SN74LVC1G123: A device that will automatically pulse for 1 second after the board has been powered on

Danilo A.

Part Number: SN74LVC1G123
Other Parts Discussed in Thread: TLV840, LM555

Hi Team,

Our customer is looking for a device that would generate an automatic pulse of 1 second after the board has been powered on. The device will remain off after the pulse of 1 second until the board has been turned off and on again. He would like to confirm if the SN74LVC1G123 can be use for his application by adding a capacitor between pin 1 and ground in the circuit of Figure 10. If the SN74LVC1G123 doesn't fit his application, can you please suggest another device?

Regards,

Danilo

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 243870 points

This device has Schmitt-trigger inputs, so generating a delayed pulse with R+C would be possible.

But this sounds like a job for a voltage supervisor with a programmable reset delay like the TLV840‍C, which needs only a single capacitor.

0 Danilo A. over 3 years ago in reply to Clemens Ladisch

TI__Mastermind 24715 points

Hi Clemens,

Thank you for you response. The customer is also considering TLV840‍, however, the time delay is less than 1 second so I would like to suggest adding a monostable device such as LM555 or SN74LVC1G123 to increase the time delay.

Regards,

Danilo

0 Emrys Maier over 3 years ago

TI__Guru* 96591 points

Hey Danilo,

What's the ramp rate for the power-on circuit? The might be able to just use a standard power on reset circuit like the one shown here: https://training.ti.com/generate-reset-signal-system-power

0 Clemens Ladisch over 3 years ago in reply to Danilo A.

Guru 243870 points

The TLV840‍C has a programmable time delay.

0 Danilo A. over 3 years ago in reply to Clemens Ladisch

TI__Mastermind 24715 points

Hi Emrys, Clemens,

Thank you for your feedback and suggestions.

Regards,

Danilo

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SN74LVC1G123: A device that will automatically pulse for 1 second after the board has been powered on