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[FAQ] TLV3604: When to use a comparator in a Time-of Flight system such as LiDAR

Part Number: TLV3604

I am trying to implement a cost-effective design circuit for a Time-of Flight distance measurement. I noticed that ADC's are commonly used in these types of designs. I would like to know when to use a comparator in a Time-of-Flight system. My design only requires distance as an output.

  • ADC’s are best for complex measurements while comparators are used to calculate simple measurements. Since distance is the focus of this design, we recommend using a high-speed comparator. A great comparator option for ToF systems is Texas Instruments’ newest high-speed comparator with LVDS outputs. The TLV3604 has just 800 ps of propagation delay and a high toggle frequency of 1.5 GHz (3.0 Gbps). It’s narrow pulse width detection capabilities of 600 ps, and input overdrive dispersion of just 450ps make it a great option as a receiver in optical ToF systems. The device has favorable specs compared to similar comparators in the same package and pinout options, and can be easily used as a drop-in replacement for ToF systems already using comparators in their receiver path.

    To summarize, a good rule of thumb is if you don’t need any measurements other than distance, it is highly advisable in this case to go with a comparator solution as part of the receiver in the ToF system. When compared to an ADC, it is easier to integrate and also allows larger distances to be accurately measured at significantly less cost.

    Please explore this app note for further explanation: