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Microchip Technology 25LC256T-E/ST16KVAO
- Part No.:
- 25LC256T-E/ST16KVAO
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC256T-E/ST16KVAO.pdf
- Description:
- IC EEPROM 256KBIT SPI 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,337
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Product details
Overview
25LC256T-E/ST16KVAO from Microchip Technology is a 256 Kbit SPI Serial EEPROM with 32,768 × 8-bit organization, 64-byte page size, and 10 MHz max clock frequency. It operates across 2.5–5.5V supply and supports Industrial (−40°C to +85°C) and Extended (−40°C to +125°C) temperature ranges. Used for nonvolatile data storage in microcontroller-based systems requiring reliable, low-power configuration memory.
For engineers reviewing the 25LC256T-E/ST16KVAO datasheet, 25LC256T-E/ST16KVAO pinout, 25LC256T-E/ST16KVAO application, or 25LC256T-E/ST16KVAO equivalent, this page delivers verified electrical specs, SPI timing constraints, write-protection behavior, endurance (1M cycles), and package-specific pin mapping for TSSOP-8 (ST) packaging.
Technical Context
The 25LC256T-E/ST16KVAO implements a standard SPI Mode 0,0/Multi-Master-compatible serial interface with separate SI (input) and SO (output) lines, CS-controlled selection, and HOLD-enabled transaction suspension. Its internal architecture includes a write-enable latch, STATUS register with WIP/WEL/BP bits, and hardware write protection via WP pin and WPEN bit.
It supports byte and page writes (up to 64 bytes within one 64-byte-aligned page), self-timed internal write cycles (≤5 ms), and block protection of 0%, 25%, 50%, or 100% of the array. Power-on defaults include reset WEL, standby mode, and high-impedance SO - ensuring safe initialization without spurious writes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256 Kbit (32,768 × 8-bit), sufficient for firmware parameter tables, calibration data, or device identity storage in resource-constrained embedded systems. |
| Interface | SPI-compatible serial bus (Mode 0,0), requiring only CS, SCK, SI, SO, WP, and HOLD - enabling minimal GPIO usage on host MCUs. |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V; scales down to 5 MHz (2.5–4.5V) and 3 MHz (1.8–2.5V), allowing flexible speed/power trade-offs across supply conditions. |
| Write Endurance | 1,000,000 erase/write cycles, supporting long-term field deployment in logging, metering, or configuration update applications. |
| Data Retention | >200 years at +25°C, ensuring archival integrity of stored settings without refresh overhead. |
| Supply Voltage Range | 2.5V to 5.5V - compatible with both 3.3V and 5V logic domains, eliminating level-shifting needs in mixed-voltage designs. |
| Standby Current | 1 µA at 5.5V and 125°C, critical for battery-powered or energy-harvesting systems requiring ultra-low quiescent power. |
Pinout & Package
25LC256T-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 1 is marked by a beveled corner or dot; orientation follows JEDEC MO-153 standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable: pulls device into active state; rising edge after WRITE sequence initiates internal 5 ms write cycle. |
| SO | Serial Data Output | Tri-state open-drain output; data valid after falling SCK edge; high-impedance when CS high or HOLD low. |
| WP | Write-Protect Pin | Hardware lock: disables STATUS register writes when WP = low and WPEN = 1; otherwise ignored. |
| VSS | Ground Reference | Primary return path for all I/O and core circuitry; must be low-impedance and decoupled near VCC pin. |
| SI | Serial Data Input | Latches instruction/address/data on rising SCK edge; requires setup/hold times per AC table (e.g., 10–30 ns). |
| SCK | Serial Clock Input | Synchronizes all transfers; rise/fall times ≤100 ns; duty cycle 40–60%; max frequency depends on VCC. |
| HOLD | Hold Input | Pauses ongoing SPI transfer without resetting state; must be asserted while SCK is low to avoid metastability. |
| VCC | Supply Voltage | 2.5–5.5V power input; requires local 0.1 µF ceramic decoupling capacitor placed ≤5 mm from pin. |
Key Features
| Feature | Design Value |
|---|---|
| Page Write Capability | 64-byte page buffer enables burst writes within aligned boundaries - reduces SPI transaction count by up to 64× vs. byte writes. |
| Hardware Write Protection | WP pin + WPEN bit combination provides tamper-resistant locking of STATUS register, preventing accidental firmware corruption. |
| Extended Temperature Support | Rated for −40°C to +125°C operation (E grade), validated for automotive under-hood and industrial control environments. |
| Low-Power Standby | 1 µA max ICCS at 125°C ensures negligible battery drain during extended sleep modes in portable equipment. |
| ESD Robustness | 4 kV HBM rating on all pins - exceeds IEC 61000-4-2 Level 2, reducing need for external protection in moderate-noise environments. |
Applications
| Industrial Sensor Node | Automotive Body Control Module |
|---|---|
|
Use Scenario: Storing calibrated sensor offsets, linearization coefficients, and last-known operational state in a wireless temperature/humidity node. IC Role / Device Role / Timing Role: Nonvolatile configuration memory interfaced via SPI to an ARM Cortex-M0+ MCU; accessed during boot and infrequently during field recalibration. Use Value: 1M endurance and >200-year retention ensure calibration data survives 10+ years of field operation without degradation or refresh. |
Use Scenario: Holding door lock actuator profiles, seat position presets, and lighting dimming curves in a LIN-connected BCM. IC Role / Device Role / Timing Role: SPI EEPROM storing user-customizable settings; read at power-up and written only during service-mode programming. Use Value: AEC-Q100 qualification and −40°C to +125°C support guarantee reliability in vehicle cabin environments subject to thermal cycling. |
| Medical Infusion Pump | Smart Energy Meter |
|
Use Scenario: Recording dose history, alarm logs, and maintenance timestamps in Class II medical-grade infusion equipment. IC Role / Device Role / Timing Role: Secure, tamper-evident data logger; WP pin permanently tied low during production to prevent runtime STATUS register modification. Use Value: Hardware write protection prevents unauthorized firmware or log tampering - satisfying IEC 62304 traceability requirements. |
Use Scenario: Storing tariff schedules, billing cycle counters, and cryptographic keys in ANSI C12.22-compliant utility meters. IC Role / Device Role / Timing Role: Trusted nonvolatile storage for security-critical parameters; accessed via isolated SPI bus with watchdog-monitored transactions. Use Value: 2.5V min operating voltage allows direct interface with meter's 3.3V rail, while 1 µA standby current extends battery backup life beyond 10 years. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 25AA256-I/ST | Wider VCC range (1.8–5.5V); identical pinout, timing, and memory map; same ST package. | Better suited for 1.8V/2.5V logic systems; not rated for +125°C operation. | Select 25AA256-I/ST only if supply voltage may drop below 2.5V and extended temperature is unnecessary. |
| AT25DF256A-SSH-T | Dual/quad SPI interface; 2.7–3.6V only; 512-byte pages; no HOLD pin; different command set. | Higher throughput in quad mode but incompatible SPI protocol; lacks hardware write protection via WP pin. | Choose AT25DF256A-SSH-T only when migrating to faster flash-based storage and redesigning driver firmware. |
Compared with 25LC256T-E/ST16KVAO, the 25AA256-I/ST offers lower-voltage flexibility but sacrifices extended temperature capability, while the AT25DF256A-SSH-T trades pin compatibility and hardware protection for higher density and quad-speed access - requiring full firmware and layout revision.
Availability
25LC256T-E/ST16KVAO is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical infusion pumps, and smart energy meters requiring stable component supply across extended temperature and long product lifecycles.
Supply support for 25LC256T-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 microcontrollers, analog, FPGA, and memory solutions, serving industrial, automotive, communications, and consumer markets with vertically integrated silicon and software tools.
The 25LC256T-E/ST16KVAO belongs to Microchip's 25XX256 family of SPI Serial EEPROMs, designed specifically for robust, low-power, pin-efficient nonvolatile storage in space- and power-constrained embedded systems.
FAQ
What is the maximum clock frequency supported by the 25LC256T-E/ST16KVAO?
The 25LC256T-E/ST16KVAO supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V ≤ VCC < 4.5V, the maximum is 5 MHz; at 1.8V ≤ VCC < 2.5V, it drops to 3 MHz. These limits are defined in Table 1-2 of the DS20001822H datasheet and reflect guaranteed AC timing margins across voltage and temperature.
Does the 25LC256T-E/ST16KVAO require external pull-up resistors on its SPI lines?
The 25LC256T-E/ST16KVAO does not require external pull-ups on SI, SCK, or CS - these inputs have CMOS thresholds and function correctly with standard MCU GPIO drive. However, SO is open-drain and requires a 4.7 kΩ pull-up to VCC for proper logic-high signaling; WP and HOLD also benefit from weak pull-ups (10–100 kΩ) to prevent floating states.
How does hardware write protection work on the 25LC256T-E/ST16KVAO?
Hardware write protection on the 25LC256T-E/ST16KVAO activates only when both the WP pin is driven low AND the WPEN bit (bit 7 of STATUS register) is set to 1. When enabled, it blocks writes to nonvolatile STATUS register bits (BP0, BP1, WPEN) - preserving block protection settings - while allowing normal memory reads and writes.
What is the page size and alignment requirement for page writes on the 25LC256T-E/ST16KVAO?
The 25LC256T-E/ST16KVAO has a fixed 64-byte page size. Page writes must begin at addresses aligned to 64-byte boundaries (e.g., 0x0000, 0x0040, 0x0080). Writing across a boundary causes wraparound within the current page - overwriting earlier bytes - so application firmware must enforce address alignment before issuing multi-byte writes.
Is the 25LC256T-E/ST16KVAO qualified for automotive applications?
Yes - the "E" suffix in 25LC256T-E/ST16KVAO denotes Extended temperature grade (−40°C to +125°C), and the device is explicitly AEC-Q100 qualified per the DS20001822H datasheet. This makes it suitable for automotive body electronics, infotainment subsystems, and other under-hood or cabin applications requiring certified reliability.
25LC256T-E/ST16KVAO Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP (0.173", 4.40mm 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:
- 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
25LC256T-E/ST16KVAO FAQ
1.How can I place an order for 25LC256T-E/ST16KVAO through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC256T-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 25LC256T-E/ST16KVAO reliable?
The price and inventory of 25LC256T-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 25LC256T-E/ST16KVAO is usually 5 days.
3.What payment methods are accepted for 25LC256T-E/ST16KVAO?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC256T-E/ST16KVAO transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC256T-E/ST16KVAO?
25LC256T-E/ST16KVAO orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC256T-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 25LC256T-E/ST16KVAO?
For technical support, including 25LC256T-E/ST16KVAO datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC256T-E/ST16KVAO requirements.
6.How does Aetrix verify that 25LC256T-E/ST16KVAO is sourced from the original manufacturer or authorized distributors?
All 25LC256T-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 25LC256T-E/ST16KVAO meets industry standards.
7.What is the process for return or replacement of 25LC256T-E/ST16KVAO?
All 25LC256T-E/ST16KVAO units undergo pre-shipment inspection (PSI). If there is an issue with 25LC256T-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 25LC256T-E/ST16KVAO part is unused and in its original packaging.
Return procedure for 25LC256T-E/ST16KVAO:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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