Renesas X28HC256PZ-15

Overview

X28HC256PZ-15 from Intersil is a 256 kbit (32k × 8), 5V-only, byte-alterable CMOS EEPROM with 150 ns access time, fabricated using textured poly floating gate technology. It supports 128-byte page writes (≤0.8 s full rewrite), DATA and Toggle bit polling for early write completion detection, and JEDEC-standard software data protection - deployed in industrial control firmware storage and embedded configuration memory.

For engineers reviewing the X28HC256PZ-15 datasheet, X28HC256PZ-15 pinout, X28HC256PZ-15 application, or X28HC256PZ-15 equivalent, key selection criteria include its 28-pin PDIP RoHS-compliant package, 100,000 write endurance, 100-year data retention, 5V ±10% operation, and compatibility with standard TTL/CMOS bus timing.

Technical Context

The X28HC256PZ-15 implements a two-line control architecture (CE/OE for reads, CE/WE for writes) to eliminate bus contention in multi-device memory arrays. Its internal logic latches address on the last falling edge of CE or WE and data on the first rising edge of either signal, enabling robust byte and page write sequencing without external high-voltage circuitry.

It features dual write status reporting via I/O7 (DATA polling) and I/O6 (Toggle bit), both mapped directly to the data bus for software-driven end-of-write detection. Hardware-level protection includes VCC sense (write inhibit below ~3.5 V) and default CE/OE/WE state enforcement during power-up/down transitions.

Key Specifications

Pinout & Package

Package: 28-pin Plastic Dual In-line Package (PDIP), RoHS-compliant, 0.6-inch width (E28.6 drawing), through-hole mountable only (not reflow-compatible).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT28C256-15PU and MX28F256K-15P, the X28HC256PZ-15 delivers true byte-alterability without erase overhead, JEDEC-standard software lock, and guaranteed 100,000-cycle endurance - making it uniquely suited for systems requiring frequent, atomic, and secure nonvolatile updates in legacy 5V parallel bus environments.

Availability

X28HC256PZ-15 is available at Aetrix Electronics and suitable for industrial control firmware storage, medical device calibration memory, and legacy point-of-sale terminal boot code requiring stable component supply across extended production lifecycles.

Supply support for X28HC256PZ-15 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

Intersil Corporation is a leading provider of precision analog and power management solutions, serving industrial, infrastructure, and high-end consumer markets with high-reliability semiconductor products.

The X28HC256PZ-15 belongs to Intersil's second-generation CMOS EEPROM product line, designed specifically for robust, 5V-only nonvolatile memory in legacy embedded systems where byte-level alterability, long data retention, and hardware/software write protection are mandatory.

FAQ

What is the maximum write speed achievable with X28HC256PZ-15?

The X28HC256PZ-15 supports 128-byte page writes, enabling full 256 kbit memory rewrite in under 0.8 seconds. Individual byte writes complete in ≤5 ms (tWC), while page write throughput averages ~160 kB/s. Actual speed depends on host bus timing and polling method - DATA polling reduces average write latency by up to 50% versus fixed-delay approaches.

Does X28HC256PZ-15 require external high-voltage circuitry for programming?

No. The X28HC256PZ-15 operates with a single 5V supply and requires no external high-voltage generators, VP-P controls, or complex programming algorithms. Its Direct Write™ cell technology enables self-timed, erase-free byte and page writes - simplifying design and reducing system BOM cost compared to older EPROM or UV-erasable devices.

How does software data protection work on X28HC256PZ-15?

X28HC256PZ-15 implements JEDEC-standard software data protection: after initial write, a three-byte sequence (AAh to 5555h, 55h to 2AAAh, A0h to 5555h) enables page writes. Once set, further writes are blocked until the sequence repeats. Protection persists across power cycles and remains active until explicitly reset using a six-step unlock algorithm.

Can X28HC256PZ-15 be used in reflow soldering processes?

No. Per Intersil documentation, the Pb-free PDIP package of X28HC256PZ-15 is qualified for through-hole wave soldering only. It is not rated for reflow soldering due to thermal limitations of the plastic body and leadframe. Reflow exposure may cause delamination, voiding, or intermetallic degradation - use only wave or hand-soldering methods.

What are the key differences between X28HC256PZ-15 and X28HC256JZ-15?

X28HC256PZ-15 uses a 28-pin PDIP package and is rated for 0°C to +70°C operation, while X28HC256JZ-15 uses a 32-pin PLCC package and same temperature range. Both share identical electrical specs (150 ns access, 100,000 cycles), but the PDIP version offers through-hole mounting and simpler PCB layout; PLCC supports higher-density surface-mount assemblies.