NXP Semiconductors PCA24S08D,112

Overview

PCA24S08D,112 from NXP Semiconductors is a 1024 × 8-bit (8 kbit) serial CMOS EEPROM with I²C-bus interface, access protection logic, and 8-block memory architecture. It operates from 2.5 V to 3.6 V, supports up to 400 kHz clock frequency, and delivers 100,000 write cycles with 10-year data retention. It is used in secure firmware storage, calibration data logging, and configuration parameter retention in industrial controllers.

For engineers reviewing the PCA24S08D,112 datasheet, PCA24S08D,112 pinout, PCA24S08D,112 application, or PCA24S08D,112 equivalent, key selection criteria include block-level read/write protection capability, SO8 package compatibility, WP/PROT pin control behavior, page-aligned 16-byte write timing (<5 ms), and I²C address mapping (A8h–AFh for main array, B8h/B9h for APP/ID pages).

Technical Context

The PCA24S08D,112 implements an I²C-compatible two-wire serial interface with slave address range A8h–AFh (main memory) and B8h/B9h (access protection and ID pages). Its internal architecture divides 8192 bits into eight 128-byte blocks, each further subdivided into eight 16-byte pages - enabling granular access control via programmable protection bits (PB) and sticky bits (SB).

Protection logic operates at three levels: full-chip write protect (WP pin HIGH), per-block access permissions (PB0–PB7), and per-page write enable for Block 0 (WPN0–WPN7). The PROT pin serves as a power-good reset signal that forces serial port reset and sets all sticky bits to '1' when asserted LOW.

Key Specifications

Pinout & Package

PCA24S08D,112 is supplied in SO8 package (SOT96-1), 3.9 mm body width, 1.27 mm lead pitch. Pins 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-RMN6TP, the PCA24S08D,112 uniquely combines I²C compatibility with multi-layer hardware/software access control - making it the only option among the three supporting certified secure parameter storage in regulated industrial and medical systems.

Availability

PCA24S08D,112 is available at Aetrix Electronics and suitable for industrial PLCs, medical calibration systems, automotive body controllers, and smart meter deployments requiring stable component supply, long-lifecycle assurance, and secure non-volatile storage.

Supply support for PCA24S08D,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 applications.

The PCA24S08D,112 belongs to NXP's serial EEPROM product line designed specifically for systems requiring tamper-resistant configuration storage, hierarchical access control, and industrial-grade reliability in constrained 3.3 V environments.

FAQ

What is the function of the PROT pin on the PCA24S08D,112?

The PROT pin on the PCA24S08D,112 is an active-LOW input that resets the serial interface and sets all sticky bits (SB0–SB7, SBAP) to logic '1' when asserted. This action locks current protection states and prevents further modification of protection registers until the next power cycle or PROT deassertion. It does not affect main memory contents but ensures deterministic recovery from fault conditions. The PCA24S08D,112 requires this pin to be pulled HIGH during normal operation to enable I²C communication.

How does the PCA24S08D,112 differ from standard 24C08 EEPROMs in pin configuration?

The PCA24S08D,112 differs from standard 24C08 devices in that pins 1, 2, and 3 are not connected (n.c.) instead of serving as address inputs (A0–A2). Pin 3 is repurposed as the active-LOW PROT input. This change eliminates hardware address selection but adds hardware-level protection reset capability. The PCA24S08D,112 uses fixed I²C addresses A8h–AFh derived from internal logic rather than external pin strapping, simplifying board design while removing address flexibility.

Can the PCA24S08D,112 perform multi-byte reads across block boundaries?

No, the PCA24S08D,112 does not allow multi-byte reads to cross 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 - not the next block. This behavior is explicitly defined in Section 6.6 as a serial EEPROM exception and ensures predictable memory access within protected zones. To read across blocks, the host controller must issue separate read commands with updated word addresses for each target block.

What happens when more than 16 bytes are transmitted during a page write to the PCA24S08D,112?

When more than 16 bytes are transmitted before the STOP condition in a page write sequence, the PCA24S08D,112 ignores the 17th and subsequent bytes - issuing no ACK and discarding the excess data. No programming occurs for those bytes, and the internal write cycle proceeds only on the first 16 valid bytes. Overlapping writes may corrupt data within the target page. The PCA24S08D,112 enforces strict 16-byte alignment; exceeding this limit requires segmented write commands with proper address incrementing between pages.

How is access protection configured for Block 0 versus Blocks 1–7 on the PCA24S08D,112?

For Blocks 1–7, access protection is controlled solely at the block level using two-bit PB fields (PB1–PB7) stored in the APP page - allowing read-only or full read/write access per block. Block 0 supports additional granularity: its eight 16-byte pages can be individually write-enabled via WPN0–WPN7 bits (in APP byte 9), but only when PB0 = 11b. If PB0 ≠ 11b, WPN bits are ignored and Block 0 protection defaults to the PB0 setting. This hierarchy makes Block 0 uniquely configurable for mixed-access applications like boot code + runtime parameters.