# ICM7555M

**HGSEMI** · Timers / Clock Oscillators · SOP-8

ICM7555M from HGSEMI, in a SOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | GND | power_in | Ground reference for the device. Connect to the negative supply rail (0V). |
| 2 | TRIG | input | Trigger input. A negative-going pulse below 1/3 VDD initiates the timing cycle, setting the output high and starting the timing capacitor discharge sequence. |
| 3 | OUT | output | Timer output. CMOS push-pull output that swings from near GND to near VDD, capable of sourcing/sinking modest load currents. |
| 4 | RESET | input | Active-low reset input. Pulling this pin below approximately 0.7V forces the output low and resets the internal flip-flop regardless of trigger state. Tie to VDD if unused. |
| 5 | CV | input | Control Voltage input. Provides access to the internal 2/3 VDD reference node, allowing modulation of the threshold levels. Typically bypassed to GND with a 10nF capacitor when unused. |
| 6 | THRES | input | Threshold input. When the voltage on this pin rises above 2/3 VDD, the internal flip-flop resets, driving the output low and initiating capacitor discharge. |
| 7 | DISCH | output | Discharge output. Open-drain N-channel output used to discharge the external timing capacitor when the internal flip-flop is reset. |
| 8 | VDD | power_in | Positive supply voltage input. Operating range 2V to 18V. |

## Key specifications

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

## Ordering variants

Same part, different packaging or reel option.

- `ICM7555MM`

## CAD (KiCad official)

- Symbol: `ICM7555M`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `icm7555m-etched.step` / `icm7555m-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `icm7555m.step` / `icm7555m.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [HGSEMI datasheet](docs/icm7555m-datasheet.pdf) (11 pp, sha256 `e95f11bad730cc7b`, retrieved 2026-08-17, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **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/icm7555m-datasheet.pdf)