GUI-based OTA sizing tool. Automates transistor-level design of CMOS Operational Transconductance Amplifiers using the gm/ID methodology. Delivers a ready-to-simulate design in minutes.
| Parameter | Value |
|---|---|
| Version | 2026.0 |
| Platform | Ubuntu 20.04 LTS or later (Linux only) |
| Distribution | ZIP archive — self-contained executable |
| Memory | 4 GB minimum; 8 GB recommended |
| Disk space | ~200 MB for AmpForge + .mdat files |
| External dependency | NGSPICE (for MOS Characterizer only) |
| Internet | One-time only (Machine ID + licence file) |
| Licence type | Node-locked (.lic file, machine-specific) |
All 14 topologies support both NMOS and PMOS input stage configurations.
| No. | Topology | No. | Topology |
|---|---|---|---|
| 1 | Differential Amplifier OTA | 8 | Two Stage Miller RHP Cancel OTA |
| 2 | Symmetrical OTA | 9 | Two Stage Cascode I/P Miller OTA |
| 3 | Symmetrical with Cascode Output OTA | 10 | Two Stage Cascode I/P Miller Null Resistor OTA |
| 4 | Folded Cascode OTA | 11 | Two Stage Cascode I/P Miller RHP Cancel OTA |
| 5 | Recycling Folded Cascode OTA | 12 | Two Stage Folded Cascode I/P Miller OTA |
| 6 | Two Stage Miller OTA | 13 | Class AB Two Stage Miller OTA |
| 7 | Two Stage Miller Null Resistor OTA | 14 | Class AB Folded Cascode Two Stage Miller OTA |
Topologies 3, 5, and 14 (Symmetrical with Cascode Output, Recycling Folded Cascode, Class AB Folded Cascode) are reserved for the full licence. The trial licence provides access to the remaining 11 topologies.
In Auto Mode, the Design Synthesizer simultaneously returns three SPICE netlists — each meets your specifications, optimised for a different operating point.
| Specification | Low Power | Balanced | High Slew Rate |
|---|---|---|---|
| Overdrive Voltage (VOV) | Least | Moderate | Highest |
| Transition Frequency (fT) | Least | Moderate | Highest |
| Power consumption | Least | Moderate | Highest |
| I/O Common Mode Voltage | Highest | Moderate | Least |
| Open Loop DC Gain potential | Highest | Moderate | Least |
| W/L Ratios | Highest | Moderate | Least |
| Slew Rate | Least | Moderate | Highest |
Pre-built .mdat files are included for three process nodes. For any other PDK, run the MOS Characterizer once to generate the database.
n18, p18, nhv, phv models. VDD = 1.8V typical.
sg13_lv_nmos, sg13_lv_pmos, HV variants. Open PDK.
nmos_3p3, pmos_3p3, 6V variants. Open PDK.
The following results are from worked Example 1 in the AmpForge User Guide — Two Stage Miller RHP Cancel OTA, SCL 180nm, Auto Mode, High Slew Rate solution.
| Parameter | Target | AmpForge Achieved | SPICE Simulation |
|---|---|---|---|
| Open Loop Gain (dB) | 55 | 55.25 | 55.2 |
| Unity Gain Bandwidth (MHz) | 1000 | 1000 | 913.82 |
| Slew Rate (V/µs) | 350 | 377 | 382.4 |
| Input Ref. Thermal Noise PSD (nV/√Hz) | 6 | 5.07 | 5.4 |
| Phase Margin (deg) | 60 | 55.27 | 55.82 |
| Total Current (mA) | — | 1.7 | 1.72 |
Technology: SCL 180nm CMOS · VDD = 1.8V · PMOS input stage · CL = 2pF
Trial and full licences available. 48-hour turnaround on the .lic file.
Request Licence