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Product Overview
MUR3040CA is a 30A 400V common-anode dual fast-recovery rectifier in TO-220AB. Two 15A diode paths share an anode, while the separate cathodes support negative-output and current-steering arrangements.
The 30A total device rating comprises two 15A diode paths. Evaluate each branch at its own current waveform and operating temperature when calculating conduction loss and the required cooling.
Key Features
● 400V repetitive peak reverse voltage and two 15A diode paths.
● 50ns maximum reverse-recovery time under the specified 0.5A test condition.
● 1.3V maximum forward voltage at 15A and 25°C.
● 250A non-repetitive surge current for a 8.3ms pulse.
Key Specifications
| Parameter | Value and conditions |
| Configuration / package | Dual common anode / TO-220AB |
| Forward current | 30A per device; 15A per diode |
| Repetitive peak reverse voltage | 400V |
| Forward voltage | 0.95V typ at IF = 15A, Tj = 125°C 1.3V max at IF = 15A, Tj = 25°C |
| Reverse recovery time | 50ns max; Tj = 25°C, IF = 0.5A, IR = 1.0A, Irr = 0.25A |
| Surge current | 250A; non-repetitive, t = 8.3ms |
| Junction to case thermal resistance | 2.0°C/W |
| Junction temperature range | −55°C to +150°C |
Current and thermal limits must be evaluated for the complete assembly. IFSM is a non-repetitive pulse rating, not a repetitive operating-current rating.
Electrical Configuration and Pinout
Two separate cathodes connect to a shared anode. With the marking face toward you and the leads pointing down, the lead functions are K1, A and K2 from left to right. The exposed metal tab is also connected to A.
Figure 1. Circuit and connection detail from the MUR3040CA datasheet, page 1. A = anode; K = cathode.
| Connection | Function |
| Left lead | K1 — first diode cathode |
| Center lead | A — common anode |
| Right lead | K2 — second diode cathode |
| Metal tab | A — electrically connected to the common anode |
Typical Applications
● Common-anode current-steering circuits.
● Complementary rectifier networks.
● Industrial inverter commutation stages.
Common Anode Paths for Polarity Specific Circuits
The CA connection is the defining selection feature. Use the shared anode and separate cathodes to match the required current paths; a common-cathode device changes the circuit connection and mounting-tab potential.
Design Notes
Evaluate each diode at its own current waveform and duty cycle. The 30A total device rating does not mean one junction can carry 30A. Check reverse-voltage peaks, including switching transients, against the 400V rating.
The metal tab carries the common anode potential. If the heatsink must remain at a different potential, use an appropriate insulating mounting interface and include its thermal resistance.
The 50ns recovery limit uses the low-current test condition in the parameter table. Evaluate recovery at the application current and temperature. The 250A surge specification is non-repetitive and must not be used as a repetitive overload rating.
FAQ
It identifies the common-anode dual configuration. The two diode anodes and the metal tab share one node.
No direct substitution should be made. CT is common cathode, so the internal polarity and tab potential are different.
No. The stated trr test uses IF = 0.5 A, IRM = 1 A, and IRR = 0.25 A at 25°C. Switching behavior changes with circuit conditions.
It depends on the required heatsink potential. Because the tab is the common anode, use an insulating interface whenever that node cannot be exposed to the heatsink.
