Inside A Mystery 1980s Filter IC Featuring Switched Capacitors

Ken Shirriff investigated a mystery 1980s chip handed to him by CuriousMarc, marked only with a cryptic date code and part number. After cracking open the ceramic package, he identified the die as a Harris HF10, a variant of National Semiconductor's MF10 dual switched capacitor filter. These chips use switched capacitors instead of resistors to create tunable low-, band-, or high-pass filters, a technique especially useful in 1980s synthesizers. A modern descendant, the TI MF10-N, still exists in PDIP and SOIC packages but no longer in CDIP, and availability appears scarce.

Why read it: Bài viết giúp hiểu về nguyên lý hoạt động và lịch sử của chip lọc tích hợp công nghệ tụ chuyển mạch trong những năm 1980.

Source: https://hackaday.com/2026/10/11/inside-a-mystery-1980s-filter-ic-featuring-switched-capacitors. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.