TH8056KDCA MELEXIS [Melexis Microelectronic Systems], TH8056KDCA Datasheet - Page 12

• Manufacturer Part Number: TH8056KDCA
• Description: Enhanced Single Wire CAN Transceiver
• Manufacturer: MELEXIS [Melexis Microelectronic Systems]

TH8056
Enhanced Single Wire CAN Transceiver
Mode 0 = 0, Mode 1 = 1 – Transmit with high voltage signals to wake up remote nodes (HVWU)
This bus includes a selective node awake capability, which allows normal communication to take place
among some nodes while leaving the other nodes in an undisturbed sleep state. This is accomplished by
controlling the signal voltages such that all nodes must wake up when they receive a higher voltage
message signal waveform. The communication system communicates to the nodes information as to which
nodes are to stay operational (awake) and which nodes are to put themselves into a non-communicating
low-power “sleep” state. Communication at the lower, normal voltage levels does not disturb the sleeping
nodes.
Mode 0 = 1, Mode 1 = 1 – Normal speed and signal voltage mode
Transmission bit rate in normal communication is 33.333 Kbits/sec.
In normal transmission mode the
TH8056 supports controlled waveform rise and overshoot times. Waveform trailing edge control is required
to assure that high frequency components are minimized at the beginning of the downward voltage slope.
The remaining fall time occurs after the bus is inactive with drivers off and is determined by the RC time
constant of the total bus load.
3.3 RxD Output pin
Logic data as sensed on the single wire CAN bus
RxD polarity
RxD = logic 1 on this pin indicates a bus recessive state (low bus voltage)
RxD = logic 0 on this pin indicates a bus normal or high-voltage bus dominant state
RxD in Sleep Mode
RxD does not pass signals to the micro processor while in sleep mode until a valid wake-up bus voltage level
is received or the Mode 0, 1 pins are not 0,0 respectively. When the valid wake-up bus signal awakens the
transceiver, the RxD pin signalizes an interrupt (logic 0 for dominant high-voltage signal). If there is no mode
change within the time stated, the transceiver reenters the sleep mode as described in 3.7
When not in sleep mode all valid bus signals will be sent out on the RxD pin.
RxD Typical Load
Resistance: 2.7 kohms
Capacitance: < 25 pF
3.4 Bus LOAD pin
Resistor ground with internal open-on-loss-of-ground protection
When the ECU experiences a loss of ground condition, this pin is switched to a high impedance state.
The ground connection through this pin is not interrupted in any transceiver operating mode including the
sleep mode. The ground connection is interrupted only when there is a valid loss of ground condition.
This pin provides the bus load resistor with a path to ground which contributes less than 0.1 volts to the bus
offset voltage when sinking the maximum current through one unit load resistor.
The transceiver’s maximum bus leakage current contribution to V
from the LOAD pin when in a loss of
ol
ground state is 50 uA over all operating temperatures and 3.5 V < V
< 26.5V.
batt
TH8056 – Datasheet
Page 12 of 26
March 2007
3901008056
Rev 012