NXP Semiconductors PCA24S08D,118

Overview

The PCA24S08D,118 from NXP Semiconductors is a 1024 × 8-bit I²C-compatible serial EEPROM with hardware-based access protection, operating from 2.5 V to 3.6 V, supporting up to 400 kHz clock frequency, and delivering 100,000 write cycles with 10-year data retention. It is used for secure parameter storage in industrial control modules where block-level read/write permissions prevent unauthorized firmware or calibration updates.

For engineers reviewing the PCA24S08D,118 datasheet, PCA24S08D,118 pinout, PCA24S08D,118 application, or PCA24S08D,118 equivalent, this page provides verified pin functions, real-world access protection behavior, block/page-level permission mapping, SO8 package mechanical details, and validated alternative parts for design continuity.

Technical Context

The PCA24S08D,118 implements an I²C slave interface with fixed 7-bit address range A8h–AFh (B2/B1 software-selectable), where the R/W bit determines operation mode. Its memory is partitioned into eight 128-byte blocks, each containing eight 16-byte pages, plus two dedicated 16-byte auxiliary pages (APP and ID) accessed via B8h/B9h device addresses.

Access protection operates at three levels: full-chip write protect (WP pin HIGH), per-block read/write permissions (PB bits in APP page), and per-page write enable for Block 0 (WPN bits). Sticky bits (SBx) lock PB/WPN configuration once cleared, and PROT pin resets sticky bits and holds serial port in reset when LOW.

Key Specifications

Pinout & Package

PCA24S08D,118 is supplied in SO8 package (SOT96-1): plastic small outline, 8 leads, 3.9 mm body width, 1.27 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24RF08C, PCA24S08D,118 removes redundant RF hardware while preserving identical protection architecture and software interface; compared with M95M01-RDW6TP, it trades SPI speed and density for I²C simplicity and hardware-enforced access segmentation essential in safety-critical firmware storage.

Availability

PCA24S08D,118 is available at Aetrix Electronics and suitable for industrial sensor calibration, secure bootloader parameter vaults, medical device configuration lockdown, and automotive diagnostic module ID storage requiring stable component supply across extended product lifecycles.

Supply support for PCA24S08D,118 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCA24S08D,118 belongs to NXP's serial EEPROM product line designed specifically for systems requiring hardware-enforced memory access control, tamper resistance, and long-term reliability in harsh environments.

FAQ

What is the function of the PROT pin on the PCA24S08D,118?

The PROT pin on the PCA24S08D,118 is an active-LOW reset input that clears all sticky bits (SB0–SB7, SBAP) and places the serial interface in reset when asserted. When HIGH, normal I²C communication resumes. This allows secure initialization sequences - for example, asserting PROT during power-up ensures protection registers start in a known unlocked state before firmware configures them. The PCA24S08D,118 does not operate correctly if PROT remains LOW during normal read/write operations.

How does the PCA24S08D,118 implement block-level write protection?

The PCA24S08D,118 uses Protection Bits (PB0–PB7) stored in the Access Protection Page (APP) to control per-block access. Each PB field is 2 bits: '11' enables full read/write, '10' allows reads only (writes NACKed), and '00'/'01' disable both. These bits are enforced only after corresponding Sticky Bits (SBx) are cleared. The PCA24S08D,118 applies this logic independently to Blocks 0–7, with Block 0 further supporting page-level write enable via WPN0–WPN7 bits.

Can the PCA24S08D,118 be used as a direct replacement for standard 24C08 EEPROMs?

The PCA24S08D,118 is pin compatible with 24C08 devices except for pins 1, 2, and 3 (n.c. vs. address pins), and supports identical I²C protocols, addressing, and timing. However, its access protection features, APP/ID page addressing (B8h/B9h), and PROT pin functionality require firmware awareness. The PCA24S08D,118 operates correctly in legacy 24C08 designs only if pins 1–3 are left unconnected and protection features remain unused.

What is the maximum clock frequency supported by the PCA24S08D,118 I²C interface?

The PCA24S08D,118 supports I²C fast-mode operation up to 400 kHz, as confirmed in its dynamic characteristics table. This allows efficient bulk reads/writes while maintaining compatibility with standard microcontroller I²C peripherals. At 400 kHz, the minimum SCL HIGH and LOW periods are 0.6 μs and 1.3 μs respectively. The PCA24S08D,118 also fully supports standard-mode (100 kHz) for backward compatibility with older controllers.

How is the ID page accessed and what data does it contain in the PCA24S08D,118?

The ID page of the PCA24S08D,118 is accessed using device address B9h and word addresses 10h–1Fh (16 bytes). It contains manufacturer-assigned identification data, including revision code (byte 15 = 10h) and reserved fields. Access requires PBAP bits in the APP page (byte 8) to be set to '11'. Reads/writes to the ID page occur one byte at a time - multi-byte transfers are NACKed. The PCA24S08D,118 returns FFh for byte 14 on read, and ignores writes to bytes 14–15, though they are acknowledged.