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Product Overview
MUR3040CR provides the negative-tandem arrangement of the 30A 400V dual fast-recovery family. It contains two 15A paths in TO-220AB, with the midpoint available at pin 2 and the metal tab.
Each internal diode is rated at 15A. The 30A total device figure does not establish a 30A series-path rating, and the two junctions must not be presented as an automatically doubled blocking-voltage rating.
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.
● 200A non-repetitive surge current per diode for a 8.3ms pulse.
Key Specifications
| Parameter | Value and conditions |
| Configuration / package | Negative tandem dual diode / 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 | 200A per diode; non-repetitive, t = 8.3ms |
| Junction to case thermal resistance | 2.5°C/W |
| Junction temperature range | −55°C to +150°C |
Current capability depends on case temperature and cooling. Use the datasheet derating curve when determining operating current.
Electrical Configuration and Pinout
With the marking face toward you and the leads pointing down, pin 1 is the outer anode, pin 2 is the intermediate node and pin 3 is the outer cathode. The two forward paths run from pin 1 to pin 2 and from pin 2 to pin 3. The metal tab is connected to pin 2.
Figure 1. Circuit and pin connections from the MUR3040CR datasheet, page 1. Pin 2 is the intermediate node and metal-tab connection.
| Connection | Function |
| Left lead / pin 1 | A — outer anode |
| Center lead / pin 2 | AK — intermediate anode/cathode node |
| Right lead / pin 3 | K — outer cathode |
| Metal tab | Pin 2 — electrically connected to the midpoint |
Typical Applications
● Negative-side converter clamps.
● Complementary commutation cells.
● Polarity-specific fast current-steering circuits.
Opposite Tandem Orientation with a Shared Midpoint
The CR current path runs from pin 1 through pin 2 toward pin 3 in the forward direction. Choose it from the circuit connection as well as its own surge and thermal ratings; rotating a CL device does not establish equivalence.
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 intermediate node and metal tab share the same potential. Do not add the two 400V junction ratings and describe the device as an 800V rectifier; series operation requires control of voltage sharing and the current in each junction.
The 50ns recovery limit uses the low-current test condition in the parameter table. Evaluate recovery at the application current and temperature. The 200A surge specification is non-repetitive and must not be used as a repetitive overload rating.
FAQ
The tandem polarity is reversed. The two parts are selected for opposite current-steering orientations even though their headline current and voltage are similar.
The local PDF labels the 200 A 8.3 ms surge value per diode. Confirm how both junctions are stressed in the intended circuit.
Use 1.3 V maximum at 25°C for worst-case conduction checks; 0.95 V at 125°C is a typical value, not a guaranteed maximum.
Specify the full CR suffix and validate the internal diode orientation, not only the TO-220AB body and 30 A 400 V ratings.
