NXP Semiconductors PCA24S08AD,112

Overview

The PCA24S08AD,112 from NXP Semiconductors is a 1024 × 8-bit I²C-compatible serial EEPROM with programmable access protection, organized into eight 128-byte blocks and supporting byte/page write (up to 16 bytes), sequential/random read, and block- and page-level write protection. It operates from 2.5 V to 3.6 V and delivers 100,000 write cycles with 10-year data retention - used in secure firmware storage, calibration data logging, and configuration management in industrial controllers.

For engineers reviewing the PCA24S08AD,112 datasheet, PCA24S08AD,112 pinout, PCA24S08AD,112 application, or PCA24S08AD,112 equivalent, this device offers verified I²C timing compliance up to 400 kHz, SO8 package compatibility with standard 24C08 footprints (pins 1–3 repurposed), and hardware-enforced memory partitioning via PROT/WP pins and dedicated Access Protection Page (APP) at B8h/B9h addresses.

Technical Context

The PCA24S08AD,112 implements an I²C-bus interface with open-drain SDA/SCL, internal power-on reset, and auto-increment addressing logic for sequential reads/writes. Its memory architecture separates main data (A8h–AFh) from protected control space (B8h/B9h), enabling independent access to 8-block APP registers and ID page.

Protection is enforced hierarchically: WP pin disables all writes when HIGH; PROT pin resets sticky bits and holds serial port in reset when LOW; and per-block PB bits (in APP) combined with SB bits determine read/write permissions - with Block 0 further subdivided into eight 16-byte pages controlled by WPN bits.

Key Specifications

Pinout & Package

PCA24S08AD,112 is supplied in SO8 package (SOT96-1), 3.9 mm body width, 8-lead plastic small outline format. Pin 1 and 2 are not connected; Pin 3 is active-LOW PROT input; Pin 4 is VSS; Pin 5 is open-drain SDA; Pin 6 is open-drain SCL; Pin 7 is active-HIGH WP; Pin 8 is VDD.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C08C-PU and M95M01-RDW6TP, the PCA24S08AD,112 uniquely delivers I²C-compatible 8-kbit storage with hardware-enforced, field-programmable memory segmentation - enabling secure multi-zone data management without protocol or footprint changes.

Availability

PCA24S08AD,112 is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data logging, and automotive body control module applications requiring stable component supply and long-term lifecycle assurance.

Supply support for PCA24S08AD,112 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 markets.

The PCA24S08AD,112 belongs to NXP's serial EEPROM product line designed for applications demanding robust non-volatile storage with hardware-backed access control - particularly where firmware integrity, calibration security, and long-term field reliability are critical.

FAQ

What is the I²C address range supported by the PCA24S08AD,112 for main memory access?

The PCA24S08AD,112 uses slave addresses A8h through AFh (hex) for accessing its main 1024-byte memory array. These addresses incorporate two software-selectable bits (B2, B1) in the address byte to select among eight 128-byte blocks. The R/W bit determines operation direction, and the device responds with ACK only when the full address matches its internal decoding logic.

How does the PROT pin affect the operation of the PCA24S08AD,112?

The PROT pin on the PCA24S08AD,112 is an active-LOW input that resets all sticky bits (SB0–SB7, SBAP) to logic 1 and holds the serial interface in reset when asserted. While PROT is LOW, no I²C transactions are processed. This provides hardware-level initialization control and ensures permission registers revert to default-unlocked state after power-on or service reset.

Can the PCA24S08AD,112 perform multi-byte writes across page boundaries?

No, the PCA24S08AD,112 does not support multi-byte writes across page boundaries. Page writes are limited to 16 bytes aligned to internal 16-byte page boundaries (00h–0Fh, 10h–1Fh, etc.). Attempting to write more than 16 bytes or crossing a page boundary results in NACK after the 16th byte and corrupts overlapping data - strict alignment is required for reliable programming.

What is the function of the Access Protection Page (APP) and how is it addressed?

The Access Protection Page (APP) in the PCA24S08AD,112 is a dedicated 16-byte EEPROM region (addressed via I²C device code B8h) storing per-block protection bits (PB), sticky bits (SB), WPN bits for Block 0, and system control flags. It is physically separate from main memory and accessed exclusively using B8h (APP) or B9h (ID page) - not A8h–AFh - ensuring isolation of security metadata from user data.

Is the PCA24S08AD,112 pin-compatible with standard 24C08 devices?

The PCA24S08AD,112 is partially pin-compatible with standard 24C08 EEPROMs: pins 4–8 (VSS, SDA, SCL, WP, VDD) match functionally, but pins 1, 2, and 3 differ - they are n.c. and PROT instead of A0, A1, A2. PCB layout must accommodate this difference; direct replacement requires verification of address pin handling and PROT/WP signal routing in the host design.