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Searcking for an IC with fast rise time low frequency

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lerameur

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Hello,

I am looking for an IC that can oscillate between (5 to 20hz) with a 1ns rise time, so square wave. It can me schmitt trigger , opamp etc.. does not really matter. 5v output
thanks in advance

Ken
 

Hi,

Missing supply voltage specification.
Missing load specification. Mind: each pF of load (stray) capacitance needs 5mA of drive current (@5V/ns).

Btw: Analog circuits (like Opamps) may be slower than digital circuits.

Klaus
 

Try 74AHC or similar. Separate oscillator and output stage, use multiple parallel output gates for better output drive. Single gate devices are preferred due to lower power supply inductance.
 

KlausST said:
Hi,

Missing supply voltage specification.
Missing load specification. Mind: each pF of load (stray) capacitance needs 5mA of drive current (@5V/ns).

Btw: Analog circuits (like Opamps) may be slower than digital circuits.

Klaus
Click to expand...

I am not sure about the load capacitive value, NOt important for now, I can increase the current if I need to. I was thinking about an opamp oscollator (multivibrator), and add a schmitt trigger on its output to increase rise time.

ken
 

Might get a "clock in a can" oscillator (fixed or VCO) with
an HCMOS output, and use the fastest AC series gate
you can find to sharpen up the drive edges. With good
layout and maybe HC drives 2 AC, 2AC drives 4AC inverters
of the hex, you should approach nS risetimes at reasonable
load. But what -is- your load? That's the other 75% of it.
 

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