I hate to be argumentative, but you can't be low drop out and use an
emitter follower. Draw the circuit and convince yourself. You would need
a high side driver scheme to drive the base/gate, and that require some
sort of boost converter. It can be done on switchmode chips, but not in
a linear
The Linear Technology LT3070 (150mV @ 5A) , LT3071, LT1580 , and
LT1581 (700 mV @ 10A) are examples:
http://www.linear.com/product/LT1580
For comparison:
http://www.linear.com/product/LT1584
The LT1580 (0.8V @ 7A) has the same topology as the LT1584 (1.5V @ 7A)
except everything but the pass
On Sat, 18 Feb 2012 18:59:21 -0800
Eric Lemmon wb6...@verizon.net wrote:
I hooked up a linear triple-output bench supply to run the Thunderbolt, and
now the 8040C locked up perfectly on the 1 PPS signal. Since I don't want
to tie up one of my bench power supplies to run the Thunderbolt, I
On 2/27/2012 12:48 AM, Attila Kinali wrote:
If you are really time-nutty, you can let the DC/DC converters produce
a voltage about 1V above what you need and use low noise LDOs (ie not
the 78xx or LM317 Co) to produce the voltages for the thunderbolt.
This should give you a 60-80dB damping
Having designed LDO chips, people expect them to perform miracles
well beyond reality. If you have a PNP pass and you are sitting near
dropout, you get control loops that are an ugly combination of a path
to keep the PNP from getting saturated plus one to control the
voltage.
I never
Having designed LDO chips, people expect them to perform miracles
well beyond reality. If you have a PNP pass and you are sitting near
dropout, you get control loops that are an ugly combination of a path
to keep the PNP from getting saturated plus one to control the
voltage.
I never
On Mon, 27 Feb 2012 01:29:11 -0800
gary li...@lazygranch.com wrote:
On 2/27/2012 12:48 AM, Attila Kinali wrote:
If you are really time-nutty, you can let the DC/DC converters produce
a voltage about 1V above what you need and use low noise LDOs (ie not
the 78xx or LM317 Co) to produce
-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Power Supply Noise Affects Thunderbolt 1 PPS
Having designed LDO chips, people expect them to perform miracles
well beyond reality. If you have a PNP pass and you are sitting near
: time-nuts-boun...@febo.com
Date: Mon, 27 Feb 2012 11:23:22
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Power Supply Noise Affects Thunderbolt 1 PPS
On Mon
-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Power Supply Noise Affects Thunderbolt 1 PPS
Having designed LDO chips, people expect them to perform miracles
well beyond reality. If you have a PNP pass and you are sitting near
dropout, you get
...@febo.com] On
Behalf Of Attila Kinali
Sent: Monday, February 27, 2012 12:48 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Power Supply Noise Affects Thunderbolt 1 PPS
On Sat, 18 Feb 2012 18:59:21 -0800
Eric Lemmon wb6...@verizon.net wrote:
I hooked up a linear
The PNP bipolar and P-channel MOSFET architectures do provide the
best low-dropout performance, but as I understand, do not provide the
best HF line rejection. Looking at the overall circuit - a high gain,
band-limited amplifier driving a P pass device puts it in a
common-base (or -gate) mode,
Ed wrote:
So, for best HF noise performance where the input noise may be
large, it's best to use a follower or shunt regulator topology,
despite the lower efficiency - unless efficiency is more important.
To put it more bluntly, the last time I looked (it has been a while,
so there may be
Well this is the granddaddy with 3V of dropout. Not much rejection at
high frequency, but the design is old. Modern LDOs are better,
especially with P-fet pass device.
http://www.ti.com/lit/ds/symlink/lm317-n.pdf
On 2/27/2012 9:13 PM, Charles P. Steinmetz wrote:
Ed wrote:
So, for best HF
I recently acquired a Symmetricom 8040C Rubidium Standard, hoping to use one
of my Thunderbolt GPSDOs to further refine its 10 MHz output. To my
surprise, connecting the 1 PPS output to the 8040C did nothing- the 1 PPS
SYNC indicator stayed dark. I hooked up my other Thunderbolt and got the
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