Microchip Technology 24CSM01-E/P

Overview

24CSM01-E/P from Microchip Technology is a 1-Mbit I²C serial EEPROM with integrated security register, ECC error correction, and AEC-Q100 automotive qualification. It operates from 1.7V to 5.5V, supports up to 3.4 MHz High-Speed I²C mode, and delivers >1 million write cycles with >200-year data retention. It is used in automotive infotainment control modules for storing calibrated sensor offsets and secure boot configuration.

For engineers reviewing the 24CSM01-E/P datasheet, 24CSM01-E/P pinout, 24CSM01-E/P application, or 24CSM01-E/P equivalent, key selection considerations include its dual-zone write protection (hardware WP pin + software-configurable 128-Kbit zones), factory-programmed 128-bit unique serial number, and extended temperature support up to +125°C for under-hood applications.

Technical Context

The 24CSM01-E/P implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress ground bounce and noise. Its memory array is organized as 512 pages × 256 bytes, enabling efficient page writes without external address latching.

It integrates three dedicated registers: a read-only Configuration register (lockable after setup), a 4-Kbit Security register split into factory-unique 128-bit serial number (0800h–080Fh) and user-programmable 256-byte ID page (0900h–090Fh), and a 24-bit Manufacturer ID register compliant with I²C standard identification protocol.

Key Specifications

Pinout & Package

24CSM01-E/P is packaged in an 8-lead PDIP (Plastic Dual In-line Package) with through-hole mounting and industry-standard 0.3-inch body width. Pin 1 is marked with a notch or dot; pin numbering follows counter-clockwise convention from top view.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24CS128-SSHL-T and BR24G128FJ-3GE2, the 24CSM01-E/P provides 8× more memory, automotive-grade reliability, and hardware-enforced security features essential for ISO 26262-compliant systems - making it the only option supporting both functional safety and cryptographic binding in a single component.

Availability

24CSM01-E/P is available at Aetrix Electronics and suitable for automotive ECU design, infotainment system personalization, and ADAS sensor calibration requiring stable component supply across multi-year production programs.

Supply support for 24CSM01-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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory solutions for automotive, industrial, and communications markets.

The 24CSM01-E/P belongs to Microchip's CS-series automotive EEPROM family, designed specifically to meet AEC-Q100 requirements and provide secure, high-reliability nonvolatile storage for safety-critical vehicle subsystems.

FAQ

What is the maximum I²C clock frequency supported by the 24CSM01-E/P?

The 24CSM01-E/P supports up to 3.4 MHz in High-Speed mode when VCC is ≥2.5V and ambient temperature is within the Industrial range (-40°C to +85°C). At lower voltages (1.7V–2.5V) or Extended temperature range (-40°C to +125°C), the maximum clock frequency is 1 MHz. This dual-speed capability allows optimized performance in engine bay environments where voltage and temperature vary significantly. The 24CSM01-E/P automatically adapts to the configured mode without external configuration.

Does the 24CSM01-E/P require external pull-up resistors on SDA and SCL lines?

Yes, the 24CSM01-E/P requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. For 3.4 MHz operation, a 330Ω resistor is recommended; for 1 MHz, 2 kΩ is typical; and for 100 kHz, 10 kΩ suffices. These values ensure rise times meet I²C specification limits while minimizing power consumption. The 24CSM01-E/P does not integrate internal pull-ups, so omission will result in communication failure.

How is the 128-bit serial number in the 24CSM01-E/P used in production systems?

The 128-bit serial number in the 24CSM01-E/P is factory-programmed and globally unique across the entire CS series. It resides at fixed address 0800h–080Fh and is read-only. In production, it serves as a hardware root of trust: binding calibration data, firmware images, or cryptographic keys to the physical unit without requiring external serialization equipment. This eliminates manual tracking and reduces line-side programming time. The 24CSM01-E/P guarantees uniqueness, enabling secure over-the-air update authorization and counterfeit detection.

Can the 24CSM01-E/P be used in systems powered by 1.8V logic rails?

Yes, the 24CSM01-E/P operates reliably from 1.7V to 5.5V, making it fully compatible with 1.8V logic systems. Its VIH threshold is VCC × 0.7 (≥1.26V at 1.8V), and VIL is VCC × 0.3 (≤0.54V), ensuring clean signal recognition. DC current draw is ≤1 mA during read operations at 1.8V, and standby current remains below 5 µA. This wide voltage range allows direct interfacing with low-power microcontrollers without level-shifting circuitry - a key advantage in battery-powered ADAS modules where the 24CSM01-E/P maintains data integrity during deep-sleep states.

What happens if the WP pin is left floating on the 24CSM01-E/P?

The WP pin on the 24CSM01-E/P must be actively driven to either VCC or VSS; leaving it floating violates the Absolute Maximum Ratings and may cause undefined behavior, including unintended write inhibition or intermittent write failures. When using legacy hardware protection mode, floating WP can result in partial or complete loss of write functionality due to input threshold ambiguity. The datasheet explicitly requires termination - for robust designs, tie WP to VSS via a 10 kΩ resistor if write-enable is needed, or to VCC if permanent protection is desired. This requirement applies regardless of whether enhanced software protection is enabled.