This article discusses 1N4148 diode specifications, replacement equivalents, and pinout. It is a high-frequency, silicon, pulsed and low-power electronic component. One of the most common devices in this class. It gained its popularity due to its good technical parameters at a fairly low cost. Gradually replaced the obsolete 1N914, which had higher leakage currents. It is manufactured by epitaxial-planar technology.
Outwardly, the 1n4148 diode looks like a zener diode, but they have a different marking. Sometimes beginners get them mixed up. However, if you look closely at the product, you can see an alphanumeric designation like “41 48” on it. This is how they are distinguished from stabilizing diodes, which usually have the stabilizing voltage indicated on the package. For example: “5.0 V”, “9.2 V”, etc.
This device is most commonly available in a DO-35 glass-metal package. The cathode lead is marked with a dark band. The weight of the product does not exceed 0.13 g. The figure below shows the appearance, dimensions, and pinout of the 1N4148.
1N4148 is also found in SMD surface mount packages 1N4148W (SOD-123), 1N4148WS (SOD-323), 1N4148WT (SOD-523). Such products are typically marked “T4”.
Diode Specifications 1N4148
- Maximum reverse voltage (VRM) up to 100 V; pulse voltage (VRRM) up to 75 V; RMS up to 75 V.
- Maximum DC locking voltage (VDC) up to 53 V.
- Maximum forward current: rectified (Io) up to 150 mA; pulsed 10 µs (IFSM) up to 500 mA;
- Power dissipation (PD) up to 500 mV.
- Temperature: crystal (TJ) -65 to + 175 oC; storage (Tstg) -65 to + 175 oC;
- Recovery time (max): 0.004 µs;
- Capacitance of Cd, 4 pF;
- The type of enclosure is DO-35.
For capacitive loads, the current value should be 20% less than the limit values.
It is worth paying attention to the fact that the specifications of this diode may vary slightly from manufacturer to manufacturer. Even in the datasheet, despite the fact that the marking of devices is the same, the information about the parameters is different, and some properties of products are not specified at all. This is due to the peculiarities of production and the desire of companies to improve the quality of their products, as well as to reduce costs and to please the consumer.
However, the modern market dictates additional rules, such as economy and ecology. Therefore, most modern silicon diodes, including the one in question, do not contain harmful substances and comply with the European standard RoHS, do not contain lead alloys.
If we judge by the limiting values of the parameters, we can note the high resistance of the diode to work at low and high ambient temperatures, some of the manufacturers indicate a range of – 65 to + 200 oC. Not many, even modern devices, can boast the ability to function in such conditions. In spite of this, it is advisable to stick to the rated values. The table below shows the electrical specs of the device from the Vishay data sheet, measured under laboratory conditions.
If you look closely, you will find that foreign manufacturers do not specify the limiting frequency of the diodes. But if we judge by the reverse recovery time (trr), for example, in 4 ns, it does not exceed 25 MHz. In practice, it can operate at values just over 100 MHz.
Breakdown voltage (VBR) for 1N4148 diode = 100V.
Equivalents for the 1N4148 diode can be found from the following components:
- 1N4150, 1N4454;
- 1N456A, 1N483;
- 1N914, 1N914A;
- 1N914B, MMSD4148;
- USM14, 1SS387, 1SS380.
Similar in functionality are:
- 1N6640, 1SS133;
- BAS34, BAS34;
- BAW27, CLL914;
- DL4148, FDLL4148;
- LL4148, LS4148;
- MMSD914, MMSD914;
- PMLL4148, 1SS355, MCL4148.
The 1N4148 even has a Russian equivalent with identical parameters – KD522B. This can also include the KD521A.
Many companies are engaged in production, the most famous of them: Vishay, NXP Semiconductors, ON Semiconductors. Less familiar to the general consumer, but found on the shelves of radio equipment: Yangzhou yangjie electronic, MIC Group Rectifiers, Diotec Semiconductor, Kingtronics International, Comchip Technology. You can download the datasheet by going to this section.