LD49100PURY

Overview

The LD49100PURY is an automotive-grade, adjustable low-dropout linear regulator manufactured by STMicroelectronics. It delivers a maximum output current of 1 A with an input voltage range spanning from 1.5 V to 5.5 V. The device features a typical dropout voltage of 200 mV at full load and maintains stability using ceramic capacitors with a minimum capacitance of 1 µF on both input and output terminals. Key electrical characteristics include a very low quiescent current of 20 µA at no load and 200 µA at 1 A load, alongside a shutdown mode consumption lower than 1 µA. The unit incorporates a 1 ms internal soft-start circuit, short-circuit constant current limiting, and thermal protection.

Feature Summary

• AEC-Q100 Grade 1 qualified for automotive reliability across -40 °C to 125 °C operating temperatures
• Ultra-low dropout voltage performance enabling efficient power regulation under minimal headroom conditions
• Integrated logic-controlled enable function allowing precise electronic shutdown with negligible standby current
• Built-in Power Good indicator providing accurate monitoring and sequencing capabilities for system control

Applications

• Infotainment systems
• Advanced Driver Assistance Systems (ADAS)
• Telematics units
• Body electronics modules

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official datasheet to confirm the adjustable output configuration. Ensure that the procurement channel sources components directly from authorized distributors or the manufacturer to guarantee authenticity. Confirm compliance with RoHS directives and ECOPACK environmental standards prior to finalizing orders. Cross-reference the part number with the latest revision history to ensure compatibility with current manufacturing specifications.

Selection Notes

Select this component when designing circuits requiring high current capability within a compact footprint for automotive environments. The adjustable output version allows flexibility in setting voltages between 0.8 V and 4.5 V using external resistors. Consider the DFN6 package dimensions and thermal resistance values when planning PCB layout to ensure adequate heat dissipation. Evaluate the need for remote sensing via the VSENSE pin if precise load regulation is critical for the application design.

Part Context

This device belongs to the LD49100 series of low-quiescent-current, low-noise regulators designed specifically for automotive applications. It shares core architectural features with other members of the family but differs in output configuration options. The series emphasizes robustness through integrated protections such as thermal shutdown and current limiting, making it suitable for demanding vehicle electronics where reliability and space efficiency are paramount.

Replacement Considerations

Compatible fixed-output variants within the same series include LD49100PU10RY, LD49100PU12RY, LD49100PU15RY, LD49100PU18RY, LD49100PU25RY, LD49100PU30RY, and LD49100PU33RY. These parts share identical pinouts and electrical characteristics except for the fixed output voltage level. Verify that the required output voltage matches one of these fixed options before substituting the adjustable PURY variant.

FAQ

What is the minimum capacitance required for stable operation?

The device requires a minimum of 1 µF ceramic capacitor on both the input and output terminals to maintain control loop stability.

How does the Power Good function operate?

The Power Good pin goes to high impedance when the output voltage exceeds the rising threshold and switches to low impedance when it falls below the falling threshold, requiring an external pull-up resistor.

Can the ADJ pin be left floating?

No, the ADJ pin must be connected to a resistor divider network to set the output voltage; leaving it floating may result in undefined output behavior.