A physics-based analytical compact model of InGaAs field-effect transistors (FETs) for digital logic applications is developed. This model neither heavily depends on parameter extraction nor requires any time-consuming computation while capturing the essential physics, enabling digital circuit design and circuit-level performance estimation for III-V FETs. The model captures short channel effects, trapezoidal-shape quantum-well energies, bias-dependent ballistic ratios, and capacitances including 2D potential profile information. Each is verified via numerical calculations and 2D electrostatic simulation, followed by a comparison of the model I-V characteristics with experiment data. Finally, the transient response of FO4 inverters demonstrates the use of the compact model for future technology circuit simulations.