The multipeak current–voltage(I–V)characteristic and hysteresis phenomena based on a series combination of several resonant tunneling diodes (RTDs) are analyzed and simulated. Our analytic model is based on a load-line technique with a piecewise-linear approximation for theI–Vcurve of RTD. The peak-to-valley current ratio ofNRTDs in series and the effects of series resistance on the combinedI–Vcharacteristic are investigated. The results provide a useful design and estimation for the multipeakI–Vcharacteristic with series-connected several RTDs before circuit accomplishment. ©1997 American Institute of Physics.