Diodes & RectifiersActive

1N4148

Manufacturer: Vishay

Figures from the datasheet: Vishay Semiconductors 81857, rev. 1.6, November 7, 2024

Vishay 1N4148 axial DO-35 switching diode. Black cathode band, 75 V continuous reverse-voltage limit and 4 ns maximum reverse recovery under the specified test conditions.

PackagesDO-35
Official Datasheet (PDF)

Technical Overview

01

Technical Overview

This reference covers Vishay 1N4148, ordering codes 1N4148-TAP and 1N4148TR, using datasheet 81857 Rev. 1.6 (07-Nov-2024). It is a silicon epitaxial planar switching diode in an axial DO-35 (DO-204AH) package. The black band identifies the cathode; CircuitBase numbers the cathode K as terminal 1 and the anode A as terminal 2 for this catalogue. These are passive terminals, not GPIO inputs with a 5 V logic-tolerance specification.

Distinguish the 75 V continuous reverse-voltage absolute limit from the 100 V repetitive peak reverse-voltage absolute limit. Breakdown voltage is separately specified at a minimum of 100 V with IR = 100 µA, tp/T = 0.01 and tp = 0.3 ms. Absolute ratings are not recommended operating points.

At TA = 25°C, maximum forward voltage is 1 V at IF = 10 mA. Maximum capacitance is 4 pF with VR = 0 V, f = 1 MHz and VHF = 50 mV. Reverse recovery is at most 4 ns with IF = 10 mA, VR = 6 V, iR = 0.1 × IR and RL = 100 Ω; the separate 8 ns test uses IF = IR = 10 mA and iR = 1 mA. Neither time is an unconditional switching guarantee.

Power dissipation is rated at 500 mW with l = 4 mm and TL <= 25°C, or 440 mW with l = 4 mm and TL = 45°C. The stated RthJA = 350 °C/W requires l = 4 mm and constant TL. The junction-temperature limit is 175°C; storage is -65 to +150°C. Evaluate the actual electrical and thermal conditions rather than treating a package rating as a guaranteed circuit current.

Package Pinout & Alternate Functions

Interactive package pinout and pin mapping for DO-35-2.

Interactive pinout diagramTop

1N4148: DO-35 package illustrationInteractive package pinout and pin mapping for DO-35.1: K2: A

Package illustration, not a dimensioned mechanical drawing.

2 / 2 pins
#Pin nameType5V TolerantAlternate functions / details
Kpassive—
Cathode K, identified by the black body band. Terminal 1 is the CircuitBase catalogue numbering convention; this is a passive diode terminal.
Apassive—
Anode A, opposite the black cathode band. Terminal 2 is the CircuitBase catalogue numbering convention; forward conventional current flows from A to K.

Key Specifications

Parametric attributes

ParameterMinTypicalMaxUnitTest condition
Repetitive Peak Reverse Voltage(V_RRM)——100VTA = 25°C
Continuous Reverse Voltage(V_R)——75VTA = 25°C
Breakdown Voltage(V_BR)100——VIR = 100 µA, tp/T = 0.01, tp = 0.3 ms, TA = 25°C
Forward Continuous Current(I_F)——300mATA = 25°C
Average Forward Current(I_F_AV)——150mAVR = 0, TA = 25°C
Repetitive Peak Forward Current(I_FRM)——500mATA = 25°C
Non-Repetitive Peak Forward Surge Current (1 µs)(I_FSM_1us)——2Atp = 1 µs, TA = 25°C
Power Dissipation(P_tot)——500mWl = 4 mm, TL <= 25°C
Forward Voltage Drop(V_F)——1VIF = 10 mA, TA = 25°C
Reverse Leakage Current(I_R)——0.025µAVR = 20 V, TA = 25°C
Reverse Recovery Time (4 ns test)(t_rr_4ns)——4nsIF = 10 mA, VR = 6 V, iR = 0.1 x IR, RL = 100 Ω, TA = 25°C
Reverse Recovery Time (8 ns test)(t_rr_8ns)——8nsIF = IR = 10 mA, iR = 1 mA, TA = 25°C
Diode Capacitance(C_D)——4pFVR = 0 V, f = 1 MHz, VHF = 50 mV, TA = 25°C

Absolute Maximum Ratings

Junction temperature≤ 175 °C
Storage temperature-65 – 150 °C
Thermal resistance θJA (DO-35)350 °C/W

Hardware Engineering Gotchas

Real-world hardware caveats, PCB layout constraints and silicon errata to know before manufacturing.

Critical

Current and power limits require their stated conditions

At TA = 25°C, the absolute ratings are IF = 300 mA continuous, IF(AV) = 150 mA with VR = 0, and IFRM = 500 mA repetitive peak. They describe different conditions. Ptot = 500 mW requires l = 4 mm and TL <= 25°C; Ptot = 440 mW is specified at TL = 45°C with the same lead length. RthJA = 350 °C/W assumes l = 4 mm and constant TL.

Mitigation

Check the actual waveform, power dissipation, lead temperature and thermal layout against the applicable ratings. Keep junction temperature within the 175°C absolute limit; do not infer a guaranteed circuit current from a single current or power rating.

Warning

Continuous reverse voltage is not the repetitive peak rating

The datasheet specifies VR = 75 V and VRRM = 100 V as distinct absolute limits. The separately tested minimum breakdown voltage of 100 V does not make 100 V a continuous operating-voltage recommendation. The black body band marks K; the catalogue terminal numbers are a display convention.

Mitigation

Identify the cathode band and check the actual reverse-voltage waveform against the appropriate continuous and repetitive peak limits. These passive terminals have no GPIO-style 5 V tolerance rating.

Warning

The 2 A surge rating applies to a 1 µs pulse

Vishay 81857 Rev. 1.6 specifies IFSM = 2 A at tp = 1 µs and TA = 25°C. It does not specify a 1 A, 1 s surge rating. This short-pulse absolute rating is not a continuous or repetitive current allowance.

Mitigation

Evaluate the intended pulse and thermal conditions using applicable manufacturer data. Do not extrapolate the 1 µs rating into an allowable longer pulse, repetition rate or energy-clamp capability.

Cross-Reference & Equivalents

Part number (MPN)ManufacturerCompatibilityElectrical differences / BOM considerations
1N914Vishaypin to pin drop inVishay 81857 explicitly names 1N914 as an electrically equivalent diode. Check the selected manufacturer part and package for the intended application; the statement does not establish identical silicon geometry or every test condition.

Official Documentation & Cited Datasheets

Primary semiconductor vendor datasheets, errata, and application notes.

DATASHEETVishay Semiconductors

1N4148 Small Signal Fast Switching Diodes Datasheet

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