Protected low-side drivers for automotive loads¶
For injectors, solenoids, relays and lamps switched to ground. Use a protected switch (active clamp, current limit, thermal shutdown), never a bare N-MOSFET: every one of these loads is inductive, and a bare FET has no clamp or limit. All parts below share one DPAK pinout, 1 input, 2 and tab drain, 3 source, and the EmbeddedEra TO-252-2 footprint.
| Part | Status (2026-10-13) | Clamp | RDS(on) at 5 V | Current limit | 3.3 V drive | Verdict |
|---|---|---|---|---|---|---|
| ST VND14NV04-E / TR-E | obsolete; Digi-Key 0, Mouser 123, LCSC 1 | 40-55 V | 35 mOhm max | 12-24 A | yes | do not design in |
| onsemi NCV8401BDTRKG | active, Digi-Key 22k, Mouser 28k, about $0.87 at 100 | 42-50 V | 28 mOhm typ | 25-35 A | yes (about 37 mOhm, about 15 A limit) | default choice |
| onsemi NCV8405BDTRKG | active | 42-51 V | 105 mOhm typ | 6-11 A | likely, untested | when a lower limit matters |
| onsemi NCV8406BDTRKG | active | 60-70 V | 210 mOhm typ | 5-9.5 A | marginal | poor fit |
- None of these is stocked at LCSC/JLC: buy at Digi-Key/Mouser and consign.
- NCV8401B's limit is higher than the VND14's, so a shorted harness wire draws more before it trips. Its turn-off is slower (about 130 us), which is fine to a few kHz.
- NCV8401A is discontinued; the B suffix is the live one.
- First used on rusefi-sti-2004 (Q1-Q20). Datasheets: onsemi ncv8401-d.pdf, ST vnd14nv04-e.pdf.
Smaller packages for light loads (2026-10-13)¶
Size the driver to the load: most ECU outputs (relays, lamps, tach) draw 0.3 A or less and do not need a DPAK.
| Part | Package | Class | Clamp | RDS(on) at 3 V | Current limit | Notes |
|---|---|---|---|---|---|---|
| Diodes ZXMS6004FFTA | SOT-23F (land C 0.95, X 0.80, Y 1.11, Y1 3.00) | lamps, tach, relay coils (<= 0.3 A) | 60-70 V | 400-600 mOhm | 0.7 A min | 90 mJ; LCSC C95063 (JLC-assemblable), Mouser 100k+; not AEC (FFQTA is, poor stock); pins 1 IN, 2 S, 3 D |
| Diodes ZXMS6006DGQ-13 | SOT-223 (tab D) | solenoids to ~1 A, spares | 60-70 V | 85-125 mOhm | 4 A min | 490 mJ, AEC-Q101, Digi-Key 11k; pins 1 IN, 2 D, 3 S |
| onsemi NCV8402ASTT1G | SOT-223 | fallback | 42-55 V | only spec'd at 5 V | 3.7-5 A at 5 V | marginal at 3.3 V drive |
| Infineon AUIPS2041 | SOT-223 | — | — | — | — | obsolete (used in the Hellen outputs module) |
Watch-outs: the ZXMS short-circuit protection is rated to 16 V (6006) / 36 V (6004) supply, so a shorted output during a load dump is not covered; the 60-70 V clamp is above a 40 V load dump. Library: EmbeddedEra:ZXMS6004FFTA (footprint SOT-23F_Diodes), EmbeddedEra:ZXMS6006DGQ-13. First used on rusefi-sti-2004: 8 DPAK + 4 SOT-223 + 8 SOT-23F instead of 20 DPAK.
What rusEFI uses (checked 2026-10-13 from their board BOMs)¶
| Board | General low-side | Heavy | Injectors / ignition |
|---|---|---|---|
| uaefi-f (newest) | 6 x ST VNLD5090 (dual SO-8) | — | — |
| hellen-112-17-b | 4 x ST VNLD5160 (dual SO-8) | — | MCZ33810 + ISL9V3040 IGBTs |
| hellen154hyundai-e | 3 x VNLD5160 + 7 x ROHM BM2LC105FJ | 1 x VND7NV04 (DPAK) | MCZ33810 + ISL9V3040 |
| hellen121vag-c, hellen72 NB2 (older) | ZXMS6005 / AUIPS2041 (SOT-223) + ULN2003 | VND7NV04 / VND14NV04 (DPAK) | — |
House choice from now on: ST VNLD5160TR-E (dual, SO-8, 41 V clamp, 160 mOhm, 3.5 A limit, auto-restart thermal shutdown, AEC-Q100; pins 1 IN1, 2 ST1, 3 IN2, 4 ST2, 5 S2, 6 D2, 7 S1, 8 D1; status pins may float). Input threshold is 1-3.5 V on paper; rusEFI drives it from 3.3 V STM32s in production. Keep one DPAK (NCV8401B or VND7NV04) for loads of ~2 A (heaters). VNLD5090 is the lower-RDS sibling but out of stock (2026-10-13). The Diodes ZXMS parts above work but their short-circuit protection is rated only to 16 V (6006) / 24 V (6005) / 36 V (6004) supply. Library: EmbeddedEra:VNLD5160TR-E (2 units). First used on rusefi-sti-2004.