High Speed One-Short/Monoastable Multivibrator

[rahulksgift]

Hi all,

Im Looking for a ultra-speed Monostable Multivibrator which can produce 2-5 Ns output Pulse width(Tw)..

Can Any one suggest me any such part which can produce this ...

Thanks
Rah

 

[barry]

You probably need to use an ECL or PECL device. I'm not sure there is a one-chip solution, but you might be able create a circuit with a flip-flop and a delay line.

 

[rahulksgift]

Thank You very much for replying....But ECL is power hungry device right?? Im Looking for a Low power Solution.

 

[barry]

Thank You very much for replying....But ECL is power hungry device right?? Im Looking for a Low power Solution.

Well, you're up against those engineering tradeoffs. Higher speed means higher power. In order to charge and discharge the capacitances in your circuit (parasitic and otherwise) requires current. i=C (dV/dT), you can't get around that.

 

[rahulksgift]

Well, you're up against those engineering tradeoffs. Higher speed means higher power. In order to charge and discharge the capacitances in your circuit (parasitic and otherwise) requires current. i=C (dV/dT), you can't get around that.

Thanks.. I found one NXP part **broken link removed** but im not able to understand what will be the minimum pulse width we can generate with this by using Minimum CX RX value....

 

[D.A.(Tony)Stewart]

NXP won't be fast enough.. Pulse Width min =10nS typ @15V from spec.

There are two general uses of one shots.

1. Pulse stretchers
2. Edge detectors.

Since you indicated the spec is "2-5 Ns" (2~5 nsec),
my guess is you want the 2nd category.

Edge detectors can be made in many ways but you must realize when you are generating nsec pulse widths, you need controlled impedance driver , controlled impedance delay line and controlled impedance output.. ECL is one such solution (50Ω)

Can you please define your Driver source and load for this pulse?

 

[rahulksgift]

NXP won't be fast enough.. Pulse Width min =10nS typ @15V from spec.

There are two general uses of one shots.

1. Pulse stretchers
2. Edge detectors.

Since you indicated the spec is "2-5 Ns" (2~5 nsec),
my guess is you want the 2nd category.

Edge detectors can be made in many ways but you must realize when you are generating nsec pulse widths, you need controlled impedance driver , controlled impedance delay line and controlled impedance output.. ECL is one such solution (50Ω)

Can you please define your Driver source and load for this pulse?

Thanks, My intention is to generate variable 2 to 10 ns pulses (By digitally controlling Rx or Cx) with One shot. And the Input for the One short is 10-20 Mhz Pulses. If am able to get 2-5 nS Pulses i can add digital control Rx and vary pulse duration. Since it is battery operated Device I cannot implement any ECL circuits also..
Regards.
Rah..

 

[D.A.(Tony)Stewart]

Without a controlled impedance value and a voltage threshold, you cannot design a microwave one shot that is voltage controlled. Especially since you have no power budget, no assumptions can be made.. Pls define all parameters of input control and output load.

 

[D.A.(Tony)Stewart]

Generally delay lines cannot be digitally controlled continuously variable at microwave speeds. like a PM modulated carrier or VCO phase control or pulse controlled one shot. But you can use fixed delay lines and choose T1, T2 T3 delay. It depends on what you are trying to accomplish in hardware vs what is normally done by DSP. At lower freq. a variable delay line can be made using a voltage controlled varicap or even using an LS123 oneshot to use the R in the RC external circuit as a voltage controlled one shot. Just some ideas for you. No answers.

 

[rahulksgift]

im interested in oneshot to use the R in the RC external circuit as a voltage controlled one shot...Further i need to explore on that...
Thank you very much for your help and suggestions..
Regards,
rah!!