Output Impedance

Jay patel

Other Parts Discussed in Thread: TMS320C5535

Hi,

I need the value of output impedance for I2S1 transmit data output pin. I didn't get any output impedance value for TMS320C5535.

How to calculate it?

I want to interface this i2s data output pin with DAC input pin and it is recommended to put series termination resistor. For that purpose i need source output impedance value.

Thanks & Regards,

Jay Patel

over 12 years ago

0 Mark M over 12 years ago

TI__Mastermind 30140 points

Hi Jay,

Could you calculate the output impedance from VOH and IOH in the Electrical Characteristics Over Recommended Ranges of Supply Voltage and Operating Temperature section of the datasheet?

Maybe this link will help: http://www.physicsforums.com/showthread.php?t=433643

Hope this helps,
Mark

0 Jay patel over 12 years ago in reply to Mark M

Prodigy 160 points

Hi Mark,

Thanks a lot for your valuable feedback.

Calculated output impedance as per suggested way is = 2.64 V(VOH)/4 ma(IOH) = 660 ohm (165 ohm for case of VOL/IOL).

But as per DAC datasheet termination resistor value should be in the range of 20 ohm to 100 ohm. So the calculated value is far away from desire one.

Thanks & Regards,

Jay Patel

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Output Impedance