LD57100J105R

Overview

The LD57100J105R is a fixed-output ultra low-dropout linear regulator from STMicroelectronics, providing a nominal output voltage of 1.05 V with a guaranteed maximum load current of 1 A. It operates within an input voltage range extending from the output level up to 5.5 V and requires a dedicated bias supply between 3.0 V and 5.5 V. The device features a typical dropout voltage of 40 mV at full load and maintains an output accuracy of ±0.5% at 25 °C. Packaged in a Flip Chip6 (0.8x1.2 mm) format, it supports operation across a temperature range of -40 °C to +85 °C.

Feature Summary

• Features an NMOS pass transistor architecture with a dedicated bias pin to enable ultra-low dropout performance even at minimal input voltages.
• Includes logic-controlled electronic shutdown that reduces total standby current consumption below 0.1 µA.
• Integrates internal short-circuit protection, thermal shutdown, and an active output discharge function for rapid capacitor discharge upon disable.

Applications

• Smartphones
• Cameras
• Low voltage post regulation

Procurement Notes

Verify the specific ordering code LD57100J105R against the manufacturer's official datasheet DS13123 Rev 6 to confirm the 1.05 V fixed output specification. Ensure the design accommodates the required external ceramic capacitors and the separate VBIAS supply rail as detailed in the application circuits section.

Selection Notes

Select this component when space-constrained designs require a high-current LDO with minimal footprint. The Flip Chip6 package maximizes board area efficiency. Designers must ensure the bias pin receives a minimum of 3.0 V or VOUT plus 1.6 V to maintain proper regulation and low dropout characteristics under all operating conditions.

Part Context

This part belongs to the LD57100 series of 1 A ultra low-dropout regulators. The series offers various fixed output voltages ranging from 0.8 V to 3.3 V, alongside adjustable versions. All variants share the same compact Flip Chip6 packaging and core protection features, differing primarily in their internal reference settings and output tolerance specifications.

Replacement Considerations

Other members of the LD57100 family provide identical functionality with different fixed output voltages, such as LD57100J100R (1.00 V), LD57100J110R (1.10 V), and LD57100J120R (1.20 V). These parts are pin-compatible and suitable for direct substitution if the system power rail requirements allow for the alternative voltage levels.

FAQ

How does the VBIAS pin affect the dropout voltage?

The VBIAS pin supplies the internal driving circuitry. To achieve the specified ultra-low dropout, the bias voltage must be maintained at a minimum of 3.0 V or VOUT plus 1.6 V, whichever is greater.

What happens to the output when the EN pin is set to low?

When the Enable pin is driven low, the device enters shutdown mode with current consumption below 0.1 µA. Simultaneously, an internal MOSFET activates to actively discharge the output capacitor.