Microchip Technology 93C46C-I/ST

Overview

93C46C-I/ST from Microchip Technology Inc. is a 1 Kbit (128 × 8 or 64 × 16) low-voltage serial EEPROM with Microwire-compatible 3-wire interface, ORG pin for runtime word-size selection, and industrial temperature range (–40°C to +85°C). It supports self-timed erase/write cycles, automatic ERAL/WRAL, and Ready/Busy status via DO pin. Used in embedded system configuration storage where nonvolatile memory with flexible data width is required.

For engineers reviewing the 93C46C-I/ST datasheet, 93C46C-I/ST pinout, 93C46C-I/ST application, or 93C46C-I/ST equivalent, key selection criteria include V_CC range (4.5–5.5 V), 8-/16-bit configurable organization, 2 ms write cycle time, 1 million endurance cycles, and SOIC-8 (ST) package compatibility with legacy board layouts.

Technical Context

The 93C46C-I/ST implements a synchronous Microwire-compatible serial interface with CS, CLK, DI, and DO signals, plus dedicated ORG pin for dynamic memory width selection between 128 × 8-bit and 64 × 16-bit configurations. Its internal logic enforces power-on write protection and requires explicit EWEN command before any erase/write operation.

Write initiation differs from AA/LC variants: on 93C46C, the rising edge of CLK on the final data bit triggers the self-timed auto-erase-and-write cycle, not the falling edge of CS. V_CC must be ≥4.5 V for ERAL and WRAL operations, and DO provides real-time Ready/Busy status only when CS is reasserted after ≥250 ns low time (TCSL).

Key Specifications

Pinout & Package

93C46C-I/ST is packaged in 8-lead SOIC (ST), with lead finish Pb-free Matte Tin. Pin 1 is CS, pin 2 is CLK, pin 3 is DI, pin 4 is DO, pin 5 is VSS, pin 6 is ORG (functional - selects 8-/16-bit mode), pin 7 is NC (no internal connection), and pin 8 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 93LC46C-I/ST and 93AA46C-I/ST, the 93C46C-I/ST offers highest noise immunity and lowest standby current in 5 V systems but lacks 3.3 V or sub-5 V flexibility - making it optimal for cost-sensitive, fixed 5 V industrial designs where supply regulation is robust.

Availability

93C46C-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration storage, legacy MCU configuration memory, and automotive body control module settings requiring stable component supply across multi-year production cycles.

Supply support for 93C46C-I/ST 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 microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 93C46C belongs to Microchip's legacy 93XX serial EEPROM product line, designed specifically for cost-effective, low-pin-count nonvolatile storage in industrial and automotive applications where Microwire compatibility and hardware write protection are critical.

FAQ

What is the minimum V_CC required for reliable operation of the 93C46C-I/ST?

The 93C46C-I/ST requires V_CC ≥ 4.5 V for all operations. Its internal voltage detector disables erase/write functions below 3.8 V to prevent data corruption. Operation at 4.4 V or lower is not guaranteed - sustained 4.5 V supply with adequate decoupling is mandatory for functional reliability and 1M endurance compliance.

How does the ORG pin affect memory access in the 93C46C-I/ST?

In the 93C46C-I/ST, tying ORG to VCC selects 64 × 16-bit organization (16-bit words, 64 addresses), while tying ORG to VSS selects 128 × 8-bit organization (8-bit bytes, 128 addresses). The instruction set and address width change accordingly - READ/WRITE require 7 address bits in x8 mode and 6 bits in x16 mode. The 93C46C-I/ST must be configured at power-up and cannot switch modes dynamically during operation.

Can the 93C46C-I/ST be used with a 3.3 V microcontroller?

No - the 93C46C-I/ST is not compatible with 3.3 V systems. Its absolute minimum V_CC is 4.5 V, and its input thresholds (VIH1 = 2.0 V, VIL1 = 0.8 V) assume a 5 V logic swing. Interfacing to a 3.3 V MCU without level translation risks unreliable opcode recognition and DO status misreads. Use 93LC46C-I/ST or 93AA46C-I/ST instead for 3.3 V or mixed-voltage designs.

What is the purpose of the NC pin (Pin 7) on the 93C46C-I/ST SOIC-8 package?

Pin 7 on the 93C46C-I/ST is designated NC (No Connection) and has no internal bond wire or circuit connection. It may be left floating, tied to ground for mechanical reinforcement, or routed as a keep-out zone. Unlike ORG (Pin 6), NC serves no functional role - misrouting it as an active signal will not affect device behavior but violates Microchip's recommended layout practice.

How does the 93C46C-I/ST handle write protection during power transitions?

The 93C46C-I/ST incorporates hardware power-on/off data protection: internal circuitry inhibits all erase/write commands when V_CC falls below ~3.8 V. Additionally, it powers up in EWDS (Erase/Write Disable) state, requiring an explicit EWEN command before any programming. This dual-layer protection prevents corruption during brown-out, reset, or hot-swap events - a critical feature confirmed in DS20001749K Section 2.6 and Table 1-1 D11.