LME49810/49811

LUKA KOLONIC

Hello all,

I have checked amp designs using LME49810/49811. They've been used in NON-INVERTING amps only, never seen the INVERTING one.

So: are they not suitable for inverting amps or just no-one has tried or published it yet?

Thanx & cheers, Luka

over 10 years ago

0 Andy Liu (BMS) over 10 years ago

TI__Guru 52115 points

Hi Luka,

I will try to give you an answer soon.

Andy

0 LUKA KOLONIC over 10 years ago

Prodigy 40 points

Thank You, Andy, much oblige

Cheers, Luka

0 Andy Liu (BMS) over 10 years ago in reply to LUKA KOLONIC

TI__Guru 52115 points

Hi Luka,

I checked with my colleague. For most Audio Power amplifier applications, we recommend the Non-Inverting type amplifier.

The reasons are:

1) The input impedance of the Non-Inverting type can be set in high like few ten KΩ.

2) Small input coupling cap can be used because the input impedance is high.

3) The input impedance is high, but once signal source is connected, the source impedance is low which is good for noise performance.

In case of Inverting amplifier, here are the disadvantages.

1) The input impedance is relatively low.

2) Need high value coupling capacitor since the input resistance is low.

Andy

0 LUKA KOLONIC over 10 years ago

Prodigy 40 points

Hi Andy,

Thank You for your thorough explanation, much oblige.

One more question following it though: since the inverting input has low input impedance, does this mean that drivers LME49810/49811 and consequently LME49830 are current feedback amplifiers by its topology (like BB OPA603 op-amp)?

Thanx,

Luka

0 Andy Liu (BMS) over 10 years ago in reply to LUKA KOLONIC

TI__Guru 52115 points

Hi Luka,

LME49810 and LME49811 are both voltage feedback amplifiers.

Andy

0 LUKA KOLONIC over 10 years ago

Prodigy 40 points

Hmmm ... that's a bit odd ... if the amp is using differential pair in the input - which is normally the case with VFA - then I'd expect both in impedances to be high.
Thank you a lot for your help.
Cheers,
Luka

Audio

Audio forum

LME49810/49811