Microchip Technology 93LC56C-E/P

Overview

93LC56C-E/P from Microchip Technology Inc. is a 2 Kbit low-voltage serial EEPROM with configurable 8-/16-bit word organization via the ORG pin, 2.5–5.5 V supply range, and industrial/automotive temperature support (−40°C to +125°C). It features Microwire-compatible 3-wire serial interface, self-timed erase/write cycles, automatic ERAL before WRAL, and 1 million endurance cycles - used for parameter storage in automotive body control modules.

For engineers reviewing the 93LC56C-E/P datasheet, 93LC56C-E/P pinout, 93LC56C-E/P application, or 93LC56C-E/P equivalent, key selection criteria include ORG-pin-configurable memory width, automotive-grade reliability, write-protection via EWEN/EWDS commands, Ready/Busy status polling on DO, and compatibility with legacy Microwire controllers requiring minimal firmware changes.

Technical Context

The 93LC56C-E/P implements a synchronous serial Microwire interface with CS/CLK/DI/DO signals and an external ORG pin that selects between 128 × 16-bit (ORG = VCC) or 256 × 8-bit (ORG = VSS) memory mapping. Its internal logic includes auto-erase-before-write, ERAL-initiated full-array erase, and WRAL with embedded ERAL - all self-timed and initiated by CS falling edge (for 93LC variants).

Power-on/off data protection is enforced by a voltage-detect circuit triggering at ~1.5 V, while write enable/disable states (EWEN/EWDS) provide software-controlled access gating. The DO pin serves dual function: serial data output during READ and Ready/Busy status indicator during programming - requiring CS high ≥250 ns after TCSL to sample.

Key Specifications

Pinout & Package

8-lead PDIP package (P suffix), with lead pitch 0.3 inch, RoHS-compliant matte tin finish. Pin 1 marked by notch or dot; pin 1 ID confirmed per Microchip DS21794G-page 17.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Compared with 93LC56B-E/P, the 93LC56C-E/P adds runtime word-width flexibility at the cost of one additional PCB trace; compared with AT25020B-MAHL-T, it retains Microwire compatibility and lower gate count but sacrifices speed and voltage range.

Availability

93LC56C-E/P is available at Aetrix Electronics and suitable for automotive body control units, industrial PLCs, medical infusion pumps, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for 93LC56C-E/P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a leading provider of microcontroller, analog, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93LC56C belongs to Microchip's legacy Microwire-compatible serial EEPROM product line, designed specifically for cost-sensitive, low-power, and automotive-qualified nonvolatile storage where simple 3-wire interface and robust write protection are prioritized over speed or density.

FAQ

What is the function of the ORG pin on the 93LC56C-E/P?

The ORG pin on the 93LC56C-E/P selects memory organization: tied to VCC for 128 × 16-bit mode, or to VSS for 256 × 8-bit mode. This pin is absent on A/B variants and must be externally biased - floating causes undefined behavior. The 93LC56C-E/P uses this pin to maintain backward compatibility with both 8-bit and 16-bit host systems without requiring separate part numbers.

Does the 93LC56C-E/P require an external pull-up resistor on the DO pin?

No, the 93LC56C-E/P does not require an external pull-up on DO. During READ, DO actively drives data; during READY/BSY polling, it outputs open-drain logic levels. When shared with DI (common in space-constrained designs), a 10 kΩ series resistor is recommended to prevent bus conflict - but no pull-up is needed. The 93LC56C-E/P internal output buffer handles drive strength per Microchip DS21794G Section 2.4.

How does write protection work on the 93LC56C-E/P?

Write protection on the 93LC56C-E/P is implemented via EWEN (Erase/Write Enable) and EWDS (Erase/Write Disable) instructions. The device powers up in EWDS state, blocking all ERASE/WRITE/WRAL commands until EWEN is issued. After programming, issuing EWDS restores protection. This two-instruction gating prevents accidental writes during power transitions - a key reliability feature confirmed in the 93LC56C-E/P functional description (DS21794G Section 2.6).

What is the maximum clock frequency supported by the 93LC56C-E/P at 3.3 V?

At V_CC = 3.3 V, the 93LC56C-E/P supports a maximum clock frequency of 2 MHz, as specified in Table 1-2 (A1, FCLK) of DS21794G. This applies to all 93LC variants across the 2.5–5.5 V range. Exceeding 2 MHz at 3.3 V violates AC timing parameters including TCKH (clock high time) and TCKL (clock low time), risking command misinterpretation or data corruption.

Can the 93LC56C-E/P be used in place of the 93LC56A-E/P without hardware changes?

Yes, the 93LC56C-E/P can replace the 93LC56A-E/P with no PCB changes if the ORG pin is tied to VSS (to enforce 256 × 8-bit mode) and the NC pin (pin 7 in PDIP) is left unconnected or grounded. Both share identical pinout, voltage range, temperature grade, and timing - the 93LC56C-E/P adds ORG functionality while maintaining full backward compatibility in x8 mode per Microchip's device selection table.