Datasheet

LTC2635
26
2635fb
operation
this effect than any other parts of this type; on the con-
trary, it allows layout-based performance improvements
to shine rather than limiting attainable performance with
excessive internal resistance.
Another technique for minimizing errors is to use a sepa-
rate power ground return trace on another board layer.
The trace should run between the point where the power
supply is connected to the board and the DAC ground pin.
Thus the DAC ground pin becomes the common point for
analog ground, digital ground, and power ground. When
the LTC2635 is sinking large currents, this current flows
out the ground pin and directly to the power ground trace
without affecting the analog ground plane voltage.
It is sometimes necessary to interrupt the ground plane
to confine digital ground currents to the digital portion
of the plane. When doing this, make the gap in the plane
only as long as it needs to be to serve its purpose and
ensure that no traces cross over the gap.
C3 C2 C1 C0 A3 A2 A1 A0
C3W
W
C2
COMMAND/ADDRESSSLAVE ADDRESS MS DATA LS DATA
C1 C0 A3 A2 A1 A0 D11 D10 D9 D8 D7 D6 D5 D4 D3
ACKACKACKACK
D2 D1 D0 X X X X
A0A1A2A3A4A5
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
A6
A0A1A2A3A4A5A6
START
STOP
FULL-SCALE
VOLTAGE
ZERO-SCALE
VOLTAGE
SDA
SCL
V
OUT
X = DON’T CARE
2635 F04
Figure 4. Typical LTC2635 Input Waveform—Programming DAC Output for Full-Scale