ACS712
Public Made by Adomby adom
Allegro Hall-effect linear current sensor, SOIC-8. Fully isolated 1.2 mohm path, analog output, ±5/20/30 A. Datasheet-verified.
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markdownACS712
Allegro MicroSystems · Hall-effect current sensor · SOIC-8
A fully integrated Hall-effect linear current sensor in a SOIC-8: current flows through an internal 1.2 milliohm copper path (pins IP+ to IP-) and the on-chip Hall sensor reports it as an analog voltage on VIOUT, with the sensing electronics galvanically isolated from the current path (up to 2.1 kV). The output sits at half-supply (2.5 V at 0 A) and swings proportionally, so it reads bidirectional AC or DC current. Factory-trimmed variants cover plus/minus 5 A (185 mV/A), plus/minus 20 A (100 mV/A), and plus/minus 30 A (66 mV/A). Runs from a single 5 V supply.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | IP+ | passive | Primary current input terminal (positive). Terminals for current being sampled; fused internally. Pins 1 and 2 are tied together to carry the sensed current into the on-die copper conduction path. |
| 2 | IP+ | passive | Primary current input terminal (positive). Terminals for current being sampled; fused internally. Pins 1 and 2 are tied together to carry the sensed current into the on-die copper conduction path. |
| 3 | IP- | passive | Primary current output terminal (negative/return). Terminals for current being sampled; fused internally. Pins 3 and 4 are tied together to carry the sensed current out of the on-die copper conduction path. |
| 4 | IP- | passive | Primary current output terminal (negative/return). Terminals for current being sampled; fused internally. Pins 3 and 4 are tied together to carry the sensed current out of the on-die copper conduction path. |
| 5 | GND | power_in | Signal ground terminal. Reference ground for VCC and VIOUT on the signal side of the isolation barrier. |
| 6 | FILTER | passive | Terminal for external capacitor (CF) that sets output bandwidth. Forms an RC filter with the internal RF(INT) ≈ 1.7 kΩ. Typical value is 1 nF for the default 80 kHz bandwidth. |
| 7 | VIOUT | output | Analog output signal. Voltage proportional to the sensed primary current IP, with a quiescent (zero-current) output of VCC × 0.5 (bidirectional variants). Sensitivity ranges from 66 to 185 mV/A depending on the current-range variant. |
| 8 | VCC | power_in | Device power supply terminal. 5.0 V nominal (4.5 V min / 5.5 V max). Typical supply current ICC ≈ 10 mA. Decouple with 0.1 µF to GND close to the pin. |
Key specifications
| Parameter | Value |
|---|---|
| Type | Hall-effect linear current sensor |
| Sensing | galvanically isolated (2.1 kV) |
| Conductor resistance | 1.2 mΩ |
| Output | analog, 2.5 V at 0 A (ratiometric) |
| Ranges | ±5 A / ±20 A / ±30 A |
| Sensitivity | 185 / 100 / 66 mV/A |
| Supply voltage | 5 V |
| Package | SOIC-8 |
Ordering variants
ACS712ELCTR-05B-T (±5 A)ACS712ELCTR-20A-T (±20 A)ACS712ELCTR-30A-T (±30 A)
CAD (KiCad official)
- Symbol:
Sensor_Current:ACS712xLCTR-20A - Footprint:
Package_SO:SOIC-8_3.9x4.9mm_P1.27mm - 3D model: SOIC-8 (KiCad packages3D)
- 3D model files:
acs712-etched.step/acs712-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);acs712.step/acs712.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Allegro MicroSystems datasheet (16 pp, sha256
21b345f7a98d3694, 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).