MCP606 Microchip Technology, MCP606 Datasheet - Page 13

• Manufacturer Part Number: MCP606
• Description: 2.5V to 5.5V Micropower CMOS Op Amps
• Manufacturer: Microchip Technology

FIGURE 3-8:
traces to minimize leakage paths to the high
impedance input pins of the MCP606/607/608/609
amplifiers.
Figure 3-8A
Figure 3-8B
Figure 3-8C
Figure 3-8D
2000 Microchip Technology Inc.
Voltage
Reference
(could be ground)
Examples of how to design PC Board
MCP60X
MCP60X
MCP60X
MCP60X
V
DD
3.5.2
The input pins of the MCP606/607/608/609 amplifiers
have a high impedance providing an opportunity for
noise injection, if layout issues are not considered.
These high impedance input terminals are sensitive to
injected currents. This can occur if the trace from a high
impedance input is next to a trace that has fast chang-
ing voltages, such as a digital or clock signal. When a
high impedance trace is in close proximity to a trace
with these types of voltage changes, charge is capaci-
tively coupled into the high impedance trace.
FIGURE 3-9:
traces allowing for coupling of signals from one trace
to another.
As shown in Figure 3-9, the value of the capacitance
between two traces is primarily dependent on the dis-
tance (d) between the traces and the distance that the
two traces are in parallel (L). From this model, the
amount of current generated into the high impedance
trace is equal to:
where:
MCP606/607/608/609
C =
w= thickness of PCB trace
L
d
= length of PCB trace
= distance between the two PCB traces
I equals the current that appears on the high
impedance trace,
C equals the value of capacitance between the two
PCB traces,
switching, and
change took to get from one level to the next.
V equals the change in voltage of the trace that is
t equals the amount of time that the voltage
w x L x e
SIGNAL COUPLING
d
o
x e
Capacitors can be built with PCB
r
(typ 0.003mm)
I = C V/ t
pF
w
PCB Trace
L
d
DS11177B-page 13
Cross-Section
PCB