LPC662AI National Semiconductor Corporation, LPC662AI Datasheet - Page 10

• Manufacturer Part Number: LPC662AI
• Description: LPC662 - Low Power CMOS Dual Operational Amplifier, Package: Soic Narrow, Pin Nb=8
• Manufacturer: National Semiconductor Corporation

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Application Hints
This would cause a 100 times degradation from the
LPC662’s actual performance. However, if a guard ring is
held within 5 mV of the inputs, then even a resistance of
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perhaps a minor (2:1) degradation of the amplifier’s
The designer should be aware that when it is inappropriate
to lay out a PC board for the sake of just a few circuits, there
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ohms would cause only 0.05 pA of leakage current, or
(b) Non-Inverting Amplifier
(a) Inverting Amplifier
FIGURE 4. Example of Guard Ring in P.C. Board Layout, using the LPC660
(Continued)
FIGURE 5. Guard Ring Connections
DS010548-20
DS010548-21
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performance. See Figure 5a , Figure 5b , Figure 5c for typical
connections
configurations. If both inputs are active and at high
impedance, the guard can be tied to ground and still provide
some protection; see Figure 5d .
is another technique which is even better than a guard ring
on a PC board: Don’t insert the amplifier’s input pin into the
(d) Howland Current Pump
of
DS010548-19
(c) Follower
guard
rings
for
DS010548-22
standard
DS010548-23
op-amp