12
Analog Front End IC TMS37122 - Reference Guide
August ’01
11
TX
Activation pin for Antenna 1 Transmission Mode. When this pin is set,
the antenna resonator 1 is initiated to oscillate. The serial data to be
transmitted must be applied at MOD pin synchronous to CLKA/M
output.
12
MOD
In
Modulation input pin used for the LF HDX FSK response. When this
pin is at low level, the on-chip modulation capacitor is not connected.
Thus the resonator 1 is operating at 134.7kHz (nominal). When this pin
is at logic high level, the on-chip modulation capacitor is connected
and the resonator 1 is operating at 123.7kHz (nominal).
13
TCLK
In
Test Clock input for the test and configuration interface. The data is
shifted in and out with the rising edge of TCLK.
14
RF2
In
Device connection pin for the antenna resonator 2. The antenna
resonator consists of a low Q, parallel LC circuit.
The other end of the resonator is connected to pin VCL.
15
RF1
In
Connection pin for the antenna resonator 1. The antenna resonator
consists of a low Q, parallel LC circuit. The other end of the resonator
is connected to pin VCL. The antenna resonator 1 has the additional
feature of being able to send data back to the base station via LF HDX
FSK modulation.
16
VCL
In
Device supply pin for LF HDX operation. The charge capacitor CL is
connected to pin VCL. The energy, which is received during the LF
charge up phase, is stored on CL and supplies the LF HDX part via the
pin VCL.
Table 1: Description of the Device’s Pins
Pin #
Pin
Dir
Description
