However, current flows through what has resistance between an GND terminal and a IN terminal. Temperature Coefficients +1 IC, COLLECTOR CURRENT (mA) Figure 8. Voltages up to 5V can be supplied to the Collector-Emitter in the reverse direction as below. (If sufficient voltage is supplied to the Collector-Emitter in reverse, deterioration such as low hFE will occur. during power-down - the base-emitter junction can be transiently reverse biased with more than the allowed 5 V, due to the slow discharge of C1. The common emitter breakdown voltage as characterized by the open base breakdown voltage, VBCEO, is therefore significantly less than the open emitter. A datasheet for a transistor lists the breakdown voltage ratings for the emitter-base, collector-base, and collector-emitter junctions. However, when the supplies collapse abrubtly - e.g. Typically this is between 5 to 7V, making the Collector-Emitter reverse voltage less than 5V. In the following (partial) circuit, the transistor is usually in its regular forward active mode. NPN: +V to Emitter, Collector grounded) is roughly equivalent to the breakdown between the Emitter and Base. Conversely, VCEO in PNP transistors is in breakdown when positive voltage is supplied to the Emitter with Collector grounded.īreakdown in the opposite direction (e.g. Anyway, as a hand-waving explanation, it's fine.Is it possible to supply voltage to the Collector-Emitter in reverse?įor NPN transistors, VCEO is in breakdown when positive voltage is supplied to the Collector pin while the Emitter is grounded. *Probably there's a more refined explanation alas, it's been long enough that I forget the intimate details of BJT operation, and whether this mode of operation has a weirder explanation, or if this really is the underlying mechanism. These curves show the relationship between three parameters: gate voltage, collector. Vcbo) and this is the explanation* why one is lower - the C-B leakage forward-biases the B-E junction, multiplying the current, effectively causing breakdown to occur earlier, i.e. Collector-to-Emitter Breakdown Voltage (BVCES). More importantly, transistor action will amplify the breakdown current, effectively lowering the breakdown voltage by how much, isn't specified here. The question naturally arises as to how such a low voltage can be used in practical applications. Its value can approach or even equal the supply voltage rating of the transistor. The exact thing you asked for, Veco, isn't usually specified, but yes, the C-B junction will be forward biased under that condition. Junction Capacitance versus Voltage The value of V(BR)CEO is sometimes misunderstood. High-speed, high-voltage HRTs with breakdown voltage exceeding 60 V have been. (Vebo is the voltage from emitter to base, the remaining terminal (collector) being 'open'.) Or in this case, potentially as low as 4V (note the limit is for guaranteed freedom from breakdown the actual zener breakdown voltage might be 5-6V, I would guess). The collector-emitter breakdown VCEOis approximately 50 V. emitter breakdown voltage with base open (BVCEO ), 187, 189, 403 Collector-emitter breakdown voltage with base shorted to emitter, 187, 189 Collector-emitter. The E-B junction has a lower breakdown voltage, typically acting something like a 7V zener diode. In and of itself, the transistor's limit, without reference to the surrounding circuit: it's right there in the screenshot, Vebo. And still others where it can't happen at all (but OP asking about this condition probably implies we're not considering that case). There are situations where it might, and others (I suspect more common) where it doesn't matter. Um? It's not a foregone conclusion that C-B forward bias causes problems.

Collector emitter breakdown voltage