MLX90109 데이터 시트보기 (PDF) - Melexis Microelectronic Systems
부품명
상세내역
일치하는 목록
MLX90109 Datasheet PDF : 17 Pages
| |||
MLX90109
125kHz RFID Transceiver
7.4. Digital demodulator
The MODE pin allows to define whether the MLX90109 will issue directly the filtered data stream on the DATA pin (MODE
floating), or decode it in Manchester (MODE = VDD) or Biphase (MODE = VSS). In these two decoding modes, the MLX90109
issues the tag data on the DATA pin at the rising edge of the clock, which is issued on the CLOCK pin. Both CLOCK and DATA
are open drain outputs and require external pull-up resistors.
SPEED
VSS
4kBaud
MODE
Biphase
(*) Internally strapped to VDD/2
FLOAT (*)
-
No decoding
VDD
2kBaud
Manchester
7.5. Antenna voltage definition
The MLX90109 is a reader IC working in a frequency range of 100 to 150kHz, and designed for use with a parallel L-C
antenna. This concept requires significantly less current than traditional serial antennas, for building up the same magnetic
field strength.
The voltage on the MODU pin (VMODU) controls the amplitude of the antenna voltage Vant, as follows:
(1)
Vant VDD VMODU VOS
with VOS, the offset relative to the VMODU level.
Note: In order to use the internal driver FET as an ideal current source, the voltage on the coil pin should remain higher than
its saturation voltage (typically 0.5V) for a driver current (Idriver) up to 14mA. As this offset can be as much as 300mV, VMODU
should be higher than 0.8V for a correct operation.
7.6. Power Down mode
By setting VMODU higher than Vpd (preferably to VDD) the MLX90109 goes in power down. The antenna voltage will fade to 0V.
The MLX90109 powers up by pulling VMODU below Vpu.
7.7. Write operation
A sequence of power up / power down periods sets the antenna voltage ON and OFF. This feature allows to simply make an
ON/OFF-keying modulated signal to the transponder.
Typically, VMODU is toggled between VDD and 0.8V. Antenna fade-out is related to the quality factor of the antenna (Qant) and
its start-up takes about 3 carrier periods.
Refer to the section “Typical operating configurations” further in this document for more detailed information and practical
hints.
REVISION 011 - JUNE 19, 2017
3901090109
Page 8 of 17
Share Link: 