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BC858 SMD PNP Transistor Data
Key transistor data for the BC858 PNP switching & general amplifier transistor (lower voltage version of the BC856) including key electrical parameters, pinout, package type and many other key transistor datasheet details.
There are several transistors in the series, BC858, and the BC856, BC857, BC859, and BC860. They are designed as PNP epitaxial silicon transistors for switching and amplifier applications.
These transistors are complementary to the BC846, BC847, BC848, and BC850 NPN series of NPN transistors.
They are stated as being suitable for automatic insertion in thick and thin film circuits (as well as normal SMT PCBs.
The BC858 is a low voltage device in this series having a VCEO and VCBO of only -30 volts.
Key datasheet details and performance parameters for the BC858 transistor.
| BC858 transistor datasheet parameters & data |
|
|---|---|
| Parameters | Details |
| Transistor type | PNP switching & amplifier |
| Package type | SOT-23 |
| Transistor SMD Ident** | 9CA, 9DC, 9CC |
| VCBO max (V) | -30 |
| VCEO max (V) | -30 |
| VEBOmax (V) | -5 |
| VCEsat (V) | 90mV typ @ I 250mV @ 100mA |
| IC max (mA) | -100 |
| TJ Max °C | 150 |
| PTOT mW | 310 |
| fT min (MHz) | 150 |
| COB | 6pF typical |
| hfe | see below |
| IC for hfe | |
| Similar / equivalents | |
Outline & pinout:
** Transistor SMD identification:
In view of the fact that it is not possible to fully mark surface mount transistors with their full part number a short form identification or marking is added to the package.
This is typically a three character identification. For the BC859 this is either 9CA, 9CB, or 9CC - these are for the different hFE classifications.
Explanation of transistor parameters
| Parameter | Explanation |
|---|---|
| VCBO Max | Maximum collector-base voltage with emitter open circuit . |
| VCEO Max | Maximum collector-emitter voltage with base open circuit. |
| VEBO Max | Maximum emitter-base voltage with collector open circuit. |
| VCEsat (included where applicable) | The voltage drop across the collector-emitter when the transistor is fully saturated (acting as a closed switch). |
| IC Max | Maximum collector current. |
| Parameter | Explanation |
|---|---|
| TJ | Maximum junction temperature. |
| PTOT Max | Maximum device dissipation normally in free air at 25°C unless other conditions indicated. |
| fT Min | Minimum cutoff frequency at which the current gain in a common emitter circuit falls to unity. |
| COB Max | Maximum collector capacitane, normally measured with emitter open circuit. |
| hFE | DC current gain for HFE at IC. [Note hfe is the small signal gain and although this may be slightly different, the transistor current gain will vary considerably from ne transistor to the next of the same type.] |
| PTOT Max | Maximum device dissipation normally in free air at 25°C unless other conditions indicated. |
These are the main transistor parameters that have been included in our list. There are others, but these help quantify the main elements of the performance of the transistor.
Please note, that the data given is the best estimate we can give within a tabulated summary of this nature. Parameters also vary between manufacturers. Electronics Notes cannot accept any responsibility for errors, inaccuracies, etc, although we do endevaour to ensure the data is as accurate as possible.
Notes and supplementary information
The BC858 is a popular surface mount PNP silicon transistor in a surface mount SOT23 package.
• Availability & sources
The device is available from a number of stockists and electronic component distributors.
• hFE for variants
The BC858 has three variants according to the gain, A: 110 - 220, B: 200 - 450, C: 420 - 800.
The suffixes A, B or C are added to the overall part number so that the required selection can be made, and the SMD markings are 9CA, 9CB, or 9CC in order for the different gain values.
• Noise performance
The BC858 is a standard transistor in the series, and although it is not particularly low noise, figures for this are given in the datasheet.
The noise performance is specified as being between 2 (typical) and 10 dB maximum with a VCE of 5V collector current Ic of 100µA, RG of 2kΩ and f = 1 kHz.
These figures are not at all bad, but if a device was needed for a low noise application, then one of te low noise variants would be a much better option - either the BC859 or BC860 would be recommended in these circumstances.
Written by Ian Poole .
Experienced electronics engineer and author.
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