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LM385: Could it be retiring?

J

Joerg

Jan 1, 1970
0
Checked a few micro-power shunt references this morning. The ROHS
compliant versions of the LM385 were called "mature" on the Arrow web
site and that word always makes my neck hairs stand up. Could this mean
it's headed for lalaland? If so, which micro-power shunt refs are
engineers using instead these days? The TLV431 is kind of out in my
case, too much cathode current.
 
D

D from BC

Jan 1, 1970
0
Checked a few micro-power shunt references this morning. The ROHS
compliant versions of the LM385 were called "mature" on the Arrow web
site and that word always makes my neck hairs stand up. Could this mean
it's headed for lalaland? If so, which micro-power shunt refs are
engineers using instead these days? The TLV431 is kind of out in my
case, too much cathode current.


Digikey has 0.6uA listed for the cathode current for
digi#296-18865-1-ND it's a TL431BCDBR
Or just type in TL431 as a keyword..Looks like there's versions that
need an idle Ic up to 1mA..

Also..as an alternative...I think I saw a micropower op amp with a
built in reference IC that can be turned into a shunt reg..
Can't remember the IC #...
But I recall finding similar IC's that had a flea power op amp but
then the fk'n build in reference was just a hog.

I just took a quick peek at this voltage reference ISL60002.. It's not
a shunt reg... just a Vref that draws 400nA...
Take it as a clue that there's gotta be something much "lighter" than
the TL431.
Maybe make a shunt reg with a flea reference + flea op amp + mosfet?

D from BC
 
J

Joerg

Jan 1, 1970
0
D said:
Digikey has 0.6uA listed for the cathode current for
digi#296-18865-1-ND it's a TL431BCDBR
Or just type in TL431 as a keyword..Looks like there's versions that
need an idle Ic up to 1mA..

A lot of the info in those tables isn't correct. The lowest cathode
current version of the 431 I have ever seen is 50uA. But down there the
selection of vendors shrinks and it consequently begins to become
expensive, meaning >15c. The run-of-the-mills TL431 varieties are
between 400uA and 1mA min.

Also..as an alternative...I think I saw a micropower op amp with a
built in reference IC that can be turned into a shunt reg..
Can't remember the IC #...
But I recall finding similar IC's that had a flea power op amp but
then the fk'n build in reference was just a hog.

I just took a quick peek at this voltage reference ISL60002.. It's not
a shunt reg... just a Vref that draws 400nA...
Take it as a clue that there's gotta be something much "lighter" than
the TL431.
Maybe make a shunt reg with a flea reference + flea op amp + mosfet?

There are some boutique chips like that. Unfortunately they also carry
boutique price tags :-(
 
S

Steve

Jan 1, 1970
0
Joerg said:
Checked a few micro-power shunt references this morning. The ROHS
compliant versions of the LM385 were called "mature" on the Arrow web site
and that word always makes my neck hairs stand up. Could this mean it's
headed for lalaland? If so, which micro-power shunt refs are engineers
using instead these days? The TLV431 is kind of out in my case, too much
cathode current.


I use LM4040, but its 60 uA min vs the 10-20u of your 385. The SC70 package
is nice, though .

National's site shows 385 in full production for all its variants, maybe its
not doomed...

Steve
 
D

D from BC

Jan 1, 1970
0
A lot of the info in those tables isn't correct. The lowest cathode
current version of the 431 I have ever seen is 50uA. But down there the
selection of vendors shrinks and it consequently begins to become
expensive, meaning >15c. The run-of-the-mills TL431 varieties are
between 400uA and 1mA min.



There are some boutique chips like that. Unfortunately they also carry
boutique price tags :-(

Yup..that ISL60002 is about $8.00CAD!!! But I mentioned it as a
benchmark example.

Is anyone going to tell Digikey than the TL431 tables are wrong???
They should have a reward program where customers get a credit for
reporting errors..
A free bag of flea power shunt regulators for every reported error! :)

D from BC
 
H

Harry Dellamano

Jan 1, 1970
0
Joerg said:
Checked a few micro-power shunt references this morning. The ROHS
compliant versions of the LM385 were called "mature" on the Arrow web site
and that word always makes my neck hairs stand up. Could this mean it's
headed for lalaland? If so, which micro-power shunt refs are engineers
using instead these days? The TLV431 is kind of out in my case, too much
cathode current.

The LM385 is a "High Side Adjustable Current Reference" vs. the TL431
family which has a low side reference. Is there any other HSACRs with low Ik
beside the LM385 in a SMD? The LM385 do not come in SMD so they probably
will be phased out.
Regards,
Harry
 
J

John Fields

Jan 1, 1970
0
Checked a few micro-power shunt references this morning. The ROHS
compliant versions of the LM385 were called "mature" on the Arrow web
site and that word always makes my neck hairs stand up. Could this mean
it's headed for lalaland?

---
National's web site says all versions are in full production, TI's
says they're active, and ON semi has zillions of 'em so probably not
to worry for a while.
 
J

Joerg

Jan 1, 1970
0
Harry said:
The LM385 is a "High Side Adjustable Current Reference" vs. the TL431
family which has a low side reference. Is there any other HSACRs with low Ik
beside the LM385 in a SMD? The LM385 do not come in SMD so they probably
will be phased out.


It does come in SOT-23 and also TSSOP. LM385M3X-1.2 would be the SOT-23
version from National, for example.
 
J

Joerg

Jan 1, 1970
0

Yes, they list them as active. I am just wondering why Arrow calls them
"mature". Usually that isn't a good sign. Also, I've had instances in
the past, like with a log amp chip, where there was full production
indication and then suddenly poof. As if someone had turned the lights
off. The purchasing manager came down the hallway, all red in the face.

I have used the LM4040 on the design that I am wrapping up right now but
on this next one 60uA would be too much. That low power requirement
bites everywhere. For example, I'd really like to use a chunk of a LP339
as a linear amp but there isn't much info around to calculate the loop
stabilization. Just hanging 1uF at the output is kind of crude and won't
work here anyway.
 
R

Robert Latest

Jan 1, 1970
0
["Followup-To:" header set to sci.electronics.design.]
It does come in SOT-23 and also TSSOP. LM385M3X-1.2 would be the SOT-23
version from National, for example.

Why doesn't the adjustable version come in SOT-23?

robert
 
H

Harry Dellamano

Jan 1, 1970
0
Joerg said:
It does come in SOT-23 and also TSSOP. LM385M3X-1.2 would be the SOT-23
version from National, for example.
Joerg, Where did you find the adjustable LM385 in a SOT-23 pack??
 
J

Joerg

Jan 1, 1970
0
Harry said:
Joerg, Where did you find the adjustable LM385 in a SOT-23 pack??

The adjustable only comes in SOIC, AFAIK. That would be LM385BM. Digikey
has some but they are kind of pricey.
 
J

Joerg

Jan 1, 1970
0
Robert said:
["Followup-To:" header set to sci.electronics.design.]

It does come in SOT-23 and also TSSOP. LM385M3X-1.2 would be the SOT-23
version from National, for example.


Why doesn't the adjustable version come in SOT-23?

No idea. Maybe the die area is too large but I can't really imagine that
on a 20uA device. It does come in SOIC though.
 

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