Author Topic: Whats The Purpose of MAX3949 Laser Driver? Confusion...  (Read 1561 times)

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Offline MechatrommerTopic starter

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Whats The Purpose of MAX3949 Laser Driver? Confusion...
« on: March 18, 2019, 01:30:30 am »
i know from the datasheet, it drives laser diode at 11Gbps. what i dont get is... TIN+ and TIN- (pin14,15) should be feed with equally fast 11Gbps input signal as well? from FPGA maybe with equally high speed RAM to store the data to be sent? i was expecting a chip that we can feed in a slow datarate data from i2c pin and be stored in ic RAM for a moment, hit a trigger (register or a pin toggle) and the chip bursts out 11Gbps, isnt that a MAX3949 capable of doing? i dont see built in memory ??? confused...
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline KaneTW

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Re: Whats The Purpose of MAX3949 Laser Driver? Confusion...
« Reply #1 on: March 18, 2019, 01:48:00 am »
No memory, you need 1 - 11GBps input.
 
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Offline MechatrommerTopic starter

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Re: Whats The Purpose of MAX3949 Laser Driver? Confusion...
« Reply #2 on: March 18, 2019, 02:00:13 am »
thanks, so what will happen if i feed it with 1Kbps input? it wont output 1Kbps i think, but a pulse or what? how did leo bodnar drive it from nothing to create a pulse? or some data stream?
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Offline amyk

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Re: Whats The Purpose of MAX3949 Laser Driver? Confusion...
« Reply #3 on: March 18, 2019, 02:32:42 am »
I believe iI's capactively coupled, so too low of a frequency won't result in much signal out.

What application are you thinking of? This is a very specialised IC used for optical fiber communications.
 
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Offline ejeffrey

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Re: Whats The Purpose of MAX3949 Laser Driver? Confusion...
« Reply #4 on: March 18, 2019, 02:34:32 am »
That chip is basically an "amplifier".  It won't output anything different than what you put in.  All the application circuits show AC coupling on the input and output.  I don't know what happens if you try to DC couple it and operate at 1 khz.  It may have some slow bias current loop for the laser diode that will cause problems if you drive it at low speed or maybe it will just work fine subject to the usual caveats about driving high speed logic.  If your 1 khz singnal doesn't have very fast rise time you will likely get multiple triggers.

An fpga is the way to do what you want.
 
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Offline KaneTW

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Re: Whats The Purpose of MAX3949 Laser Driver? Confusion...
« Reply #5 on: March 18, 2019, 02:47:42 am »
Leo uses a comparator (https://www.analog.com/en/products/adcmp572.html) with ultrafast rise times.
 
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Offline MechatrommerTopic starter

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Re: Whats The Purpose of MAX3949 Laser Driver? Confusion...
« Reply #6 on: March 18, 2019, 03:26:22 am »
What application are you thinking of? This is a very specialised IC used for optical fiber communications.
i just want to explore and understand. the possibility of say, as a square wave (or bits) generator, or simply fast rise time step/pulse generator as leo bodnar did.

Leo uses a comparator (https://www.analog.com/en/products/adcmp572.html) with ultrafast rise times.
yes thats earlier version. later version he uses this MAX3949 laser driver. thats why i have the datasheet ;)

Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 


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