LM9040M National Semiconductor, LM9040M Datasheet - Page 8

• Manufacturer Part Number: LM9040M
• Description: Dual Lambda Sensor Interface Amplifier
• Manufacturer: National Semiconductor

Open Input Pins Defaults
In the cases where both the inverting and non-inverting pins
are open the non-inverting condition (i e voltage divider
across the output) will be the dominant condition
Any common mode signal seen by inverting input pin should
not be allowed to exceed the Common Mode voltage range
Exceeding the positive Common Mode voltage limit could
cause the inverting input pin voltage comparator to act as if
the inverting input pin is open Since the comparator circuit
is not part of the switched capacitor network there is no
frequency limitation on the signal to the comparator Any
transient on the inverting input pin which goes above the
comparator threshold will immediately cause the output to
switch to the open sensor mode The output will return to
normal operation when the voltage on the inverting input
falls below the comparator threshold
(Continued)
FIGURE 11 Typical Application
8
Supply Bypassing
For best performance the LM9040 requires a V
which is stable and noise free The same 5V V
used for the A D converter is the recommended V
ply During operation the device will generate current spikes
coincident with the clock edges Inadequate bypassing will
cause excessive clock noise on the outputs as well as
noise on the V
passed with a minimum 0 1
Ground pin and should be located as close to the device as
possible Some applications may require an additional
4 7
other switched capacitor devices running off the same 5V
supply line The Signal and Digital Ground pins should be
tied together as close to the device as possible
F tantalum capacitor especially if there are several
CC
line The LM9040 V
F capacitor to the Signal
CC
pin should be by-
TL H 12372 – 21
REF
CC
CC
supply
supply
sup-