BC557 SOT 23 PDF

BC557 SOT 23 PDF

Product data sheet. Supersedes data of Apr Oct DISCRETE SEMICONDUCTORS. BC; BC PNP general purpose. PNP general-purpose transistors in a small SOT23 (TOAB) Surface-Mounted Device. (SMD) plastic package. Table 1. Product overview. Low noise input stages of audio frequency equipment. DESCRIPTION. PNP transistor in a SOT23 plastic package. NPN complements: BC

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The base internal current is mainly by diffusion see Fick’s law and. Wikimedia Commons has media related to Bipolar junction transistors.

Bipolar junction transistor

A BJT consists of three differently doped semiconductor regions: For DC conditions they are specified in upper-case. Jan 31, 3. It is less than unity due to recombination of charge carriers as they cross the base region. I’m working on two tables, a short one for inclusion within the body of the transistor chapter, and a long one to be placed at the back of the book. Please improve this article by removing excessive or inappropriate external links, and converting useful links where appropriate into footnote references.

Darlington transistor Sziklai pair Cascode Long-tailed pair. The BJT remains a vc557 that excels in some applications, such as discrete bc55 design, due to the very wide selection of BJT types available, and because of its high transconductance and output resistance compared to MOSFETs. A small current leaving the base is amplified in the collector output. This ratio usually has a value close to unity; between 0.

In addition to normal breakdown ratings of the device, power BJTs are subject to a failure mode called secondary breakdownin which excessive current and normal imperfections in the silicon die cause portions of the silicon inside the device to become disproportionately hotter than the others. This section’s use of external links may not follow Wikipedia’s policies or guidelines.

Working on a table for our book, soliciting your opinions, info and advice. The collector—base junction is reverse-biased, and so little electron injection occurs from the collector to the base, but electrons that diffuse through the base towards the collector are swept into the collector by the electric field in the depletion region of the collector—base junction.


That is, a PNP transistor is “on” when its base is pulled low relative to the emitter. The same description applies to a PNP transistor with reversed directions of current flow and applied voltage. The electrons in the base are called minority carriers because the base is doped p-type, which makes holes the majority carrier in the base. This barrier arrangement helps reduce minority carrier injection from the base when the emitter-base junction is under forward bias, and thus reduces base current and increases emitter injection efficiency.

BC [] : Sunrom Electronics/Technologies

In addition, higher doping in the base can improve figures of merit like the Early voltage by lessening base narrowing. Microelectronic Circuits, second ed. SOT sott component soldering? The diagram shows a schematic representation of an NPN transistor connected to two voltage sources. In analog circuit design, the current-control view is sometimes used because it is approximately linear.

Both types of BJT function by letting a small current input to the base control an amplified output from the collector. The incidental low performance BJTs inherent in CMOS ICs, however, are often utilized as bandgap voltage referencesilicon bandgap temperature sensor and to handle electrostatic discharge.

Ebers—Moll model for an NPN transistor. For the CE topology, an approximate h-parameter model is commonly used which further simplifies the circuit analysis. Jan 31, A History of the World Semiconductor Industry. For a figure describing forward and bd557 bias, see semiconductor diodes.

Semiconductor Device Physics and Simulation. Bv557 example, in the typical grounded-emitter configuration of an NPN BJT used as a pulldown switch in digital logic, the “off” state never involves a reverse-biased junction because the base voltage never goes below ground; nevertheless the forward bias is close enough to zero that essentially no current flows, so this end of the forward active region can be regarded as the cutoff region.


This variation in base width often is called the Early effect after its discoverer James M. This section may be too technical for most readers to understand. By using this site, you agree to the Terms of Use bd557 Privacy Policy.

The collector—base junction is reverse biased in normal operation. The thin shared base and asymmetric collector—emitter doping are what differentiates a bipolar transistor from two separate and oppositely biased diodes connected in series.

By convention, the direction of current on diagrams is shown as the direction that a positive charge would move. That drift component of transport aids the normal diffusive transport, increasing the frequency response of the transistor by st the transit time across the base. When the base—collector voltage reaches a certain device-specific value, the base—collector depletion region boundary meets the base—emitter depletion region boundary.

As shown, the h-parameters have lower-case bcc557 and hence sott AC conditions or analyses. Bipolar transistors can be combined with MOSFETs in an integrated circuit by using a BiCMOS process of wafer fabrication to create circuits that take advantage of the application strengths of both types of transistor.

The h-parameter model as shown is suited to low-frequency, small-signal analysis. The 32 of symmetry is primarily due to the doping ratios of the emitter and the collector.

SiGe Heterojunction Bipolar Transistors. For translinear circuitsin which the exponential I—V curve is key to the operation, the transistors are usually modeled as voltage-controlled current sources whose transconductance is proportional to their collector current.

The resulting reduction in minority carrier lifetime causes gradual loss of gain of the transistor. Transistor modeling Transistor types Bipolar transistors.