Multi Range ADC with PGA !!!

[ranaya]

hi every1...

I'm luking for a multi range (-/+ 10 V) ADC (12 bit or higher) unit with internal PGA ! my objective is to implement a data acquisition system, supports wide range analog signals, with a programmable gain to minimize the board space. I searched over the web,but most of the ADCs with an internal PGA only support -/+ 5 analog input voltage range. All multi range (-/+ 10 V) ADCs dont have PGAs but provide higher ADC resolution.

Is there any alternative to achieve this problem ? (without using additional I/O s of the processor)

Thanx

 

[FoxyRick]

You don't mention some parameters, like SE/differential, conversion rate, budget, etc.

Maxim do a lot of interesting ADC's. Like the MAX1300/MAX1301 which has a PGA, +/- 12V input range, multi-channel input multiplexor, serial interface.

**broken link removed**

Another option is to find an ADC with an i2c interface, and a PGA with an i2c interface. i2c uses addresses on the chips (usually selectable by a couple of pins to ground or Vcc) so your processor can just send the address on the serial lines - no additional i/o's needed.

 

[ranaya]

You don't mention some parameters, like SE/differential, conversion rate, budget, etc.

Maxim do a lot of interesting ADC's. Like the MAX1300/MAX1301 which has a PGA, +/- 12V input range, multi-channel input multiplexor, serial interface.

**broken link removed**

Another option is to find an ADC with an i2c interface, and a PGA with an i2c interface. i2c uses addresses on the chips (usually selectable by a couple of pins to ground or Vcc) so your processor can just send the address on the serial lines - no additional i/o's needed.

Dude... now here, PGA does not give a gain like 1x, 2x or 64x. when i connect a mV value range to the analog input, since no gain provided does it measure accurately ??

 

[FoxyRick]

Another part missing from your specifications then - minimum required full scale range.

The PGA in that part gives 1,2,4 ranges. I'm aware of other parts with more flexible PGA's, but not that meet your other requirements. You are looking for a 'one chip does it all' solution.

If you find one, that's affordable, please let me know because I don't know of one.

One of my main areas of interest is designing high precision and accuracy instrumentation and such a chip, if it had good specifications would be very interesting.

I really think you are going to have to use multiple chips to achieve your full list of requirements.

 

[ranaya]

Thanx @FoxyRick for ur quick reply ! As u said im gonna use separate ADC with a PGA, or it's better to use dedicated analog input so i can amplify mV range inputs of it ! Thnx again