The LT ®1529/LT1529-3.3/LT1529-5 are 3A low dropout regulators with micropower quiescent current and shut- down. The devices are capable of supplying 3A of output current with a dropout voltage of 0.6V. Designed for use in battery-powered systems, the low quiescent current, 50µA operating and 16µA in shutdown, make them an ideal choice. The quiescent current is well controlled; it does not rise in dropout as it does with many other low dropout PNP regulators. Other features of the LT1529 /LT1529-3.3/LT1529-5 in- clude the ability to operate with small output capacitors. They are stable with 22µF on the output while most older devices require up to 100µF for stability. Small ceramic capacitors can be used, enhancing manufacturabiltiy. Also the input may be connected to voltages lower than the output voltage, including negative voltages, without re- verse current flow from output to input. This makes the LT1529/LT1529-3.3/LT1529-5 ideal for backup power situations where the output is held high and the input is at ground or reversed. Under these conditions, only 16µA will flow from the OUTPUT pin to ground. The devices are available in 5-lead TO-220 and 5-lead DD packages.
The LT1529 family provides 3 A low‑dropout regulation with a dropout voltage of only 0.6 V at full load. Both fixed‑output (3.3 V and 5 V) and adjustable versions are available, offering very low quiescent current (50 µA) and a shutdown current of 16 µA, making them ideal for battery‑powered applications. The devices include reverse‑battery protection and operate with small output capacitors (minimum 22 µF).
Pin functions are defined for output, sense, adjust and shutdown control, with the SHDN pin (pin 4) providing an active‑low shutdown capability. The regulators are offered in 5‑lead TO‑220 and 5‑lead DD plastic packages, and detailed electrical characteristics, typical performance curves, and recommended layout guidelines are provided.
| Dropout Voltage | 0.6 V at 3 A |
|---|---|
| Maximum Output Current | 3 A |
| Quiescent Current (normal) | 50 µA |
| Shutdown Current | 16 µA |
| Fixed Output Voltages | 3.3 V and 5 V |
| Input Voltage Range (LT1529‑3.3) | 3.8 V to 15 V |
| Minimum Output Capacitor | 22 µF |
| Package Types | 5‑lead TO‑220 and 5‑lead DD |
The dropout voltage is 0.6 V at a 3 A output current.
In shutdown the device draws only 16 µA.
A minimum of 22 µF is required on the output.