# AT24LC128M

**HGSEMI** · EEPROM · SOP-8

AT24LC128M from HGSEMI, in a SOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | A0 | input | Device address input that is hardwired or left floating; if floating and board VCC-plane coupling is under 3 pF it is internally pulled down to GND, and if coupling exceeds 3 pF the datasheet recommends connecting it to GND. |
| 2 | A1 | input | Device address input that is hardwired or left floating; if floating and board VCC-plane coupling is under 3 pF it is internally pulled down to GND, and if coupling exceeds 3 pF the datasheet recommends connecting it to GND. |
| 3 | NC | unconnected | No connect pin. |
| 4 | GND | power_in | Ground reference for the device. |
| 5 | SDA | bidirectional | Open-drain bidirectional serial data pin for two-wire transfer that may be wire-ORed with other open-drain or open-collector devices and is normally pulled high by an external device. |
| 6 | SCL | input | Serial clock input where data is clocked into the EEPROM on the positive edge and clocked out on the negative edge. |
| 7 | WP | input | Write-protect input: connecting to GND allows normal write operations, while connecting to VCC inhibits all memory writes (full array protection); if floating and coupling is under 3 pF it is pulled down to GND, and above 3 pF the datasheet recommends connecting it to GND. |
| 8 | VCC | power_in | Power supply, specified from 1.8 V to 5.5 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | HGSEMI |
| Package | SOP-8 |
| Category | Memory |
| Pins | 8 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Supply Voltage (range for VCC1 row) | VCC1 | 1.8 |  | 5.5 | V |  | 9 |
| Supply Voltage (range for VCC2 row) | VCC2 | 2.5 |  | 5.5 | V |  | 9 |
| Supply Voltage (range for VCC3 row) | VCC3 | 2.7 |  | 5.5 | V |  | 9 |
| Supply Voltage (range for VCC4 row) | VCC4 | 4.5 |  | 5.5 | V |  | 9 |
| Operating Ambient Temperature | TA | -40 |  | 85 | ℃ | Recommended operating range | 9 |
| DC Supply Voltage |  | -0.3 |  | 6.5 | V |  | 8 |
| Operating Ambient Temperature |  | -40 |  | 85 | ℃ |  | 8 |
| Storage Temperature |  | -55 |  | 125 | ℃ |  | 8 |
| Input Low Level | VIL | -0.6 |  |  | V |  | 9 |
| Output Low Level (VCC = 5.0V) | VOL3 |  |  | 0.4 | V | VCC =5.0V; IOL= 3.0 mA | 9 |
| Output Low Level (VCC = 3.0V) | VOL2 |  |  | 0.4 | V | VCC =3.0V; IOL= 2.1 mA | 9 |
| Output Low Level (VCC = 1.8V) | VOL1 |  |  | 0.2 | V | VCC =1.8V; IOL= 0.15 mA | 9 |
| Supply Current READ | ICC1 |  | 0.4 | 1 | mA | VCC = 5.0V; READ at 400 kHz | 9 |
| Supply Current WRITE | ICC2 |  | 2 | 3 | mA | VCC = 5.0V; WRITE at 400 kHz | 9 |
| Standby Current (VCC = 1.8V) | ISB1 |  | 0.6 | 1 | µA | VCC = 1.8V; VIN= VCC or VSS | 9 |
| Standby Current (VCC = 2.5V) | ISB2 |  | 1 | 2 | µA | VCC = 2.5V; VIN= VCC or VSS | 9 |
| Standby Current (VCC = 2.7V) | ISB3 |  | 1 | 2 | µA | VCC = 2.7V; VIN= VCC or VSS | 9 |
| Standby Current (VCC = 5.0V) | ISB4 |  | 1 | 3 | µA | VCC = 5.0V; VIN= VCC or VSS | 9 |
| Input Leakage Current | ILI |  | 0.1 | 3 | µA | VIN= VCC or VSS | 9 |
| Output Leakage Current | ILO |  | 0.05 | 3 | µA | VOUT = VCC or VSS | 9 |
| Input/Output Capacitance (SDA) | CI/O |  |  | 8 | pF | VI/O = 0V | 9 |
| Input Capacitance (A0, A1, A2, SCL) | CIN |  |  | 6 | pF | VIN = 0V | 9 |
| Clock Frequency, SCL | fSCL |  |  | 400 | kHz |  | 9 |
| Clock Pulse Width Low | tLOW | 1.2 |  |  | µs |  | 9 |
| Clock Pulse Width High | tHIGH | 0.6 |  |  | µs |  | 9 |
| Noise Suppression Time | tI |  |  | 50 | ns |  | 9 |
| Clock Low to Data Out Valid | tAA | 0.1 |  | 0.9 | µs |  | 10 |
| Time the bus must be free before a new transmission can start | tBUF | 1.2 |  |  | µs |  | 10 |
| Start Hold Time | tHD.STA | 0.6 |  |  | µs |  | 10 |
| Start Setup Time | tSU.STA | 0.6 |  |  | µs |  | 10 |
| Data In Hold Time | tHD.DAT | 0 |  |  | µs |  | 10 |
| Data In Setup Time | tSU.DAT | 100 |  |  | ns |  | 10 |
| Inputs Rise Time | tR |  |  | 0.3 | µs |  | 10 |
| Inputs Fall Time | tF |  |  | 300 | ns |  | 10 |
| Stop Setup Time | tSU.STO | 0.6 |  |  | µs |  | 10 |
| Data Out Hold Time | tDH | 50 |  |  | ns |  | 10 |
| Write Cycle Time | tWR |  |  | 5 | ms |  | 10 |

## CAD (KiCad official)

- Symbol: `AT24LC128M`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `at24lc128m-etched.step` / `at24lc128m-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `at24lc128m.step` / `at24lc128m.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [HGSEMI datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589838214539210752) (13 pp, sha256 `4c0cd875d4ced8b2`, retrieved 2026-10-18, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/at24lc128m-datasheet.pdf)