Buffer and PWM output

Julien Djn

Other Parts Discussed in Thread: 74AC16244, SN74AHC16244

Hello,

I look for a buffer to insert between a PWM output (DSP F28335 GPIO configured as ePWM output ; switching frequency : 50kHz) and a RC-filter.

My aim is to filter the PWM output to be able to display the value on an oscilloscope (some kind of digital-to-analog converter).

I worked before with the 74HC241, which works well but has only 8 inputs.

My need is 16 bits : I found the 74AC16244 that seems to match.

Could you please confirm if I can use this component instead of the 74HC241 ? Is it ok considering the problematic of rising/falling edges time, etc ... ?

Thank you,

Best regards,

Julien

over 8 years ago

0 ShreyasRao over 8 years ago

TI__Guru 57640 points

Hi Julien ,

I would suggest you to also consider SN74AHC16244. The 74AC16244 has requirement of 10ns/V which may be restrictive. The HC devices are little more tolerant to slower signals.
www.ti.com/.../sdya009c.pdf
The designing with logic guide shows the input transition rate w.r.t HC devices in terms of ns/V .

0 Julien Djn over 8 years ago in reply to ShreyasRao

Intellectual 840 points

Hi Shreyas,

Great, thank you for your help.

In case I would need it, can I increase my switching frequency up to 100kHz with the SN74AHC16244 ?

Best regards,

Julien

0 ShreyasRao over 8 years ago in reply to Julien Djn

TI__Guru 57640 points

Julien ,

It can support frequency of up to 110Mhz on the output , so 100 KHz is not a problem.
Just to note that the dynamic current increases with the switching frequency.

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Buffer and PWM output