My Inquiry
My Account
Microchip Technology 25LC256-E/ST
- Part No.:
- 25LC256-E/ST
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
25LC256-E/ST.pdf
- Description:
- IC EEPROM 256KBIT SPI 8TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,386
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
25LC256-E/ST from Microchip Technology Inc. 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 robust write protection and low-power operation.
For engineers reviewing the 25LC256-E/ST datasheet, 25LC256-E/ST pinout, 25LC256-E/ST application, or 25LC256-E/ST equivalent, key selection criteria include SPI timing compliance at 10 MHz, hardware write-protection via WP pin and STATUS register, 1 μA standby current, and AEC-Q100 qualification for automotive use.
Technical Context
The 25LC256-E/ST implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI (data in) and SO (data out) lines, controlled by CS, SCK, and optional HOLD. Its internal architecture includes an 8-bit instruction register, page latches, and high-voltage generator for EEPROM programming.
Write operations require explicit WREN instruction followed by CS high-to-low transition to initiate self-timed internal write cycle (≤5 ms). Block protection is configurable via BP0/BP1 bits to protect none, 1/4, 1/2, or all of the 32 KB array - independent of software control and retained across power cycles.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 32,768 × 8-bit (256 Kbit) nonvolatile EEPROM array |
| Interface | SPI-compatible serial bus (Mode 0,0 or 1,1), with dedicated SI/SO pins and CS/SCK/HOLD/HP control |
| Max Clock Frequency | 10 MHz at VCC ≥ 4.5V; supports full-speed operation in industrial and extended temp ranges |
| Page Size | 64-byte page buffer enables efficient burst writes within physical page boundaries |
| Write Endurance | 1,000,000 erase/write cycles per memory location, validated at 25°C and 5.5V |
| Data Retention | Greater than 200 years at 25°C, ensuring long-term reliability in unpowered storage |
| Supply Voltage | 2.5V to 5.5V - compatible with 3.3V and 5V logic systems without level shifting |
| Standby Current | 1 μA at 5.5V and 125°C - critical for battery-backed or energy-constrained applications |
Pinout & Package
25LC256-E/ST is housed in an 8-lead Thin Shrink Small Outline Package (TSSOP), 4.4 mm body width, RoHS-compliant, with gull-wing leads and JEDEC MO-153AC footprint. Pin 1 marked by notch or dot; pin numbering follows standard TSSOP convention (counterclockwise from notch).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select Input | Active-low enable signal; must be low for SPI communication; rising edge initiates internal write cycle after valid command sequence |
| SO | Serial Data Output | Tri-state output delivering read data on falling edge of SCK; high-impedance when CS high or HOLD active |
| WP | Write-Protect Pin | Hardware-level protection control; disables STATUS register writes when WP = low and WPEN = 1 in STATUS register |
| VSS | Ground Reference | Primary return path for all internal circuitry and I/O; must be connected before VCC during power-up |
| SI | Serial Data Input | Accepts instructions, addresses, and write data on rising edge of SCK; sampled only when CS is low |
| SCK | Serial Clock Input | Synchronizes all SPI transfers; defines timing for SI sampling (rising edge) and SO update (falling edge) |
| HOLD | Hold Input | Pauses ongoing SPI transaction without resetting state; requires SCK low before assertion; tri-states SO during hold |
| VCC | Supply Voltage | Power input for core logic and EEPROM array; supports 2.5–5.5V range with built-in power-on reset and data protection circuitry |
Key Features
| Feature | Design Value |
|---|---|
| Self-timed write cycle | Internal 5 ms max write completion eliminates need for external timing control or polling overhead |
| Programmable block protection | BP0/BP1 bits allow selective write-protection of 0%, 25%, 50%, or 100% of memory - nonvolatile and immune to software faults |
| HOLD functionality | Enables host MCU to suspend EEPROM access mid-transaction for higher-priority interrupt servicing without data loss |
| Low-power standby mode | 1 μA max ICCS at 125°C ensures minimal quiescent draw in always-on or battery-powered systems |
| AEC-Q100 qualification | Qualified for automotive applications (Grade 1: –40°C to +125°C), including engine control, ADAS, and infotainment subsystems |
| ESD robustness | 4 kV HBM ESD protection on all pins reduces susceptibility to handling damage and system-level transients |
Applications
| Automotive Instrument Clusters | Industrial PLC Configuration Storage |
|---|---|
Use Scenario: Storing calibrated sensor offsets, user preferences, and trip data in digital dashboards with frequent power cycling. IC Role / Device Role / Timing Role: Nonvolatile configuration and runtime parameter storage interfaced directly to PIC or ARM-based cluster MCUs via SPI. Use Value: AEC-Q100 qualification ensures reliability over 15+ year vehicle lifetime; 1 μA standby current minimizes battery drain during ignition-off periods. |
Use Scenario: Retaining ladder logic parameters, I/O mapping, and calibration tables in programmable logic controllers deployed in factory automation. IC Role / Device Role / Timing Role: SPI EEPROM providing field-updatable firmware configuration data accessible during boot and runtime. Use Value: 1M endurance supports daily reconfiguration cycles over 27 years; block protection prevents accidental overwrite of critical safety settings. |
| Medical Diagnostic Device Logs | Smart Energy Meter Firmware Settings |
Use Scenario: Recording diagnostic event timestamps, error codes, and calibration history in portable ultrasound or ECG units. IC Role / Device Role / Timing Role: Secure, tamper-resistant data logger interfaced to low-power Cortex-M0+ MCU with HOLD support for real-time interrupt handling. Use Value: Hardware WP pin + STATUS register lock prevents unauthorized modification of regulatory-critical log data; >200-year retention meets FDA archival requirements. |
Use Scenario: Storing tariff schedules, metering constants, and cryptographic keys in ANSI C12.22-compliant smart meters operating in harsh outdoor environments. IC Role / Device Role / Timing Role: Trusted nonvolatile storage for security-critical parameters accessed during secure boot and OTA updates. Use Value: Extended temperature rating (–40°C to +125°C) ensures operation inside sealed meter enclosures; 4 kV ESD withstand protects against installation surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25DF041A-SSH-T | 4 Mbit density, quad SPI interface, 85 MHz max clock; no HOLD pin; different status register layout | Better suited for high-throughput firmware storage; lacks HOLD and hardware WP pin required for deterministic interrupt handling | Select only if higher density and faster read speed outweigh loss of HOLD and simplified write-protection scheme |
| BR25L256FJ-WE2 | 256 Kbit, 3-wire SPI (shared IO), 20 MHz max clock; 1.7–5.5V VCC; no WP pin; software-only protection | Lower pin count saves board space but removes hardware-enforced write lockout; not AEC-Q100 qualified | Prefer for cost-sensitive consumer designs where automotive qualification and hardware WP are unnecessary |
Compared with AT25DF041A-SSH-T and BR25L256FJ-WE2, the 25LC256-E/ST uniquely combines AEC-Q100 qualification, dedicated HOLD and WP pins, and guaranteed 1 μA standby current - making it the only choice for automotive and industrial systems requiring deterministic, fault-tolerant nonvolatile storage.
Availability
25LC256-E/ST is available at Aetrix Electronics and suitable for automotive instrument clusters, industrial PLCs, medical diagnostic loggers, and smart energy meter firmware storage requiring stable component supply and long-term lifecycle support.
Supply support for 25LC256-E/ST 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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The 25LC256-E/ST belongs to Microchip's serial EEPROM product line, engineered specifically for reliable, low-power, SPI-based nonvolatile data storage in automotive, industrial, and medical applications demanding AEC-Q100 compliance and extended temperature operation.
FAQ
What is the maximum clock frequency supported by the 25LC256-E/ST?
The 25LC256-E/ST supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V to 4.5V, the maximum is 5 MHz, and at 1.8V to 2.5V, it drops to 3 MHz. These limits are defined in Table 1-2 AC Characteristics and apply across both Industrial and Extended temperature ranges. The 25LC256-E/ST datasheet specifies these values under actual operating conditions, not theoretical maximums.
Does the 25LC256-E/ST support hardware write protection?
Yes, the 25LC256-E/ST supports hardware write protection via the WP pin in conjunction with the WPEN bit in its STATUS register. When WP is low and WPEN = 1, writes to nonvolatile STATUS register bits are disabled - protecting configuration settings even during firmware faults. This dual-layer protection is confirmed in Table 2-3 and Figure 2-7 of the official DS20001822H datasheet.
What package type is used for the 25LC256-E/ST?
The 25LC256-E/ST uses an 8-lead Thin Shrink Small Outline Package (TSSOP) with 4.4 mm body width, per Microchip's packaging specification C04-057-ST. The "ST" suffix explicitly denotes this TSSOP variant, distinct from PDIP (P), SOIC (SN/SM), or DFN (MF) packages listed in the Device Selection Table on page 1 of DS20001822H.
Is the 25LC256-E/ST qualified for automotive applications?
Yes, the 25LC256-E/ST is AEC-Q100 qualified for automotive use, specifically Grade 1 (–40°C to +125°C). This qualification is explicitly stated in the Features section on page 1 of DS20001822H and confirmed in the Device Selection Table under "Temp. Ranges" where "E" (Extended) is listed alongside package code "ST". It is suitable for engine control, ADAS, and body electronics.
How many write/erase cycles does the 25LC256-E/ST guarantee?
The 25LC256-E/ST guarantees 1,000,000 write/erase cycles per memory location, as specified in Table 1-3 (Param. No. 21) and the Features list on page 1 of DS20001822H. This endurance rating is validated at 25°C and VCC = 5.5V, and applies to all 32,768 bytes of the EEPROM array - not just a subset or typical value.
25LC256-E/ST 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:
- 10 MHz
- Write Cycle Time - Word, Page:
- 5ms
- Access Time:
- -
- Voltage - Supply:
- 2.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-TSSOP
25LC256-E/ST FAQ
1.How can I place an order for 25LC256-E/ST through Aetrix?
Please submit a Request for Quotation (RFQ) for 25LC256-E/ST 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/ST reliable?
The price and inventory of 25LC256-E/ST 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/ST is usually 5 days.
3.What payment methods are accepted for 25LC256-E/ST?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 25LC256-E/ST transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 25LC256-E/ST?
25LC256-E/ST orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 25LC256-E/ST 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/ST?
For technical support, including 25LC256-E/ST datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 25LC256-E/ST requirements.
6.How does Aetrix verify that 25LC256-E/ST is sourced from the original manufacturer or authorized distributors?
All 25LC256-E/ST 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/ST meets industry standards.
7.What is the process for return or replacement of 25LC256-E/ST?
All 25LC256-E/ST units undergo pre-shipment inspection (PSI). If there is an issue with 25LC256-E/ST, 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/ST part is unused and in its original packaging.
Return procedure for 25LC256-E/ST:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
25LC256-E/ST Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
-
AT24C02C-SSHM-T
Microchip Technology
-
24LC01BT-I/OT
Microchip Technology
-
M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
-
AT24C08C-STUM-T
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
