MCZ33990EF Freescale Semiconductor, MCZ33990EF Datasheet - Page 13

• Manufacturer Part Number: MCZ33990EF
• Description: IC TRANSCEIVER J-1850 BUS 8-SOIC
• Manufacturer: Freescale Semiconductor

Specifications of MCZ33990EF

• Applications: *
• Interface: *
• Voltage - Supply: *
• Package / Case: 8-SOIC (3.9mm Width)
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

transition before 96 μs, one logic state is inferred. If there is a
bus transition after 96 μs, the other logic state is inferred. The
“end of data” bit is a logic [0] and lasts 200 μs. If there is no
activity on the bus for 280 μs to 320 μs following a broadcast
message, multiple unit nodes may arbitrate for control of the
next message. During an arbitration, after the “start of frame”
bit has been transmitted, the secondary node transmitting the
most consecutive logic [0] bits will be granted sole
transmission access to the bus for that message.
Loss of Assembly Ground Connection
device level is that all pins of the 33990, with the exception of
BUS and LOAD, see a very low impedance to V
switch connected to it that is normally saturated to ground.
This pulls the LOAD-side of the external resistor (tied from
BUS to LOAD) to ground under normal conditions. The LOAD
pin switch is essentially that of an “upside down” FET, which
is normally biased “on” so long as module ground is present
Analog Integrated Circuit Device Data
Freescale Semiconductor
The definition of a loss of assembly ground condition at the
The LOAD pin of the device has an internal transistor
MCU
V
BAT
+VBAT
SLEEP
TX
RX
4X/LOOP
Figure 14. Typical Application
BAT
.
33990
LOAD
BUS
GND
and biased “off” when loss-of-ground occurs. When a loss of
assembly ground occurs, the load transistor switch is self-
biased “off”, allowing no more than 100 μA of leakage current
to flow in the LOAD pin. During such a loss of assembly
ground condition, the BUS and LOAD pins exhibit a high
impedance to V
to V
sourcing any current or loading the bus, which would cause a
corruption of any data being transmitted on the bus. While a
particular assembly is experiencing a loss of ground, all other
assembly nodes are permitted to function normally. It should
be noted that with other nodes existing on the bus, the bus
will always have some minimum / maximum impedance to
ground as shown in
Loss of Assembly Battery Connection
device level is that the V
impedance to V
between these pins and ground.
The definition of a loss of assembly battery condition at the
10.6
BAT
470pF
47
. During this condition the BUS pin is prevented from
kΩ
μ
H
BAT
BAT
; all other pins will exhibit a low impedance
, but there is some undefined impedance
Table
BAT
Secondary
Primary
6, page 11.
Nodes
Node
pin of the 33990 sees an infinite
FUNCTIONAL PIN DESCRIPTION
TYPICAL APPLICATIONS
33990
13