In the not-too-distant past, designers were forced to use discrete transistors and logic gate ICs to build up complex devices. With the recent trend of greater miniaturization and integration, today’s semiconductor IC options have become highly specialized for particular applications. You can find ASICs for just about any application, leaving many high voltage/current discrete transistors confined to the field of power electronics.
The 2SA1015-Y is a simple bipolar junction transistor (BJT) in a TO-92 package. While the 2SA1015-Y has gone obsolete, it is still available from a range of secondhand distributors. Since it is undoubtedly present in older systems, it may need to be replaced with a new component or a different transistor during maintenance. If this is the case, you may need access to a 2SA1015-Y datasheet and some compatible replacement parts.
The 2SA1015-Y is a through-hole PNP BJT transistor that was originally manufactured by Toshiba as a high voltage/low current transistor for building simple amplifiers and other low-speed switching circuits. Although it was originally manufactured by Toshiba, it has since been marked obsolete and is currently manufactured by Micro Commercial Components and Unisonic Technologies, both Taiwanese component manufacturers.
The 2SA1015-Y datasheet versions you’ll find from these different manufacturers have very similar specifications, as is the case for many components with generic part numbers. Some of the important specifications and absolute maxima are shown in the table below:
|Voltage for collector cut-off (abs. max.)||– 50 V|
|Max. DC current gain||Approx. 400|
|Collector-emitter saturation voltage||Approx. -0.3 V|
|Base-emitter saturation voltage||Approx. -1.1 V|
|Collector output capacitance||~10 pF, varies with frequency (see below)|
|On-state resistance||~10 Ohms, varies with base current and frequency|
These specifications make the 2SA1015-Y ideal for simple common emitter amplifier circuits operating at high voltage and low current. Some example applications for this component include:
- Low current linear regulator circuits that can withstand high input voltage
- Low-current electrical switches
- Low-to-moderate frequency oscillators and amplifiers
Regarding oscillators, one problem with using a 2SA1015-Y for this type of circuit is that not all datasheets will list a gain-bandwidth product for the device. The 2SA1015-Y datasheet from Unisonic Technologies shows a gain-bandwidth increasing from 40 MHz to a maximum value of 200 MHz at a collector current of approximately -10 mA. This is due to the nonlinear collector output capacitance. Note the earlier datasheet from Toshiba lists a gain-bandwidth product up to 300 MHz.
These specifications make the 2SA1015-Y and similar components useful in a range of analog systems operating at low frequency and moderate voltage. If you have an older system with 2SA1015-Y transistors and it needs an upgrade, you can find a 2SA1015-Y datasheet and parts from secondhand distributors, or you can select a comparable discrete transistor.
Replacements for the 2SA1015-Y
If you need to repair an existing system that uses the 2SA1015-Y with a replacement component, one option is the 2SC1815, also originally produced by Toshiba. With essentially the same specifications, this is a complementary transistor to the 2SA1015-Y, except it is an NPN transistor. It comes in the same footprint and has undergone multiple revisions over its lifetime. In addition to being produced by Toshiba, the 2SC1815 was later produced by Micro Commercial Components, and a Pb-free variant is now produced by the Central Semiconductor Corporation (MPN# 2SC1815-PBFREE). The two transistors’ electrical profiles, operating temperature ratings, and other characteristics are nearly identical. This particular component is an appropriate replacement for a 2SA1015-Y, should you ever need one, although it requires rewiring the collector and base connections.
If you want to stick with a PNP transistor, there are plenty of other discrete transistors that will satisfy the -50 V collector-emitter voltage rating with -150 mA collector current. However, these alternatives may not come in the same package as the 2SA1015-Y. Newer BJTs typically come in an SOT package for surface mounting. One alternative part that comes in a TO-92 package is the KSA1281YTA from ON Semiconductor.
Where to Get a New 2SA1015-Y
Since the 2SA1015-Y is currently marked as obsolete, designers working with BJT components need the ability to quickly find new 2SA1015-Y components, should they be needed for legacy systems. They also need tools to find replacements for a 2SA1015-Y when updating old designs or building a new analog system.
Identifying obsolete components can be difficult without supply chain visibility tools or services. If you need to find a replacement for an obsolete component, the right search tools will help you identify and access a range of components, including in-production, obsolete, NRND, and EOL parts. This may be a better option than using specialty obsolete electronic parts search engines that specialize in vintage or discontinued components. When you use a service like Ultra Librarian, you’ll have access to:
- Verified CAD models, including 2D footprints and 3D STEP files
- Stocks and prices from authorized and secondhand distributors
- A summary of technical specifications
- Component datasheets
- Lifecycle status for each component
Whether you need to find a 2SA1015-Y datasheet or a replacement BJT component, Ultra Librarian gives you access to the search features you need to find transistors and other parts. In addition to sourcing data from a range of distributors, you’ll also have access to CAD models for your components in vendor-neutral file formats. Working with Ultra Librarian takes the guesswork out of your next design. Register today for free.