1N4148 signal diode explained

The 1N4148 is a standard silicon switching signal diode. It is one of the most popular and long-lived switching diodes because of its dependable specifications and low cost. Its name follows the JEDEC nomenclature. The 1N4148 is useful in switching applications up to about 100 MHz with a reverse-recovery time of no more than 4 ns.

History

Texas Instruments announced the 1N914 diode in 1960.^[1] It was registered at JEDEC by Texas Instruments no later than 1961, and was second-sourced by 11 manufacturers that same year.^[2]

The 1N4148 was registered at JEDEC in 1968 as a silicon switching signal diode for military and industrial applications.^[3] It was second-sourced by many manufacturers; Texas Instruments listed their version of the device in an October 1966 data sheet.^[4]

These 1N914 and 1N4148 have an enduring popularity in low-current applications.^[5]

Overview

As the most common mass-produced switching diode, the 1N4148 replaced the older 1N914. They can be used interchangeably, and are cross-reference replacements for each other. They differed mainly in their leakage current specification, however, today most manufacturers list common specifications. For example, Vishay lists the same leakage current for both parts:

• 25 nA at -20 V, 25°C
• 5 μA at -75 V, 25°C
• 50 μA at -20 V, 150°C

Packages

The JEDEC registered part numbers 1N914 and 1N4148 were originally only available in an axial package, but over time similar parts became available in surface-mount packages too.

Through-hole package:

• 1N4148 in DO-35 glass axial package.

Surface-mount packages:

• LL4148 in MiniMELF package.
• 1N4148W in SOD-123 package.
• 1N4148WS in SOD-323 package.
• 1N4148WT in SOD-523 package.

Note: Some 1N4148 family surface-mount packages are marked with "T4" text.

Specifications

Absolute maximum ratings (stress ratings, consult datasheet for recommended ratings)

• V_RRM = 100 V  (maximum repetitive reverse voltage)
• I_O = 200 mA  (average rectified forward current)
• I_F = 300 mA  (DC forward current)
• I_f = 400 mA  (recurring peak forward current)
• I_FSM = 1 A at 1 s pulse width; 4 A at 1 μs pulse width (non-repetitive peak forward surge current)

Electrical and thermal characteristics

• V_F = 1 V at 10 mA (maximum forward voltage)^[6]
• V_R = 75 V at 5 μA; 100 V at 100 μA (minimum breakdown voltage and reverse leakage current)
• t_rr = 4 ns (maximum reverse-recovery time)
• P_D = 500 mW (maximum power dissipation)

See also

• 1N400x general-purpose diodes
• 1N58xx Schottky diodes
• Diode logic

Further reading

Historical databooks

• Transistor and Diode Data Book (1973, 1236 pages), Texas Instruments
• Diode Data Book (1978, 210 pages), Fairchild
• Rectifiers and Zener Diodes Data Book (1988, 508 pages), Motorola
• Rectifier Device Data Book (1995, 410 pages), Motorola

Notes and References

1. Web site: Texas Instruments 1N914 / 1N916 New Product Advertisement . Electronic Industries magazine . 201 . March 1960.
2. Web site: Semiconductor Diode & Rectifier Characteristics Tabulation . Derivation and Tabulation Associates . 209 . April 1961.
3. Web site: Announcement of Electron Device Type Registration, Release No. 4443A. . The Joint Electron Device Engineering Council . November 25, 1968 . May 15, 2021 . subscription.
4. The Transistor and Diode Data Book, Texas Instruments Incorporated, publication no. CC-413 71243-73-CSS, no date, page 10-34
5. Web site: A Tutorial on Diodes . . https://web.archive.org/web/20221127223101/https://www.nutsvolts.com/magazine/article/just_for_starters_200409 . November 27, 2022 . 14 . September 2004 . live.
6. Book: The Semiconctor Data Library . 1973 . Motorola Semiconductor Products . 73 . 4th.