MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

Features

Up to 200mW output power

3.3V and 5V supply

Complies with ISO 15693-2

Complies with ISO 14443-2 A

Low external component count

Short to mid range applications

High performance at minimum system cost

Applications

Any domain from Freight tracking systems, to Access control.

Proximity Smart card base station reader

ISO15693 up to 20cm with smart card size inlays.

Custom protocol 13.56MHz read/write base stations

Ordering Information

Part

No.

Temperature

suffix Package

code

MLX90121

C (0癈 to 70癈)

FR (SSOP 20)

MLX90121

(-40癈

85癈)

(SSOP

20)

Description

The MLX90121 is an ISO compliant smart labels and
smart cards reader circuit. Applications range from
freight identification systems to access control.
The main features include user selectable
modulation depth in write mode, whereas single sub
carrier AM or FSK modulations are recognized in the
read mode.
The receiver is based on a diode envelope detector,
followed by an IF filter and amplifier. A logarithmic
amplifier is used for single sub carrier AM detection,
ensuring fast and clean data recovery. The limiting
output of the log amp is used for FSK recovery.
The transmitter uses a built in open drain output
transistor, which can provide up to 200 miliwatts of
RF power to a 50 ohms load with a 5 volts power
supply using the recommended matching network.
This is suitable for most short to mid range
applications. A simplified antenna and matching
network can be used, at the expense of a reduced
reading range, for example in hand-held readers
applications. An external transistor may be used to
boost the RF power level and achieve a greater
reading range.
The digital interface provides data to be processed
by a micro-controller. The chip is configured with a
shift register. Communication with the circuit is
achieved by means of a serial link.

Functional Diagram

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

Table of contents

1. Electrical Specifications........................................................................3

2. Absolute Maximum Ratings..................................................................6

3. Functional Description.........................................................................7

4. Typical Communication........................................................................8

5. Recommended application schematic....................................................8

6. Register Configuration.........................................................................9

7. Reliability Information..........................................................................10

8. ESD Precautions..................................................................................10

9. Packaging Information ........................................................................10

10. Disclaimer..........................................................................................13

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

1. Electrical Specifications

= -40

C to 85

C, V

= 5V (unless otherwise specified)

Parameter Symbol

Test

Conditions

Min

Typ

Max

Units

General DC Parameters

Operating supply voltage range

VDD

5.5

Supply ripple

See note 0

mVpp

Standby current consumption (Istb)

Istb

VDD =5.5 V

Idle mode current consumption (Idle1)
(Analog section off)

IDDQ1

External clock, VDD=5.5 V

Idle mode current consumption (Idle2)
(Analog section off)

IDDQ2

On board resonator, VDD=5.5V

Operating current (Iop)

IDD

Transmit current (Itr)

ITX

100

120

Transmitter specifications

Max peak voltage applied on drain of output

transistor

Maximum output transistor power dissipation

500

Output transistor ON resistance

Id = 50 mA

Output power for five volts operation

See note 1

180

200

Amplitude modulation depth adjustment range in

10% mode.

External resistor connected between

MOD pin and ground, See note 1

90 % D

Amplitude modulation depth in 10% mode

With nominal external resistor (12W),

See note 1

10 12 16 %

Minimum depth for 100% ASK

See note 1

Rise and fall time for 100% ASK

See note 1

2.5

祍

Rise and fall time for 10% modulation depth

With nominal external resistor (12W),

See note 1

1.5

祍

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

Parameter Symbol

Test

Conditions

Min

Typ

Max

Units

Receiver specifications

Small signal input impedance (RX)

100

200

Input RF voltage range (RX � VSS)

With 1 k series external resistor

1.8 - 4.9

Vdd

Receiver sensitivity (FSK)

See note 2

-40

-65

dBm

Baseband receiver sensitivity (FSK)

See note 3

-40

-65

dBm

FSK IF filter cut off points

130

200-

1400

1800

kHz A

Total gain, in FSK mode

100 120 140 dB

Log amplifier section

Limiting gain

Sensitivity for AM recovery

-40

-55

Sensitivity for FM recovery

-40

-65

dBm

RSSI Analog output

Driving capability

5pF //

200 k

External current source

Internal current source

Serial Link and digital I/O

Output voltage low

Vol

Iolmax=1mA

0.2

0.4

Output voltage high

Voh

4.6

4.8

Output current drive

Iol

Vol

0.4 Volt

Input voltage high

Vih

0.7 Vdd

Vdd + 0.3 V

Input voltage low

Vil

-0.3

0.3 Vdd

Maximum CK frequency

MHz

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

Parameter Symbol

Test

Conditions

Min

Typ

Max

Units

Crystal Oscillator

Frequency range (Fxtal)

13.56 16

MHz

Start-up time (Tstart)

Xtal series resistance

100

External clock signal specifications

see note 4

Min sine wave amplitude AC coupled
Input on pin XIN

Vdd Vpp

Min sine wave amplitude, DC coupled
Input on pin XIN

Input has to be centered around

Vdd/2

Vdd

Vpp

XBUF output specifications

XBUF Low Level (Col)

Sink current = 1mA

0.2

0.4

XBUF High Level (Coh)

Sink current = 1mA

4.6

4.8

Rise and fall times (10%-90%)

1k load resistor //12pF

Notes:

Parameter categories: A means 100% production tested, C means correlation tested (parameters whose values can be
inferred from other measurements, but are pertinent as a design aid to the end user), D means guaranteed by design.

0) The maximum ripple can create a reduction of the reading distance in order of 10%. Frequency: 0 to 15MHz.

1) Parameter measured using recommended output matching network.

2) This parameter is specified with the chip wired as specified in the typical application circuit provided below, with the
transmitter switched on. It cannot be measured during the final test.

3) This parameter is measured at base band for all specified modulation modes. The measurement is made at
RSSI output with the input diode detector bypassed.

4) The external clock symmetry is of paramount importance. It has a direct influence on the transmitter output power.
When using a sine wave as external clock input, it must not show visible distortion. In case a square wave is used, its
duty cycle has to be equal to 50%.

Fig 2: chip talks

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

3. Functional description

Power supply

The 90121 requires a nominal 5 volts external power
supply. Operation is guaranteed between 3 Volts
and 5.5 Volts, with reduced output power between 3
Volts and 5 volts. The current drain depends on the
antenna impedance and the output matching
network configuration. Power supply ripple and
noise will severely degrade the overall system
performance.

Transmitter:

The output transistor is a low Ron MOSFET. The
drain is directly accessible on the TX pin. A
recommended application schematic optimized to
drive a resistive fifty ohms antenna with a five volts
power supply is provided as a part of this
specification. A simple resonant circuit or/and a
simpler matching network can be connected to the
output. In the latter case, the general performance
and harmonic suppression will be reduced.

100 % modulation is achieved by switching the
output transistor, while MOD is connected to ground.
10% modulation is realized by adding an external
resistor (12Ohm) between MOD and VSS1.
Modulation is realized by a second low ohmic
MOSFET which shorts this external resistor.
The external resistor provides the default modulation
depth setting. It is possible to increase this resistor to
further increase the modulation depth .

Receiver

The receiver input is typically connected to the
antenna through an external resistor. The modulation
from the tag is then recovered by means of a diode
envelope detector.

FSK recovery

The demodulated input signal is amplified and band
pass filtered. The filter has a typical bandwidth of
200 to 1400 kHz. The total gain of the IF filter strip is
about 40dB. The signal is then hard limited by a 80
dB amplifier, and fed to the comparator.

ASK recovery

For ASK recovery, the high pass sections of the
filters are bypassed, to avoid falling edge
degradation by the filter settling time. The signal is
essentially DC coupled and fed to the input of the

amplifier. The amplifier also serves as envelope
detector. The demodulated output is then fed to the
comparator.

Reference clock and internal oscillator

The reference clock has to be applied to the XTAL1
pin. A sine wave centered at VCC/2 or a CMOS
logic compatible signal are acceptable external
system clocks. The built-in reference oscillator will
work either with a quartz crystal or a ceramic
resonator. The nominal system clock frequency is

13.56 MHz, but the oscillator may work at any
frequency from 4 MHz to 16 MHz.

Reset defaults and power management

After a power on reset has been performed, the
device is placed in its default configuration. There
are three available power modes:

In the first mode, the device is fully powered.

In the idle mode, only the reference oscillator
and a minimal set of associated circuitry are
running.

In the power down mode, the device internal
bias system is completely switched off.

Serial communication interface

The communication interface normally uses four
wires:

CK, serial clock for register data. Input with anti-
glitches.

DIN, data input for register or modulation

DOUT, data output

Mode, selection between register and
modulation

LTC, Low Time Constant: used to change the
time constant in the comparator (AM)

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Oct/02

Rev. 003

6. Register Configuration

At start up, all bits are at `0'.

# Bit

Purpose

Binary MSB first (Hex)

To bypass all the filters and gain blocks

- AM : 1
- FSK : 0

1-7 Test

Normal use = 0

8-9 Comparator Threshold

Normal use = 10 (0x2)

To reduce the voltage drop of the detector

VDD= 5V : 0
VDD= 3.3V: 1

To reduce the baud rate (AM only)

26kbaud = 0
6.6kbaud = 1

To use a subcarrier at 847kHz

AM, ISO 14443 = 1
Else =0

Modulation depth

10% : 1
100% : 0

14-16 Power Management

Carrier On : 001 (0x1)
Low Power : 010 (0x2)
Power down: 100 (0x4)

17-24 Test

Normal use = 0

25-26 Select DOUT

AM : 00 (0x0)
FSK : 10 (0x2):
- output = 1 when fsubc = 423kHz
- output = 0 when fsubc = 484kHz

Select XBUF, buffered output clock speed

13.56MHz : 1
6.78MHz : 0

Example settings (MSB first)

AM, VDD=5V, High Baudrate, 15693, 100%,

0000 0000 0000 0110 0010 0000 0001

FSK VDD=5V, High Baudrate, 15693, 100%,

0101 0000 0000 0110 0010 0000 0000

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Rev. 003

7. Reliability Information

Our devices are classified and qualified regarding their suitability for infrared, vapor phase and wave soldering
with usual SnPb-lot (melting point at 183degC).
The following test methods are applied:

IPC/JEDEC J-STD-020A (issue April 1999)

Moisture/Reflow Sensitivity Classification For Non-hermetic Solid State Surface Mount Devices

CECC00802 (issue 1994)

Standard Method For The Specification of Surface Mounting Components (SMDs) of Assessed Quality

MIL 883 Method 2003 / JEDEC-STD-22 Test Method B102

Solderability

The application of Wave Soldering for SMDs is allowed only after consulting Melexis regarding assurance of
adhesive strength between device and board.

For all soldering technologies deviating from a.m. standard conditions (regarding peak temperature,
temperature gradient, temperature profile etc) additional classification and qualification tests have to be agreed
upon with Melexis.

For more information on manufacturability/solderability see quality page at our website:

http://www.melexis.com/

8. ESD Precautions

Electronic semiconductor products are sensitive to Electro Static Discharge (ESD).
Always observe Electro Static Discharge control procedures whenever handling semiconductor products

9. Packaging Information

See following pages for the SSOP20 outline.

PINOUT

Nr Name Description

1 VDD1 Output stage supply

2 TX

Output stage drain (Transmitter)

3 MOD Modulation

resistor

4 VSS1 Output

stage

ground

5 XOUT Crystal

output

6 XIN Crystal

input

7 VSS2 Digital

ground

8 XBUF Crystal

buffered

output

9 LTC

AM time constant switch input

10 TEST Test input: ground for normal

operation.

Nr Name Description

11 DOUT Data

output

12 VDD2 Supply

connection

13 DIN Data

input

14 MODE Selection of DIN input: register or

modulation

15 CK

Serial clock for register data

16 RSSI

FM, AM or RSSI signal output

17 VDD3

Input stage supply

18 n.c.

Not connected, leave floating for
normal use

19 VSS3

Input stage ground

20 RX

Input stage (Receiver)

MLX90121

13.56MHz RFID Transceiver

3901090121

Page

Rev. 003

10. Disclaimer

Devices sold by Melexis are covered by the warranty and patent indemnification provisions
appearing in its Term of Sale. Melexis makes no warranty, express, statutory, implied, or by
description regarding the information set forth herein or regarding the freedom of the described
devices from patent infringement. Melexis reserves the right to change specifications and prices
at any time and without notice. Therefore, prior to designing this product into a system, it is
necessary to check with Melexis for current information. This product is intended for use in
normal commercial applications. Applications requiring extended temperature range, unusual
environmental requirements, or high reliability applications, such as military, medical life-support
or life-sustaining equipment are specifically not recommended without additional processing by
Melexis for each application.
The information furnished by Melexis is believed to be correct and accurate. However, Melexis
shall not be liable to recipient or any third party for any damages, including but not limited to
personal injury, property damage, loss of profits, loss of use, interrupt of business or indirect,
special incidental or consequential damages, of any kind, in connection with or arising out of the
furnishing, performance or use of the technical data herein. No obligation or liability to recipient
or any third party shall arise or flow out of Melexis' rendering of technical or other services.
� 2002 Melexis NV. All rights reserved.

For the latest version of this document, go to our website at:

www.melexis.com

Or for additional information contact Melexis Direct:

Europe and Japan:

All other locations:

Phone: +32 13 67 04 95

Phone: +1 603 223 2362

E-mail: sales_europe@melexis.com

E-mail: sales_usa@melexis.com

QS9000, VDA6.1 and ISO14001 Certified

协谢械泻褌褉芯薪薪褘泄 泻芯屑锌芯薪械薪褌: MLX90121

协谢械泻褌褉芯薪薪褘泄泻芯屑锌芯薪械薪褌: MLX90121