Full reference for installation, the Design Synthesizer, MOS Characterizer, and worked examples.
AmpForge is distributed as a ZIP archive for Ubuntu / Linux only. The archive extracts to a directory containing the executable, installer script, and documentation.
sudo apt updatesudo apt install ngspicesudo add-apt-repository universe then repeat step 2.sudo apt install fonts-dejavu-coreunzip AmpForge_2026.0.zipcd AmpForge_2026.0chmod +x install.sh./install.sh (use sudo ./install.sh for all users)The installer adds AmpForge OTA Compiler to your Applications menu. It can also be run directly from the terminal at /opt/ampforge/AmpForge (system-wide) or ~/.local/share/ampforge/app/AmpForge (per-user).
Licence activation is a one-time process, required on the first launch.
The End User Licence Agreement appears on first launch. Read it and click I Accept. This is remembered — it will not appear again on this machine.
After accepting, the Licence Activation window shows your Machine ID — a short code in the format A1B2-C3D4-E5F6-0718. Click the box to copy it.
Complete the Licence Request Form with your Machine ID and send it to support@bharatanalogtech.com. You will receive a .lic file within 48 hours.
Launch AmpForge, click Select License File in the Licence Activation window, and browse to your saved .lic file. A confirmation message shows your licence expiry date and OTA design count.
| Item | Requirement |
|---|---|
| Operating system | Ubuntu 20.04 LTS or later (Linux) |
| Memory | 4 GB minimum; 8 GB recommended |
| Disk space | ~200 MB for AmpForge + space for .mdat files and design outputs |
| NGSPICE | Required for the MOS Characterizer |
| Internet | One-time only — to email Machine ID and receive the .lic file |
The Design Synthesizer is the primary OTA sizing module. Given a topology, supply voltage, performance specifications, and a pre-characterised MOS database (.mdat), it searches the full transistor sizing space and returns ready-to-simulate SPICE netlists.
It operates in two modes: Auto Mode (automated design space exploration, three solutions) and Manual Mode (user-specified channel length and overdrive voltage, one solution).
Auto Mode autonomously explores the complete design space and simultaneously returns three optimised solutions — Low Power, Balanced, and High Slew Rate — each meeting your specified targets.
| Field | Symbol | Unit | Required |
|---|---|---|---|
| Open Loop DC Gain | AV | dB | Yes |
| Unity Gain Bandwidth | UGB | MHz | Yes |
| Phase Margin | PM | ° | Yes |
| Slew Rate | SR | V/µs | Optional (enter 0) |
| Input-Referred Thermal Noise PSD | Vn,th | nV/√Hz | Optional (enter 0) |
| Capacitive Load | CL | pF | Yes |
| Resistive Load (Class AB only) | RL | kΩ | For Class AB topologies |
Manual Mode lets you specify the transistor channel length and overdrive voltage directly, giving full control over the operating point. Use this to fine-tune an Auto Mode result, optimise for a specific corner, or size a single MOSFET.
| Field | Effect |
|---|---|
| Design Channel Length (L) | Longer L → higher gain, lower flicker noise, lower bandwidth |
| Design Overdrive Voltage (VOV) | Higher VOV → higher SR and fT, costs power; lower VOV → higher gain, better common mode range |
After a successful run, the Design Synthesizer writes to the output directory:
*.sp — SPICE subcircuit netlist with transistor instances, biasing, and PDK compatibility notes*_mos_size_summary.csv — W, L, fingers, ID, and VOV per transistor*_design_results.csv — achieved vs. target for gain, UGB, PM, SR, noise*_voltage_ranges.csv — input and output common mode voltage ranges*_noise_summary.csv — thermal noise PSD, flicker noise, integrated RMS noiseThe MOS Characterizer generates the .mdat MOS characteristic database used by the Design Synthesizer. It runs NGSPICE locally on the foundry SPICE model file, sweeping channel length, VGS, and VDS to extract DC, AC, and noise parameters. The foundry model file never leaves your machine.
This is a one-time activity per PDK process node. AmpForge ships with pre-built .mdat files for SCL 180nm, IHP 130nm, and GF 180nm.
| Field | Description |
|---|---|
| Library Path | Full absolute path to foundry PDK SPICE library (.lib, .spi, or .l) |
| Process Corner | Typical process corner name, e.g. tt_18, mos_tt |
| Control File | Optional — required for some PDKs (e.g. IHP). Leave blank if not needed. |
| Parameter | Recommended step |
|---|---|
| Channel Length (µm) | 0.1 |
| VGS (V) | 0.005 |
| VDS — 180nm and below (V) | 0.05 |
| VDS — above 180nm (V) | 0.1 |
| Foundry | MOS Model | Type | Instance Prefix | LMIN (µm) | LMAX (µm) |
|---|---|---|---|---|---|
| SCL 180nm | n18, p18 | NMOS / PMOS | M | 0.18 | 3.6 |
| SCL 180nm | nhv, phv | NMOS / PMOS | M | 0.35 | 6 |
| GF 180nm | nmos_3p3, pmos_3p3 | NMOS / PMOS | X | 0.28 | 6 |
| IHP 130nm | sg13_lv_nmos | NMOS | X | 0.13 | 2.6 |
| TSMC 65nm | nch_mac, pch_mac | NMOS / PMOS | X | 0.06 | 1.2 |
| Parameter | Value |
|---|---|
| Technology | SCL 180nm CMOS |
| VDD | 1.8V |
| Input Stage | PMOS |
| Open Loop DC Gain | 55 dB |
| Unity Gain Bandwidth | 1000 MHz |
| Phase Margin | 60° |
| Slew Rate | 350 V/µs |
| Thermal Noise PSD | 6 nV/√Hz |
| Capacitive Load | 2 pF |
n18, PMOS model = p18. Click Load Models.Target: 70 dB gain, 75 MHz UGB, 70° PM, 50 V/µs SR, 8 pF load, NMOS input. Lmin Multiplier = 2.
Achieved (Balanced solution): Gain 72.3 dB · UGB 75 MHz · SR 62.83 V/µs · PM 71.21°. SPICE verified to within 1.3% on UGB and 0.3% on SR.
Same specifications as Example 2. The Recycling Folded Cascode achieves equivalent UGB and slew rate at 57% of the total current compared to the Folded Cascode — demonstrating the topology selection trade-off.
Achieved (Balanced): Gain 72.53 dB · UGB 75 MHz · SR 74.61 V/µs · Current 0.91 mA (vs. 1.59 mA for Folded Cascode).
Fine-tuning Example 3 to increase output swing. Starting from the Auto Mode balanced solution CSV, channel length and overdrive voltage are carried across to Manual Mode. Overdrive voltage of current source and cascode transistors is reduced by 20mV.
Result: I/O common mode ranges improved by 80mV. Gain 72.46 dB · UGB 75 MHz maintained.
| Symptom | Solution |
|---|---|
| Permission denied on launch | chmod +x AmpForge |
| Licence not valid for this machine | Network card replaced or OS reinstalled — send current Machine ID to support for a replacement .lic file |
| Invalid or tampered licence file | Re-request the .lic file. Save the email attachment directly to disk — never copy-paste its contents. |
| NGSPICE errors or MOS Characterizer fails | Verify NGSPICE is installed (ngspice -v). Check sweep ranges, corner name, instance and subcircuit name, and control file path. |
| Console tables appear misaligned | sudo apt install fonts-dejavu-core |
| System clock rollback detected | Set the correct system date and time. |
| Topology locked (trial licence) | Topologies 3, 5, 14 require a full licence. Contact support to upgrade. |
For licensing enquiries, replacement licence files, or technical assistance, contact support@bharatanalogtech.com. Include your Machine ID and any error messages displayed by AmpForge.
Starting AmpForge from a terminal window (/opt/ampforge/AmpForge) is the fastest way to diagnose a problem — all messages are printed to the terminal.