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Old 2nd August 2007, 03:18 PM   #1
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Default New Op Amps from NS

Two new op amp families for high-end audio applications from National Semiconductor set new standards for performance. The ±17 V/34 V LME497xx (single, dual, and quad versions available) family and the ±22 V/44 V LME49860 dual device offer extremely low distortion, low noise, high speed, and high output drive. High-performance devices are needed in audio systems, where the serial string of amplifiers in a signal path will contribute cumulative deficiencies, usually analyzed via worst-case or root-sum-square error budgets.


In addition to the 0.00003% THD+N (total harmonic distortion plus noise) specification , the op amps come with voltage noise of just 2.7 nV/root-Hz and current noise of 1.2 pA/root-Hz at 1 kHz. Input bias current is also low, at 10 nA. Output current is up to 26 mA (44 V devices) and 45 mA (34 V devices), and the amplifiers can handle 600 Ů loads. Gain bandwidth product of 55 MHz, 1/f noise corner at 60 Hz, and slew rate of 20 V/ěsec round out the key specifications. PSRR and CMRR are 120 dB.
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Old 2nd August 2007, 05:26 PM   #2
DcibeL is offline DcibeL  Canada
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LME497x is the LM456x.
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Old 23rd July 2008, 03:00 AM   #3
lineup is offline lineup  Sweden
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LME49860 as mentioned in first post is a real killer!
The absolute max Supply Voltage is 2 x 23 Volt. Recommended is max 2 x 22 Volt.

Very good data for audio.
==========================================
Input bias current: 10 nA (max 72 nA)
Input noise: 2.7 nV/Hz
Slewrate: 20 V/uS
GainBW: 55 MHz
PSRR & CMRR: better than 120 dB

Data at +- 22 Volt.
==========================================
Maximum input Voltage: +21.0 / -20.8
Maximum output Voltage: +21.0 / -21.0 (into 2 kOhm)
Maximum output Current: 30 mA (minimum into 600 Ohm)
==========================================

I prefer to use SINGLE Op-Amps. The single version is LME49870
Product pages with Datasheets:
http://www.national.com/pf/LM/LME49860.html
http://www.national.com/pf/LM/LME49870.html

PS.
I downloaded the spice model for LME49860 (same for LME49870)
I ran some circuit tests.
The results corresponds rather well with figures found in datasheets.
Like maximum Output Current/Voltage and Gain BandWidth
So, I would say, it is a useful spice model.

LME49860 Spice ZIP-file
http://www.national.com/models/spice/audio/LME49860.zip


Regards, Lineup
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Old 28th July 2008, 04:25 AM   #4
lineup is offline lineup  Sweden
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Default Re: New Op Amps from NS

Quote:
Originally posted by trunkmonkey
Two new op amp families for high-end audio applications from National Semiconductor set new standards for performance. The ±17 V/34 V LME497xx (single, dual, and quad versions available) family and the ±22 V/44 V LME49860 dual device offer extremely low distortion, low noise, high speed, and high output drive.
trunkmonkey
So, how would you say LME49870 compares to e.g. AD797?
What I can see it is better on a number of data figures.
Maybe better retire the AD797 as top of the line Op-Amp for audio.
It has had its best day.

Now things envolve.
Evolution takes place.
Quote:
.. for the times
they are a'changin'
you better start swimming .. or you'll sink like a stone
.. for the times
they are a'changin'


(Bob Dylan USA 196x)
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Old 11th August 2013, 01:10 AM   #5
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Well, the AD797 still outdoes the LM49870 in terms of equivalent input noise, by nearly 3 to 1. So AD797's is still king in high circuits!
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