The SN65LBC182 and SN75LBC182 are differential
data line transceivers with a high level of ESD protection
in the trade-standard footprint of the SN75176. They are
designed for balanced transmission lines and meet
ANSI standard TIA/EIA-485-A and ISO 8482. The
SN65LBC182 and SN75LBC182 combine a 3-state,
differential line driver and differential input line receiver,
both of which operate from a single 5-V power supply.
The driver and receiver have active-high and active-low
enables, respectively, which can be externally
connected together to function as a direction control.
The driver outputs and the receiver inputs connect
internally to form a differential input/output (I/O) bus port
that is designed to offer minimum loading to the bus.
This port operates over a wide range of common-mode
voltage, making the device suitable for party-line
applications. The device also includes additional
features for party-line data buses in electrically noisy
environment applications such as industrial process
control or power inverters.
The SN75LBC182 and SN65LBC182 bus pins also
exhibit a high input resistance equivalent to one-fourth
unit load allowing connection of up to 128 similar
devices on the bus. The high ESD tolerance protects
the device for cabled connections. (For an even higher
level of protection, see the SN65/75LBC184, literature
The differential driver design incorporates
slew-rate-controlled outputs sufficient to transmit data
up to 250 kbps. Slew-rate control allows longer
unterminated cable runs and longer stub lengths from
the main backbone than possible with uncontrolled
voltage transitions. The receiver design provides a
fail-safe output of a high level when the inputs are left
floating (open circuit). Very low device supply current
can be achieved by disabling the driver and the receiver.
The SN65LBC182 is characterized for operation from
40°C to 85°C, and the SN75LBC182 is characterized
for operation from 0°C to 70°C.