[time-nuts] LT3042, etc. Re: HP E1938A schematics.

[Glen English VK1XX]

RRR . you are right about drop and noise..

For others not familiar with this behaviour, one thing when looking is 
PSRR etc  on LDOs..take a good look at this value VERSUS dropout / 
headroom . Most devices are in the toilet when dropout is nigh... In my 
SDRs I (used) to run 2V around  for 1.8V point of load LDO supplies. 
PSRR 100k went up alot when I bumped the supply rail to 2.2V...


On 9/07/2019 10:44 AM, jimlux wrote:
> On 7/8/19 4:53 PM, Richard (Rick) Karlquist wrote:
>>
>>
>> On 7/8/2019 11:09 AM, jimlux wrote:
>>
>>>
>>> Not only are they low noise, but they have spectacularly good HF 
>>> rejection across the regulator up to 10s of MHz.
>>>
>>
>> In the 5071A, I wanted high bandwidth PSRR and stumbled across
>> a designer's manual (HP internal document) for the MMS Modular
>> Measurement System.  They described a regulator with a common base
>> pass transistor and an op amp, with a bandwidth approaching 1 MHz.
>> Quite state of the art for the time.  I copied the design in several
>> 5071A modules.  We used it to regulate +5V from the Vicor modules down to