MC33690DWE Freescale Semiconductor, MC33690DWE Datasheet - Page 12

• Manufacturer Part Number: MC33690DWE
• Description: IC STAND ALONE TAG READER 20SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MC33690DWE

• Rf Type: Read / Write
• Frequency: 125kHz
• Features: Wide Supply Voltage Range
• Package / Case: 20-SOIC (0.300", 7.50mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Standalone Configuration with Two-Wire Bus
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When a low level is applied on MODE1 and a high level on MODE2, the circuit is in configuration B (see
pin is set as an output sending the demodulated data.
The AM pin is set as a VSUP referenced input pin receiving the amplitude modulation and the shutdown/wake-up commands.
Forcing high and low levels on AM achieves the amplitude modulation by switching on/off both antenna drivers. This amplitude
modulation can be monitored on the K output and allows antenna short and open circuit diagnosis. The circuit can be put into
standby mode by forcing the AM line at zero during more than 2 ms. The circuit sends an acknowledge pulse before entering
into standby mode.
In standby mode, the oscillator and most of the internal biasing currents are switched off. Therefore, the functions (tag reader
and ISO 9141 driver) are inactive except for the voltage regulator and the ISO 9141 receiver on pin AM. The driver output TD1
forces a low level and TD2 a high level. A rising edge on AM wakes up the circuit. After completion of the wake-up sequence,
the circuit is automatically set in read mode.
In configuration B, DOUT and Rx outputs always force a low level and Tx is disabled.
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Read and write sequences:
Entering into standby mode:
Coming out of standby mode:
Standalone Configuration with Two-Wire Bus
AM line
K line
AM line
K line
AM line
K line
standby mode
Figure 8. Modes Access Description in Two-wire Bus Configuration
t Š T1
data read
T1
AM line high
drivers on
Reset
MC33690 Standalone Tag Reader Circuit, Rev. 5
Figure 9. Configuration B State Diagram
Wake-up
T2
wake-up sequence
AM
acknowledge
switching
TD1/2
T2
AM line low
AM line high
Standby
drivers off
1
1
AM line low
T1 £ AM line low
TD1/2 off
1
1
data write modulation
AM line monitoring
data write
1
1
standby mode
data read
0
0
Freescale Semiconductor
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0
Figure
0
0
25). The K