AD8646: new high current opamp suitable for cmoys?
Feb 28, 2008 at 8:13 AM Thread Starter Post #1 of 1

balou

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hi,
I got a mail from Analog Devices a few days back, about a new opamp (among other things). And the new AD8646 looks quite interesting.

Here's the sales pitch:
Quote:

AD8646 24 MHZ RAIL-TO-RAIL DUAL AMPLIFIER

The AD8646 and the AD8647 are the dual, and the AD8648 is the quad,
rail-to-rail, input and output, single-supply amplifiers featuring
low offset voltage, wide signal bandwidth, low input voltage, and
low current noise. The AD8647 also has a low power
shutdown function.

The combination of 24 MHz bandwidth, low offset, low noise, and very
low input bias current makes these amplifiers useful in a wide
variety of applications. Filters, integrators, photodiode
amplifiers, and high impedance sensors all benefit from the
combination of performance features. AC applications benefit from
the wide bandwidth and low distortion. TheAD8646/ AD8647/AD8648
offer high output drive capability, which is excellent for audio
line drivers and other low impedance applications.


so basically: a rail-to-rail JFET opamp, bandwidth a little higher and slew rate a little lower than an OPA2132, 1/50 of the input bias current, but an output current of 120mA. And operating voltage from 2.7 to 5.5v.
4xAA unbuffered Cmoy?
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It should be more stable than the cranky AD8397, and idle current is a lot lower at 2mA compared to 15mA. Basically, a high-current low-voltage dropin replacement for other commonly used cmoy opamps. I'll try to get a few of them and try out how they sound.

P.S.: this opamp might be suitable for an ipod-powered amplifier. A very small ipod powered amp
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