The SG29125/125A is a dual 12V/5V positive voltage regulator introduced by LINFINITY Microelectronics Inc. in 1994. One output is a high current (up to 1000 mA) regulator that can be turned on or off by a high impedance low current TTL compatible switch. The second or standby output remains on regardless.
The SG29125/125A is a dual 12 V/5 V positive voltage regulator. One output delivers up to 1000 mA and can be switched on or off with a TTL‑compatible pin, while the standby output remains on continuously. The device features a very low dropout voltage (0.55 V at 10 mA) and a micropower standby mode that reduces quiescent current to about 2 mA.
The datasheet provides absolute maximum ratings, thermal data, recommended operating conditions, and detailed electrical characteristics. Application notes describe typical circuits, external capacitor requirements, and how to disable the standby output. Protection functions include reverse‑battery protection, 60 V load‑dump protection, over‑voltage shutdown, short‑circuit and thermal overload protection.
| Output voltages | 12 V (high‑current), 5 V (standby) |
|---|---|
| Maximum high‑current output | 1000 mA |
| Dropout voltage (500 mA) | 0.45 V |
| Dropout voltage (1000 mA) | 0.7 V |
| Quiescent current (standby) | 2 mA |
| Operating temperature range | -40 °C to 85 °C |
The dropout voltage is 0.45 V at a load current of 500 mA.