Bourns Inc. TIP31C-S
Full Technical Specifications
11 Parameters| Parameter / Attribute | Specification / Value |
|---|---|
| Mounting | Through Hole |
| FET type | NPN |
| Voltage - collector emitter breakdown | 100 V |
| Current - collector (Ic) | 3 A |
| Current - collector cutoff | 300µA |
| DC current gain (hFE) (Min) @ ic, vce | 10 @ 3A, 4V |
| Power - max | 40 W |
| Operating temperature | -65°C~150°C(TJ) |
| Package | Tube |
| Case | TO-220-3 |
| Vce saturation (Max) @ ib, ic | 1.2V @ 375mA, 3A |
Need Stock or a Drop-in Second-Source for TIP31C-S?
Package: TO-126 (SOT-32) · Pin-compatible replacements with immediate Shenzhen spot stock
The BD139 / BD140 pair is Europes bench transistor: drivers, small audio stages, series-pass elements in linear regulators and zener-boosted circuits. Production is continuous across many fabs, and the real decisions are grade and mounting: the -10 / -16 gain groups change base drive margins, the metal tab on the back is the collector (not an isolated heatsink surface), and the tempting swap to the higher-current 2SD882 quietly lowers the voltage ceiling from 80V to 30V.
Verified Pin-Compatible Replacements (4 verified alternatives)
Double the Current in the Same Mould
Shenzhen Spot Stock (24-48h Dispatch)
NPN rated 30V VCEO / 3A where the BD139 is 80V / 1.5A: double the current, less than half the voltage ceiling. Same TO-126 E-C-B lead arrangement.
VCEO 30V (VCBO 40V); IC 3A; Ptot 10W class without extra heatsinking - check the exact vendor curve.
High-Voltage, Lower-Current Direction
Shenzhen Spot Stock (24-48h Dispatch)
NPN rated 300V / 0.5A in the same TO-126 outline - the high-voltage direction instead of the high-current one. PNP complement is the MJE350.
VCEO 300V; IC 0.5A - one third of the BD139 current.
More Power if the Board Makes Room
Shenzhen Spot Stock (24-48h Dispatch)
NPN 100V / 3A in TO-220 - the step up when the BD139 died from dissipation, not from drive.
VCEO 100V; IC 3A; Ptot 40W class with a heatsink.
The PNP Half of the Pair
Shenzhen Spot Stock (24-48h Dispatch)
The PNP complement: -80V / -1.5A with the same gain-group system. Order the pair together for complementary stages.
VCEO -80V; IC -1.5A; same 12.5W class dissipation.
Buyer & Quality Checklist for Sourcing Alternatives
- Read the gain group: BD139-10 (hFE roughly 63-160) and BD139-16 (roughly 100-250) change the base drive budget. Replacing a -16 with a -10 in a marginal driver is how repaired stages fail again.
- The TO-126 metal tab is the collector, electrically live. When bolting to a grounded heatsink, a mica/insulator kit is mandatory - the classic bolt-through-ground short.
- Watch the voltage direction of any substitution: 2SD882 doubles current but drops the ceiling to 30V; MJE340 raises voltage but drops current to 0.5A. Read both numbers before committing.
- In complementary stages, replace BD139 and BD140 together and from the same production lot; the gain-group system exists precisely because the pair has to match.
- For more dissipation, move to TO-220 (TIP31C / TIP32C) but plan the lead forming and heatsink: TO-220 is B-C-E, not the TO-126 E-C-B order.
Frequently Asked Technical Questions
Q: Can I replace a BD139 with a BD140?
A: No - the BD139 is NPN and the BD140 is PNP. They are complements designed to work against each other, not substitutes. The same caution applies to every complementary pair on this site.
Q: Is 2SD882 a good replacement for BD139?
A: In low-voltage circuits (up to about 30V) it is fine and doubles the current. Above 30V it is out of ratings - the BD139 is the 80V part. Check the rail first, then the gain.
Q: Why does a BD139 keep failing in my linear regulator?
A: Almost always dissipation: the TO-126 package handles roughly 12W with a good heatsink, far less without one, and the tab is the live collector. Check the actual voltage drop times current, then the insulator mounting.