DS10BR254: Maximum Capacitance Load

Mark Philip Felipe

Genius 10820 points

Part Number: DS10BR254
Other Parts Discussed in Thread: DS25BR440

Hi Team,

For DS10BR254 and DS25BR440, what is the maximum capacitance load?

Thank you.

-Mark

over 2 years ago

0 Nasser Mohammadi over 2 years ago

TI__Guru* 93670 points

Hi Mark,

Input and output capacitance are 1.7pf and 1.2pf respectively. However, these are typical values so please add 25/30% to accommodate part to part variation.

Regards,Nasser

0 Mark Philip Felipe over 2 years ago in reply to Nasser Mohammadi

TI__Genius 10820 points

Hi Nasser, Thank you for supporting.

Some follow-up questions,

1. The capacitance values given are for the input and output capacitances of the device itself. Does this mean that the DS25BR440 or DS10BR254 devices are characterized with no loading on the outputs? If that is the case, how does output loading affect the datasheet parameters?
2. The datasheets indicate that the devices are designed to drive balanced copper cabling. How do I determine the maximum length of cable that can be driven?
3. Do either of the devices have a minimum operating frequency? My input signal will be around 40MHz.

0 Nasser Mohammadi over 2 years ago in reply to Mark Philip Felipe

TI__Guru* 93670 points

Hi Mark,

1). In production, devices are tested using DC and AC test circuit as shown in the data sheet.

2). These are LVDS buffers. IBIS file along with s-parameter of your cable or media can be used to some level of signal integrity. Alternatively you can build a test board using this part with your media or cable and allow some margin.

3). You can use these parts from DC.

Regards,Nasser

0 Mark Philip Felipe over 2 years ago in reply to Nasser Mohammadi

TI__Genius 10820 points

Hi Nasser,

Is there any data on the maximum length cable that it can drive at 40MHz?

0 Nasser Mohammadi over 2 years ago in reply to Mark Philip Felipe

TI__Guru* 93670 points

Hi Mark,

At 40MHz, there is not as much loss but it all depends on the cable type or loss profile. However, this data is not available.

Regards,Nasser

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DS10BR254: Maximum Capacitance Load