MLX90109
125kHz RFID Transceiver
9. Typical configuration: READ ONLY
9.1. Application diagram
The MLX90109 is a highly integrated reader IC. In the application schematic below, only two resistors to set VMODU are
required, next to the antenna inductance and tune capacitor. Capacitors C1 and CD can be added for a better noise
cancellation.
VDD
VDD
Microcontroller
CD=100nF
L, C
1
8
C1
2
7 DATA
3
6 CLOCK
4
5 MODE
SPEED
9.2. Absolute minimum schematic
The interface with the microcontroller can be realized with only one connection. In this case, the mode pin is left floating
and the integrated decoding is not used.
VDD
VDD
Microcontroller
CD=100nF
L, C
1
8
C1
2
7 DATA
SPEED
3
6 CLOCK
4
5 MODE
9.3. Power consumption
If the power consumption is not critical and the reader does not have to be put in power down, the MODU voltage can be
strapped to the required level (between 0.8V and Vpd). However, the power consumption can be reduced by controlling the
voltage on VMODU pin (e.g. with an IO port of a microcontroller).
REVISION 011 - JUNE 19, 2017
3901090109
Page 11 of 17