[time-nuts] Hp10811 parts ref

[Charles Steinmetz]

Didier wrote:

> The LM208 is a single op-amp with low offset (<3mV) and low bias current.

Even 3mV offset is verging on horrible for a "precision" opamp these 
days -- it's hard to find any respectable opamp that doesn't do lots 
better.

The secret sauce of the LMx08 series is the super-beta input pair, which 
matches FET opamps for input current but also holds that low (room-temp) 
input current over the full temperature range (the input current of FET 
opamps generally rises by at least 10x to more than 1000x at warmer to 
hot temperatures).

There is no need for extraordinary measures -- there are a number of 
more modern opamps specifically designed to upgrade LMx08 sockets.  The 
OP77 is one:

<http://pdf.datasheetcatalog.com/datasheet/analogdevices/206654345OP77_c.pdf>

The LT1012 and OP97 are two more.  I've used both extensively, and 
finally settled on the OP97 for this sort of application:

<http://pdf.datasheetcatalog.com/datasheet/analogdevices/140679914OP97_d.pdf>

Best regards,

Charles