Thank you for your interests in XMODEL. XMODEL is a plug-in engine that enables analog/mixed-signal simulation in SystemVerilog. This allows mixed-signal ICs to be verified in a single simulation platform, SystemVerilog, without using SPICE or AMS co-simulation, which tends to be slow and break the established digital verification flows, such as UVM.

If you are looking for a fast-running SPICE simulator, I am afraid that XMODEL is not it. XMODEL is not a SPICE-compatible simulator. XMODEL runs simulations in SystemVerilog and because of that, it can only perform time-domain, transient simulations, and cannot natively perform frequency-domain or small-signal analyses like SPICE. XMODEL cannot directly read in SPICE netlists as-is or understand the SPICE commands and options as-is -- they will need to be translated in SystemVerilog. If you are simply looking for a fast SPICE, you may find these differences unpleasing.

While XMODEL does offer a significant speed-up compared to SPICE, much of that speed-up comes from the fact that XMODEL uses simplified device models and higher-abstraction models. Taking a PLL for example, you can achieve 20~30x speed-up just by modeling your VCO as a functional model, producing a clock signal whose frequency varies with the input voltage. MODELZEN can extract both a circuit-level model and functional model from your VCO automatically. Another part of the XMODEL's speed-up is contributed by its unique event-driven algorithm, which makes XMODEL significantly faster than Real-Number Verilog (RNV). To learn more, watch this video.

XMODEL is ideal for people who must include analog circuits in their SystemVerilog simulations in order to verify the functionality of the entire mixed-signal system. For example, many people find XMODEL attractive especially when verifying large mixed-signal feedback loops, such as equalizer adaptation loops in wireline transceivers, digital calibration/compensation loops in data converters, digitally-controlled phase-locked loops (PLLs) and DC-DC converters, etc.

Thank you for your interests in XMODEL. XMODEL is a plug-in engine that enables analog/mixed-signal simulation in SystemVerilog. This allows mixed-signal ICs to be verified in a single simulation platform, SystemVerilog, without using SPICE or AMS co-simulation, which tends to be slow and break the established digital verification flows, such as UVM.

If you are looking for a fast-running SPICE simulator, I am afraid that XMODEL is not it. XMODEL is not a SPICE-compatible simulator. XMODEL runs simulations in SystemVerilog and because of that, it can only perform time-domain, transient simulations, and cannot natively perform frequency-domain or small-signal analyses like SPICE. XMODEL cannot directly read in SPICE netlists as-is or understand the SPICE commands and options as-is -- they will need to be translated in SystemVerilog. If you are simply looking for a fast SPICE, you may find these differences unpleasing.

While XMODEL does offer a significant speed-up compared to SPICE, much of that speed-up comes from the fact that XMODEL uses simplified device models and higher-abstraction models. Taking a PLL for example, you can achieve 20~30x speed-up just by modeling your VCO as a functional model, producing a clock signal whose frequency varies with the input voltage. MODELZEN can extract both a circuit-level model and functional model from your VCO automatically. Another part of the XMODEL's speed-up is contributed by its unique event-driven algorithm, which makes XMODEL significantly faster than Real-Number Verilog (RNV). To learn more, watch this video.

XMODEL is ideal for people who must include analog circuits in their SystemVerilog simulations in order to verify the functionality of the entire mixed-signal system. For example, many people find XMODEL attractive especially when verifying large mixed-signal feedback loops, such as equalizer adaptation loops in wireline transceivers, digital calibration/compensation loops in data converters, digitally-controlled phase-locked loops (PLLs) and DC-DC converters, etc.