Description

MC33690 Standalone Tag Reader Circuit, Rev. 5

Freescale Semiconductor

5

1

Description

1.1

Tag Reader Module

The tag reader module is dedicated for automotive or industrial applications where information has to be transmitted

contactless.The tag reader module is a write/read (challenge/response) controller for applications that a demand high security

level.

The tag reader module is connected to a serial-tuned LC circuit that generates a magnetic field power supplying the tag. The

use of a synchronous sample and hold technique allows communication with all available tags using admittance switching

producing absorption of the RF field.

Load amplitude or phase shift modulation can be detected at high bit rates up to 8 kHz. The typical operational carrier frequency

of the tag reader module with an 8 MHz clock is 125 kHz.

11

AGND

Demodulator ground

12

CEXT

Comparator reference input

13

DOUT

Demodulator output (5V)

14

LVR

Low Voltage Reset input/output

15

XTAL2

Oscillator output

16

XTAL1

Oscillator input

17

AM

Amplitude modulation input

18

K

ISO 9141 transmitter output and receiver input

19

Rx

ISO 9141 receiver monitor output

20

Tx

ISO 9141 transmitter input

Table 3. Pin Function Descriptions (continued)