Microchip Technology AT24CS32-MAHM-E

Overview

AT24CS32-MAHM-E from Microchip Technology is a 32-Kbit I²C-compatible serial EEPROM with factory-programmed 128-bit unique serial number, organized as 4,096 × 8 bits, operating from 1.7V to 5.5V, and rated for -40°C to +85°C industrial temperature range. It supports 1 MHz Fast Mode Plus (2.5–5.5V), includes hardware write-protection via WP pin, and delivers ultra-low standby current of 6 µA max - used for secure device identification and configuration storage in embedded controllers.

For engineers reviewing the AT24CS32-MAHM-E datasheet, AT24CS32-MAHM-E pinout, AT24CS32-MAHM-E application, or AT24CS32-MAHM-E equivalent, key selection considerations include its guaranteed unique 128-bit serial number (non-volatile, non-overlapping across CS Series), 5 ms max self-timed write cycle, 1,000,000 write endurance, and compatibility with I²C bus topologies supporting up to eight devices via A0/A1/A2 address inputs.

Technical Context

The AT24CS32-MAHM-E implements a two-wire I²C slave interface with Schmitt-triggered, noise-filtered SCL/SDA inputs and open-drain bidirectional SDA. Its internal architecture integrates a high-voltage generation circuit for EEPROM programming, hardware address comparator for multi-device bus arbitration, and power-on reset (POR) with 100 µs tPUP delay before command acceptance.

It features dual memory addressing: standard EEPROM access uses device type identifier '1010' (0xAh) with A0–A2 hardware address bits, while the dedicated 128-bit serial number block uses '1011' (0xBh) - both blocks are electrically isolated, with serial number permanently locked and consuming zero user memory space.

Key Specifications

Pinout & Package

AT24CS32-MAHM-E is packaged in an 8-lead SOIC (Small Outline Integrated Circuit) with standard 150-mil body width and gull-wing leads. Pin 1 is marked by a beveled corner or dot; package is RoHS-compliant, halide-free, and lead-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24CS32-MAHM-E, AT24C32D-MAHM-E offers identical memory density and packaging but omits the 128-bit serial number - making it suitable for cost-sensitive, non-secure applications. M95320-DRE6TP/K provides SPI compatibility and similar endurance but introduces interface redesign effort and loses hardware-based device identity assurance.

Availability

AT24CS32-MAHM-E is available at Aetrix Electronics and suitable for industrial automation, smart metering, and secure IoT edge devices requiring stable component supply, long-lifecycle support, and guaranteed factory-serialized identity.

Supply support for AT24CS32-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 Inc. is a U.S.-based semiconductor company specializing in microcontrollers, analog components, and memory solutions, with global manufacturing and quality certifications including ISO 9001 and IATF 16949.

The AT24CS32-MAHM-E belongs to Microchip's CS Series Serial EEPROM product line, designed specifically to embed unclonable hardware identity into resource-constrained embedded systems while maintaining full backward compatibility with standard I²C EEPROM protocols.

FAQ

What is the function of the WP pin on the AT24CS32-MAHM-E?

The WP (Write-Protect) pin on the AT24CS32-MAHM-E controls hardware-level write inhibition: when driven high to VCC, it locks the entire 32-Kbit memory array against all write operations, including byte, page, and serial number reads (though serial number remains readable). When tied to GND, normal write functionality is enabled. If left floating, the pin is internally pulled down - but Microchip recommends hardwiring WP to a known state to prevent noise-induced protection errors. This feature safeguards critical configuration data in AT24CS32-MAHM-E deployments.

Does the AT24CS32-MAHM-E require external pull-up resistors on SDA and SCL lines?

Yes, the AT24CS32-MAHM-E requires external pull-up resistors on both SDA and SCL lines because SDA is open-drain and SCL is an input-only clock line. 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 - values chosen to meet rise-time constraints (tR ≤ 300 ns) under 100 pF bus capacitance. Failure to install appropriate pull-ups will result in communication failure or intermittent ACK/NACK errors in AT24CS32-MAHM-E I²C transactions.

How is the 128-bit serial number accessed in the AT24CS32-MAHM-E?

The 128-bit serial number in the AT24CS32-MAHM-E is accessed via a dedicated I²C device address using the 4-bit type identifier '1011' (0xBh), distinct from the standard EEPROM address '1010' (0xAh). The full 7-bit slave address becomes 0xB8–0xBF depending on A2–A0 settings. The 16-byte serial number resides in a read-only memory block outside the 4,096-byte user array and cannot be modified, erased, or overwritten - it is permanently programmed and verified during Microchip's wafer test. This ensures deterministic, collision-free identity retrieval in every AT24CS32-MAHM-E unit.

What is the maximum write cycle time for the AT24CS32-MAHM-E?

The maximum write cycle time for the AT24CS32-MAHM-E is 5 ms per byte or page, as specified in the datasheet's AC Characteristics table (tWR). This self-timed internal programming duration applies to both byte and 32-byte page writes and is independent of I²C clock speed. During this period, the device does not acknowledge new I²C commands and holds SDA low after the final ACK - host software must implement acknowledge polling or fixed-delay waits before issuing subsequent operations. This timing guarantee is validated across the full -40°C to +85°C temperature range and 1.7V–5.5V supply, ensuring predictable behavior in AT24CS32-MAHM-E embedded systems.

Can multiple AT24CS32-MAHM-E devices share the same I²C bus?

Yes, up to eight AT24CS32-MAHM-E devices can share a single I²C bus using hardware address inputs A0, A1, and A2. Each pin accepts GND or VCC to configure a unique 3-bit slave address extension, resulting in seven usable addresses (0x50–0x56) plus one reserved for serial number access (0xB8–0xBF). All devices respond only to their configured address prefix, enabling concurrent read/write operations without contention. This cascading capability is fully supported in AT24CS32-MAHM-E and maintains signal integrity with proper bus pull-up sizing and layout practices.