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1N4148 cross reference & equivalent replacements
Industry part1N4148
Equivalents stocked3 Weforsemi types
PackagesSOD-123 · SOD-523 · LL-34
Forward currentIF(AV) 150 mA class
The 1N4148 is the industry's standard small-signal fast switching diode, and it is one of the part numbers our sourcing team is asked for most. This page is a cross reference, written the way the term is used in component purchasing: the parts below are equivalent replacements from our own Weforsemi line, matched by function, package and published ratings — they are not original-manufacturer 1N4148 parts, and the original remains available through our sourcing service if your approved-vendor list requires it.
Three stocked equivalents cover the three footprints buyers actually use: SOD-123 for the mainstream SMD layout, SOD-523 for ultra-small designs, and LL-34 for the glass-sealed cylindrical format. Published data for each is quoted from the manufacturer's product pages; the full datasheet governs any design-in and is confirmed at quotation.
Choosing between the three equivalents
Start with the footprint, because that is what the PCB already has. The VC1N4148WB in SOD-123 is the default replacement for the common two-lead plastic surface-mount layout; its published features are a plastic surface-mounted package with two leads, IF(AV) of 150 mA and reverse current of 1 µA, and the platform listing classes it at Vr 75 V. The VC1N4148WTB in SOD-523 serves boards laid out for the smaller package: the published description is a 100 V fast switching diode in an ultra-small surface-mount package with high conductance, intended for general-purpose switching. The VC4148K is the LL-34 glass-sealed option — an epitaxial silicon switching diode in a planar, glass-sealed construction — for designs that specify the cylindrical glass format.
After footprint, check the two ratings that decide most substitutions: repetitive reverse voltage against your rail, and average forward current against your signal load, both with margin. If the original circuit relies on a specific reverse-recovery behaviour, say so in the enquiry — switching speed is the third parameter we confirm against the datasheet before quoting an equivalent as a drop-in.
What "equivalent" means on this page
Equivalent here means: same device function (small-signal fast switching), a package that fits the intended footprint, and published ratings in the same class as the industry part. It does not mean identical silicon, and it does not transfer any original manufacturer's approvals. Marking codes differ — our parts carry Weforsemi markings (for example the VC1N4148WB marking shown on its product documentation) — so incoming inspection should be briefed when a line changes from an original part to an equivalent.
If your BOM is under change control, treat this page as the starting shortlist: send the exact industry part number and the target footprint, and we return the matching equivalent with its datasheet for your engineering sign-off before any order.
Cross reference — industry part to Weforsemi equivalent
| Industry part | Our equivalent | Package | Published data |
|---|---|---|---|
| 1N4148 (SMD, mainstream footprint) | VC1N4148WB | SOD-123 | IF(AV) 150 mA; IR 1 µA; fast switching; listed at Vr 75 V |
| 1N4148 (SMD, ultra-small footprint) | VC1N4148WTB | SOD-523 | 100 V fast switching diode; ultra-small surface-mount package; high conductance |
| 1N4148 (glass cylindrical format) | VC4148K | LL-34 | Glass-sealed epitaxial silicon switching diode; planar structure |
Parameters are quoted from the manufacturer's published product pages. Confirm the full datasheet specification before design-in; ratings are confirmed at quotation.
Questions & answers
Is the VC1N4148WB a drop-in replacement for the 1N4148?
It is positioned as the equivalent for the SOD-123 footprint and the same switching-diode class, with published IF(AV) of 150 mA. Drop-in status for a specific board is confirmed against both datasheets — footprint, pinout and ratings — before quotation; send us the original part's full designation.
Can you supply the original 1N4148 instead?
Yes, through the sourcing service, subject to stock and channel availability. Tell us the original manufacturer if your AVL names one.
Do the equivalents carry the same marking as the original?
No. They carry Weforsemi part markings, so your incoming inspection and SMT program should be updated when a line is switched.
See also: Switching diodes · SMD diodes · 1N5819 cross reference