25LC256

@@ -0,0 +1,53 @@+# 25LC256++**Microchip Technology** · 256 Kbit SPI EEPROM · SOIC-8++A 256 Kbit (32 KB) serial EEPROM with an SPI interface, in SOIC-8, the SPI counterpart of the I2C 24LC256. It stores settings, calibration, and logs that must survive power loss, with a rated endurance over one million erase/write cycles and data retention beyond 200 years. Data is written a byte or a 64-byte page at a time and read sequentially at up to 10 MHz over the four-wire SPI. A hardware write-protect pin plus block-protect bits guard part or all of the array against accidental writes, and a HOLD pin pauses a transfer without dropping chip select. Runs 1.8-5.5 V.++## Pinout++| Pin | Name | Type | Function |+|---|---|---|---|+| 1 | CS | input | Chip Select input (active-low, overbar CS). Drive low to select the device and initiate an SPI instruction; drive high to deselect and place SO in high-impedance. Requires TCSS setup (≥50 ns @ Vcc≥4.5 V) before the first SCK edge. |+| 2 | SO | output | Serial Data Output (MISO). Shifts data out on the falling edge of SCK, MSB first. High-impedance when CS is high or HOLD is low. Drive strength: VOH = Vcc-0.5 V @ IOH = -400 µA. |+| 3 | WP | input | Write-Protect input (active-low, overbar WP). When low and the WPEN bit in the status register is set, prevents writes to the status register (hardware write-protect). Tie high (or leave floating with pull-up) for normal operation. |+| 4 | VSS | power_in | Ground reference for all supply, logic, and I/O signals. Connect to system 0 V. |+| 5 | SI | input | Serial Data Input (MOSI). Command bytes, addresses, and write data are shifted in on the rising edge of SCK, MSB first. Data setup Tsu ≥ 10 ns @ Vcc ≥ 4.5 V. |+| 6 | SCK | input | Serial Clock Input. Provides the clock for all serial data transfers on SI/SO. Maximum 10 MHz @ Vcc ≥ 4.5 V (5 MHz @ 2.5-4.5 V, 3 MHz @ 1.8-2.5 V for 25AA256). Supports SPI Mode 0,0 and Mode 1,1. |+| 7 | HOLD | input | Hold input (active-low, overbar HOLD). Drive low to pause the current SPI transaction while CS remains asserted; SO goes high-impedance and SI/SCK transitions are ignored. Drive high to resume. Tie high if not used. |+| 8 | VCC | power_in | Supply voltage input. 2.5-5.5 V for 25LC256 (1.8-5.5 V for 25AA256). Absolute max 6.5 V. Typical operating current 2.5 mA read / 0.6 mA write @ 5.5 V; standby 0.1 µA typ. Decouple with 0.1 µF close to the pin. |++## Key specifications++| Parameter | Value |+|---|---|+| Type | Serial EEPROM (non-volatile) |+| Density | 256 Kbit (32 KB) |+| Interface | SPI (up to 10 MHz) |+| Write | byte or 64-byte page |+| Endurance | 1,000,000+ cycles |+| Retention | >200 years |+| Protection | WP pin + block-protect bits |+| Supply voltage | 1.8-5.5 V |+| Package | SOIC-8 |++## Ordering variants++- `25LC256-I/SN (SOIC-8)`+- `25LC256-I/P (PDIP-8)`++## CAD (KiCad official)++- Symbol: `Memory_EEPROM:25LCxxx`+- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`+- 3D model: SOIC-8 (KiCad packages3D)++## Provenance++Data extracted from the manufacturer datasheet, not a distributor listing:++- **Datasheet:** [Microchip Technology datasheet](https://ww1.microchip.com/downloads/aemDocuments/documents/MPD/ProductDocuments/DataSheets/25AA256-25LC256-256K-SPI-Bus-Serial-EEPROM-20001822H.pdf) (31 pp, sha256 `b25667250a0ee8d3`, retrieved 2026-08-17, tier: manufacturer)+- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.+- **CAD:** KiCad official libraries (CC-BY-SA 4.0).++[Datasheet PDF](docs/25lc256-datasheet.pdf)

@@ -0,0 +1,36 @@+{+  "slug": "25lc256",+  "version": "0.1.0",+  "type": "component",+  "description": "Microchip 256 Kbit (32 KB) SPI EEPROM, SOIC-8. Byte/page write, 1M+ cycles, write protect. The SPI 24LC256. Datasheet-verified.",+  "tags": [+    "component",+    "memory",+    "eeprom",+    "spi",+    "non-volatile",+    "soic-8",+    "microchip"+  ],+  "dependencies": {},+  "hero": {+    "type": "image",+    "path": "docs/hero.png"+  },+  "files": [+    "page.json",+    "README.md",+    "25lc256.kicad_sym",+    "25lc256.kicad_mod",+    "25lc256.glb",+    "docs/hero.png",+    "docs/25lc256-datasheet.pdf",+    "viewers/symbol.html",+    "viewers/footprint.html"+  ],+  "visibility": "public",+  "author": {+    "name": "Ray",+    "email": "[email protected]"+  }+}\ No newline at end of file