FPGA plus Mixed Signal ASIC Conversion

Convert your FPGA and discrete analog design into a low cost, high performance via configurable ASIC.

Migrating your mixed signal design to a Triad VCA means:

  • Reduced cost
  • Lower power
  • Better integration
  • Improved reliability
  • IP Protection

If you thought that you could not afford a mixed signal ASIC then please consider the Triad advantage:

  • Industry’s lowest NRE for mixed signal ASICs
  • Accelerated development cycle (no full-custom layout needed)
  • Fabrication time of 4 weeks
  • Triad supports a wide range of conversion engagement models including complete turn-key design

FPGAs are a very good way to prototype a digital design.

Triad Semiconductor is a fabless supplier of via-configurable array (VCA) mixed signal ASICs. Triad VCAs combine silicon-proven analog and digital circuits onto a single semiconductor die.

The mixed signal resources of a VCA are overlaid with a global routing fabric. Wafers containing VCA die are then partially processed and staged at the foundry where they await customization.

A customer’s mixed signal design is configured onto a VCA platform by a single ASIC fabrication mask layer. As the name implies, via-configurable arrays utilize a single via layer mask to interconnect and configure resources throughout the VCA.

Users create VCA designs using industry standard design tools such as HDL/Schematic entry, simulation, and digital synthesis. Triad’s design flow supports any number of EDA tools that are capable of outputting digital gate-level netlists and SPICE-compatible analog netlists.

Triad’s via-only mixed-signal aware place and route software takes as input the user’s mixed signal netlist and outputs a via pattern when fabricated against staged VCA wafers results in an ASIC customized to deliver the functionality of the designer’s circuit.

Reduce cost

FPGAs are expensive devices… By migrating the entire design to a VCA mixed signal ASIC, both the FPGA and external components are all combined on the same die and inside the same package. This level of integration greatly reduces the required silicon area, removes package pins and results in significant system BOM cost savings.

Many mixed signal designs contain an FPGA plus analog components such as Op-Amps, analog to digital converters (ADC), digital to analog converters (DAC), and discrete resistors, capacitors, switches, and transistors. In addition to high unit cost of the FPGA, the bill of material (BOM) cost for the analog components can also be quite expensive.

While converting the FPGA to an all digital ASIC may seem like a good way to reduce system cost it can be of limited value in a mixed signal design. Yes, the silicon for a digital ASIC will be smaller than the FPGA silicon but there are more components to the system cost. If the FPGA is simply replaced with an ASIC, then all the I/O required to interface to the external analog components is still needed. If the design contains ADCs and DACs then dozens of pins will be required to connect these components to the digital-only ASIC. These wide buses on the ASIC and external parts increase the package cost for each part and the overall system BOM cost.

Configuration memories add cost… Many popular FPGAs store their configuration bit streams in expensive external configuration memories. Converting the design into a Triad VCA eliminates the area and expense of these configuration memories.

Improve Integration

Size does matter… For many space constrained applications integration of the mixed signal design into a chip-sized solution is the only option. VCA technology allows designers to integrate a rich set of analog and digital resources into space saving single integrated solutions.

An FPGA plus external mixed signal components often results in a lot of area consumed on a printed circuit board (PCB). Saving money by integration is important. Equally important for many applications is the need to fit a design into a smaller physical space. Absorbing the FPGA ADCs, DACs, resistors, capacitor, op-amps, voltage regulators, non-volatile memory (NVM), and transistors into the mixed signal VCA can reduce a PCB module into a small light weight single chip solution.

Higher Performance

Smaller, faster, cheaper… Via-configurable ASICs provide improved performance over PCB solutions implemented as an FPGA plus discrete analog components.

The ASIC-like architecture of a VCA is faster and less noisy than an FPGA solution. Additionally, VCA analog design techniques allow for the creation of high precision, low-noise analog and mixed signal functions that don’t require factory calibration or trimming. These same functions implemented as discrete analog functions on a PCB often require expensive precision components and time consuming and expensive factory calibration processes.

Just what is an FPGA gate anyway?… FPGA marketing material always talks about “system gates” as some sort of resource that enables FPGAs to talk about 100K or one million “system gate” gate counts. In practice, VCA ASIC designers find that an FPGA design that required 100K to 200K FPGA ‘gates’ may require as little as 10,000 VCA ASIC gates. FPGA “system gates” attempt to credit the FPGA with some equivalent gate count based on the amount of embedded memory within the FPGA. In fact, FPGA vendors have in recent years done a pretty good job in encouraging users to utilize these memory resources for FIFO and other processing units. When the designer has looked to migrate a memory-rich FPGA design to an ASIC design they often found that extensive use of memories made the standard-cell based implementation of the ASIC larger than would have been anticipated.

Triad VCA ASICs contain logic tiles populated with via configurable ASIC gates so that Triad gate counts are much more like traditional 2-input NAND gate ASIC gate counts. Plus, VCA logic tiles contain integrated distributed memories in single-port and dual-port configurations which absorb FPGA memory resources without introducing routing blockages. The distributed memory in the logic tiles is in fact quite porous in the global routing fabric layers of the device. From a silicon area point of view the VCA distributed memory is effectively free since it is underneath the logic routing channels.

IP Protection

Stealing an FPGA design is too easy… Placing a mixed signal design into a via-configurable ASIC provides much stronger protection of the design IP and prevents cloning.

FPGAs are programmed using bit streams stored in external configuration memories. These memories are completely insecure allowing anyone to intercept the FPGA bit stream as it goes between the memory and the FPGA. With the bit stream, the design can be reverse engineered or simply replicated.

FPGA designs are vulnerable to cloning. Reverse engineering an FPGA bit stream back to a working netlist requires a fair amount of engineering effort. More likely in some of today’s outsourced manufacturing environments it the risk of FPGA cloning. A contract manufacturer may produce a given number of FPGA-based products for their customer and in addition to these legitimately manufactured products they may clone the FPGA and illegally produce extra units that the manufacturer then directly sells in the market place.

Lower Power

FPGAs are power hungry… Power consumption can be reduced more than 10x by converting an FPGA design to a via-configurable ASIC.

The massive amounts of active switching and high current drivers within an FPGA make such devices terribly power hungry. Via configured ASICs on the other hand use low resistance metal and via connections which greatly reduce capacitances and switch currents and hence power consumption.

External busses burn power… Many mixed signal designs interface FPGAs to high speed ADCs and DACs with wide, fast switching parallel busses. The I/O drivers in the FPGA and the data converters consume large amounts of current. By integrating the ADCs and DACs with the digital logic on the same VCA ASIC, the high current I/O is replaced with much lower power internal busses.

Improved Reliability

Make things simple to make them more reliable… VCA ASICs contain fully-characterized, silicon-proven mixed signal resources that are delivered as factory-tested, packaged parts that significantly reduce manufacturing complexity and improve product reliability.

More components mean more problems… A PCB design consisting of an FPGA plus a wide variety of external mixed signal components is a much more complicated manufacturing process than placing a single via configurable device onto a PCB. The handling, assembly, and soldering of all the parts on a complex mixed signal PCB is often a major source of reduced product reliability. Reduced reliability results in increased factory test cost, scrap cost, rises in product failure rates, and increased warranty service costs.

VCA Mixed Signal Resources

Triad’s via configurable array (VCA) platforms contain a rich assortment of essential mixed signal design elements. The silicon-proven resources can be combined to develop single chip solutions for a wide variety of applications.

VCA Mixed Signal IP List

Digital Resources

  • Logic – gate counts from 1K to 500K ASIC gates
  • Memory – distributed and block RAMs (single-port, dual-port, register file)
  • ROM – via configurable
  • EEPROM – 128-bits to 512Mbits
  • 300 MHz PLL
  • Programmable Delay Line

Data Converters

  • Sigma Delta Modulator
  • 16-bit Sigma Delta ADC (200KSPS)
  • 12-bit SAR ADC (5 MSPS)
  • 12-bit Pipelined ADC (50 MSPS)
  • 6-10 bit R2R DAC (1 MSPS)
  • 12-bit Current Steering DAC(50 MSPS)

Op-Amp / OTAs

  • Single Ended Op-Amp/OTA
  • Fully Differential Op-Amp/OTA
  • Low-Power Op-Amp/OTA
  • Wideband Op-Amp/OTA
  • Low-Noise Op-Amp/OTA
  • Programmable Gain Amplifiers
  • Instrumentation Amplifiers

Analog Building Blocks

  • Comparators
  • Integrators
  • Resistors
  • Capacitors
  • Transmission Gates
  • Switches (SPST, SPDT)
  • Discrete Transistors (N, P)
  • Temperature Sensors
  • Analog Multiplexers
  • Voltage Regulators
  • H-Bridges
  • High Current Outputs
  • High Voltage Support(20, 40, 120V)
  • Pulse Width Modulators (PWM)
  • Switched Capacitor Filters(LP, BP, HP, Notch)
  • Digital Potentiometers
  • CMOS/TTL I/O
  • LVDS I/O
  • High Voltage I/O
  • Analog I/O

Engagement Models

Triad is here to help… Triad’s engineering team is experienced in ASIC, FPGA, and VCA design and they are ready to help quickly and efficiently convert FPGA plus discrete analog designs to a single chip VCA solution.

Turn-key design… Many customers opt to let Triad’s VCA development team handle the entire job of converting an existing PCB design to a VCA ASIC. For a turn-key migration, Triad FAEs and engineers work with the customer to analyze the discrete design, develop a specification for the VCA ASIC and perform all of the engineering necessary to convert the design to a VCA.

For customers with working FPGA designs and moderate analog design complexity, Triad can convert the design into a VCA format in as little as 8 weeks. Following design completion, Triad and the customer undergo a joint design review and submit or tape-out the design to the foundry for single mask fabrication. Prototypes are available from the foundry 4 weeks after tape-out.

Customer-driven design… Customers can create a complete mixed signal VCA design using their own tools along with Triad’s mixed signal design kit (MDK). The Triad MDK contains VCA primitive datasheets, SPICE-compatible macro models of analog components, digital simulation libraries, and digital synthesis libraries. Customers perform HDL/Schematic capture for the analog and digital portions of the design, perform simulation, and digital synthesis. The synthesized gate-level netlist of the digital design along with the SPICE netlist for the analog section is submitted to Triad. Triad and the customer perform a joint preliminary design review and Triad provides the back and place and route services using VCA-specific via-only place and route software. After place and route, Triad and the customer undergo a final joint design review and submit or tape-out the design to the foundry for single mask fabrication. Prototypes are available from the foundry 4 weeks after tape-out.

Cooperative Design… Triad engineering is available to work with the customer to successfully migrate an FPGA plus discrete analog design to a VCA. The customer may have expertise in digital design but may be lacking in analog design capacity or vice versa. Triad engineering is available to provide analog digital or mixed signal design services as needed to migrate the design to a VCA.

Triad is here to help designer successfully and cost effectively convert designs to a VCA solution.