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Microchip Technology 25LC256-E/ST16KVAO
- Part No.:
- 25LC256-E/ST16KVAO
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC256-E/ST16KVAO.pdf
- Description:
- IC EEPROM 256KBIT SPI 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,799
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Product details
Overview
25LC256-E/ST16KVAO from Microchip Technology Inc. is a 256 Kbit SPI Serial EEPROM with 32,768 × 8-bit organization, 64-byte page size, and 2.5–5.5 V supply range. It supports up to 10 MHz clock frequency, delivers 5 mA max write current at 5.5 V, and offers 1 μA standby current - enabling low-power embedded data logging in automotive control modules.
For engineers reviewing the 25LC256-E/ST16KVAO datasheet, 25LC256-E/ST16KVAO pinout, 25LC256-E/ST16KVAO application, or 25LC256-E/ST16KVAO equivalent, key selection criteria include industrial temperature support (−40°C to +85°C), hardware write protection via WP pin, HOLD functionality for interrupt-safe SPI pauses, and AEC-Q100 qualification for automotive use.
Technical Context
The 25LC256-E/ST16KVAO implements a standard SPI Mode 0,0 interface with separate SI/SO lines, CS-controlled device selection, and HOLD-driven transaction suspension. Its internal architecture includes a write-enable latch, nonvolatile STATUS register with BP0/BP1 block protection bits, and high-voltage generator for EEPROM programming.
It features self-timed internal write cycles (≤5 ms), sequential read with automatic address increment, and page-write capability limited to 64-byte boundaries. Write operations require explicit WREN instruction, and hardware write protection engages only when both WPEN bit is set and WP pin is low.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8-bit) - sufficient for firmware parameter storage, calibration tables, or event logs in resource-constrained controllers. |
| Interface | SPI-compatible serial bus (Mode 0,0) - interoperable with PIC® and most MCU SPI peripherals without protocol translation. |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5 V - enables fast configuration reads and rapid parameter updates in real-time systems. |
| Page Size | 64 bytes - defines maximum contiguous write length; crossing page boundary wraps data within same page, requiring software boundary checks. |
| Endurance & Retention | 1,000,000 erase/write cycles and >200 years data retention - validated for long-life deployment in automotive ECUs and industrial controllers. |
| Operating Temp | −40°C to +85°C (Industrial grade) - certified for under-hood and factory-floor environments without derating. |
| Supply Voltage | 2.5 V to 5.5 V - compatible with 3.3 V and 5 V logic domains, eliminating level-shifting in mixed-voltage designs. |
Pinout & Package
25LC256-E/ST16KVAO is packaged in an 8-lead TSSOP (ST) with 0.65 mm pitch, 4.4 mm body width, and RoHS-compliant matte tin finish. Pin numbering follows standard TSSOP orientation with Pin 1 at top-left corner (not rotated).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable; must be held low for full SPI transaction; rising edge initiates internal write cycle after valid write sequence. |
| SO | Serial Data Output | Tri-state output; data shifts out on falling SCK edge; enters high-Z when CS high or HOLD low. |
| WP | Write-Protect Pin | Hardware lock for STATUS register writes when WPEN bit = 1; no effect on memory writes unless configured in STATUS register. |
| VSS | Ground Reference | Primary return path for all I/O and core circuitry; requires low-impedance connection to minimize noise coupling into EEPROM array. |
| SI | Serial Data Input | Accepts instructions, addresses, and data on rising SCK edge; latched synchronously to avoid metastability in noisy environments. |
| SCK | Serial Clock Input | Master-generated clock; timing parameters (e.g., TCSS, TCSH) define setup/hold margins critical for reliable communication at 10 MHz. |
| HOLD | Hold Input | Pauses ongoing SPI transfer without resetting state; must be asserted while SCK is low to guarantee deterministic behavior during MCU interrupt servicing. |
| VCC | Supply Voltage | Power input for core logic and EEPROM programming; internal charge pump enables write operation across full 2.5–5.5 V range. |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Configurable via STATUS register (BP0/BP1) to protect none, upper 1/4, upper 1/2, or entire 32 KB array - prevents accidental overwrites of critical calibration or security data. |
| Power-On Write Protection | Write enable latch resets at power-up, and WP pin + WPEN bit provide hardware-enforced lockout - eliminates risk of spurious writes during brown-out or reset conditions. |
| HOLD Functionality | Enables atomic pause/resume of SPI transfers without retransmission - essential for time-critical applications where host MCU must service higher-priority interrupts mid-sequence. |
| AEC-Q100 Qualification | Qualified per Automotive Electronics Council stress test requirements - validates reliability for engine control, ADAS, and body electronics deployments. |
| ESD Robustness | ≥4 kV HBM ESD rating on all pins - ensures survivability during board handling, assembly, and field operation in electrically noisy vehicle environments. |
Applications
| Engine Control Unit (ECU) | Industrial PLC Configuration Storage |
|---|---|
|
Use Scenario: Storing fuel map coefficients, sensor calibration offsets, and fault code history in gasoline/diesel engine management systems. IC Role / Device Role / Timing Role: Nonvolatile parameter repository accessed via SPI during boot and runtime; retains data across ignition cycles and battery disconnects. Use Value: Enables adaptive learning and diagnostics without external backup power; AEC-Q100 qualification ensures operation across −40°C to +85°C ambient ranges. |
Use Scenario: Holding ladder logic configuration, I/O mapping, and user-defined alarm thresholds in programmable logic controllers. IC Role / Device Role / Timing Role: Persistent settings store accessed during cold start; supports field updates via HMI or remote maintenance tools. Use Value: 1M endurance allows daily reconfiguration over 27+ years; 64-byte page writes optimize update efficiency for modular parameter sets. |
| Medical Infusion Pump Calibration | Smart Meter Firmware Parameters |
|
Use Scenario: Securing drug delivery rate tables, dose limits, and operator audit logs in Class II medical devices. IC Role / Device Role / Timing Role: Tamper-resistant data vault; WP pin + STATUS register lock prevents unauthorized modification of safety-critical values. Use Value: >200-year data retention meets FDA long-term traceability requirements; 1 μA standby current extends battery life in portable units. |
Use Scenario: Storing tariff schedules, metering constants, and cryptographic keys in utility smart meters deployed in outdoor enclosures. IC Role / Device Role / Timing Role: Secure, field-updatable parameter bank interfaced via isolated SPI to metrology SoC. Use Value: Hardware write protection blocks firmware corruption during power glitches; extended temperature support handles −25°C to +70°C outdoor thermal cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25SF041-SSHD-B | 4 Mbit density, quad-SPI interface, 1.7–2.0 V min VCC, no HOLD pin | Higher capacity and faster quad-read mode, but lacks HOLD for interrupt-safe operation and requires 1.7 V minimum supply | Choose for high-speed firmware storage where HOLD is unnecessary and voltage headroom permits lower VCC |
| BR25L256FJ-WE2 | 256 Kbit, 1.7–5.5 V, built-in error correction (ECC), no WP pin, SOIC-8 only | Includes single-bit ECC for enhanced data integrity in radiation-prone environments, but lacks hardware write protection pin | Prefer for mission-critical industrial systems requiring bit-error resilience, where WP-based protection is implemented in firmware instead |
Compared with AT25SF041-SSHD-B and BR25L256FJ-WE2, the 25LC256-E/ST16KVAO uniquely balances AEC-Q100 qualification, HOLD functionality for deterministic SPI pausing, and dedicated WP pin for hardware-enforced STATUS register locking - making it optimal for automotive and safety-aware embedded control.
Availability
25LC256-E/ST16KVAO is available at Aetrix Electronics and suitable for automotive control units, industrial PLCs, medical infusion pumps, and smart metering systems requiring stable component supply across extended product lifecycles.
Supply support for 25LC256-E/ST16KVAO 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
Microchip Technology Inc. is a leading provider of microcontroller, analog, FPGA, and memory solutions, serving automotive, industrial, consumer, and communications markets with vertically integrated silicon and development tools.
The 25LC256 belongs to Microchip's serial EEPROM product line, designed specifically for robust, low-power, SPI-based nonvolatile data storage in harsh environments - emphasizing reliability, long-term data integrity, and automotive-grade qualification.
FAQ
What is the operating voltage range for the 25LC256-E/ST16KVAO?
The 25LC256-E/ST16KVAO operates from 2.5 V to 5.5 V DC. This wide supply range allows direct integration with both 3.3 V and 5 V microcontroller systems without level shifters. Performance specifications - including 10 MHz max clock and 5 mA write current - are guaranteed across this full range, with timing parameters adjusted per VCC tier (e.g., 10 MHz only at VCC ≥ 4.5 V).
Does the 25LC256-E/ST16KVAO support hardware write protection?
Yes, the 25LC256-E/ST16KVAO supports dual-layer hardware write protection: the WP pin can disable STATUS register writes when the WPEN bit is set, and the STATUS register's BP0/BP1 bits allow configurable block-level memory protection. This combination prevents accidental overwrites of calibration data or security keys even during power transients or firmware faults.
What package type is used for the 25LC256-E/ST16KVAO?
The 25LC256-E/ST16KVAO uses an 8-lead TSSOP (Thin Shrink Small Outline Package) with 4.4 mm body width and 0.65 mm lead pitch, designated by the "ST" suffix in Microchip's packaging nomenclature. It is RoHS-compliant, JEDEC-standardized, and optimized for automated surface-mount assembly with verified land pattern dimensions.
How does the HOLD pin function in the 25LC256-E/ST16KVAO?
The HOLD pin in the 25LC256-E/ST16KVAO suspends an ongoing SPI transaction without resetting internal state. When pulled low while SCK is low, it places SI, SO, and SCK in high-impedance and ignores further input transitions - allowing the host MCU to service urgent interrupts. Resuming requires bringing HOLD high while SCK remains low, after which communication continues seamlessly from the exact byte position.
Is the 25LC256-E/ST16KVAO qualified for automotive applications?
Yes, the 25LC256-E/ST16KVAO is AEC-Q100 qualified for automotive use and rated for Industrial temperature range (−40°C to +85°C). Its qualification includes stress testing for thermal cycling, humidity, and electrical robustness - confirming suitability for engine control, body electronics, and ADAS subsystems where reliability under vibration and thermal extremes is mandatory.
25LC256-E/ST16KVAO Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- EEPROM
- Technology:
- EEPROM
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- SPI
- Clock Frequency:
- 5 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
25LC256-E/ST16KVAO FAQ
1.How can I place an order for 25LC256-E/ST16KVAO through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC256-E/ST16KVAO 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 25LC256-E/ST16KVAO reliable?
The price and inventory of 25LC256-E/ST16KVAO are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC256-E/ST16KVAO is usually 5 days.
3.What payment methods are accepted for 25LC256-E/ST16KVAO?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC256-E/ST16KVAO transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC256-E/ST16KVAO?
25LC256-E/ST16KVAO orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC256-E/ST16KVAO 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 25LC256-E/ST16KVAO?
For technical support, including 25LC256-E/ST16KVAO datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC256-E/ST16KVAO requirements.
6.How does Aetrix verify that 25LC256-E/ST16KVAO is sourced from the original manufacturer or authorized distributors?
All 25LC256-E/ST16KVAO 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 25LC256-E/ST16KVAO meets industry standards.
7.What is the process for return or replacement of 25LC256-E/ST16KVAO?
All 25LC256-E/ST16KVAO units undergo pre-shipment inspection (PSI). If there is an issue with 25LC256-E/ST16KVAO, 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 25LC256-E/ST16KVAO part is unused and in its original packaging.
Return procedure for 25LC256-E/ST16KVAO:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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