Linear Technology's LT1121IST-5 Voltage Regulator

The LT1121IST-5 is a high-performance low dropout voltage regulator (LDO) from Linear Technology, designed to provide a stable 5V output with a wide input voltage range. This device is particularly suitable for battery-powered systems, portable devices, and other applications where power efficiency and minimal voltage drop are crucial.

Key Features

• Low Dropout Voltage: The LT1121IST-5 boasts an extremely low dropout voltage, typically only 0.45V at a full load of 150mA. This feature ensures efficient operation even when the supply voltage is only slightly above the regulated output voltage, making it ideal for battery-operated devices where the input voltage may decline over time.
• High Output Accuracy: This regulator maintains a high accuracy with a guaranteed output voltage within ±3% over the full line, load, and temperature range. The precision output helps to ensure reliable operation of sensitive electronic circuits.
• Low Quiescent Current: With a quiescent current of just 30μA (typical) in operation and 16μA in shutdown, the LT1121IST-5 conserves battery life by minimizing its own power consumption when active and reducing it even further when the device is in standby mode.
• Thermal Protection and Current Limiting: Built-in thermal shutdown and current limiting protect the device and the load from damage due to overheating and overcurrent conditions.
• Stable with Low ESR Capacitors: The LT1121IST-5 remains stable with output capacitors as low as 3.3μF, allowing the use of modern low equivalent series resistance (ESR) capacitors which can be smaller, cheaper, and more reliable than older, larger capacitors.

Applications

With its robust feature set, the LT1121IST-5 is versatile for a range of applications, including:

• Portable Computers and Electronics
• Battery-Powered Equipment
• Automotive Power Supplies
• Industrial Supplies
• Avionics and Military Systems

The LT1121IST-5 is available in a compact SOT-223 package, making it suitable for space-constrained applications while providing excellent power dissipation capabilities. Its performance and small footprint make it an excellent choice for designers looking for a reliable and efficient voltage regulation solution.