LM3687TLX-1812/NOPB

Overview

The LM3687TLX-1812/NOPB is a dual-output power management integrated circuit manufactured by Texas Instruments, formerly National Semiconductor. It integrates a synchronous step-down DC-DC converter and a low-dropout linear regulator (LDO) within a single package. The device operates with an input voltage range of 2.7V to 5.5V and features a switching frequency of 1.8MHz. Output 1 provides a fixed 1.8V at up to 400mA from the buck converter, while Output 2 supplies a fixed 1.2V at up to 350mA from the LDO. It is housed in a compact 9-DSBGA package suitable for space-constrained portable applications.

Feature Summary

• Integrates a high-efficiency synchronous buck converter and a precision LDO in a single component
• Supports wide input voltage ranges suitable for single-cell lithium-ion battery systems
• Features a high switching frequency to minimize external passive component size
• Includes thermal shutdown protection for enhanced operational reliability

Applications

• Portable media players and handheld devices requiring multiple regulated rails
• Smartphones and mobile phones utilizing single-cell lithium-ion power sources
• Personal digital assistants (PDAs) and GPS navigation units
• Wireless communication modules needing efficient power conversion

Procurement Notes

Verify the manufacturer designation carefully, as Texas Instruments acquired National Semiconductor; datasheets may list either entity. Confirm the suffix 'NOPB' indicates lead-free and RoHS compliance. Ensure the specific output voltage configuration matches the design requirements, as other variants exist within the LM3687 family. Check current availability status directly with authorized distributors due to potential supply chain fluctuations.

Selection Notes

Select this component when a system requires both high-efficiency switching regulation for higher current loads and low-noise linear regulation for sensitive analog circuits. The 1.8MHz switching frequency allows for smaller inductors and capacitors compared to lower-frequency alternatives. Consider the 9-DSBGA package constraints regarding PCB layout and thermal dissipation capabilities during the design phase.

Part Context

This part belongs to the LM3687 series of dual-output PMICs designed for portable electronics. It combines the benefits of switching regulators and LDOs to optimize efficiency and noise performance. The 'TLX' suffix typically denotes tape and reel packaging, while '1812' specifies the fixed output voltages of 1.8V and 1.2V.

Replacement Considerations

Consult official substitution guides for equivalent parts such as the LM3687QML or other TI PMICs with similar dual-output configurations. Verify pin compatibility and electrical specifications before replacing components in existing designs.