Please note that these notes include updates and should replace any earlier versions you may have.  Major updates since the 9-22-2007 edition are noted below in the “Updates” section.

The L-17D application notes provided here were prepared primarily for individuals with prior experience with the L-17C.  For those who have had no prior L-17C experience, we have made the L-17C application notes available, since the L-17D notes frequently refer to procedures used for the L-17C.  A brief description of the major differences between the L-17C and the L-17D is included in the L-17D notes.

Also enclosed is specific information concerning values of components which have been used in tuning an L-17D for operation on the PC17D-2 test board. First time L-17D users may find this information particularly useful.

If you have technical questions concerning the L-17D, please contact Dr. David Dorfan.  You may reach him by E-mail at dave_dorfan@anadyneinc.com.  If a telephone conversation is needed, a date and time can be set up by E-mail.  Dave is the designer of both the L-17C and L-17D log amps, and has had considerable experience in working with the L-17D over the past year.  He also has worked with a beta-site using the L-2010 in die form.  (The L-17D is a packaged L-2010 die.)  Dave is looking for feedback from both L-17D and L-2010 users.  If any problems you encounter are ones with which he is familiar, he will be happy to tell you how to resolve them.  If it is a new problem, he will work with you to identify a satisfactory solution in a timely manner.

UPDATES

The major differences since the 9-22-2007 edition of the L-17D Application Notes are:

1. The two subsections marked “Caution” on pages 25 and 27.
2. An additional section (Section 8) titled “Packaging” starting on page 34
3. An additional section (Section 9) titled “Reliability of the L-2010 and L-17D” on page 37.
4. The following corrections have been made in the long paragraph of page 24 (page 23 of the 9-22-2007 version):

Line 3: (C1) is changed to (C4)
Line 5: (C5) is changed to (C2)

Two major updates (not yet in the application notes):   First, for very fast recovery times for the L-17D (≈ 50 ns from full power) it is necessary to limit the input to A2 at about 250 mv.  ANADYNE has a design for a limiter that exhibits very little temperature dependence.  If the limiting voltage is strongly temperature dependent, a simple design of recovery nets for A2 (e.g. a simple Schottky to ground) is more difficult.  This new circuit design will be made available to L-17D or L-2010 users upon request.

Second, it is no longer possible to make an extended range logger by joining the summing pins from two L-17D chips. The outputs of the two IC's must be summed using a summing amplifier. Many users have chosen to build their extended range loggers this way anyhow. They can continue to follow this procedure.
With the L-17C there was a noticeable deterioration in rise time as the S+ and S- pins were high output impedance points and the log stages ran low currents, so the stray capacitance caused severe slowing. We attempted to correct this with the L-17D but the new version does not function satisfactorily and should not be used to sum.

The third and fourth major updates are included in the following ANADYNE User Note dated 5/15/09 starting on the next page.