The HT27LC512 chip family is a low-power, 512K bit, +3.3V electrically one-time pro- grammable (OTP) read-only memories (EPROM).
The HT27LC512 is a low‑power, 64 K × 8‑bit one‑time programmable (OTP) CMOS EPROM from Holtek. It operates from a single +3.3 V supply, offers a fast 120 ns read access time, and includes CMOS and TTL compatible I/O.
The datasheet describes pin assignments, absolute maximum ratings, DC and AC electrical characteristics, and the fast interactive programming algorithm (Vpp = 12.2 V–40.2 V, typical 75 µs per byte). It also covers standby modes, two‑line output control, and recommended decoupling capacitors for stable operation.
| Organization | 64K × 8‑bit |
|---|---|
| Supply Voltage | +3.3 V |
| Programming Voltage (VPP) | 12.2 V to 40.2 V |
| Read Access Time | 120 ns |
| Active Current | 15 mA max |
| Package Types | 28‑pin DIP/SOP, 32‑pin PLCC |
The device requires a VPP of 12.2 V to 40.2 V.
Typical programming time is 75 µs per byte.
It is available in 28‑pin DIP/SOP and 32‑pin PLCC packages.