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ADS1209: What are major diffferent points between ADS1209 and ADS1205?

Part Number: ADS1209
Other Parts Discussed in Thread: ADS1205

 Hello guys,

 One of my customers is considering using ADS1209 for their next products.

 But they are interesting in ADS1205 too.

 They have a question as the below.

 Could you please give me your reply?

 Q. What are major diffferent points between ADS1209 and ADS1205?

     I think the points are the below.

     If you know any other major different point, please let me know?

    

          ADS1209     ADS1205

Analog Input         -0.92*VREF~           -0.8*VREF~

Range(V)              +0.92*VREF             +0.8*VREF

INL(LSB, Max)      -8~+8                      -3~+3                            

                            (Vin=2.3Vpp)           (Vin=2.0Vpp)

Linearity(bit)        13                             14

Ambient                 -40~105                  -40~85

Temperature

Ta(degree C)

Package              TSSOP-24pin           VQFN-24pin

Power                   100                           80            

Dissipation

(mW, Max, CLKSEL=1)

 

 Your reply would be much appreciated.

 Best regards,

 Kazuya.

  • Hi Kazuya,

    Besides the points you already mentioned, the ADS1205 has 2x the bandwidth.  Otherwise, they are very similar.

  •  Hi Tom,

     Thank you very much for your reply.

     Could I ask you a few additional questions as the follow?

     Q. As you said, I can see "Effective resolution of 14 bits can be obtained with a digital filter bandwidth

         of 40kHz at a modulator rate of 10MHz." in DESCRIPTION section of ADS1205 datasheet.

         Also I can see "Effective accuracy of 14 bits can be obtained with a digital filter bandwidth

         of 20kHz at a modulator rate of 10MHz." in DESCRIPTION section of ADS1209 datasheet.

         But I can't see any other description about this bandwidth difference on other pages.

         Is there any description about the bandwidth on other pages? 

         Also, Is there any different parameter of electrical characteristics

         between 40kHz digital filter bandwidth and 20kHz one?

     Could you please give me your reply?

     Thank you again and best regards,

     Kazuya.

  • Hi Kazuya,

    I am beginning to think the 20kHz bandwidth statement in the ADS1209 datasheet is a typo.  These older modulators included an internal modulator clock divider which I assumed was the reason for the difference in the two datasheet descriptions.  All of the electrical characteristics in both datasheets show (see conditions at the top of the page) a 20MHz CLKIN, Sinc3 filter and OSR of 256.  The 20MHz CLKIN gets divided by 2 for a 10MHz modulator clock. 

    The bandwidth is the modulator clock divided by the OSR, so 10MHz/256 = 39.062 kHz should be the bandwidth for both the ADS1205 and ADS1209. So, the main difference is in the linear input range - +/-92% Vref versus +/- 80%.