What this 1Kbit EEPROM does on the board
The Microchip 93C46C-I/SN is a 1Kbit serial EEPROM with a Microwire interface, in an 8-pin SOIC package. It stores configuration data, calibration constants, or small lookup tables that need to survive power loss. The 3 MHz clock rate is the fastest in the 93C46 family, so it reads and writes quicker than the 2 MHz 'A' or 'B' variants.
Memory organization: 128 x 8 or 64 x 16
The 93C46C can be configured as 128 bytes (128 x 8) or 64 words (64 x 16), selected by the ORG pin. This is the advantage over the fixed-organization 93C46A (128 x 8 only) and 93C46B (64 x 16 only). If your firmware expects byte-wide addressing, wire ORG low; for 16-bit word access, pull it high. The 2ms write cycle time applies per word or page write regardless of organization.
Active lifecycle — no obsolescence worry
No last-time-buy notice, no end-of-life risk. It is ROHS3 compliant.
Swapping it in the field
No hot-air station needed. If you are replacing a 93C46A or 93C46B, check the ORG pin wiring — the 93C46C gives you both organizations, but the board must set it correctly. The 3 MHz clock is backward-compatible with 2 MHz bus masters, so it drops right into existing Microwire designs.