In this work, a novel concept of 2-bit-per-cell (2B/C) is introduced to realize high-density OTP PUF from a new scheme of dielectric breakdown. This PUF shows 105x of large window, good immunity to high-temperature disturbance, and excellent retention under 150°C baking, which are particularly for automotive applications. In terms of security, this PUF exhibits near ideal normal distribution of hamming distance and narrow distribution of hamming weight. The bit error rates are low, 0.78% at 25°C and 1.95% at 150°C, benchmarked on a 256-bit array. Finally, the security test of this PUF against the hackers' attack from the machine learning process has been proved to have high security. Overall, the proposed 2B/C OTP PUF demonstrated great potential for IoT security in 5G era.