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MMBT3904LT1HTSA1

Infineon Technologies

Infineon MMBT3904LT1HTSA1 NPN general-purpose transistor, 40 V Vceo, 200 mA Ic, 300 MHz fT, 330 mW power dissipation, PG-SOT23 surface-mount package. Last Buy lifecycle stage.

Infineon Technologies MMBT3904LT1HTSA1
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[IN STOCK] In Stock: 620 pcs
$0.06/ pc

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MOQ 5 · Tape & Reel (TR) Cut Tape (CT) · RoHS · EIA-481 · DAP/DDP · T/T

[ORIGINAL SEALED] [PRE-SHIP HD PHOTOS] [30D WARRANTY · COC] [TRACKED DAP/DDP]

Technical specifications

MMBT3904LT1HTSA1 specifications
Parameter / AttributeSpecification / Value
MountingSurface Mount
FET typeNPN
Voltage - collector emitter breakdown40 V
Current - collector (Ic)200 mA
Current - collector cutoff50nA (ICBO)
DC current gain (hFE) (Min) @ ic, vce100 @ 10mA, 1V
Power - max330 mW
Frequency - transition300MHz
Operating temperature150°C (TJ)
PackageTape & Reel (TR) Cut Tape (CT)
CaseTO-236-3, SC-59, SOT-23-3
Vce saturation (Max) @ ib, ic300mV @ 5mA, 50mA
100% Footprint Match · Solder-Ready (No PCB Redesign Needed)

Need Stock or a Drop-in Second-Source for MMBT3904LT1HTSA1?

Package: TO-92 / SOT-23 · Pin-compatible replacements with immediate Shenzhen spot stock

Footprint Match 98%
Supply Chain & Allocation Reality:

The 2N3904 NPN and its 2N3906 PNP complement are the American small-signal standard: 40V, 200mA, 625mW, TO-92 with E-B-C lead order, gain optimized around 10mA, and SOT-23 twins (MMBT3904 / MMBT3906) in more new designs than the through-hole originals. The repair trap has two layers: the European counterpart BC547 is C-B-E in the same TO-92 body - a straight insertion swaps emitter and collector into reverse-active operation - and the SOT-23 twins number their pins 1 = Base, 2 = Emitter, 3 = Collector, which follows neither lead order. Every substitution in this family answers the pinout question before the electrical one.

Verified Pin-Compatible Replacements (3 verified alternatives)

BC547 / BC557 onsemi / Nexperia / ST TO-92
Functional Equivalent
Availability & Target Pricing:

The European Counterpart, C-B-E Reversed

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The functional twin from the other design culture: 45V, 100mA, the same 300MHz-class fT - and the mirrored lead order (C-B-E against E-B-C) that makes the socket, not the spec, the first question.

The same small-signal envelope; the BC547 comes in A/B/C gain groups (110-800 hFE) where the 2N3904 ships one broad 100-300 band.

Compatibility & Drop-In Notes: Substitution rule: re-form the leads or rotate the part - and check the current direction of the substitution. A 200mA 2N3904 position is kinder to a 100mA BC547 than the reverse; circuits that selected a C-grade BC547 for gain need the budget re-checked, not just the socket.
Package & Solder Footprint: Same TO-92 body and footprint; different internal lead assignment - the flat-face drawing decides, never the silhouette.
Shenzhen Warehouse Stock & MOQ: Both families stocked in depth; the pairing covers both design cultures on one quote.
Request Volume Quote for BC547 / BC557 Compare MMBT3904LT1HTSA1 vs BC547 / BC557 Spec Matrix
2N2222A onsemi / ST / Fairchild lineage TO-92
100% Drop-in (Zero Code Change)
Availability & Target Pricing:

The Same Pins With Three Times the Muscle

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The higher-current sibling in the same E-B-C order and 40V class: 600-800mA against 200mA, gain optimized around 150mA, fT 250-300MHz - the standard step up for relay, LED and small-motor duty.

Same 40V VCEO; the plastic TO-92 version shares this pinout exactly, which is why repair benches stock both in one drawer.

Compatibility & Drop-In Notes: Substitution arithmetic is one-directional comfort: the 2N2222A in a 2N3904 socket is free headroom; the 2N3904 in a 2N2222A position works only inside the smaller current budget. Both directions keep the E-B-C order, so the question is amps, not pins.
Package & Solder Footprint: Plastic TO-92, E-B-C; metal can, its own drawing.
Shenzhen Warehouse Stock & MOQ: Universal stock; the two parts quote naturally together.
Request Volume Quote for 2N2222A Compare MMBT3904LT1HTSA1 vs 2N2222A Spec Matrix
2N4401 / 2N4403 onsemi TO-92
100% Drop-in (Zero Code Change)
Availability & Target Pricing:

The Quiet 600mA Middle Step

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The in-between option of the US lineup: 40V, 600mA, E-B-C order, fT 250MHz - closer to the 2N3904 noise behavior than the 2N2222A, at higher current than the 2N3904.

Same 40V class across the trio.

Compatibility & Drop-In Notes: Where a circuit oscillates on 2N2222A gain bandwidth or lacks margin on 2N3904 current, this is the middle rung - same pins, same family culture, the small-signal engineering compromise.
Package & Solder Footprint: TO-92, E-B-C, matching the 2N3904 socket directly.
Shenzhen Warehouse Stock & MOQ: Stocked; the professional middle option the module trade forgets exists.
Request Volume Quote for 2N4401 / 2N4403 Compare MMBT3904LT1HTSA1 vs 2N4401 / 2N4403 Spec Matrix
Buyer & Quality Checklist for Sourcing Alternatives
  • The pocket-sized pinout map of small-signal TO-92: American parts (2N3904, 2N3906, 2N2222A plastic) are E-B-C, European parts (BC547, BC337) are C-B-E, and Japanese parts (2SC945, 2SA733) are E-C-B. Three standards, one body - check the flat-face drawing even when the cross-reference list says equivalent.
  • The SOT-23 twins renumber: MMBT3904 / MMBT3906 are 1 = Base, 2 = Emitter, 3 = Collector - neither the TO-92 order nor a scaled copy of it. Reflow repairs that swap by remembered position are the same trap in a smaller package.
  • Reverse-active operation is the silent failure of a flipped swap: the part conducts and may even pass a diode test, but hFE collapses to a fraction and saturation voltage climbs - a circuit that works but weakly after a transistor change should be re-checked for a rotated emitter and collector.
  • Gain groups matter by design culture: BC547 ships as A/B/C bands (110-220 / 200-450 / 420-800) and circuits select them; the 2N3904 ships one 100-300 band. Substituting a selected-band part with a generic one needs the bias network reviewed, not just the socket.
  • Current ceilings decide the direction: 2N3904 at 200mA optimized for 10mA, 2N4401 at 600mA, 2N2222A at 600-800mA optimized near 150mA, BC547 at 100mA. Stepping down in a driver that legitimately passed more current is the classic post-repair smoke test failure.
  • Keep the cans apart: the metal TO-18 2N2222 (and 2N2907) do not share the plastic E-B-C circle. One drawer label per package, or the next repair inherits the mistake.
Frequently Asked Technical Questions

Q: Can I replace a BC547 with a 2N3904?

A: Electrically they overlap (45V/100mA against 40V/200mA small-signal NPN), but the TO-92 lead orders are mirrored: BC547 is C-B-E and the 2N3904 is E-B-C. A straight insertion runs the part reverse-active with collapsed gain - re-form the leads, or substitute within the same pinout culture.

Q: What is the difference between 2N3904 and 2N2222A?

A: Same E-B-C pinout and 40V class, different current: the 2N3904 carries 200mA with gain optimized near 10mA, the 2N2222A 600-800mA optimized near 150mA. Using the 2222A in a 3904 socket is free headroom; the reverse is safe only inside the 200mA budget.

Q: Why does a transistor work but with terrible gain after a swap?

A: Emitter and collector are most likely exchanged: reverse-active operation conducts at a small fraction of the rated hFE with a higher saturation voltage. Check the flat-face pin drawing of both parts - C-B-E and E-B-C look identical from across the bench.

Technical details

40 V, 200 mA, 300 MHz — the general-purpose NPN workhorse

The Infineon MMBT3904LT1HTSA1 is a small-signal NPN transistor in the ubiquitous 3904 family, packaged in a PG-SOT23 surface-mount case. It delivers a 40 V collector-emitter breakdown voltage and a 200 mA continuous collector current rating, making it a standard choice for general-purpose switching, signal amplification, and logic-level translation up to a few MHz. The 300 MHz transition frequency tells you it can handle pulse edges cleanly into the low-MHz range, though the practical switching speed depends on your base-drive circuit and load capacitance.

100 minimum hFE and 300 mV saturation — the switching budget

The DC current gain is guaranteed at a minimum of 100 when biased at 10 mA collector current and 1 V Vce. That floor lets you size the base resistor for saturated switching without over-drive margin guesswork. The maximum Vce saturation of 300 mV at 5 mA base current and 50 mA collector current keeps the on-state voltage drop low enough that dissipation in a 200 mA relay or LED driver stays within the 330 mW package limit, provided the duty cycle is accounted for.

Infineon has announced end-of-life for this specific suffix variant, meaning the factory window for new orders is closing. If you have an active BOM line using this order code, the immediate decision is whether to place a last-time buy for remaining production requirements or to qualify a replacement.

MMBT3904LT1HTSA1
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