ON Semiconductor LL4148

In electronic applications, the LL4148 diode is a well-known small-signal fast-switching diode. A diode is a component used in various applications such as rectification, signal clipping, and voltage regulation. In this article, we will take a close look at the LL4148 diode, its pinout, datasheet, specifications and compare it to similar diodes such as the 1N4148. We will also cover its package types, footprint, price, and replacement alternatives.

Table of Contents

• What is the LL4148 Diode?
• LL4148 LED SMD
• Fairchild Semiconductor LL4148
• Benefits of Fairchild Semiconductor LL4148
• LL4148 Replacement
• LL4148 Datasheet
• Package and Footprint
• Sum up
• Frequently Asked Questions

What is the LL4148 Diode?

Introduction to LL4148 DiodeHigh-Speed Switching: The LL4148 Diode. It's often used in applications where fast reset time is critical, and in digital circuit applications or low-power signal processing applications. This diode is highly popular for use in consumer electronics, communication systems, and other small signal diodes that must switch and rectify devices.

Pinout of the LL4148 Diode

LL4148 Diode Pinout

Knowing the LL4148 diode pinout is important for their correct incorporation in a circuit. You may find the LL4148 in a small SMD (Surface-Mounted Device) package.

LL4148 pinout information is rather simple:

Anode (A): The positive side of the diode where positive input would be connected.

Cathode (K): The negative side of the diode which is coupled to the output of the circuit.

Usually, cathodes are marked with a band on most applications and this becomes useful for identifying polarity in a circuit.

Key Advantages of the LL4148

Rapid switching time: With a reverse recovery time of just 4ns, it is well-suited for high-speed circuits.

Low capacitance: The diode has low capacitance characteristics due to which it is extensively used in high-frequency applications.

Compact Size: The SMD packaging allows for use in small printed circuits when space is at a premium.

LL4148 Applications

The LL4148 diode diffusion was used in many applications due to its speed, efficiency, and small size. Some common uses include:

SIGMA-DELTA (ΣΔ) MODULATOR: A circuit used in analog-to-digital conversion to filter and quantify signals.

Rectification: It is a process used for rectification in power supplies and radio frequency circuits.

Featured Applications: Used as Switching Protection Circuit to avoid sensitive components from getting damaged by excess voltage.

LL4148 LED SMD

Microsystems and RF devices also offers the LL4148 LED SMD, which uses a standard LL4148. The LED version of the LL4148, which acts as a fast-switching diode, possesses integrated light-emitting capabilities. This makes it valuable in adding light emission and fast switching capabilities in small packages, such as for status indicators and signal lights in small devices.

Fairchild Semiconductor LL4148

One such component often used by engineers is the LL4148 Fairchild Semiconductor variant due to its high quality manufacturing and dependable performance. Fairchild Semiconductor, now part of ON Semiconductor, has historically been associated with nailing down specifications and solid components. Their LL4148 diodes are no exception and are used in a wide range of industries from automotive to telecommunications and consumer electronics.

Benefits of Fairchild Semiconductor LL4148

High part quality: Repeatability of performance across large batches of elements.

Widely available: One of Fairchild's strengths is that engineers know they will be able to source LL4148 diodes.

Cost-performance ratio: LL4148 pricingFairchild is generally a par price which carries with it some additional peace of mind from a support and longevity perspective.

LL4148 Replacement

Due to availability problems or particular circuit requirements, an engineer may occasionally need to seek for a LL4148 substitute. Here are a few possible substitutes for LL4148:

1N4148: The 1N4148 is one of the most common replacement option with specifications very close and widely available. In applications needing a more mature component, this might be the way to go.

1N4148W: The 1N4148W is a version of the 1N4148 that is intended for surface-mount packaging.

1N914: A very common small-signal diode with characteristics similar to the LL4148.

LL4148 vs 1N4148

The LL4148 and 1N4148 comparison is often brought up because their characteristics are so similar. The forward voltage, reverse recovery time and current handling capability of both diodes are almost same. But the LL4148 has slightly higher reverse leakage current under some conditions, which may be undesired in some low-leakage circut where it is important to have minimal leakage current. The decision between the two diodes really comes down to specific application needs and factors, like operating temperature, recovery time, and budget.

When Choosing a Replacement

Example of characteristics to match when selecting a replacement diode:

Reverse Voltage (VR)

Forward Current (IF)

Reverse Recovery Time (trr)

Package Type

LL4148 Datasheet

The LL4148 datasheet is a vital source of information that covers primary specs essential for comprehending the performance limitations of this diode in terms of its maximum ratings and operating boundaries. Now, let's dive into the important parts of the LL4148 datasheet.

Maximum Ratings

Reverse Voltage (VR): 100V

Forward Current (IF): 300mA

Surge Current: 1 second for 500mA

Reverse recovery time (trr): ~4ns (it would be ideal for high-speed switching).

Electrical Characteristics

Forward Voltage (VF): Generally 1.0V @ 10mA, but it depends on the current they run.

Reverse Leakage Current (IR): Usually 25nA/100V reverse voltage

Package and Footprint

The LL4148 is usually found in a small SMD package, but for example in the DO-35 package. There is a PCB footprint for this small package, LE 4148.

LL4148 Package

Sum up

The LL4148 diode is well-suited for a high-speed, small-signal service. Also its Quick switching time, small size, and reliable performance have made it a common part of consumer electronics, and telecommunications. You need to understand its datasheet, pinout, and applications for successful integration into a variety of circuits. So, whether you plan to use it within a basic rectifier circuit or a speedy logic switch, the LL4148 provides flexibility and reliability for its cost.

Engineers and hobbyists alike may find the LL4148 footprint and replacement by comparing it with similar diodes such as the 1N4148.

Frequently Asked Questions

What is the price of the LL4148?

The LL4148 costs around $0.10 to $0.15 in bulk, making it an affordable choice for mass production.

What is the reverse recovery time of the LL4148?

The LL4148 has a reverse recovery time of 4 nanoseconds, making it suitable for high-speed switching applications.

What is the maximum reverse voltage of LL4148?

The maximum reverse voltage of the LL4148 is 100V.

What is the forward voltage drop of LL4148?

The forward voltage drop of LL4148 is about 1.0V (at 10mA).

How to recognize the polarity of LL4148?

The negative terminal (cathode) of the LL4148 is indicated by a marked strip, and the positive terminal (anode) is the other end.

Is the LL4148 suitable for high frequency applications?

Yes, the LL4148 is suitable for high frequency applications due to its low capacitance and fast switching characteristics.

Is the LL4148 economical in mass production?

Yes, the unit price of LL4148 is usually in the range of $0.10 to $0.15, making it suitable for mass production.