MLX90109EDC Melexis Inc, MLX90109EDC Datasheet - Page 13

• Manufacturer Part Number: MLX90109EDC
• Description: IC RFID TXRX 125KHZ 8-SOIC
• Manufacturer: Melexis Inc
• Series: MLX90109r

Specifications of MLX90109EDC

• Rf Type: Read / Write
• Frequency: 125kHz
• Features: Low Power Consumption
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MLX90109EDCTR

13 FAQ
The amplitude of the MLX90109 antenna can be adjusted on the fly by changing the MODU pin level
between V
antenna according to a voltage step on MODU pin, and a transient waveform will appear on the voltage
antenna. This particular waveform may disturb the transponder and in the worst case (modulation depth more
than 20%) the MLX90109 may stop its oscillation.
Using the MLX90109 with proportional modulation (modulation depth less than 100%) is not recommended
and supported by Melexis and must be evaluated case by case.
The reading distance depends on the complete system composed by the reader and the transponder. A
reading distance with the MLX90109 transceiver up to 15cm has been demonstrated with a specific reader’s
antenna (diameter = 130mm, Inductance = 44 H, Quality factor Q
a credit card size antenna (80 x 50mm).
The current flowing through the antenna (I
specification of the MLX90109 (Auto start-up impedance, the maximum driver current I
The voltage on the antenna cannot be increased as it is limited by the power supply V
V
reception, it is not possible to use an external power transistor supplied with a higher voltage than V
Melexis has developed an 18mm coil which is used on the evaluation board EVB90109. Please contact your
sales channel if you wish to purchase production quantities.
The DATA and CLOCK are open-drain drivers which require external pull-up resistors. The values are not
critical therefore, to reduce the general power consumption, we recommend to use high ohmic (100k ohm)
pull up resistances.
3901090109
Rev 008
MODU
13.1 Is it possible to make proportional modulation (depth less than 100%) with the
MLX90109?
13.2 How should I read data information from a transponder up to 15cm?
13.3 Is it possible to increase the output power of the MLX90109 transceiver?
13.4 Are there any specific coils available for the MLX90109 transceiver?
13.5 What are the recommended pull-up values on DATA and CLOCK pins?
+V
os
). Moreover, as the MLX90109 uses the same connection (COIL ) for the transmission and the
MODU
= 0.8V and V
pd
. However, the MLX90109 cannot change instantaneously the voltage on its
ANT
) can be maximized by a careful design, respecting the design
Page 13 of 15
ant
= 87.2@125kHz) and a transponder with
125kHz RFID Transceiver
MLX90109
DRIVER
).
DD
Data Sheet
Jun/06
(V
ant
DD
.
V
DD
-