NCE4012S vs NCE4015S vs NCE6012AS: Full Comparison

The one-line summary: all three are the same physical socket; the 4015S adds current and pulse headroom at double the gate charge, and the 6012AS adds 20V of margin and the family's best 4.5V row — at 93nC, the heaviest gate of the trio.

But here's the surprise the table hides: at 4.5V drive, the 60V sibling beats both 40V parts — 12mΩ at 6A against the 4012S's 18mΩ at 8A and the 4015S's 15mΩ at 8A.

Drive the decision with three rows: rail voltage, 4.5V-row need, and driver gate-charge budget.

When to Use the NCE4015S

The 4015S is the family step-up: 3A more continuous current and a 70A pulse budget in the same footprint, with 10mΩ max at 10V.

It earns its place when the load genuinely runs 12-15A, when pulse events are part of the design, or when the last 2mΩ pays in heat at 10V drive.

The cost is real: 60nC of gate charge — double the 4012S. If your driver was sized for the 4012S's 30nC, the swap needs a driver check, not just a footprint check.

When to Use the NCE6012AS

The 6012AS is the margin play: 60V against the 4012S's 40V, same 12A class, same footprint — for rails that spike past 40V, or for clean 24V systems where 40V leaves too little headroom.

Its hidden card is the 4.5V row: 12mΩ max guaranteed at 4.5V — the best logic-level row in the 12A class, on any of these parts. If the board drives the gate at 5V and wants minimum conduction loss at 12A, this is the one.

The price is the driver: 93nC of gate charge and 4100pF of input capacitance. A 5V rail with a weak gate stage will struggle; this die wants a real driver.

When NOT to Use These Parts at All

When the circuit can slam the drain with unclamped inductive energy. None of these three publishes a numeric E_AS row — clamp the rail (TVS or RCD snubber) or use a part that publishes one, like the 30V-class NCE3018AS (204mJ with conditions) if your rail fits under 30V.

When the gate is a 3.3V GPIO. The best 4.5V row here (6012AS) still stops at 4.5V; nothing below that is specified on any of the three. Use a driver or a low-voltage-specified part.

When a seller pitches the AO4404-class 30V parts as 40V drop-ins. The AOS AO4404A datasheet says 30V, 8.5A at T_A, ±12V gate, 24mΩ max at 10V — a different voltage class, a different drive envelope, and a gate-rail trap for 12V drivers.

Pinout & Layout Notes

Why does the footprint check come first? Because every SOP-8 single-MOSFET in this class shares the same pins — 1-3 Source, 4 Gate, 5-8 Drain — so the swap is layout-free. The electrical check is where replacements die.

Other Alternatives Worth Knowing

• NCE4009S — the family entry die (40V/9A, 22.9nC). Right when the load is under ~9A and the driver is weak; wrong when the 4012S's 10-12A duty is real.
• NCE3018AS — the 30V-class part with the family's only published avalanche ladder (E_AS 204mJ with test conditions). If your rail fits under 30V and stall is the risk, this is the one with a number.
• AO4404A (AOS) — 30V/8.5A with a ±12V gate per the AOS datasheet. Not a 40V replacement — but knowing why it isn't stops the most common mis-buy in this socket.

Frequently Asked Questions

Q1: Can I swap in the NCE4015S or NCE6012AS without changing the PCB?

A: Yes — all three share the SOP-8 footprint and pinout. Pins 1-3 Source, 4 Gate, 5-8 Drain are identical, so the swap is layout-free. The checks that matter are electrical: rail voltage against the 40V rating, and driver strength against 60nC or 93nC of gate charge.

Q2: Which replacement has the best 5V-logic row?

A: The NCE6012AS — 12mΩ max at 4.5V, guaranteed at 6A. That beats the 4015S's 15mΩ at 8A and the 4012S's 18mΩ at 8A. But it costs 93nC of gate charge to drive. For 5V-logic boards with a real driver, the 60V part is the low-voltage champion; with a weak driver, the 4012S is the safer swap.

Q3: Why is the AO4404A not a drop-in?

A: Because it's a 30V part with a ±12V gate. Per the AOS datasheet: 30V drain rating, 8.5A continuous at T_A = 25°C, 24mΩ max at 10V, and a gate rating of ±12V. A 40V socket replacement needs 40V of margin; a 12V gate rail sits at the AO4404A's absolute limit. Some market listings mislabel it as 40V — the AOS datasheet wins.

Q4: What about stall or unclamped inductive loads?

A: Clamp — none of these three publishes an E_AS row. The 4012S, 4015S, and 6012AS v1.0 datasheets carry no numeric avalanche rating. For stall-prone duty, add a TVS or RCD snubber across the rail — or use the NCE3018AS (204mJ with conditions) if your rail fits under 30V.

Q5: Is 40V enough, or should I step to the 60V part?

A: 40V covers 12V-system transients; 60V covers clean 24V and nastier spikes. If your rail is 12V-class with occasional spikes, 40V is the right margin. If the design sees 24V rails, load-dump exposure, or spikes that clear 40V, the NCE6012AS shares the footprint and covers it.

Q6: How do I verify a genuine NCE4012S when sourcing?

A: Measure R_DS(on) at both drive points. A genuine part reads within 12mΩ (10V/10A) and 18mΩ (4.5V/8A) maxes. A remarked smaller die fails the 4.5V/8A check by 1.5-2×. Gate capacitance tracks die area — an honest 12A-class part measures near the 1780pF typical. Check the marking reads NCE4012S, cleanly laser-etched.

Q7: Which applications actually buy the 4012S over the bigger dies?

A: 10-12A UPS changeover, 5V-logic switching, and commutation duty. From what we see in Shenzhen (2025–2026), the 4012S is the family's volume seller: it is the stop where current, gate charge, and the published trr spec balance — before the 4015S's 60nC tax applies.

Q8: Can I parallel two of these for more current?

A: Yes — with like-for-like parts on shared copper. Two 4012S on shared drain copper with equal gate traces form a practical 20A+ stage. Don't parallel different dies: uneven R_DS(on) means uneven current sharing and hot spots.