ADC12J4000 DIFFERENTIAL INPUT

Michael Robertson52

Other Parts Discussed in Thread: ADC12J4000

I read in the user manual that the ADC12J4000 has DIFFERENTIAL INPUT via board modification, just wondering how to perform the mod?

over 8 years ago

0 Rajesh over 8 years ago

Expert 1010 points

Hi,

I was unable to trace the exact ckt, but it will help u: refer the datasheet page number: 84 & 85 images
www.ti.com/.../adc12j4000.pdf
Figure 100. ADC12J4000 Layout Example 1 — Top Side
Figure 101. ADC12J4000 Layout Example 2 — Bottom Side

Some note provided on the above two images about the single ended & differential input configurations

Regards,
Rajesh

0 Rajesh over 8 years ago in reply to Rajesh

Expert 1010 points

0 Michael Robertson52 over 8 years ago in reply to Rajesh

Prodigy 180 points

What value capacitors do I use?

0 Rajesh over 8 years ago in reply to Michael Robertson52

Expert 1010 points

I was unable to find the exact capacitor value in the data sheet, but the above snap is found in the datasheet.

Any TI person can comment on the exact value.

Regards,

Rajesh

0 Neeraj Gill over 8 years ago in reply to Rajesh

TI__Mastermind 20541 points

Hi Rajesh,

Here are instruction to go from single-ended to differential input on ADC12J4000

1. S/E input, AC-coupled:

a. Default populate option

b. Balun is {400MHz, 3GHz}

2. Differential DC-coupled:

a. Remove C3, C5.

b. Populate C1 = C6 = 0 ohm.

3. Differential AC-coupled:

a. Remove C3, C5.

b. Populate C1 = C6 = 100 pF.

This information is also available on the first page of schematic for adc12j4000 evm which can be downloaded from TI website(it is under adc12jxx00 design package folder).

I have also attached the snapshot below.

Here is the link

Regards,

Neeraj Gill

Data converters

Data converters forum

ADC12J4000 DIFFERENTIAL INPUT