Background Noise using SPAD array

[shjayago]

Heya, 

 

Is it possible to see the background light (intensity/histogram) without actually transmitting, using a VL53L8 or VL53L9?

We don't want to measure the distance to objects. We just want to be able to use the SPAD array to get histogram for each zone. 

Its a high volume use-case, so would be great if we can achieve this.

 

regards

Shjayago

[AScha.3]

Hi,

just to see the background light - why you dont use a device , that's built for this : a cheap camera/video chip ?

[John E KVAM]

An interesting question. Although I can't imagine what you would get. That histogram is created by turning on the VCSEL maybe a million times, catching a bunch of photons after every flash and building up the bin data.

I don't think the histogram would have any meaning if you just started capturing photons.

ST makes the SPAD array and we would be overjoyed to build an array for you. Initial cost is kind of high though. 

I think it's a million or two dollars for the first 5 wafers. 

So it has to be a REALLY high volume application to make it worth it. 

The thing that makes this chip work is the tight coupling of the VCSEL driver and the SPAD array. I'm afraid if you decoupled these elements, it would be extremely hard to get the timing right. 

But if that is what you really wanted to do, I expect we could find some way to disable the VCSEL.

If you think you have a good shot at an innovative product, go to the community page, click on support and find a someone in sales. They can and will get you to a marketing person who can explain how to go about the next steps. 

- john

[Saeid]

Hi John,

Where can I get the datasheet of VL53L9CX  ? I need the foot print and the communication information. 

Tnx in advance. 

[Anne BIGOT]

Hello Saied,

The VL53L9CX is not yet in mass production. It is planned beginning of Q2'2026. The datasheet will be shared at that time.
Best regards

[RogerM]

Shjayago,
The VL53L8 can output the ambient-light-level-per-zone, this is the background light level seen between VCSEL pulses. Is this what you want? There is no histogram associated with this data, it is just a single value per zone.

However, you do need to run the device in ranging mode to get this data out i.e. the VCSEL will be active between the ambient level measurements. But if all you are interested in is the ambient level data you can set the integration time, i.e. the active ranging period, to a short period to minimise the power used.

Roger