1N4938 is a small signal diode produced by Fairchild Semiconductor Corporation. The maximum reverse voltage of this diode is 200 V, the average rectified forward current is 500 mA, the non-repetitive peak forward surge current is 1.0 A or 4.0 A, the storage temperature range is -65 to +200°C, the operating junction temperature is 175°C, the maximum power dissipation is 500 mW, the junction to ambient thermal resistance is 300°C/W, the breakdown voltage is 200 V, the forward voltage is 1.0 V, the reverse leakage is 100 nA or 100 µA, the total capacitance is 5 pF, and the reverse recovery time is 50 ns.
The 1N4938 is a small‑signal diode supplied in a DO‑35 axial package. It is intended for general‑purpose rectification and switching applications where low forward voltage and fast recovery are required.
The datasheet lists absolute maximum ratings such as a 200 V reverse voltage and 500 mA average forward current, along with thermal data (500 mW dissipation, 300 °C·W junction‑to‑ambient resistance) and detailed electrical characteristics including forward voltage, reverse leakage, capacitance, and reverse‑recovery time. Usage notes warn that the ratings assume a 200 °C maximum junction temperature and that pulsed or low‑duty‑cycle operation should be discussed with the factory.
| Maximum Repetitive Reverse Voltage | 200 V |
|---|---|
| Average Rectified Forward Current | 500 mA |
| Peak Forward Surge Current (1 µs) | 4.0 A |
| Peak Forward Surge Current (1 s) | 1.0 A |
| Power Dissipation | 500 mW |
| Thermal Resistance (J‑A) | 300 °C·W |
| Forward Voltage (I = 100 mA) | 1.0 V |
| Reverse Leakage (V = 75 V) | 100 nA |
| Operating Junction Temperature | 175 °C |
| Storage Temperature Range | -65 to +200 °C |
The maximum repetitive reverse voltage is 200 V.
The diode is rated for an operating junction temperature of 175 °C.
No, Fairchild does not authorize its use in life‑support devices without written approval.