SN75ALS181 Signaling rate

na na78

Guru 16770 points

Other Parts Discussed in Thread: SN75ALS181, SN65HVD3083E

We can not find signaling rate of SN75ALS181 on the datasheet.

What is maximum signaling rate?

BestRegards

over 8 years ago

0 na na78 over 8 years ago

Guru 16770 points

Hi

I would appreciate if you could reply.

BestRegards

0 Clemens Ladisch over 8 years ago

Guru 316760 points

The web site say 10 Mbps.

The largest delay in the datasheet is 25 ns, which would correspond to 40 Mbps, but you could get larger delays when those test conditions (R_L = 54 Ω, C_L = 50 pF) are not true in your circuit.

0 na na78 over 8 years ago in reply to Clemens Ladisch

Guru 16770 points

Hi Clemens

Yes, the web site says 10Mbps.

We are making comparison table for sn65hvd3083e vs SN75ALS181 to offer our customer.
Actually, SN65HVD3083E's datasheet says its signaling rate is 1Mbps.

So, we are concerned if we can trust the data the web says because the signaling rate of SN75ALS181 is not on the datasheet... (Normally you should follow the datasheet, right?)

BestRegards

0 na na78 over 8 years ago in reply to na na78

Guru 16770 points

Hi

Additionally, the unit load of SN75ALS181 seems to be not described on the datasheet too.

BestRegards

0 Clemens Ladisch over 8 years ago in reply to na na78

Guru 316760 points

You can derive the signaling rate from the signaling delays, as shown above.

One unit load corresponds to a receiver impedance of 12 kΩ; 32 parallel receivers and two 120 Ω termination resistors would result in a driver load impedance of 54 Ω (see The Unit Load in RS485).

The SN75ALS181 can drive 32 unit loads (as shown in the driver characteristics), and its receiver shows up as one unit load (as shown in the receiver characteristics).

0 Ron Michallick over 8 years ago in reply to na na78

TI__Guru**** 164876 points

Clemens,

10 Mbps is the standard speed. Slower and faster devices will mention speed in the data sheet.
SN75ALS181 is 10 Mbps

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SN75ALS181 Signaling rate