Mitsubishi M54617P Datasheet
MITSUBISHI <CONTROL / DRIVER IC>
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M54617P
LAN TRANSCEIVER
DESCRIPTION
The M54617P is an integrated circuit for two-wire system LAN
transceivers in compliance with J1850.
It has a built-in function detecting bus-line abnormality, and allows
ERR signal to turn to “L” in case of abnormality. In addition, the
selector permits the output of normal bus signal.
Turning the standby signal to “L” provides a low current dissipation
status, when both BUS(+) and BUS(-) of the driver are turned OFF.
Further, inputting “H” level to ERR pin when in the standby mode
allows error output to be reset.
FEATURES
●Compliance with SAE J1850 standards
●Built-in function detecting bus-line abnormality
APPLICATION
LAN transceivers in general and other communication transceivers
(The M59330P having the same function is available as a vehicleloaded LAN transceiver).
PIN CONFIGURATION (TOP VIEW)
Data input
Standb
Error I/O
Data output
input
STB
ERR
RX
TX
1
2
3
4
Outline 8P4
M54617P
8
7
6
5
VDD
BUS(+
BUS(-)
SS
V
Power supply
Bus-line I/O
GND
BLOCK DIAGRAM
1
Data input
Standby
input
Error I/O
Data output R
TX
STB
ERR
2
3
X
4
Standby control
circuit
Abnormality
detection circuit
Selector
Output control
circuit
Overcurrent
detection circuit
Driver
Driver
BUS (+) signal
detection
circuit
BUS (-) signal
detection
circuit
Filter
8
7
6
5
DD
V
BUS (+)
BUS (-)
V
SS
Power
supply
Bus-line
I/O
GND
MITSUBISHI <CONTROL / DRIVER IC>
FUNCTION
Pin function
Pin No. Pin name I/O Function
1
TX Input Data signal input pin
2
STB Input
3
ERR I/O
Standby signal input pin
L: standby mode, H: normal operation
Error signal output pin and error reset input pin
“L” level output when abnormal transmission route is detected
Error reset with “H” level input when in the standby mode
M54617P
LAN TRANSCEIVER
4
5
6
7
8
X Output Signal output pin from transmission route
R
SS Input Grounding pin
V
BUS(-) I/O Signal output pin to transmission route and signal input pin from transmission route (negative logic)
BUS(+) I/O Signal output pin to transmission route and signal input pin from transmission route (positive logic)
DD Input
Power supply pinV
ABNORMALITY DETECTION OF TRANSMISSION
ROUTE AND COMMUNICATION FUNCTION
The M54617P uses its driver overcurrent detection function and
transmission signal logic abnormality function to perform the
abnormality detection of the transmission route, and outputs error
signal (ERR(3 pin) = “L”).
In addition, switching the signal that is output to Rx pin (pin 4)
according to the abnormality occurrence status permits
communication after abnormality has occurred.
(1) Overcurrent detection
BUS(+) pin (pin 7) and BUS(-) pin (pin 6) drivers of M54617P are
equipped with an overcurrent detection circuit. When overcurrent
flows to a driver, the driver is turned OFF to output error signal
(ERR (pin 3) = “L”). Once an overcurrent is detected, the driver
maintains the OFF status until the error is reset.
In addition, each driver of BUS(+) pin (pin 7) and BUS(-) pin (pin 6)
is independent, and both may be turned OFF depending upon the
abnormality occurrence status.
A built-in filter for the prevention of malfunction due to overcurrent
when the driver is turned ON does not permit the detection of the
overcurrent status for a short time (several hundred ns). Detection
current is set to about 180mA.
(3) Communication function
The M54617P ordinarily outputs the differential signals of BUS(+)
(pin 7) and BUS(-) (pin 6). When abnormality is detected, signals to
be output to Rx pin (pin 4) are switched according to the status.
When overcurrent is detected, the driver or the transmission route
in which overcurrent is detected is considered abnormal, and error
signal is output, and concurrently the signal of another
transmission route is output to Rx output (pin 4).
As described in the above section (1), both drivers are turned OFF
in some cases. In these cases, Rx output (pin 4) is fixed to “L”.
When logic abnormality is detected, error signal (ERR (pin 3) = “L”)
is output, and concurrently Rx output (pin 4) is turned to “L”. After
error signal is output, the transmission route in which the edge of
transmission signals is detected is considered normal, and such
signal is output to Rx output (pin 4).
In switching operation of error signal output and Rx output the
priority is given to overcurrent detection over logic abnormality
detection.
(2) Logic abnormalitydetection
The M54617P transmission signals operate in the opposite phase
to each other, and abnormal transmission route is detected by
comparing these signals. Upon comparing respective signals after
a set time on the basis of the edge of transmission routes BUS(+)
and BUS(-), any disagreement is regarded as abnormal
transmission, and error signal (ERR (pin 3) = “L”) is output. In order
to be well timed with that edge as a new standard, abnormality is
detected when signal disagreement continues for more than a set
time. Setting time is set to about 4.2µs.
Logic abnormality detection does not cope with more than one
error mode.
Detection of logic abnormality alone does not allow the driver to be
turned OFF. Abnormality detection allows the driver to be turned
OFF only when overcurrent is detected.
Table 1. Abnormalitymode and abnormalitydetection function
Abnormality mode Error output
1
2
BUS(+)
3
4
5
BUS(-)
6
7
BUS(+) and BUS(-) short
GND short
VDD short
Open
GND short
V
DD short
Open
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes Yes
Yes No
Communication after
abnormality is detected
MITSUBISHI <CONTROL / DRIVER IC>
M54617P
LAN TRANSCEIVER
Abnormality
detection method
(2)
(1), (2)
(2)
(1), (2)
(2)
(2)
(1)
ERROR RESET
Error output of the M54617P can be reset by turning to the standby
mode (STB pin (pin 2) = “L”), followed by inputting “H” level to ERR
pin (pin 3). In this case, all operations are cleared that relate to
abnormality detection including overcurrent detection and switching
of Rx output.
I/O EQUIVALENT CIRCUIT
Tx and STB input
1
STANDBY MODE
The M54617P can be set to the low current dissipation mode by
turning STB pin (pin 2) to level “L”.
Standby mode does not allow the driver and overcurrent detection
function to be operated, but logic abnormality detection function
operates, which permits detection other than abnormality relating
to overcurrent detection. However, it provides error signal output
only, but no switching of Rx output signal.
Rx output when in the standby mode outputs the logic sum of
BUS(+) and BUS(-) signals.
ERR I/O
2
3
Rx output
BUS(+) and BUS(-) I/O
4
BUS (+)
BUS (-)
Filter time constant
RC = 110E-9 (standard)
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