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FPGA vs ASIC, What to Choose?

January 30, 2016, anysilicon

This is a high level article for those who are debating whether to use FPGAs or ASICs and need some technical and commercial insight to help ease the decision process. Both technologies, ASICs and FPGAs are absolutely fantastic and have great benefits but it’s up to you to figure out, based on your product which technology to use. In some cases there is a clear advantage to FPGAs and in other cases ASICs are in advantage.

 

In this article you find the main differences and comparisons in between the two technologies: FPGA vs ASIC. If you are still unsure about which path to choose, please contact our staff here.

 

FPGAs

 

FPGAs (Field Programmable Gate Arrays) are chips created originally in 1985 to perform only digital functions but today they have already both analog and mixed signal blocks. Customers like to use FPGA because they are easy to use, and cost effective reprogrammable devices.  FPGA are known for their flexibility and their ability to be reprogrammed in the field. There is no need to have a full blown design flow and tooling, therefore the NRE investment is very low and as consequence time to market is fast.

 

The problem is that FPGAs are not fully customable, for example, one cannot add a specific analog block or integrate RF capability into an FPGA, those functionalities need to be implemented by external ICs, thus making the product larger in size and more costly.

 

ASICs

 

ASICs (Application Specific Integrated Circuits) are specific chips (as the name suggest) used to implement both analog and digital functionalities in high volume or high performance. ASICs are full custom therefore they require higher development costs in order to design and implement (NRE). Moreover, unlike the FPGAs chips, they are not reprogrammable and therefore a change requires again NRE payment.

 

On the other side, however, ASICS are much denser, and one can integrate several different functionalities into one chip and therefore offer small size, low power and low cost solution.

 

FPGA vs ASIC small

(get here a higher resolution image)

 

FPGA vs ASIC Frequently Asked Questions

 

Question:

 

I need a chip with flexibility to accommodate future updates, should I use an FPGA?

 

Answer:

 

If you mean future hardware changes (compared to software updates), then an FPGA would be the best solution because an FPGA can be updated with new hardware functionality. ASIC’s hardware is constant and not suited for future updates. Today, there are ASIC IP cores that offer FPGA functionality that can be embedded into the ASIC, allowing parts of the ASIC to be programmable.

 

Question:

 

My initial budget is low, and I expect low volume production, should I use an FPGA?

 

Answer:

 

Absolutely. FPGA does not require costly EDA tools or any production tooling (such as maskset). If your production volume is low, then FPGA would be an ideal solution. ASIC will start showing a financial benefit in mid-size and high volume production runs and has higher upfront cost and steep learning curve.

 

Question:

 

My design is power sensitive, which technology to choose, ASIC or FPGA?

 

Answer:

 

It’s most likely that ASIC would be the best solution in case you need to design your circuit to use less power. FPGA does not provide a lot of room for power optimization, while a custom-made ASIC can be definitely designed to consume very low power. In addition to that, there are power management method used in ASIC to allow further power optimization such as power gating and clock gating.

 

Question:

 

My design needs to run at extremely high speed, would ASIC be the best solution?

 

Answer:

 

Yes, an optimized design running on an ASIC would run faster than a general-purpose FPGA.

 

Question:

 

Our design has at least 50% analog circuitry, which technology would be the best match?

 

Answer:

 

If the analog circuitry does not exist as part of the FPGA offering (such as SERDES or ADC blocks) then the only choice you have is to go for the ASIC path. An ASIC can accommodate both Analog and Digital blocks easily.

 

 

Price Comparison FPGA vs ASIC

 

Let’s take an example that shows the total cost of ASIC and FPGA technology including both NRE and production unit price.

 

ASIC NRE: $1.5M

ASIC Unit Cost: $4

 

FPGA NRE: $0

FPGA Unit Cost: $8

 

ASIC-vs-FPGA-total-comparison_new

 

 

The graph clearly shows that after volume of 400K units, ASICs are starting to be more cost effective. Therefore, despite the fact that the ASIC project requires $1.5M in NRE, after 400K unit the ASIC is starting to return the investment, compared to an FPGA.

 

Conclusion

 

In conclusion, both ASIC and FPGA are technologies with different benefits, however their difference relies on costs, NRE, performance and flexibility. In general, we can say that for lower volumes’ designs, FPGA flexibility allows to save costs and obtain better results; while ASICs chips are more efficient and cost effective on high volume applications.

 

Next Steps – ASIC

 

If you are looking for an ASIC design company you may want to start your journey on this page.

 

Next Steps – FPGA

 

However, if you are seeking an FPGA design company try this website.

 

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