SN75LVCP600: signal polarity and the place of this device

Noriyuki Takahashi

Genius 9630 points

Part Number: SN75LVCP600

Hi team,

I have two questions.

1. SATA signal polarity should be matched with SN75LVCP600 Rx/Tx polarity?

e.g.

SATA + is connected to RX+

SATA - is connected to RX-

2. The datasheet mentions that the device should be placed within 6mil to RX.

If the distance is closer than 6mil, is this more helpful for the equalize function? or almost same performance even if the distance become closer than 6mil?

BTW, the unit of <6 " of figure 9 in the datasheet is mil, right?

Regards,

Noriyuki Takahash

over 4 years ago

0 Brian Zhou over 4 years ago

TI__Guru** 111740 points

1: yes.

2: if closer than 6mils, you can lower EQ setting.

3: you are right.

0 Noriyuki Takahashi over 4 years ago in reply to Brian Zhou

TI__Genius 9630 points

Brian,

2. Do you mean that placing the device to SATA Host/Sink closer than 6mil is recommended?

Just wondering whether the device should be placed as close to SATA Host/Sink as possible.

Regards,

Noriyuki Takahashi

0 Lee Sledjeski over 4 years ago in reply to Noriyuki Takahashi

TI__Mastermind 43795 points

Hi,

The units in Figure 9 are inches. The figure is showing that the LVCP600 outputs should be 6 inches or closer to the SATA Rx inputs.

Regards,

Lee

0 Noriyuki Takahashi over 4 years ago in reply to Lee Sledjeski

TI__Genius 9630 points

Please let me confirm about Q2 again.

2. The datasheet mentions that the device should be placed within 6inch to RX.

If the distance is closer than 6inch, is this more helpful for the equalize function? or almost same performance even if the distance become closer than 6mil?

Brian mentions that if closer than 6inch, you can lower EQ setting. What does mean in terms of system level?

Lowering EQ setting is better for system and why?

Regards,

Noriyuki Takahashi

0 Lee Sledjeski over 4 years ago in reply to Noriyuki Takahashi

TI__Mastermind 43795 points

Hi,

With a shorter distance to the SN75LVCP600 Rx there will be a lower amount of attenuation of the incoming signal. With lower attenuation the device equalization should also be decreased to optimize the SN75LVCP output waveform. If the signal is over-equalized, the SN75LVCP600 will start to add deterministic jitter to the signal at its output reducing the eye opening.

There is a short blog on this topic here.

https://e2e.ti.com/blogs_/b/analogwire/archive/2016/06/13/eye-doctor-why-too-much-equalization-boost-is-bad-for-your-link-health-part-1

Regards,

Lee

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SN75LVCP600: signal polarity and the place of this device