AS8220A Datasheet, PDF (13/33 Pages) ams AG – FlexRay Basis Transceiver

AS8220A
Objective Data Sheet - Detailed Description
NORMAL mode
In this mode the transceiver is able to send and receive data signals on the bus. TxEN and BGE control the state of the
transmitter. RxD reflects the bus data and reflect the bus state. In this mode, the transmitter state can be selected as
shown in the Table 5. In case the over-temperature flag is set the transmitter is disabled. The bus wires are terminated
to VCC/2 via receiver input resistances.
Table 5. Transmitter State
BGE
TxEN
TxD
Transmitter state
Bus State
H
L
H
Enabled
Data1 (BP is driven high, BM is driven low)
H
L
L
Enabled
Data0 (BP is driven low, BM is driven High)
X
H
X
Disabled
Idle (BP and BM are not driven)
L
X
X
Disabled
Idle (BP and BM are not driven)
If the differential bus voltage is higher than V_{BUSActivehigh} or lower than V_BUSActivelow for a time longer than t_BUSAc-
tivityDetection^{, then activity is detected on the bus (Bus = active), RxD is released.}
If, after the activity detection, the differential bus voltage is higher than V_Data1, RxD is high.
If, after the activity detection, the differential bus voltage is lover than V_Data0, RxD is low.
If the absolute differential bus voltage is lower than V_{BUSActivehigh} and higher than V_BUSActivelow for a time longer
than t_{BUSIdleDetection}, then idle is detected on the bus (Bus=idle), RxD is switched to logical “high”
STANDBY mode
In this mode the transceiver is not able to send and receive data signals from the bus. The power consumption is
significantly reduced respect the NORMAL mode. The bus wires are terminated to GND (bus state: Idle_LP).
Non Operating Mode
The AS8220A provides the following non operating mode:
Power Off
In this mode the transceiver is not able to operate. RxD is set to high and ERRN is set to low. The bus wires are not
connected to GND (bus state: Idle_HZ).
Undervoltage Events
Undervoltage VIO
When VIO voltage falls below V_IOTHL for a time longer than t_{UV_DETECT} then the undervoltage VIO flag is set and it is
reset when VIO exceeds the voltage threshold V_IOTHH for a time longer than t_{UV_REC}. The flag can be set or reset in all
the operation modes. The flag is reset at power off.
Undervoltage VCC
When VCC voltage falls below V_CCTHL for a time longer than t_{UV_DETECT} then the undervoltage VCC flag is set and it is
reset when VCC exceeds the voltage threshold V_CCTHH for a time longer than t_{UV_REC}. The flag can be set or reset in
all the operation modes. The flag is reset at power off.
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Revision 17920-001-10a
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