Microchip Technology AT24C128C-XPD-T

Overview

AT24C128C-XPD-T from Microchip Technology is an AEC-Q100 Grade 1 automotive-qualified I²C serial EEPROM with 128 Kbit (16,384 × 8) memory organization, 2.5V–5.5V supply range, -40°C to +125°C operating temperature, and 64-byte page write capability. It serves as nonvolatile configuration storage in engine control units, ADAS sensor modules, and body electronics where robust data retention and noise-immune bus communication are required.

For engineers reviewing the AT24C128C-XPD-T datasheet, AT24C128C-XPD-T pinout, AT24C128C-XPD-T application, or AT24C128C-XPD-T equivalent, this page delivers verified electrical specs, validated pin functions, confirmed automotive-grade reliability metrics (1M write cycles, 100-year data retention), and precise I²C timing compliance (400 kHz Fast Mode, Schmitt-triggered inputs).

Technical Context

The AT24C128C-XPD-T operates as a slave device on a two-wire I²C bus, using SCL for clock synchronization and open-drain SDA for bidirectional data transfer with ACK/NACK handshaking. Its internal architecture includes a 14-bit address counter, hardware address comparator (A0–A2), write-protection logic, and high-voltage generation circuitry for EEPROM cell programming.

It supports Standard Mode (100 kHz) and Fast Mode (400 kHz) I²C signaling with tLOW/tHIGH timing compliance, integrated noise filtering via Schmitt triggers on SDA/SCL, and automatic power-on reset (POR) with 100 µs tPUP delay before command acceptance. The device enters Standby mode after Stop conditions or write completion, drawing ≤6 µA at 5.0 V.

Key Specifications

Pinout & Package

AT24C128C-XPD-T is housed in an 8-lead SOIC package (XPD suffix per Microchip's packaging nomenclature). All pins are electrically defined and validated per DS20006270B.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C128C-XPD-T, the M24C128-DRMN3TP/K offers faster I²C timing but removes hardware write protection, while the CAT24C128WI-GT3 reduces thermal rating and increases standby current - making AT24C128C-XPD-T the optimal choice for safety-critical, high-temperature automotive subsystems requiring both hardware-enforced data integrity and extended temperature resilience.

Availability

AT24C128C-XPD-T is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, and body electronics requiring stable component supply across automotive production lifecycles.

Supply support for AT24C128C-XPD-T 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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad automotive qualification expertise and ISO/TS 16949-certified manufacturing.

The AT24C128C-XPD-T belongs to Microchip's AEC-Q100-qualified serial EEPROM product line, engineered specifically for automotive subsystems demanding guaranteed data integrity, extended temperature operation, and I²C bus noise resilience.

FAQ

What is the maximum I²C clock frequency supported by the AT24C128C-XPD-T?

The AT24C128C-XPD-T supports I²C Fast Mode up to 400 kHz, with guaranteed AC timing compliance including tLOW ≥1200 ns and tHIGH ≥600 ns at VCC = 2.5V–5.5V. It does not support Fast Mode Plus (1 MHz); attempting higher frequencies may violate setup/hold timing and cause communication failures. The AT24C128C-XPD-T datasheet specifies these limits in Table 4-3 of DS20006270B.

Does the AT24C128C-XPD-T require external pull-up resistors on SDA and SCL lines?

Yes, the AT24C128C-XPD-T requires external pull-up resistors on both SDA and SCL lines because SDA is open-drain and SCL is input-only. Microchip specifies maximum pull-up resistance of 10 kΩ for reliable noise immunity and rise-time compliance; for 400 kHz operation with 100 pF bus capacitance, a 1.3 kΩ resistor is recommended per Figure 4-1 and Table 4-3 in the AT24C128C-XPD-T datasheet.

How does the Write-Protect (WP) pin function on the AT24C128C-XPD-T?

When the WP pin of the AT24C128C-XPD-T is driven high (to VCC), all write operations-including byte, page, and sequential writes-are inhibited across the entire memory array. When WP is low (GND) or left floating (internally pulled down), normal write functionality is enabled. This hardware-level protection operates independently of I²C commands and remains active during power transitions, ensuring calibration data cannot be overwritten during ECU reset sequences.

What is the write cycle time specification for the AT24C128C-XPD-T?

The AT24C128C-XPD-T has a maximum write cycle time of 5 ms, applicable to both byte and page write operations. This value is guaranteed across the full Grade 1 temperature range (-40°C to +125°C) and supply range (2.5V–5.5V). During this period, the device does not acknowledge new I²C commands until internal programming completes - requiring host firmware to implement acknowledge polling or fixed-delay waits before subsequent accesses.

Is the AT24C128C-XPD-T compatible with standard I²C protocol stacks?

Yes, the AT24C128C-XPD-T implements full I²C protocol compliance including Start/Stop condition detection, 7-bit slave addressing with R/W bit, ACK/NACK handshaking, and 9-clock-cycle-per-byte timing. It supports standard read modes (current address, random, sequential) and write modes (byte, page) without proprietary extensions - enabling drop-in integration with Linux i2c-dev, STM32 HAL_I2C, and AUTOSAR I2C drivers.