OPA693: 1:8 Analog Fanout Driver:

DeWei Lan

Prodigy 250 points

Part Number: OPA693
Other Parts Discussed in Thread: OPA692, OPA3692, , OPA3693

I'd like to make a circuit with fanout analog signal 1:8.

First page of OPA692 shows circuit correspond our requirement, just adopt 2*OPA692

Lately, I found OPA3692 has 3 channel, maybe I could implement like:

But I have a 2 problems:

(1)

The output current for both the OPA3692 (3ch) and OPA692 (1ch) in the datasheet is 190mA.

OPA692 use 190mA, no problem.

Is OPA3692 190mA per channel or 190mA/4 per channel?

(2)

I also discover OPA693 which has similar configuration, but it only drive 2 channel(datasheet)

and max output of OPA693 is 120mA, which is about half of OPA692.

So I guess to drive "sufficient" current, it should be 50mA per output channel.

(50 ohm terminated and RG316 cable)

Right?

over 2 years ago

0 kai klaas69 over 2 years ago

Guru 140200 points

Hi Dewei,

has this thread here to do with this one?

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1114448/lmh6722-layout-suggestion-for-fanout-input-opa-v

Kai

0 DeWei Lan over 2 years ago in reply to kai klaas69

Prodigy 250 points

Hi @kai klaas69:

Yes, this is derived from the thread https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1114448/lmh6722-layout-suggestion-for-fanout-input-opa-v

I think those subject are difference, so I create the new thread as here.

0 Sima Jalaleddine over 2 years ago

TI__Mastermind 25505 points

Hello Dewei,

1) That is a good observation. I believe it is per channel as suggested by the first figure on page 8 of the OPA3693 datasheet. I will look into this, and get back to you.

2) This thread contains more information: https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/444012/high-speed-video-amp-video-splitter

OPA692 should be used instead of the OPA693 if driving more than two lines. It depends on the power output on each line, but if symmetrical then that is correct. The middle two figures on page 10 of the OPA693 datasheet.

Thank you,
Sima

0 DeWei Lan over 2 years ago in reply to Sima Jalaleddine

Prodigy 250 points

Hi @SimaJalaleddine:

Many thanks your reply.

(1)

I go to read this page:

but I don't find information about these thing(current) from those chart.

Could you hint me where I am lost?

(2)

What's "symmetrical" you mean?

Is same output configure drive?

Such as this picture:

Fanout to 4 channels which is same signals.

+1 Sima Jalaleddine over 2 years ago in reply to DeWei Lan

TI__Mastermind 25505 points

Hello DeWei,

Sorry, I meant to say OPA3692's datasheet:

The spec is for each channel: (Dual Supply)

It decreases slightly for single supply config.

Similarly, for the OPA3693: page 10, Figure 21.

2) As in if each path has the same impedance, which is true for the figure you have shown. The total output current/power for each line/channel should follow the spec.

Thank you,

Sima

Amplifiers

Amplifiers forum

OPA693: 1:8 Analog Fanout Driver: