AN201 Vishay Intertechnology, AN201 Datasheet - Page 4

• Manufacturer Part Number: AN201
• Description: High-performance Multiplexing With The DG408
• Manufacturer: Vishay Intertechnology

Figure 6 shows a typical data multiplexing system. Because
the multiplexer feeds a very high impedance, its input offset is
a function of its on-resistance and the on-state leakage of the
switch plus the amplifier bias current.
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4
AN201
Vishay Siliconix
Reference
Thermo
Voltage
Couple
Gauge
Strain
V–
p+
FIGURE 5. Cross Section of a High Voltage Silicon Gate CMOS Device
p+ Buried Layer
Multiplexer
É É É
n+
r
S
DS(on)
DG408
Pump
Meter
n-Channel
p-Well
Silicon
Gate
I
D(on)
FIGURE 6. Typical Data Aquisition System
n+
D
I
BIAS
p+
+
–
n– Substrate
Amplifier
Demultiplexer
n+
DG408
V
For the DG408/409 typical specifications, this offset will be
V
OFFSET
OFFSET
Converter
Expitaxial Layer (n–)
p+
A/D
S
É É É
p-Channel
= r
= 100
Silicon
Gate
DS(on)
Converter
p+
D
Link
D/A
(500 pA + 30 pA) = 53 nV
(I
D(on)
Processor
n+
+ I
Link
(BIAS)
V+
)
Document Number: 70600
05-Aug -99