7905 Voltage Regulator IC

Technical Details

• Operating Temperature: 0°C to +125°C.

• Storage Temperature: -65°C to +150°C.

• Pin Configuration: 1: Ground, 2: Input, 3: Output (Note: This differs from the 78xx series).

Prototyping and Engineering Tips from Robogears

• Pinout Difference Warning: CRITICAL: The pinout of the 7905 is NOT the same as the 7805. For a 7905, the pins are: Pin 1 = Ground, Pin 2 = Input, Pin 3 = Output. Connecting it like a 7805 (where Pin 1 is Input) will result in no output or potential damage to the IC.

• Input Voltage Polarity: Remember that the input voltage must be more negative than the output. To get -5V out, you should provide an input between -7V and -25V DC.

• Capacitor Selection: For stable operation, always place a 2.2µF Tantalum or 10µF Electrolytic capacitor on the output pin and a 0.33µF or 1µF capacitor on the input pin. These capacitors must be rated for at least 16V or 25V and placed as close to the IC pins as possible.

• Heatsink Necessity: If you are dropping a large voltage (e.g., from -15V down to -5V) at high current, the IC will generate significant heat. Use a TO-220 Aluminum Heatsink and thermal paste. Without a heatsink, the internal thermal protection will kick in and shut down the output.

• Common Grounding: In a dual-supply setup (+5V and -5V), ensure that the Ground (GND) pins of both the 7805 and 7905 are tied to the same common ground point in your circuit to maintain a consistent reference.

Package Includes

• 1 x 7905 Negative 5V Voltage Regulator IC (TO-220)

Disclaimer: Product images are shown for illustrative purposes only. The exact branding placement on the metal tab or the finish of the plastic housing may vary slightly between manufacturing batches, but all technical specifications and performance standards remain as described.

Safety Warning: Ensure correct polarity of input voltage; reversed negative input can destroy the IC. Always verify the pinout with a multimeter before powering up a new circuit. Do not exceed the 1.5A current limit for extended periods without active cooling.