Looking for a PSPICE model of the good old LM1877

[Dr. Dagor]

Hi...
Has anyone got a PSPICE model of the LM1877. I know it's just a low
bandwidth, high output (far from ideal) op amp. But I don't trust my
own sub circuit model building skills yet.

Thanks.

 

[Jim Thompson]

On 22 Dec 2003 14:08:33 -0800, drdagor@hotmail.com (Dr. Dagor) wrote:

Hi...
Has anyone got a PSPICE model of the LM1877. I know it's just a low
bandwidth, high output (far from ideal) op amp. But I don't trust my
own sub circuit model building skills yet.

Thanks.

Download the OpAmp symbol from my website and fill in the blanks from
the data sheet.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Dr. Dagor]

Thanks Jim... I'll give it a try.

By the way... the gain of the part is given as 70db in the data sheet.
Should I leave in the default value of 100K?

Also... The power band width is given as 65KHz. (This is a cheap
audio chip.) Should that be entered as 0.065 on the GBW? I can't
read Bode plots, but the slope runs from 70db at 1khz to 10db at 1mhz
if that helps.

 

[Jim Thompson]

On 23 Dec 2003 13:43:03 -0800, drdagor@hotmail.com (Dr. Dagor) wrote:

Thanks Jim... I'll give it a try.

By the way... the gain of the part is given as 70db in the data sheet.
Should I leave in the default value of 100K?

70dB = 316K

Also... The power band width is given as 65KHz. (This is a cheap
audio chip.) Should that be entered as 0.065 on the GBW?

Slew rate S = 2*pi*f(power-band-width)*VP = 2*pi*65K*11.3 = 4.6E6(V/s)

So set S = 4.6

I can't
read Bode plots, but the slope runs from 70db at 1khz to 10db at 1mhz
if that helps.

Set GBW = 2.5 (dimensions internally are MHz)

Not enough information to set PM so leave at default of 45

(Of course twiddle VP and VN to fit your supplies.)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.