Analog Integrated Circuit Device Data

12

Freescale Semiconductor

33390

TYPICAL APPLICATIONS

“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

The definition of a loss of assembly ground condition at the

device level is that all pins of the 33390, with the exception of

The LOAD pin of the device has an internal transistor

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

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

prevented from 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 Table 5, page 10.

Loss of Assembly Battery Connection

The definition of a loss of assembly battery condition at the

between these pins and ground.