NXP Semiconductors PCA24S08AD,118

Overview

The PCA24S08AD,118 from NXP Semiconductors is a 1024 × 8-bit I²C-compatible serial EEPROM with hardware-based access protection, organized into eight 128-byte blocks and supporting byte/page write (up to 16 bytes), sequential/random read, and programmable block- and page-level read/write permissions. It operates from 2.5 V to 3.6 V and delivers 100,000 write cycles with 10-year data retention - deployed in secure firmware storage, calibration data logging, and configuration management for industrial controllers.

For engineers reviewing the PCA24S08AD,118 datasheet, PCA24S08AD,118 pinout, PCA24S08AD,118 application, or PCA24S08AD,118 equivalent, this device offers verified I²C timing compliance up to 400 kHz, SO8 package compatibility with standard 24C08 footprints (with pin 1–3 reassignment), WP/PROT hardware lock control, and dedicated Access Protection Page (APP) addressing via B8h/B9h commands.

Technical Context

The PCA24S08AD,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 architecture separates main data (1024 × 8 bits) from protected metadata: two additional 128-bit pages store access control (APP) and ID information, accessed only via alternate device addresses B8h/B9h.

Protection logic uses sticky bits (SB0–SB7, SBAP) and 2-bit protection fields (PB0–PB7, PBAP) stored in EEPROM to enforce per-block read/write permissions; Block 0 further supports eight individual 16-byte page write-protection bits (WPN0–WPN7). The PROT pin resets the serial interface and sets all sticky bits on LOW assertion.

Key Specifications

Pinout & Package

PCA24S08AD,118 is supplied in SO8 package (SOT96-1), 8-lead plastic small outline, 3.9 mm body width. Pin 1 and 2 are not connected; pin 3 is active-low PROT reset input; pin 7 is active-high WP write protect; pins 5 (SDA) and 6 (SCL) are open-drain I²C bus interfaces.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C08C-PU and M95M01-RMN6TP, the PCA24S08AD,118 uniquely integrates hardware-enforced, field-programmable access control at the device level - eliminating reliance on software-only safeguards and enabling true separation of trusted vs. modifiable data regions within a single I²C slave.

Availability

PCA24S08AD,118 is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, and automotive infotainment systems requiring stable component supply, long-term data integrity, and hardware-backed memory protection.

Supply support for PCA24S08AD,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 PCA24S08AD,118 belongs to NXP's serial EEPROM product line designed for systems demanding hardware-enforced data integrity, tamper resistance, and seamless integration into I²C-based embedded control architectures.

FAQ

What is the function of the PROT pin on the PCA24S08AD,118?

The PROT pin on the PCA24S08AD,118 is an active-low reset input that places the I²C interface in reset state and sets all sticky bits (SB0–SB7, SBAP) to logic '1' when held LOW. This action prevents modification of protection bits until the pin is released HIGH, ensuring deterministic recovery of access control states after power-up or fault conditions. The PCA24S08AD,118 requires this signal to initialize its protection hierarchy before normal I²C communication begins.

How does the PCA24S08AD,118 differ from standard 24C08 EEPROMs in pin assignment?

The PCA24S08AD,118 differs from standard 24C08 devices in pins 1, 2, and 3: pins 1 and 2 are not connected (n.c.), whereas standard 24C08 uses them for address inputs A0 and A1; pin 3 is the active-low PROT reset input, not address bit A2. All other pins (VSS, SDA, SCL, WP, VDD) retain identical functions and positions. This reassignment enables hardware reset and protection state initialization unavailable in legacy 24C08 parts.

Can the PCA24S08AD,118 perform multi-byte reads across block boundaries?

No, the PCA24S08AD,118 does not support multi-byte reads crossing block boundaries. When a sequential read reaches the end of a 128-byte block, the internal address counter wraps around to the start of that same block rather than advancing to the next block. This behavior is explicitly defined in Section 6.6 of the PCA24S08AD,118 datasheet as a functional exception versus standard 24C08 devices and must be accounted for in host firmware address management.

What addressing scheme does the PCA24S08AD,118 use for its Access Protection Page (APP)?

The PCA24S08AD,118 uses dedicated I²C device addresses B8h (write) and B9h (read) to access its Access Protection Page (APP) and ID page - distinct from the main memory's A8h–AFh address range. The second byte (word address) must be 00h–0Fh for APP and 10h–1Fh for ID; multi-byte transfers to these pages are NACKed. This isolation ensures protection metadata cannot be altered via standard memory commands, preserving security integrity in the PCA24S08AD,118.

Is the PCA24S08AD,118 compatible with 400 kHz Fast-mode I²C timing?

Yes, the PCA24S08AD,118 fully supports Fast-mode I²C operation up to 400 kHz, as confirmed in Table 8 of its datasheet under "Fast-mode I²C-bus" conditions. It meets all timing parameters including tLOW (1.3 μs min), tHIGH (0.6 μs min), tf (300 ns max), and tr (300 ns max) with CL = 100 pF. No external speed-binning or derating is required - the PCA24S08AD,118 operates reliably across its full 0–400 kHz range within specified VDD and temperature limits.