Microchip Technology 24AA515T-I/SM

Overview

24AA515T-I/SM from Microchip Technology Inc. is a 64K × 8 (512 Kbit) I²C-compatible serial EEPROM with 1.7V–5.5V supply operation, 400 kHz max clock frequency (100 kHz below 2.5V), and industrial temperature range (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protect (WP pin), and Schmitt-trigger inputs for noise immunity-used in low-power embedded systems for parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 24AA515T-I/SM datasheet, 24AA515T-I/SM pinout, 24AA515T-I/SM application, or 24AA515T-I/SM equivalent, key selection considerations include its 1.7V minimum VCC, 100 nA typical standby current, cascading support for up to four devices on one bus, and compatibility with standard I²C master controllers in space-constrained industrial and portable designs.

Technical Context

This device implements a two-wire I²C interface with slave addressing via A0/A1 pins and fixed A2 tied to VCC, enabling up to four devices per bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic supporting byte and page writes with self-timed erase/write cycles.

It supports three read modes-current address, random, and sequential-with address boundary segmentation at 0000h–7FFFh and 8000h–FFFFh. Write protection is controlled solely by the WP pin state, sampled at the Stop bit of each write command, and does not affect read operations.

Key Specifications

Pinout & Package

24AA515T-I/SM is housed in an 8-lead SOIJ (Small Outline Integrated Circuit, J-bend) package, 5.28 mm wide, RoHS-compliant and Pb-free. Pin 1 is A0 (chip select), pin 2 is A1 (chip select), pin 3 is A2 (hardwired to VCC), pin 4 is VSS (ground), pin 5 is SDA (bidirectional open-drain serial data), pin 6 is SCL (serial clock input), pin 7 is WP (write-protect input), and pin 8 is VCC (power supply).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC515-I/SM, the 24AA515T-I/SM enables lower-voltage operation critical for battery-powered systems; compared with AT24C512-MAHM-T, it offers SOIJ-8 compatibility for space-constrained layouts but trades off maximum clock speed for footprint continuity.

Availability

24AA515T-I/SM is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical diagnostics, automotive body control modules, and portable instrumentation requiring stable component supply across extended product lifecycles.

Supply support for 24AA515T-I/SM 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 24AAxx EEPROM product line is engineered for robust, low-power nonvolatile data storage in resource-constrained embedded systems-emphasizing wide voltage range, high endurance, and industrial temperature resilience.

FAQ

What is the minimum supply voltage required for reliable operation of the 24AA515T-I/SM?

The 24AA515T-I/SM operates reliably down to 1.7V, making it compatible with 1.8V logic families and battery-powered systems where voltage may sag under load. This specification is validated across the full industrial temperature range (–40°C to +85°C) and applies to both read and write functions. Below 1.7V, functionality is not guaranteed, and I²C communication may fail or become intermittent.

How does the WP pin function on the 24AA515T-I/SM, and what happens if it's left unconnected?

The WP (Write-Protect) pin on the 24AA515T-I/SM must be actively driven to either VSS (to enable writes) or VCC (to disable writes). If left floating, the device behavior is undefined and may result in partial or failed write operations. The pin is sampled only at the Stop bit of each write command, so toggling WP mid-cycle has no effect. For safety-critical applications, tying WP to VCC via a pull-up resistor is recommended unless dynamic write-enable control is required.

Can the 24AA515T-I/SM be used in a system with multiple I²C EEPROMs on the same bus, and how many are supported?

Yes, the 24AA515T-I/SM supports cascading up to four devices on a single I²C bus using the A0 and A1 address pins. Each device is assigned a unique 2-bit hardware address, allowing independent addressing within the same 7-bit I²C slave address space. The A2 pin is non-configurable and must be tied to VCC; it does not contribute to device addressing. This configuration enables up to 2 Mbit of contiguous EEPROM capacity across the bus.

What is the maximum page write size supported by the 24AA515T-I/SM, and what happens if more than 64 bytes are sent before the Stop condition?

The 24AA515T-I/SM supports a maximum page write size of 64 bytes. If more than 64 bytes are transmitted before the Stop condition, the internal address pointer wraps around within the current page, overwriting previously loaded data starting from the page base address. This behavior is intentional and documented-application firmware must enforce page boundaries (aligned to 64-byte intervals) to avoid unintended data corruption during multi-byte writes.

Does the 24AA515T-I/SM support sequential reads across the full 64K address space, or are there limitations?

The 24AA515T-I/SM supports sequential reads only within two fixed 32K-byte blocks: 0000h–7FFFh and 8000h–FFFFh. Attempting to read past 7FFFh will cause the internal address pointer to roll over to 0000h, and reading past FFFFh rolls over to 8000h. To read the entire memory linearly, software must issue separate sequential read commands for each block or use random-read addressing with explicit address pointers.