AC PARAMETER TEST CIRCUIT AND WAVEFORMS

UC5172

APPLICATIONS

Slew Rate Programming

Slew rate for the UC5172 is set up by a single external re-

sistor connected between the SRA pin and ground. Slew

rate adjustments can be approximated by using the fol-

lowing formula:

V/

µs =

20

Ω)

The slew rate resistor can vary between 2k and 10k

Ω

which allows slew rates between 10 to 2.2V/

µs, respec-

shown in the typical characteristics.

Waveshaping of the output lets the user control the level

of interference (near-end crosstalk) that may be coupled

to adjacent circuits in an interconnection. The recom-

mended output characteristics for cable length and data

rates can be found in EIA standard EIA-423A. Approxima-

tions of these standards are given by the following equa-

tions:

Max. Data Rate = 300/t (For data rates 1k to 100k bit/s)

Max. Cable Length (feet) = 100 x t (Max. length 4000

feet)

where t is the transition time from 10% to 90% of the out-

put swing in microseconds. For data rates below 1k bit/s,

t may be up to 300 microseconds.

The UC5172 has been used in applications up to

460KBPS.

AC CHARACTERISTICS

Driver Slew Rate

3