Electronic Components Datasheet Search |
|
LMC6081AIM Datasheet(PDF) 8 Page - National Semiconductor (TI) |
|
|
LMC6081AIM Datasheet(HTML) 8 Page - National Semiconductor (TI) |
8 / 12 page Applications Hints (Continued) ure 4. To have a significant effect, guard rings should be placed on both the top and bottom of the PC board. This PC foil must then be connected to a voltage which is at the same voltage as the amplifier inputs, since no leakage current can flow between two points at the same potential. For example, a PC board trace-to-pad resistance of 10 12 Ω, which is nor- mally considered a very large resistance, could leak 5 pA if the trace were a 5V bus adjacent to the pad of the input. This would cause a 100 times degradation from the LMC6081’s actual performance. However, if a guard ring is held within 5 mV of the inputs, then even a resistance of 10 11 Ω would cause only 0.05 pA of leakage current. See Figure 5 for typi- cal connections of guard rings for standard op-amp configurations. 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 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 board at all, but bend it up in the air and use only air as an in- sulator. Air is an excellent insulator. In this case you may have to forego some of the advantages of PC board con- struction, but the advantages are sometimes well worth the effort of using point-to-point up-in-the-air wiring. See Figure 6. Latchup CMOS devices tend to be susceptible to latchup due to their internal parasitic SCR effects. The (I/O) input and output pins look similar to the gate of the SCR. There is a minimum cur- DS011423-6 FIGURE 4. Example of Guard Ring in P.C. Board Layout DS011423-7 Inverting Amplifier DS011423-8 Non-Inverting Amplifier DS011423-9 Follower FIGURE 5. Typical Connections of Guard Rings DS011423-10 (Input pins are lifted out of PC board and soldered directly to components. All other pins connected to PC board). FIGURE 6. Air Wiring www.national.com 8 |
Similar Part No. - LMC6081AIM |
|
Similar Description - LMC6081AIM |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |