SN74LVTH125: rise time and fall time

Johnny Guo

Expert 4910 points

Part Number: SN74LVTH125

Hi, team,

I have one question about SN74LVTH125 may need your help.

What is the rise time and fall time of SN74LVTH125?

Thanks.

Johnny

over 5 years ago

0 Emrys Maier over 5 years ago

TI__Guru* 96591 points

Hi Johnny,
Under what conditions?

I at least need to know the load and the supply voltage to help you.

0 Johnny Guo over 5 years ago in reply to Emrys Maier

TI__Expert 4910 points

Emrys,

The power supply is 3.3V, load is open or 50ohm. The Tr/Tf of input signal is <5ns.

Thanks.
Johnny

0 Emrys Maier over 5 years ago in reply to Johnny Guo

TI__Guru* 96591 points

Hey Johnny,
Assuming a 15pF load (open is not a valid load condition... ie you can't have zero load in the real world)

The expected rise time would be 2.5ns, and the expected fall time would be 0.7ns. This will be dependent on the actual load capacitance.... 15 pF is just an estimation for a direct connection between two CMOS devices.

I would recommend against using this device with a 50 ohm load since that will produce up to 66mA, and the device has a maximum recommended current of -32/+64mA.

0 Johnny Guo over 5 years ago in reply to Emrys Maier

TI__Expert 4910 points

Emrys,

Could you recommend a device pin-to-pin with SN74LVTH125, but with stronger driving capability? In customer's application, actual load capacitance is not very small with TVS in circuit, the Tr test result is ~10ns.

What's more, is there any buffer p2p with SN74LVTH125 that can drive 50ohm load under 3.3V power?

Thanks.

Johnny

0 Emrys Maier over 5 years ago in reply to Johnny Guo

TI__Guru* 96591 points

Hi Johnny,
There isn't a pin-to-pin device with higher drive strength available at 3.3V.

The best solution is to parallel two channels.

0 Johnny Guo over 5 years ago in reply to Emrys Maier

TI__Expert 4910 points

Thanks Emrys.

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SN74LVTH125: rise time and fall time