LD57100J100R

Overview

The LD57100J100R is a fixed-output low-dropout linear regulator providing 1.0 V at up to 1 A. It utilizes an NMOS pass transistor with a dedicated bias pin (VBIAS) for ultra-low dropout performance, typically 40 mV at full load. The input voltage range extends from the output voltage to 5.5 V, while the bias supply requires 3.0 V to 5.5 V. Quiescent current is 35 µA typical. The device features logic-controlled shutdown consuming less than 0.1 µA, internal current limiting, and thermal protection. It is housed in a Flip Chip6 package measuring 0.8 x 1.2 mm.

Feature Summary

• Ultra-low dropout voltage achieved via dedicated bias pin driving the NMOS pass transistor gate
• Logic-controlled electronic shutdown with integrated output active discharge function
• High accuracy output voltage tolerance of ±0.5% at 25 °C and ±1% over temperature
• 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 LD57100J100R against the manufacturer's datasheet to confirm the 1.0 V fixed output voltage and Flip Chip6 packaging. Ensure the design accounts for the required VBIAS pin voltage constraints, which must be between 3.0 V and 5.5 V or at least 1.6 V above the output voltage. Confirm that the application environment operates within the specified -40 °C to +85 °C temperature range for guaranteed electrical characteristics.

Selection Notes

Select this component when space-constrained designs require a high-current LDO with minimal voltage headroom. The dedicated bias pin allows operation even when the main input voltage is very close to the output level. Consider the Flip Chip6 package dimensions for PCB layout optimization. Ensure the application can provide the necessary bias voltage to the VBIAS pin to maintain the ultra-low dropout performance specified in the datasheet.

Part Context

The LD57100 series belongs to STMicroelectronics' portfolio of high-accuracy voltage regulators designed for battery-operated applications. This specific part is a fixed-output variant within the family, distinguished by its 1.0 V nominal output. The series emphasizes space efficiency through its compact Flip Chip6 footprint and low quiescent current consumption, targeting portable electronics where power management and physical size are critical constraints.

Replacement Considerations

Consult the official STMicroelectronics datasheet for verified substitute part numbers within the LD57100 series or other compatible LDO families. Do not assume functional equivalence based on generic specifications; verify pin compatibility, electrical parameters, and package dimensions against the source documentation before substitution.

FAQ

How does the VBIAS pin affect the dropout voltage?

The VBIAS pin supplies the internal control circuitry and biases the gate of the NMOS pass transistor. Maintaining the VBIAS voltage at least 1.6 V above the output voltage (minimum 3.0 V) ensures the transistor remains fully enhanced, enabling the ultra-low dropout performance even at very low input voltages.

What is the function of the SNS/FB pin in the fixed version?

In the fixed output version, such as the LD57100J100R, the SNS/FB pin serves as the Output Voltage Sense pin. It should be connected to the load using a separate PCB track to compensate for voltage drops across the board traces, ensuring accurate regulation at the load point.