Microchip Technology AT24CS02-MAHM-E

Overview

AT24CS02-MAHM-E from Microchip Technology is a 2-Kbit (256 × 8) I²C-compatible serial EEPROM with a factory-programmed, permanent 128-bit unique serial number, operating from 1.7V to 5.5V and rated for -40°C to +85°C industrial temperature range. It supports Standard (100 kHz), Fast (400 kHz), and Fast Mode Plus (1 MHz) I²C protocols and features hardware write protection via the WP pin.

For engineers reviewing the AT24CS02-MAHM-E datasheet, AT24CS02-MAHM-E pinout, AT24CS02-MAHM-E application, or AT24CS02-MAHM-E equivalent, key selection considerations include its guaranteed unique serialization, ultra-low standby current (≤6 μA), 1,000,000 write endurance, 100-year data retention, and compatibility with space-constrained designs using the 8-pad UDFN package.

Technical Context

The AT24CS02-MAHM-E implements a two-wire I²C slave interface with Schmitt-triggered, noise-filtered SDA and SCL inputs, supporting bidirectional data transfer with ACK/NACK handshaking. Its internal architecture includes a dedicated 128-bit read-only serial number block separate from user memory, ensuring no consumption of the 256-byte EEPROM array.

It uses an on-chip high-voltage generation circuit for write operations, enabling self-timed internal write cycles completing in ≤5 ms. The device enters Standby mode after power-up stabilization, Stop condition reception, or write cycle completion, drawing ≤6 μA at VCC = 5.5V.

Key Specifications

Pinout & Package

AT24CS02-MAHM-E is supplied in an 8-pad UDFN (2 mm × 3 mm, 0.5 mm pitch) package with wettable flank leads, RoHS-compliant and halide-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24CS02-MAHM-E, AT24C02D-SSHM-T offers identical memory size and voltage range but omits the differentiating 128-bit UID and uses a larger SOIC package, while M95M02-DFMN6TP trades I²C compatibility and UID for SPI interface and 1000× greater density - neither provides drop-in replacement capability due to interface or feature mismatch.

Availability

AT24CS02-MAHM-E is available at Aetrix Electronics and suitable for industrial sensor nodes, smart meter modules, medical diagnostic devices, and asset tracking tags requiring stable component supply, long-term data integrity, and guaranteed hardware uniqueness.

Supply support for AT24CS02-MAHM-E 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 is a leading provider of microcontrollers, analog, FPGA, and memory solutions, with a focus on embedded control and connectivity.

The AT24CS02-MAHM-E belongs to Microchip's CS Series Serial EEPROM product line, designed specifically to simplify manufacturing traceability and reduce system-level UID implementation complexity through factory-programmed, globally unique serial numbers.

FAQ

What is the function of the WP pin on the AT24CS02-MAHM-E?

The WP (Write-Protect) pin on the AT24CS02-MAHM-E provides hardware-level inhibition of all write operations to the EEPROM array when driven high (to VCC). When connected to GND, normal read and write functions operate. If left floating, the pin is internally pulled down, enabling writes by default - though Microchip recommends tying it to a defined logic level to prevent noise-induced misoperation. This feature ensures robust protection of critical configuration or calibration data in the AT24CS02-MAHM-E.

Does the AT24CS02-MAHM-E require external pull-up resistors on SDA and SCL lines?

Yes, the AT24CS02-MAHM-E requires external pull-up resistors on both SDA and SCL lines because SDA is open-drain and SCL is a CMOS input. Microchip specifies maximum pull-up values of 10 kΩ for 100 kHz, 4 kΩ for 400 kHz, and 1.3 kΩ for 1 MHz operation, with recommended resistor values ≤10 kΩ to ensure proper rise times and noise immunity. These resistors are mandatory for reliable I²C communication and are not integrated into the AT24CS02-MAHM-E itself.

How is the 128-bit serial number accessed in the AT24CS02-MAHM-E?

The 128-bit serial number in the AT24CS02-MAHM-E is accessed via the I²C bus using a distinct device address prefix: '1011' (0xBx) instead of the standard EEPROM address prefix '1010' (0xAx). After sending the 0xBx address byte, the master reads 16 consecutive bytes (128 bits) starting from offset 0x00 in the serial number block. This block is read-only, permanently programmed during wafer test, and does not consume any of the 256-byte user EEPROM space in the AT24CS02-MAHM-E.

What is the maximum write cycle time for the AT24CS02-MAHM-E?

The maximum write cycle time for the AT24CS02-MAHM-E is 5 ms, applicable to both byte-write and page-write operations. This self-timed internal cycle is handled entirely by the device; no external timing control is needed. During this period, the AT24CS02-MAHM-E does not acknowledge I²C commands (ACK polling returns NACK until complete), allowing the host controller to manage bus arbitration efficiently without fixed delays.

Is the AT24CS02-MAHM-E compatible with 1.8V I²C systems?

Yes, the AT24CS02-MAHM-E is fully compatible with 1.8V I²C systems: it operates from 1.7V to 5.5V, supports Standard Mode (100 kHz) and Fast Mode (400 kHz) down to 1.7V, and meets I²C electrical specifications including VOL ≤ 0.2V at IOL = 0.15 mA when VCC = 1.7V. Its Schmitt-triggered inputs and noise filtering ensure reliable operation in mixed-voltage designs where the AT24CS02-MAHM-E interfaces directly with 1.8V microcontrollers.