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Microchip Technology 25LC256T-H/SN
- Part No.:
- 25LC256T-H/SN
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
25LC256T-H/SN.pdf
- Description:
- IC EEPROM 256KBIT SPI 5MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,007
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Product details
Overview
25LC256T-H/SN from Microchip Technology Inc. is a 256-Kbit SPI serial EEPROM organized as 32,768 × 8-bit memory, operating over 2.5V–5.5V supply and supporting up to 5 MHz clock (at VCC ≥ 4.5V). It features byte/page write, hardware write protection via WP pin and STATUS register, and AEC-Q100 qualification for automotive high-temp operation (−40°C to +150°C). Used in engine control units for calibration storage.
For engineers reviewing the 25LC256T-H/SN datasheet, 25LC256T-H/SN pinout, 25LC256T-H/SN application, or 25LC256T-H/SN equivalent, key selection criteria include extended temperature support, 64-byte page size, HOLD functionality for interrupt-safe SPI pauses, and block-level write protection configuration.
Technical Context
The 25LC256T-H/SN implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, and HOLD for full protocol compliance. Its internal architecture includes a status register with WIP, WEL, BP0/BP1, and WPEN bits enabling nonvolatile block protection and hardware write-enable control.
It supports self-timed internal write cycles (≤6 ms), sequential read with automatic address increment, and power-on data protection via reset of the write enable latch. The HOLD pin suspends ongoing transfers without resetting the sequence, maintaining state across host interrupt servicing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Density | 256 Kbit (32,768 × 8-bit organization) - defines maximum nonvolatile storage capacity for firmware parameters or sensor calibration tables |
| Supply Voltage | 2.5V–5.5V - enables direct interfacing with 3.3V and 5V microcontrollers without level-shifting |
| Max Clock Speed | 5 MHz at VCC ≥ 4.5V - supports fast read/write throughput in time-critical automotive subsystems |
| Page Size | 64 bytes - constrains maximum contiguous write length per command; crossing page boundaries wraps data within same physical page |
| Write Cycle Time | ≤6 ms - determines minimum interval between write commands; impacts real-time logging latency |
| Endurance | >1,000,000 erase/write cycles - ensures long-term reliability in cyclic data logging applications |
| Data Retention | >200 years - guarantees calibration data integrity over full vehicle service life without refresh |
| Temp Range | −40°C to +150°C - qualified per AEC-Q100 Grade 0 for under-hood automotive environments |
Pinout & Package
8-Lead SOIC (SN) package, 3.90 mm body width, RoHS-compliant matte tin finish, JEDEC MS-012AC variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS (Pin 1) | Chip Select Input | Active-low enable signal; must be low for all SPI operations; rising edge initiates internal write cycle after valid write sequence |
| SO (Pin 2) | Serial Data Output | Tri-state output delivering read data on falling SCK edge; enters high-Z when CS is high or HOLD is asserted |
| WP (Pin 3) | Write-Protect Pin | Hardware lock for STATUS register writes when WPEN=1; no effect on array writes unless configured via BP bits |
| VSS (Pin 4) | Ground | Reference return path for all digital and analog circuitry; requires low-impedance PCB connection |
| SI (Pin 5) | Serial Data Input | Latches instruction, address, and data on rising SCK edge; sampled first after CS goes low |
| SCK (Pin 6) | Serial Clock Input | Synchronizes all SPI transfers; timing constraints (e.g., TH, TSU) apply across full temp/voltage range |
| HOLD (Pin 7) | Hold Input | Pauses active SPI transfer without resetting state; must be driven low while SCK is low to activate |
| VCC (Pin 8) | Supply Voltage | Power input for core logic and EEPROM array; bypass capacitor required per datasheet layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Block Write Protection | Configurable via BP0/BP1 bits to protect none, upper 1/4, upper 1/2, or entire array - prevents accidental overwrite of critical firmware sections |
| HOLD Functionality | Enables safe SPI pause/resume during host interrupts - eliminates need to retransmit partial commands in real-time systems |
| Self-Timed Internal Write | 6 ms max write cycle with automatic completion detection - removes external timing dependency and simplifies firmware polling |
| Power-On Write Protection | Write enable latch resets at power-up - prevents spurious writes during brown-out or startup transients |
| AEC-Q100 Qualification | Grade 0 (−40°C to +150°C) qualification - validates reliability for engine control, transmission, and exhaust aftertreatment modules |
| ESD Robustness | >4 kV HBM - enhances field reliability in manufacturing and service environments with minimal handling controls |
Applications
| Engine Control Unit (ECU) | Advanced Driver Assistance Systems (ADAS) |
|---|---|
Use Scenario: Storing adaptive fuel trim values, knock sensor learning maps, and OBD-II diagnostic trouble codes across ignition cycles. IC Role / Device Role / Timing Role: Nonvolatile parameter storage with guaranteed retention >200 years and endurance >1M cycles under thermal cycling. Use Value: Enables closed-loop engine optimization without battery-backed SRAM, reducing BOM cost and board space. | Use Scenario: Logging radar calibration offsets and camera alignment parameters during vehicle assembly and dealer programming. IC Role / Device Role / Timing Role: SPI-configurable, page-write-capable EEPROM interfaced directly to ADAS SoC's SPI master port. Use Value: Supports field-updatable calibration data with hardware write protection to prevent corruption during OTA updates. |
| Industrial Motor Drives | Commercial HVAC Controllers |
Use Scenario: Retaining motor thermal model coefficients, encoder zero-point offsets, and fault history logs in variable-frequency drives. IC Role / Device Role / Timing Role: High-temp EEPROM (−40°C to +150°C) co-located near power stage for direct thermal coupling. Use Value: Eliminates need for external temperature compensation by storing coefficients validated at end-of-line burn-in. | Use Scenario: Storing seasonal schedule profiles, zone-specific PID tuning parameters, and filter maintenance counters in rooftop units. IC Role / Device Role / Timing Role: SPI EEPROM accessed by HVAC MCU during boot and runtime for configuration persistence. Use Value: Ensures consistent comfort settings across power failures and firmware upgrades without cloud dependency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25DF256A-SHN-T | 256-Mbit density, quad SPI interface, 8-pin SOIC but different pinout (no HOLD); 3V-only supply (2.7–3.6V) | Higher density for firmware image storage; lacks HOLD and WP pins - unsuitable for interrupt-driven automotive logging | Select only if quad SPI bandwidth and larger capacity outweigh loss of HOLD/WP functionality and voltage compatibility |
| BR25H256FJ-WE2 | 256-Kbit SPI EEPROM, same 8-pin SOIC, −40°C to +125°C (not +150°C), 1.7–5.5V supply, 10 MHz max clock | Broader VCC range and faster clock, but lower max operating temperature - insufficient for under-hood AEC-Q100 Grade 0 | Prefer for industrial 125°C applications where higher speed and wider voltage margin are critical |
Compared with AT25DF256A-SHN-T and BR25H256FJ-WE2, the 25LC256T-H/SN uniquely delivers AEC-Q100 Grade 0 qualification, integrated HOLD functionality for deterministic SPI pausing, and hardware write protection with configurable block granularity - making it the only option qualified for safety-critical automotive powertrain storage.
Availability
25LC256T-H/SN is available at Aetrix Electronics and suitable for automotive powertrain control, ADAS calibration storage, and industrial motor drive parameter retention requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 25LC256T-H/SN 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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory products, with global design and manufacturing infrastructure.
The 25LCxxx family was designed specifically for robust, high-reliability serial EEPROM applications in automotive, industrial, and medical systems requiring extended temperature operation and AEC-Q100 compliance.
FAQ
What is the maximum clock frequency supported by the 25LC256T-H/SN across its full voltage and temperature range?
The 25LC256T-H/SN supports up to 5 MHz at VCC ≥ 4.5V and −40°C to +150°C; at 2.5V ≤ VCC < 4.5V, maximum clock drops to 3 MHz. These AC timing limits are fully characterized and guaranteed per DS20002131D, Table 1-2. The 25LC256T-H/SN maintains these speeds without derating across its full AEC-Q100 Grade 0 temperature range.
How does the HOLD pin function during an active SPI read or write sequence in the 25LC256T-H/SN?
The HOLD pin on the 25LC256T-H/SN suspends ongoing SPI communication without resetting the internal state. When pulled low while SCK is low, SI/SO/SCK enter high-impedance and all inputs (except CS) are ignored. To resume, HOLD must be raised while SCK is low. This behavior is defined in Section 2.6 and Figure 1-1 of the 25LC256T-H/SN datasheet.
Can the 25LC256T-H/SN be used as a direct replacement for the 25LC256 without modification?
Yes - the 25LC256T-H/SN is the tape-and-reel, high-temp (H-grade) version of the base 25LC256, sharing identical pinout, electrical specs, and functional behavior. The "T" suffix denotes tape-and-reel packaging, and "H" confirms extended temperature qualification. No PCB or firmware changes are required when upgrading from 25LC256 to 25LC256T-H/SN.
What write protection mechanisms are implemented in the 25LC256T-H/SN, and how are they configured?
The 25LC256T-H/SN implements dual-layer write protection: (1) software-controlled block protection (BP0/BP1 bits in STATUS register) to lock 0%, 25%, 50%, or 100% of memory; and (2) hardware write protection enabled by WP pin + WPEN bit. Configuration is done via WRSR instruction; protection states persist through power cycles. Details are in Tables 3-2, 3-3, and 5-1 of the 25LC256T-H/SN datasheet.
What is the page size of the 25LC256T-H/SN, and why does it matter for firmware update routines?
The 25LC256T-H/SN has a 64-byte page size, meaning up to 64 contiguous bytes can be written in a single page-write command. Exceeding this or crossing page boundaries causes wraparound within the current page - potentially overwriting prior data. Firmware update routines must align writes to page boundaries and limit payload size to ≤64 bytes per WRITE instruction to ensure correctness, as specified in Section 3.3 and Figure 3-3 of the 25LC256T-H/SN datasheet.
25LC256T-H/SN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 6ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
25LC256T-H/SN FAQ
1.How can I place an order for 25LC256T-H/SN through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC256T-H/SN 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 25LC256T-H/SN reliable?
The price and inventory of 25LC256T-H/SN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 25LC256T-H/SN is usually 5 days.
3.What payment methods are accepted for 25LC256T-H/SN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC256T-H/SN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC256T-H/SN?
25LC256T-H/SN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC256T-H/SN 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 25LC256T-H/SN?
For technical support, including 25LC256T-H/SN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC256T-H/SN requirements.
6.How does Aetrix verify that 25LC256T-H/SN is sourced from the original manufacturer or authorized distributors?
All 25LC256T-H/SN 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 25LC256T-H/SN meets industry standards.
7.What is the process for return or replacement of 25LC256T-H/SN?
All 25LC256T-H/SN units undergo pre-shipment inspection (PSI). If there is an issue with 25LC256T-H/SN, 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 25LC256T-H/SN part is unused and in its original packaging.
Return procedure for 25LC256T-H/SN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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