On 20/04/15 23.44, Jim Thompson wrote: ...
or this:
Glenn
On 20/04/15 23.44, Jim Thompson wrote: ...
or this:
Glenn
Valcom still uses it in their 8" talkback ceiling speakers.
-- ,-. Give More expect less Love More \_/ argue less Listen More talk less {|||)< Don Kuenz Laugh More complain less Dream More / \ doubt less Hope More fear less `-' Breathe More whine less
I'm a big fan of Monticelli's output stage, but it relies on multiple area-matched transistors, as you get in an IC, but not so easily in a discrete circuit. It'd be cool to find a high-current op-amp with a Monticelli output stage, but this would probably not be an inexpensive part.
-- Thanks, - Win
Interesting. I'll spin it up and check stability. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
I retrieved a copy of the Monticelli paper... lots of feed-forward gimmicks required to keep it stable... but it's of sufficient interest that I will thoroughly dissect it. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
I like it for it's DC stability and predictability, and it's class AA otput characteristics. But it's still a transconductance current out, even if well controlled. So when dealing with capacitive loads it's doubly important to add the necessary internal (capacitive) feedback to drive down the open-loop output impedance, at high frequencies. The Zout plots you typically see are quite revealing.
-- Thanks, - Win
Here's the class-AB power booster (+/-100mA) design I did a few years back... it's RRIO, unity gain...
...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
How much loop gain does your power booster have (at DC), and what's its bandwidth and slew rate?
-- Thanks, - Win
That was some years ago, I'll have to revisit it. But I remember it was in an integrator loop with signal at 200kHz. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
load)...
DC Loop Gain: 40dB
Slew rate: 5V/usec
Swing: Within 150mV of each rail
Output stage (class-AB) overlap current: 4mA ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Hi,
You may be interested to try an improved LM386 spice model that is available in the free, online EasyEDA suite here:
You can copy the subcircuit by following the instructions in the schematic.
The LM386EE/NJM386EE spice subcircuit model offers improved modelling of output voltage self-centring, typical quiescent and input bias currents and unloaded bandwidth. Output swing is however still a little optimistic with < 8 Ohm load resistances but given the accurate output centring, less so that the original Dilatush model and the later LTspice implementation.
The reason for this output optimism is unclear. To help improve the model in this area, if anyone is willing to share scope traces of the LM386 output voltage driving into clipping with loads of between 4 - 16 Ohms, please contact me.
:)
[snip]
How? I can't see a way to copy the subcircuit, only ways to simulate it with easyeda. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Methinks snipped-for-privacy@gmail.com is just pimping for EasyEDA. I can find no retrievable subcircuit declaration there. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Maybe it's time to look at the modern cruftsmanlike audio amps:
There's PCBs with this chip, for sale at under $1 on eBay... and it may have other interesting uses (like making HF triangle waves for diode/capacitor multiplier HV supplies).
If you're into ebay buying there's another PAM amp delivering 1+1 watt class D, and its supplied asssembled AND delivered direct from China for 65p = $1!
NT
Hi Jim,
Since I posted to this forum, the EasyEDA website has been updated so
(i) you now have to register to run the simulation in that particular project and (ii) therefore, the instructions in the schematic are a bit misleading now.
However, if you register and then go to:
and then click on the green "Open in Editor" button on the upper right of the window, this will open the project in the EasyEDA Editor window.
(The button is actually this link:
If you then click on the tab labelled "Demonstrating the EasyEDA LM386 spice subckt model" you will be able to run the example.
Alternatively, here is a link to the file which you can run in "Anonymous mode" for which you do not need to register:
Just do Ctrl+R to run it.
Either way, tThe instructions in that example explain quite clearly two ways to download the netlist:
"To view the netlist (including the LM386EE subckt), do: Green Man > Simulation Results... > Download netlist or: Super Menu > Miscellaneous > Netlist for Document > Spice..."
However for the avoidance of doubt - and despite your rather ungracious comment - here is a simple copy of the netlist:
********************************************** **********************************************:)
Andy
My followup's probably too late for the OP. That said, my current project uses a LM386. Allow me to followup for posterity's sake.
Dr. Wickert at UCCS generously makes the requisite LM386 LTSpice symbol (.asy) and subcircuit data (.lib) files available to the public. Wickert's .lib file seems almost identical to Jim's. You can download Wickert's LM386 archive in zipped format at:
The zipped archive contains the following files:
lm386.asy Symbol file. Just drop it into your project folder to use it.
LM386.lib Subcircuit data file. Just drop it into your project folder.
lm386.pdf Datasheet.
headphone_amp.asc A sample LTSpice circuit that uses the LM386.
Thank you,
-- Don Kuenz KB7RPU
Things like power supply decoupling subtleties are unlikely to be modeled accurately.
-- John Larkin Highland Technology, Inc lunatic fringe electronics
thanks, it may prove useful in future.
NT
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