LD57100J120R

Overview

The LD57100J120R is a fixed-output ultra low-dropout linear regulator from STMicroelectronics, providing a nominal output voltage of 1.2 V with a guaranteed maximum load current of 1 A. It utilizes an NMOS pass transistor biased by a dedicated pin to achieve an ultra-low dropout voltage of 40 mV typ at full load. The device operates with an input voltage range extending from the output voltage up to 5.5 V and requires a separate bias supply between 3.0 V and 5.5 V. It features high accuracy with ±1% output tolerance across the operating temperature range (-40 °C to +85 °C) and includes logic-controlled shutdown, thermal protection, and active output discharge.

Feature Summary

• Ultra-low dropout performance enabled by a dedicated bias pin for the NMOS pass transistor gate
• Logic-controlled electronic shutdown function with integrated active output discharge
• High precision regulation with ±1% output voltage tolerance over the full temperature range
• Integrated short-circuit current limiting and thermal shutdown protection

Applications

• Smartphones
• Cameras
• Low voltage, low noise post regulation

Procurement Notes

Verify the specific ordering code LD57100J120R against the manufacturer's datasheet DS13123 Rev 6 to confirm the 1.2 V fixed output configuration. Ensure the design accommodates the required external ceramic capacitors on VIN, VBIAS, and VOUT pins for stability. Confirm that the PCB layout supports the Flip Chip6 package dimensions and recommended footprint specifications provided in the official documentation.

Selection Notes

Select this component when a compact solution is required for battery-operated applications needing high efficiency at low input-to-output differentials. The dedicated bias pin allows operation even when the main input voltage is very close to the regulated output level. Consider the Flip Chip6 package size constraints and ensure the application environment stays within the specified -40 °C to +85 °C operating temperature range.

Part Context

This part belongs to the LD57100 series of 1 A ultra low-dropout LDOs. The series offers various fixed output voltages and an adjustable version, all sharing the same core architecture and Flip Chip6 packaging. The J120 suffix specifically denotes the 1.20 V fixed output variant within this family, designed for space-constrained portable electronics requiring stable power delivery.

Replacement Considerations

Other members of the LD57100 series such as LD57100J100R or LD57100J105R share identical pinouts and functional characteristics but provide different fixed output voltages. Verify that the alternative part number matches the required system voltage before substitution.

FAQ

How does the LD57100J120R achieve ultra-low dropout performance?

It uses an NMOS pass transistor whose gate is biased by a dedicated VBIAS pin. This allows the device to maintain regulation even when the input voltage is very close to the output voltage.

What happens to the output when the enable pin is set to a low logic level?

The device enters shutdown mode, reducing total current consumption to less than 0.1 µA. Additionally, an internal MOSFET activates to actively discharge the output capacitor.