LMX2594: Grounding Scheme for Two LMX2594 Device in single card

Nilesh Makwana

Part Number: LMX2594
Other Parts Discussed in Thread: TPS7A4501M

Hi,

Pl. advice about grounding scheme for LMX2594 if we are using two such LMX2594 in single card along with TCXO and TPS7A4501M to avoid coupling of outputs and interference.

over 2 years ago

0 Noel Fung over 2 years ago

TI__Guru** 120630 points

Hi There,

I think you need individual shielding rather than separated ground.

0 Nilesh Makwana over 2 years ago in reply to Noel Fung

Prodigy 60 points

Individual shielding means in different mechanical cavity? if it is not possible to provide individual cavity than?

0 Nilesh Makwana over 2 years ago in reply to Noel Fung

Prodigy 60 points

Hi, Apart from above mentioned query, LMX2594 Data sheet suggest (page number 65) if not used, RampClk, RampDir and SysRefReq can be grounded on the DAP.

Question : Grounding is required directly or using 1 KOhm register. ?

We are also not using Sync pin. so can we ground it with DAP?

0 Nilesh Makwana over 2 years ago in reply to Noel Fung

Prodigy 60 points

Hi,

Hi, Apart from above mentioned query, LMX2594 Data sheet suggest (page number 65) Hows the thermal vias is different from normal vias.

0 Nilesh Makwana over 2 years ago in reply to Noel Fung

Prodigy 60 points

what is the difference between VCO ground and normal ground for LMX2594. For example Pin 36 and Pin 37. (page number 7 of data sheet)

0 Noel Fung over 2 years ago in reply to Nilesh Makwana

TI__Guru** 120630 points

Hi There,

The used pins can be short to ground directly or via a small resistor.

Datasheet Page 75 has the recommended land pattern.

The name of the GND pin tells which building block is using it, we need to connect these GND together externally. I don't see a real benefit to separate these GND.

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LMX2594: Grounding Scheme for Two LMX2594 Device in single card