which has been programmed with the most recent
WRITE_TAG_N command is used. If no WRITE_TAG_N was issued so far, a default N=0 (transparent mode) will be
assumed.
WRITE_TAG-mode is terminated immediately by a low to high transition at SCLK. As a result, the driver resume their
initial state, regardless the actual state of the modulation pulse timer.
Table 5
WRITE_TAG command sequence
BIT NO.
Command
9.4
7
6
5
4
3
2
1
0
1
1
0
−
−
−
−
−
REMARK
no response
READ_PHASE
This command is used to read the antenna´s phase TANT, which is measured at every carrier cycle. The phase is coded
binary in D5-D0.
Table 6
READ_PHASE command sequence
BIT NO.
7
6
5
4
3
2
1
0
Command
0
0
0
0
1
0
0
0
Response
0
0
D5
D4
D3
D2
D1
D0
9.5
REMARK
SET_SAMPLING_TIME
This command specifies the demodulator sampling time Ts. The sampling time is coded binary in D5-D0.
Table 7
SET_SAMPLING_TIME command sequence
BIT NO.
Command
printed 1998 Apr 20
7
6
5
4
3
2
1
0
1
0
D5
D4
D3
D2
D1
D0
11
REMARK
no response
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
9.6
PCF7991AT
GET_SAMPLING_TIME
This command is used to read back the sampling time Ts set with SET_SAMPLING_TIME. The sampling time is coded
binary in D5-D0.
Table 8
GET_SAMPLING_TIME command sequence
BIT NO.
7
6
5
4
3
2
1
0
Command
0
0
0
0
0
0
1
0
Response
0
0
D5
D4
D3
D2
D1
D0
9.7
REMARK
SET_CONFIG_PAGE
This command is used to configure the receiver characteristics (cutoff frequencies, gain factors) and the different
operation modes. P1 and P0 select one of four configuration pages.
Table 9
SET_CONFIG_PAGE command sequence
BIT NO.
Command
7
6
5
4
3
2
1
0
REMARK
0
1
P1
P0
D3
D2
D1
D0
no response
Table 10 SET_CONFIG_PAGE mapping
BIT NO.
P1
P0
D3
D2
D1
D0
SET_CONFIG_PAGE 0
0
0
GAIN1
GAIN0
FILTERH
FILTERL
SET_CONFIG_PAGE 1
0
1
PD_MODE
PD
HYSTERESIS
TXDIS
SET_CONFIG_PAGE 2
1
0
THRESET
ACQAMP
FREEZE1
FREEZE0
SET_CONFIG_PAGE 3
1
1
DISLP1
DISSMART
COMP
FSEL1
FSEL0
COMMAND/PAGE NO.
printed 1998 Apr 20
12
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
PCF7991AT
Table 11 Configuration bit description
BIT NAME
RESET
CONDITION
DESCRIPTION
FILTERH
main low pass cutoff frequency
0
0: fL = 3 kHz; 1: fL = 6 kHz
FILTERL
main high pass cutoff frequency
0
0: fH = 40 Hz; 1: fH = 160 Hz
GAIN0
amplifier_0 gain factor
0
0: gain0 = 16; 1: gain0 = 32
GAIN1
amplifier_1 gain factor
1
0: gain1 = 6.22; 1: gain1 = 31.5
TXDIS
disable antenna driver
0
0: driver active; 1: driver inactive
HYSTERESIS
data comparator hysteresis
0
0: hysteresis OFF; 1: hysteresis ON
PD
Power-down mode enable
0
0: device active; 1: Power-down mode
PD_MODE
select Power-down mode, if PD = 1
0
0: Idle mode; 1: Power-down mode
FREEZE0
receiver characteristics override
0
see Note 1
FREEZE1
receiver characteristics override
0
see Note 1
ACQAMP
store signal amplitude as reference
for later amplitude comparison
0
see Section 8.5.5
THRESET
reset threshold generation of digitizer
0
see Note 3
FSEL0
clock frequency select LSB
0
see Note 2
FSEL1
clock frequency select MSB
0
DISSMARTCOMP disable smart comparator
0
0: comparator = ON, 1: comparator = OFF
DISLP1
0
0: low pass = ON, 1: low pass = OFF
disable main low pass
Note
1. In order to achieve fast receiver settling the amplifier and filter characteristics can temporarily be overridden:
REMARK
FREEZE 1
FREEZE 0
0
0
normal operation according to configuration page 0
0
1
main low pass is frozen and main high pass is initialized to QGND
1
0
main low pass is frozen and the time constant of the main high pass is reduced by a
factor of 16 for FILTERH = 0 and by a factor of 8 for FILTERH = 1
1
1
time constant of the main high pass is reduced by a factor of 16 for FILTERH = 0
and by a factor of 8 for FILTERH = 1. Second high pass is initialized to QGND
2. In order to derive an antenna carrier frequency fTX of 125 kHz; the clock divider has to be programmed as follows:
FSEL0
FSEL1
OSCILLATOR FREQUENCY
0
0
4 MHz
0
1
8 MHz
1
0
12 MHz
0
1
16 MHz
3. If the THRESET is set, the threshold generator is disabled and initialized according to the receive signal conditions.
printed 1998 Apr 20
13
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
9.8
PCF7991AT
GET_CONFIG_PAGE
This command has three functions:
1. Reading back the configuration parameters set by SET_CONFIG_PAGE command
2. Reading back the transmit pulse width programmed with WRITE_TAG_N
3. Reading the system status information
P1 and P0 select one of four configuration pages. The response (X3 X2 X1 X0 D3 D2 D1 D0) contains the contents of
the selected configuration page in its lower nibble. For P = 0 or P = 1 the higher nibble reflects the current setting of N
(the transmit pulse width). For P = 2 or P = 3 the system status information is returned in the higher nibble.
Table 12 GET_CONFIG_PAGE command sequence
BIT NO.
7
6
5
4
3
2
1
0
Command
0
0
0
0
0
1
P1
P0
Response
X3
X2
X1
X0
D3
D2
D1
D0
REMARK
Table 13 GET_CONFIG_PAGE mapping
BIT NUMBER
COMMAND / PAGE NO.
7
6
5
4
3
2
2
0
GET_CONFIG_PAGE 0
N3
N2
N1
N0
D3
D2
D1
D0
GET_CONFIG_PAGE 1
N3
N2
N1
N0
D3
D2
D1
D0
GET_CONFIG_PAGE 2
0
0
AMPCOMP
ANTFAIL
D3
D2
D1
D0
GET_CONFIG_PAGE 3
0
0
AMPCOMP
ANTFAIL
D3
D2
D1
D0
Table 14 Status Bit description
BIT NAME
DESCRIPTION
ANTFAIL
antenna failure
see Section 8.5.6
AMPCOMP
amplitude comparison result
see Section 8.5.5
10 LIMITING VALUES
Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings
only and operation of the device at these or at any other conditions above those given in the characteristics sections of
this specification is not implied. Exposure to limiting values for extended periods may affect device reliability.
SYMBOL
PARAMETER
MIN.
VI
input voltage at any PIN except RX
−0.3
MAX.
UNIT
+6.5
V
VI
input voltage at any PIN except RX
−0.3
VDD +0.3
V
VIRX
input voltage at RX pin
−10
+12
V
Tj
maximum junction temperature
140
°C
Tstore
storage temperature range
+125
°C
printed 1998 Apr 20
−65
14
Philips Semiconductors
Product Specification
Advanced Basestation IC
PCF7991AT
11 DC CHARACTERISTICS
All voltages are measured to VSS, Tamb = −40 to +85°C, fTX = 125 kHz; unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
Supply
VDD
supply voltage
VDD with respect to VSS
5.0
5.5
V
ION
operating supply current
VDD = 5.5 V, ITX1 = ITX2 = 0
4.5
4.0
10
mA
IID
current in Idle mode
VDD = 5.5 V; see Note 1
0.2
0.4
mA
IPD
current in Power-down mode VDD = 5.5 V; see Note 1
7.0
20
µA
Antenna Driver (TX1, TX2)
ITXCW
output peak-current
continuous wave
200
mAp
ITXpulse
output peak-current
On/Off-ratio = 1:4
ton < 400 ms
400
mAp
ROTX
output resistance
full bridge, ROTX = ROTX1 +
ROTX2
2.5
7.0
Ω
Receiver input (RX)
VIRX with respect to QGND
−8
VIRX
input voltage range
+8
Vp
VQGND
analog ground
0.35 VDD
0.42 VDD
0.5 VDD
V
RIRX
impedance input
17
25
33
kΩ
VDTH
diagnostic threshold level
−1.5
−1.15
−0.8
V
VDTH with respect to QGND
Digital input (DIN, SCLK)
VIH
data input voltage HIGH
0.7 VDD
VDD +0.3 V
VIL
data input voltage LOW
−0.3 V
0.3 VDD
Digital output (DOUT)
VOL
output voltage LOW
IOL max = +1 mA
IOL
output drive capability
VOL ≤ 0.4 V
0.4
1
Note
1. Does not include power consumption of XTAL or other external components.
printed 1998 Apr 20
15
V
mA
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
PCF7991AT
12 AC CHARACTERISTICS
Tamb = −40 to +85°C, fTX = 125 kHz; unless otherwise specified.
SYMBOL
PARAMETER
CONDITIONS
MIN.
TYP.
MAX.
UNIT
XTAL Oscillator (XTAL1, XTAL2)
fOSC
frequency range
TSUP
start-up time
RFB
feedback resistance
depending on FSEL
4
16
MHz
4
10
ms
1.3
3
MΩ
XTAL1 to XTAL 2
0.5
depending on FSEL
4
16
MHz
40
60
%
External Clock Input (XTAL1)
fEXT
frequency range
duty cycle
CXTAL1
input capacitance
XTAL1
5
pF
Serial Interface
TS
set-up time
MODE pin at VSS
50
ns
TH
hold time
MODE pin at VSS
50
ns
VRX
receiver sensitivity
VRX with respect to
QGND
2
1
TRCV0
receiver delay
FILTERL = 0
290
310
340
µs
TRCV1
receiver delay
FILTERL = 1
160
175
190
µs
± 5.7
°
see Note 1
5
ms
see Note 1
500
µs
1.5
ms
10
µs
Receiver
phase measurement error
mVpp
Recovery from clock stable to demodulator valid
TRPD
recovery time demodulator
Recovery from WRITE-pulse
TRWD
recovery of demodulator
Recovery from AST-step
TRAST
recovery of demodulator
see Note 1
0.7
Response delay data input to antenna driver
TDITX
response delay DIN to TX
MODE pin at VSS;
see Note 2
Note
1. Specific command sequence required.
2. Applicable for WRITE_TAG and WRITE_TAG_N commands. Due to device internal signal synchronization
measures, TDITX is the response delay between a change at DIN and the resulting change at the antenna drivers.
In the case of N is zero, TDITX applies for both the rising and failing transition at DIN, while for N unequal zero it applies
for the rising transition at DIN only.
printed 1998 Apr 20
16
Philips Semiconductors
Product Specification
Advanced Basestation IC
PCF7991AT
13 PACKAGE
SO14: plastic small outline package; 14 leads; body width 3.9 mm
SOT108-1
D
E
A
X
c
y
HE
v M A
Z
8
14
Q
A2
A
(A 3)
A1
pin 1 index
θ
Lp
1
L
7
e
0
detail X
w M
bp
2.5
5 mm
scale
DIMENSIONS (inch dimensions are derived from the original mm dimensions)
UNIT
A
max.
A1
A2
A3
bp
c
D (1)
E (1)
e
HE
L
Lp
Q
v
w
y
Z (1)
mm
1.75
0.25
0.10
1.45
1.25
0.25
0.49
0.36
0.25
0.19
8.75
8.55
4.0
3.8
1.27
6.2
5.8
1.05
1.0
0.4
0.7
0.6
0.25
0.25
0.1
0.7
0.3
0.010 0.057
0.004 0.049
0.01
0.019 0.0100 0.35
0.014 0.0075 0.34
0.16
0.15
0.050
0.028
0.024
0.01
0.01
0.004
0.028
0.012
inches 0.069
0.244
0.039
0.041
0.228
0.016
θ
Note
1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.
REFERENCES
OUTLINE
VERSION
IEC
JEDEC
SOT108-1
076E06S
MS-012AB
printed 1998 Apr 20
EIAJ
EUROPEAN
PROJECTION
ISSUE DATE
95-01-23
97-05-22
17
o
8
0o
Philips Semiconductors
Product Specification (Rev. 1998 Apr 20)
Advanced Basestation IC
PCF7991AT
14 DEFINITIONS
Peak-to-peak of arbitrary shaped signals:
Vpp, Ipp
Zero-to peak of arbitrary shaped signals:
V p, Ip
Data sheet status
Objective specification
This data sheet contains target or goal specifications for product development.
Preliminary specification
This data sheet contains preliminary data; supplementary data may be published later.
Product specification
This data sheet contains final product specifications.
Limiting values
Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or
more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation
of the device at these or at any other conditions above those given in the Characteristics sections of the specification
is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information
Where application information is given, it is advisory and does not form part of the specification.
15 LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Philips customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.
printed 1998 Apr 20
18
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© Philips Electronics N.V. 1997
SCA55
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