Page 1
MLX90108
64bit Read Only Transponder
MLX90108 64bit Read Only Transponder Page 1 of 6 Rev1.6 5-Feb-01
Features
• Very small chip size
• Optimized for Low cost
• Integrated tuning and buffer capacitance
• Low power consumption, for maximum operating distance
• Deep modulation for maximum reading distance
• Operating frequency [100; 150kHz]
• Mask programmable modulation schemes and data rates.
Applications
• Automotive Key, Access control, ID cards, Laundry ticketing, Consumer goods, Industrial
Applications
Ordering Information
Part No. Temperature Range Package
MLX90108 25 °C Consumer Sawed wafer on frame, with/without Gold bumps
-40 to 85 °C Automotive Bare die in blistertape with/without Gold bumps
SOIC-8 150mils
Production parts available Q2 2000
Functional Diagram Description
The MLX90108 is a dedicated 64 bit Read Only
(RO) Transponder (TAG). Clock and power
supply are taken from the electromagnetic field.
By switching a resistor in parallel to the resonant
circuit formed by the integrated tuning capacitor
and the external coil, the transponder amplitude
modulates the electromagnetic field. Encoding of
the data and data rate depend on the version.
It is a low cost solution for high volume
applications. The tuning and buffer capacitors are
integrated on chip. Operating frequency (SRF)
range is [100; 150]kHz.
The unique identification code (ID) is EEPROM
programmed in test mode during probing. Data
coding and data rate are mask programmed. An
optimized layout for gold bumps and a standard
version are available for all options. This allows
the device to be integrated into any assembly
form.
Coil
GND
MLX90108
C
tune
L
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MLX90108
64bit Read Only Transponder
MLX90108 64bit Read Only Transponder Page 2 of 6 Rev1.6 5-Feb-01
MLX90108 Electrical Specifications
All specifications are valid for Manchester, Biphase and PSK encoding, and for 2kbaud and 4kbaud and
8kbaud data rate options, Toper = -40°C to 85°C, Operating frequency = 120kHz (unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Units
Regulated supply voltage VDD (2) 1.2 4.0 V
Sensitivity level Manch/Biph Vac (3) 200 150 mV
Sensitivity level PSK Vac (3) 600 400 mV
EEPROM data retention Tret Critical reading ID 10 1000 year
Weak power: Vac = 200mVpp 0.2 4 V(4)
Medium power: Vac = 5Vpp 2.8 7.5 V(4)
Modulation Depth ASK
High power: Vac = 20Vpp 5 10 V(4)
Coil-GND tune capacitor Toper=25oC 77.2 80 82.8 pF(5)
IclampLow VdutDC = +/- 2V 40 1000 nADC input current clamping
IclampHigh VdutDC = +/- 10V 1 3.5 10 mA
Notes:
Note (1): All specification values are tested 100%, or
guaranteed by characterization.
Note (2): Maximum supply voltage is generated by
forcing 10mA between coil and ground pin.
Note (3): Continuous (without POR restart) normal
reading of the 64bit ID on test set up as depicted
besides.
Note (4): Min = Vbottom (modulation on),
Max = Vtop (modulation off).
Note (5): Statistical spread on wafer basis within one lot is 3.5%. Temperature shift is typically -0.5% on -40°C,
and +1% at 85°C. On the MLX90108D a maximum Lot to lot spread of 20% is possible: average of a lot can vary
between 64 and 96pF.
Vac
50
90108
DUT
Vdut
C1 C2
Cpar=10pF
L=6.8mH
Qrc @ 120KHz=48.8
C1+C2=250pF
Vin
COIL
GND
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MLX90108
64bit Read Only Transponder
MLX90108 64bit Read Only Transponder Page 3 of 6 Rev1.6 5-Feb-01
General Description
The MLX90108 is a 64 bit Read Only (RO)
transponder. The integrated tune capacitance
and the external coil form a resonant LC antenna
that absorbs part of the electromagnetic energy
radiated by the transceiver LC antenna.
Physically, a magnetic coupling occurs between
the transceiver, also referred to as "reader", and
transponder antennas
To amplitude modulate (AM) the RF carrier, the
transponder damps the electromagnetic field by
switching a resistor in parallel with its coil. This
way the transponder repetitively transmits its 64
bit-identification code (ID) to the reader base
station.
Frequency tuning
Tuning and buffer capacitors are integrated to
optimize total system cost.
The 80pF integrated tuning capacitor is +/-20%
accurate from batch to batch. A spread of max
+/-2.5% is guaranteed across a full batch, which
is typically 200k dice.
Clock Extractor:
Master clock is taken from the carrier frequency
which is picked up on the coil. Depending on the
options, the carrier frequency is divided by
16(8kBaud: PSK only), 32(4kbaud) or
64(2kbaud)to generate the bit rate.
VDD regulator:
Supply voltage is taken from the AC voltage
induced in the coil. Overvoltage protection is
done by current clamping.
POR level
When the transponder is placed in an external
radio frequency (RF) field of appropriate
frequency and amplitude, the internal power
supply (VDD) can build up as charge on the
integrated buffer capacitance. The modulation
resistor is switched on and off as soon as VDD
has reached the Power On Reset (POR) level.
When the modulation resistor is switched on, the
LC circuit is no longer tuned, therefore no energy
is taken from the field, and VDD drops due to
internal consumption. Hence, by switching the
modulation resistor on and off, it is possible to
oscillate around the POR level. This
phenomenon is referred to as hiccuping.
The modulation resistor is switched off when the
transponder drops below the POR level.
Sensitivity level
The minimum electromagnetic force (e.m.f.)
needed to avoid hiccuping is defined by Vacsens.
At this level the power supply will not drop below
the POR level while the modulation resistance is
switched on during modulation.
Modulator
The modulator consists of a modulation resistor
that is switched in parallel with the resonant LC
circuit (antenna). The MLX90108 offers different
encoding schemes and AM modulation
techniques, which are discussed below, each
optimized for maximum operating and reading
distance under different field conditions.
EEPROM
The Identification code is written in EEPROM
during wafer test. After POR the device will read
out the data periodically. Data retention is
guaranteed as specified (Tret, Ncyc).
Block diagram
Coil
GND
Clock
extractor
Divider by
64, 32 or 16
Modulator
Memory
Array
C
TUNE
C
BUFFER
Data encoder
Sequencer
VDD
regulator
AC
+
VDD
VDD
MLX90108
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MLX90108
64bit Read Only Transponder
MLX90108 64bit Read Only Transponder Page 4 of 6 Rev1.6 5-Feb-01
X 1 1 1 1 0 1 0Binary Data
Modulation Output
1 1 0 0
Memory Output
Manchester Code
Coding schemes
Biphase/Manchester AM
Biphase and Manchester are Amplitude
Modulation encoding schemes, which rely on the
build up of the voltage on the transponder
resonant circuit during a certain period, defined
by the baudrate.
In weak RF fields the quality factor of the
transponder antenna is significant, therefore the
rising edge is much slower than the falling edge
of the envelope. Consequently a symmetrically
driven modulator gives an asymmetrical envelope
on the reader antenna. This is anticipated by
delaying each falling edge by a fixed number of
RF clock pulses. The modulator is hence driven
asymmetrical. Each ON state is reduced by 8 (4)
clocks in 2 (4) kBaud mode, and each OFF state
is prolonged by the same amount. This
guarantees good reading in strong and weak
fields, at large distance and in proximity of the
reader antenna.
Manchester:
For a “1” bit, there is a transition from 0 to 1 in the
middle of the bit period. Reciprocal, for a “0” logic
bit there is a transition from 1 to 0 in the middle of
the bit period.
Biphase:
At the beginning of each bit, a transition will
occur. A logic bit “1” will keep its state for the
whole bit duration and a logic bit “0” will show a
transition in the middle of the bit duration.
Phase Shift keying (PSK) AM
PSK is an Amplitude Modulation encoding
scheme that relies on the change of phase of the
modulation. Every other period, i.e. at half the
carrier frequency, the field is modulated.
Therefore the voltage can not build up on the
transponder resonant circuit, and hence the
sensitivity level is much higher than for the other
coding schemes.
Each data bit lasts for 16 carrier periods. A 180°
phase shift occurs at the beginning of a data bit
when a logic “0” is read from the memory. There
is no phase shift when a logic “1” is read from the
memory.
PSK readers operate in the frequency domain.
Therefore the demodulation is insensitive to skew
in the time domain.
The modulation depth is still optimized for
different field strengths, and reading distances.
Speed
Clocks
per Bit
Clocks ‘ON’ state Clocks ‘OFF’ state
2kbaud
(MAN/BI)
64 Long ON = 64 - 8
Short ON = 32 - 8
Long ON = 64 + 8
Short ON = 32 + 8
4kbaud
(MAN/BI)
32 Long ON = 32 – 4
Short ON = 16 – 4
Long ON = 32 + 4
Short ON = 16 + 4
8kBaud
(PSK)
16 No asymmetrical behavior
PSK Code
Memory output
coil
Modulation output
"0" on serial out
"1" on serial out
X 0 1 1 0 1 0 0Binary Data
Modulation Output
1 1 0 0
Memory Output
Biphase Coding
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MLX90108
64bit Read Only Transponder
MLX90108 64bit Read Only Transponder Page 5 of 6 Rev1.6 5-Feb-01
Unique Features
• Flexible configuration.
• Small chip size
• Large reading distance
• Ready for direct bonding
Cross Reference
This product is compatible with EM Marin
EM4002 family, or any other RO transponder in
the 120kHz range.
Absolute Maximum Ratings
Maximum Power Supply (VDDmax) -0.7 to 7V
Maximum current forced between coil and
ground pin (Icoilmax)
+ / - 30mA
Operating Frequency (Freq) 60 to 150kHz
Normal Operating Temperature (Toper)
-40 to 85°C
Maximum Storage Temperature in SO8
(Tstore)
-55 to 125°C
Electrostatic discharge (HBM) on coil pin
(Vesdcoil)
500V
Electrostatic discharge (HBM) on other pins
(Vesd)
1500V
ESD Precautions
Electronic semiconductor products are sensitive
to Electro Static Discharge (ESD).
Always observe Electro Static Discharge control
procedures whenever handling semiconductor
products.
Disclaimer
Melexis reserves the right to periodically make
modifications to product specifications. The
information included herein is believed to be
accurate and reliable. However, Melexis
assumes no responsibility for its use, nor for any
infringements of patents or other rights of third
parties which may result from its use.
Ordering Information
Part No. Basic option
• MLX90108D*: with gold bumps
• MLX90108E*: without gold bumps
Part No. Coding and Data rate
• MLX90108*A: Manchester @4kBaud
• MLX90108*B: Manchester @2kBaud
• MLX90108*C: Biphase @4kBaud
• MLX90108*D: Biphase @2kBaud
• MLX90108*G: PSK @8kBaud
Delivery form and testing level
• Sawn on Blue foil: 25 °C
• Sawn in Blister tape: 25 °C
• SO8 Automotive: -40 °C to 85 °C
• SO8 Consumer: 25 °C
The MLX90108 is qualified according to
automotive standards.
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MLX90108
64bit Read Only Transponder
MLX90108 64bit Read Only Transponder Page 6 of 6 Rev1.6 5-Feb-01
90108E-SO8 Pinout
Pin Name Function
1 COIL Coil connection 1
2 TEST Pin to set chip in test mode
3 TEST Pin to set chip in test mode
Keeping at Vdd/2 will reset the chip
4 VSS Coil connection 2 / ground connection
5 VSS Coil connection 2 / ground connection
6 TEST Pin to set chip in test mode
7 VDD External chip supply for testmode
8 VSS Coil connection 2 / ground connection
90108E Chip dimensions
All dimensions in microns
90108D Chip dimensions
All dimensions in microns
1375 +/- 10
600
1025 +/- 10
Bump High : 25 +/- 5
IC Thickness : 280 +/- 25
200 325 200
130
TEST
TEST
COIL
TEST
VDD
VSS
1
2
3
4
5
6
7
8
MLX
90108E
VSSVSS
8
1
x 2
67
1170
1150
185
370
x x 3
400
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