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Renesas X28HC256PZ-90
- Part No.:
- X28HC256PZ-90
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-DIP (0.600", 15.24mm)
- Datasheet:
-
X28HC256PZ-90.pdf
- Description:
- IC EEPROM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,706
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Product details
Overview
X28HC256PZ-90 from Intersil is a 256k-bit (32k × 8), 5V-only, byte-alterable EEPROM with 90ns access time, fabricated using textured poly floating gate CMOS technology. It supports 128-byte page writes (≤0.8s full rewrite), DATA and Toggle bit polling for early write completion detection, and JEDEC-standard software data protection. It serves as nonvolatile configuration storage in industrial control modules requiring reliable, low-voltage reprogramming.
For engineers reviewing the X28HC256PZ-90 datasheet, X28HC256PZ-90 pinout, X28HC256PZ-90 application, or X28HC256PZ-90 equivalent, this page delivers verified electrical specs, PDIP-28 package mapping, endurance (100,000 cycles), data retention (100 years), and real-world timing behavior under 5V ±10% operation - all critical for legacy system refresh, firmware parameter storage, and power-cycle-resilient design validation.
Technical Context
The X28HC256PZ-90 implements a two-line control architecture (CE/OE for reads, CE/WE for writes) to eliminate bus contention in multi-device memory arrays. Its Direct Write™ cell structure enables single 5V supply operation with no external high-voltage programming circuitry, erase-before-write, or complex algorithms.
It features dual write-status signaling: I/O7 DATA polling (complement read during programming) and I/O6 Toggle bit (state alternation until write completion). Hardware protection includes VCC sense (write inhibit below ~3.5V) and signal-level inhibition via OE HIGH, WE HIGH, or CE HIGH during power transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256 kbit (32,768 × 8 bits) - provides sufficient space for boot parameters, calibration tables, and device identity in embedded controllers. |
| Access time | 90 ns - enables direct interface with 8-bit microcontrollers running at ≤10 MHz without wait states. |
| Write cycle time | 3–5 ms typical - defines minimum system delay between consecutive byte writes unless polling is used. |
| Endurance | 100,000 write cycles per byte - supports field-updatable firmware storage in industrial equipment with multi-year service life. |
| Data retention | 100 years at +25°C - ensures long-term integrity of stored configuration data without battery backup. |
| Supply voltage | 5 V ±10% - compatible with standard TTL/CMOS logic rails and legacy 5V power domains. |
| Operating temperature | 0°C to +70°C - qualified for commercial-grade applications including test equipment and peripheral controllers. |
| Power consumption | 60 mA active / 500 µA standby - enables low-quiescent-power operation in always-on systems with periodic updates. |
Pinout & Package
Package: 28-pin Plastic Dual In-line Package (PDIP), RoHS compliant, body width 0.600 inch (E28.6 drawing).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address inputs | 15-bit address bus selecting one of 32,768 bytes; A7–A14 define page address for 128-byte page writes. |
| I/O0–I/O7 | Bi-directional data bus | 8-bit parallel interface for read/write; I/O6 and I/O7 carry toggle and data polling status during internal programming. |
| CE | Chip Enable | Active-low primary device select; must be LOW for all read/write operations; drives device into standby when HIGH. |
| OE | Output Enable | Active-low output control; enables data drivers during reads; HIGH during writes to prevent bus conflicts. |
| WE | Write Enable | Active-low write strobe; latches data on rising edge; controls initiation and timing of byte/page programming cycles. |
| VCC | Power supply | +5 V supply pin; requires local 0.1 µF ceramic decoupling per device to suppress transient current spikes. |
| VSS | Ground | Reference ground; must be connected directly to system common ground plane with low-inductance path. |
Key Features
| Feature | Design Value |
|---|---|
| 90 ns access time | Enables zero-wait-state integration with legacy 8-bit MCUs (e.g., 8051, Z80) operating at up to 10 MHz clock frequency. |
| 128-byte page write | Reduces total programming time for bulk updates: full 32k-byte memory rewrite completes in under 0.8 seconds. |
| DATA polling (I/O7) | Allows host software to poll completion status without interrupts or external hardware - simplifies firmware implementation. |
| Toggle bit polling (I/O6) | Eliminates need to store last written address/data; toggling ceases only when write is complete - robust for multi-device arrays. |
| JEDEC software data protection | Nonvolatile lock activated by 3-byte sequence; prevents accidental writes during power-up/down and runtime - enhances field reliability. |
| Direct Write™ cell | Textured poly floating gate technology ensures 100,000 write cycles and 100-year data retention without wear leveling or ECC overhead. |
Applications
| Industrial PLC Configuration Storage | Medical Device Calibration Data |
|---|---|
|
Use Scenario: Storing I/O mapping, PID tuning constants, and alarm thresholds in programmable logic controllers deployed in factory automation environments. IC Role / Device Role / Timing Role: Nonvolatile parameter register accessed during boot and runtime; 90 ns read speed supports deterministic scan cycle execution. Use Value: Eliminates need for battery-backed SRAM; 100,000-cycle endurance accommodates weekly calibration updates over 10+ years. |
Use Scenario: Retaining sensor offset/gain coefficients and patient-specific therapy settings in portable infusion pumps and diagnostic monitors. IC Role / Device Role / Timing Role: Secure configuration vault; software data protection prevents corruption during unexpected power loss during firmware update. Use Value: 100-year data retention meets medical device regulatory requirements for lifetime traceability without periodic refresh. |
| Test Equipment Firmware Patching | Legacy Industrial Gateway Bootloader |
|
Use Scenario: Field-updating instrument firmware patches and measurement algorithm revisions in benchtop oscilloscopes and signal generators. IC Role / Device Role / Timing Role: Secondary code storage executed after primary ROM boot; page write capability enables fast patch loading via serial interface. Use Value: 0.8 s full-memory rewrite allows sub-second firmware recovery - critical for minimizing instrument downtime during service. |
Use Scenario: Holding bootloader configuration (network IP, UART baud rate, watchdog timeout) in DIN-rail-mounted protocol gateways interfacing Modbus RTU to Ethernet. IC Role / Device Role / Timing Role: Power-cycle-resilient settings store; VCC-sense hardware protection ensures no spurious writes during brown-out conditions. Use Value: RoHS-compliant PDIP-28 package supports through-hole wave soldering - ideal for long-lifecycle industrial PCB manufacturing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT28C256-15PU | 150 ns access time; same 28-pin PDIP, 5V-only, 32k×8 architecture; 100,000 cycles endurance. | Larger read access time increases MCU wait states; lacks Toggle bit polling (only DATA polling). | Select when cost sensitivity outweighs timing performance and simplified polling is acceptable. |
| MX28LV256APCI-90G | 90 ns access; 28-pin SOIC (not PDIP); 3.3V/5V tolerant; software protection via 6-byte unlock sequence. | Requires PCB redesign for SOIC footprint; supports dual-voltage systems but not drop-in PDIP replacement. | Choose for new designs needing 3.3V compatibility or higher-density packaging; not suitable for PDIP socket reuse. |
Compared with AT28C256-15PU and MX28LV256APCI-90G, the X28HC256PZ-90 uniquely combines 90 ns speed, PDIP-28 legacy compatibility, dual polling methods, and JEDEC-standard software protection - making it optimal for upgrading existing 5V industrial controllers without layout changes or firmware rewrite.
Availability
X28HC256PZ-90 is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, and test equipment requiring stable component supply across extended product lifecycles.
Supply support for X28HC256PZ-90 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 semiconductor manufacturer specializing in precision analog and power management ICs for industrial, infrastructure, and high-end consumer markets.
The X28HC256PZ-90 belongs to Intersil's second-generation CMOS EEPROM product line, designed specifically for robust, 5V-only nonvolatile storage in legacy and long-lifecycle embedded systems where reliability and ease of integration are paramount.
FAQ
What is the maximum operating temperature range for the X28HC256PZ-90?
The X28HC256PZ-90 is specified for commercial operation from 0°C to +70°C. This range is confirmed in the Ordering Information table (Page 2) and Recommended Operating Conditions (Page 4) of the FN8108 Rev 5.00 datasheet. It is not rated for industrial (-40°C to +85°C) operation - that specification applies to variants with "I" suffixes like X28HC256PIZ-90.
Does the X28HC256PZ-90 require external high-voltage programming circuitry?
No. The X28HC256PZ-90 operates with a single 5V supply and uses Intersil's Direct Write™ floating gate technology. As stated on Page 1, it requires "No external high voltages or VP-P control circuits," and all write operations are self-timed with no erase-before-write requirement - eliminating need for charge pumps or HV generators.
How does software data protection work on the X28HC256PZ-90?
Software data protection on the X28HC256PZ-90 is enabled by writing three specific values (0xAA, 0x55, 0xA0) to addresses 0x5555, 0x2AAA, and 0x5555 respectively. Once set, the device remains write-protected across power cycles until the six-step reset sequence is issued. This feature is detailed in Figures 12–15 and Pages 12–14 of the datasheet.
Can the X28HC256PZ-90 be used in place of the X28HC256PZ-15?
Yes, the X28HC256PZ-90 is a direct functional upgrade to the -15 variant, offering faster 90 ns access versus 150 ns. Both share identical PDIP-28 packaging, pinout, voltage, temperature, and command sets. No hardware or firmware changes are needed - the -90 improves system timing margin while maintaining full backward compatibility.
What is the purpose of the NC pins on the X28HC256PZ-90 PDIP package?
The X28HC256PZ-90 in PDIP-28 has no NC (No Connect) pins. Per the Pin Descriptions table (Page 3), all 28 pins are assigned: A0–A14 (15 pins), I/O0–I/O7 (8), CE, OE, WE, VCC, VSS. Unlike PLCC variants which list NC pins (e.g., pins 1, 12, 17, 26), the PDIP version fully utilizes all leads - confirming no unused terminals exist in this package variant.
X28HC256PZ-90 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 28-DIP (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- 90 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-PDIP
X28HC256PZ-90 FAQ
1.How can I place an order for X28HC256PZ-90 through Aetrix?
Please submit a Request for Quotation (RFQ) for X28HC256PZ-90 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for X28HC256PZ-90 reliable?
The price and inventory of X28HC256PZ-90 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X28HC256PZ-90 is usually 5 days.
3.What payment methods are accepted for X28HC256PZ-90?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X28HC256PZ-90 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for X28HC256PZ-90?
X28HC256PZ-90 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your X28HC256PZ-90 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for X28HC256PZ-90?
For technical support, including X28HC256PZ-90 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X28HC256PZ-90 requirements.
6.How does Aetrix verify that X28HC256PZ-90 is sourced from the original manufacturer or authorized distributors?
All X28HC256PZ-90 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that X28HC256PZ-90 meets industry standards.
7.What is the process for return or replacement of X28HC256PZ-90?
All X28HC256PZ-90 units undergo pre-shipment inspection (PSI). If there is an issue with X28HC256PZ-90, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The X28HC256PZ-90 part is unused and in its original packaging.
Return procedure for X28HC256PZ-90:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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