7905 Negative Voltage Regulator 5V 1.5A TO-220
The 5V-7905 Negative Voltage Regulator is an electronic component designed to provide a stable negative output voltage of -5V, typically used in power supply circuits for electronic systems that require negative voltage. It operates in a wide input voltage range, typically from +12V to +24V DC, and provides a constant negative 5V output for use in various applications.
The name 7905 signifies two meaning, “79” means that it is a negative voltage regulator and “05” means that it provides 5V as output. So our 7905 will provide a -5V output voltage. The output current of this IC can go up to 1.5A, but the IC suffers from heavy heat loss hence a Heat sink is recommended for projects that consume more current. For example if the input voltage is 12V and you are consuming 1A, then (12-5) * 1 = 7W. This 7 Watts will be dissipated as heat.
Features
- Fixed −5V output with tight tolerance options (AC and C versions).
- Output current capability up to 1.5A with internal current limiting and thermal shutdown.
- Short-circuit protection and Safe Operating Area (SOA) protection for rugged operation.
- Low quiescent current and good line/load regulation for stable operation.
- Low dropout voltage (typical 1.4V@1A).
- Wide operating and storage temperature ranges suitable for industrial use.
PINOUT
| Pin Number | Pin Name | Description |
| 1 | Ground (Gnd) | Unregulated Input Voltage |
| 2 | Input (V+) | Connected to Ground |
| 3 | Output (Vo) | Outputs Regulated -5V |
Note: Complete Technical Details can be found at the LM7905 voltage regulator datasheet given at the end of this page.
Specifications
| Physical | |
| Case/Package | TO-220 |
| Mount | Through Hole |
| Number of Pins | 3 |
| Technical | |
| Dropout Voltage | 1.4 V |
| Max Input Voltage | -35 V |
| Max Operating Temperature | 150 °C |
| Max Output Current | 1.5 A |
| Min Input Voltage | -7 V |
| Min Operating Temperature | 0 °C |
| Min Output Voltage | -5 V |
| Nominal Output Voltage | -5 V |
| Number of Channels | 1 |
| Number of Outputs | 1 |
| Number of Regulators | 1 |
| Output Current | 1.5 A |
| Output Type | Fixed |
| Output Voltage | -5 V |
| Polarity | Negative |
| Power Supply Rejection Ratio (PSRR) | 60 dB |
| Quiescent Current | 3 mA |
| Tolerance | 10 % |
Why do we need Negative Voltage Regulators?
Negative voltage regulators are mainly used in Op-Amp and other circuits where a negative supply voltage is needed. In many cases where an Op-Amp is working in dual mode power supply a negative voltage will be regulated by these 79XX ICs. Also these IC’s will be able to source current into the ground rail instead of sinking it as normally.
Applications
- Constant -5V output regulator to for op-amp signals
- Adjustable Output Regulator
- Current Limiter for certain applications
- Regulated Dual Supply
This is a typical application circuit of the 7905 IC. We just need two capacitors of vale 2.2uf and 1uf to get this IC working.
The input capacitor 2.2uF is a ceramic capacitor that deals with input inductance problem and the output capacitor 1uF is also a ceramic capacitor that adds to the stability of the circuit. These capacitors should be placed close to the terminals for them to work effectively. Also they should be of ceramic type, since ceramic capacitors are faster than electrolytic.
Documents
| Datasheet | LM7905 |
| CAD Files | Download |