MCZ33989EG Freescale Semiconductor, MCZ33989EG Datasheet - Page 47

• Manufacturer Part Number: MCZ33989EG
• Description: IC SYSTEM BASIS CHIP CAN 28-SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MCZ33989EG

• Applications: *
• Interface: *
• Voltage - Supply: *
• Package / Case: 28-SOIC (7.5mm Width)
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TX and RX Pins
depends on the V2 status. RX is a push-pull structure,
supplied by V2. When V2 is set at 5V, and CAN is in normal
mode, RX reports the bus status. When V2 is off RX is low.
Minimum Baud Rate
200 µs), a minimum Baud rate is required in order to get good
behavior: once TX permanent dominant is detected the CAN
driver is off.
frame is 12 (6 bits of active error flag and its echo error flag).
60 KBaud.
Analog Integrated Circuit Device Data
Freescale Semiconductor
The TX pin has an internal pull up to V2. The state of TX
As TX permanent dominant is detected after TDOUT (min
The maximum number of consecutive dominant bits in a
200 µs/12 = 16.7 µs. The minimum Baud rate is 1/6.7 µs =
CAN signal with slew rate 0 selected
CAN bus
RT
Differential termination concept
CANH
CANL
(partial drawing)
MC33989
Figure 36. Normal Mode and Slew Rate Selection
Gnd
R=60 ohms, CL = CH = 100pF
TX
RX
Figure 37. Bus Termination
CAN bus
Normal Mode and Slew Rate Selection
are available. The slew rate affects the recessive to dominant
and dominant to recessive transitions. This affect is also the
delay time from the TX pin to the bus, and from the bus to RX.
The loop time is thus affected by the slew rate selection.
CANH, CANL, TX and RX.
Termination
termination:
The slew rate selection is done via the SPI. Four slew rates
The following figure is an illustration of the slew rate on
The MC33989 supports the two main types of bus
• Differential termination resistors between CANH and
• Split termination concept, with mid point of the
CANL lines.
differential termination connected to gnd through a
capacitor.
CAN signal with slew rate 3 selected
RT /2
RT /2
Split termination concept
CANH
CANL
(partial drawing)
SUPPLEMENTAL APPLICATION NOTES
MC33989
Gnd
TYPICAL APPLICATIONS
TX
RX
33989
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