PRODUCT SPECIFICATION
TMC1203
2.
Segregate traces:
•
•
•
•
A/D analog
D/A analog
Clocks
Digital
5.
Treat analog inputs as transmission lines. Cleanly route
traces over the ground plane bearing in mind that the
return currents will flow through the ground plane
beneath the traces. Do not route digital traces nearby.
A few inches of digital trace less than a few line widths
from an analog trace will cross-couple noise into
adjacent analog circuits.
3.
The power plane for the TMC1203 should be separate
from that which supplies the rest of the digital circuitry.
A single power plane should be used for all of the V
DD
pins. If the power supply for the TMC1203 is the same
as that of the system's digital circuitry, power to the
TMC1203 should be decoupled with ferrite beads and
0.1mF capacitors to reduce noise.
The ground plane should be solid, not cross-hatched.
Connections to the ground plane should have very short
leads.
Decoupling capacitors should be applied liberally to
V
DD
pins. Remember that not all power supply pins are
created equal. They supply different circuits on the inte-
grated circuit, each of which generate varying amounts
and types of noise. For best results, use 0.1mF ceramic
capacitors. Lead lengths should be minimized. Ceramic
chip capacitors are the best choice.
If the digital power supply has a dedicated power plane
layer, it should not be placed under the TMC1203, the
voltage reference, or the analog inputs. Capacitive cou-
pling of digital power supply noise from this layer to the
TMC1203 and its related analog circuitry can have an
adverse effect on performance.
CLK
X
should be handled carefully. Jitter and noise on
this clock may degrade performance. Terminate the
clock line, if needed, to eliminate overshoot and ringing.
6.
7.
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4.
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