Texas Instruments LM3673TL-1.875/NOPB

Overview

LM3673TL-1.875/NOPB from Texas Instruments is a fixed-output 1.875 V, 350-mA synchronous step-down DC-DC converter optimized for single Li-Ion battery-powered portable electronics. It operates from 2.7 V to 5.5 V input, delivers 2 MHz fixed-frequency PWM switching with automatic PFM mode transition below ~50 mA, and achieves 16 µA typical quiescent current in light-load operation. It powers core logic rails in mobile phones and digital cameras requiring stable low-noise 1.875 V supply.

For engineers reviewing the LM3673TL-1.875/NOPB datasheet, LM3673TL-1.875/NOPB pinout, LM3673TL-1.875/NOPB application, or LM3673TL-1.875/NOPB equivalent, key selection criteria include its DSBGA-5 package footprint, internal 0.5 V reference, 750 mA typical peak switch current limit, shutdown current of 0.01 µA, and compatibility with 2.2 µH inductors and 10 µF ceramic output capacitors.

Technical Context

The LM3673TL-1.875/NOPB implements voltage-mode control with input-voltage feedforward for tight line regulation, and integrates both PFET high-side and NFET synchronous rectifier switches. Its feedback loop references an internal 0.5 V bandgap, with the fixed 1.875 V output derived via internal resistor divider (VOUT = 0.5 V × 3.75).

It supports three functional modes: PWM (≥80 mA load, 2 MHz fixed frequency), PFM (light load, variable frequency, 16 µA IQ), and shutdown (<0.4 V on EN, 0.01 µA ISHDN). Thermal shutdown engages at TJ ≈ 150°C, and undervoltage lockout prevents operation below VIN = 2.7 V.

Key Specifications

Pinout & Package

LM3673TL-1.875/NOPB uses a 5-pin DSBGA package (1.413 mm × 1.083 mm, 0.5 mm pitch) with bottom-side solder balls. The package is optimized for thermal performance in space-constrained portable PCBs and requires controlled-environment reflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down DC-DC converter applications.

Compared with TPS62231DRYR and AP63202WU-18, LM3673TL-1.875/NOPB offers the exact 1.875 V output needed for legacy TI OMAP and Qualcomm Snapdragon core rails, maintains lowest quiescent current in PFM mode, and fits the smallest standard DSBGA footprint-making it optimal for cost- and size-sensitive upgrades of existing designs.

Availability

LM3673TL-1.875/NOPB is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, portable WLAN modules, and MP3 players requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LM3673TL-1.875/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer markets.

The LM3673 product line targets ultra-compact, battery-optimized DC-DC conversion in portable electronics, emphasizing minimal external component count, sub-20 µA light-load IQ, and DSBGA packaging for thin-profile handsets and wearables.

FAQ

What is the recommended input capacitor for LM3673TL-1.875/NOPB?

The LM3673TL-1.875/NOPB datasheet specifies a 4.7 µF X5R/X7R ceramic capacitor placed as close as possible to the VIN and GND pins. This value ensures adequate high-frequency decoupling for the 2 MHz switching node, suppresses input voltage ripple under 350 mA load steps, and maintains stability across temperature and DC bias. Larger values (e.g., 10 µF) may improve hold-up time but do not enhance regulation performance.

Does LM3673TL-1.875/NOPB require external feedback resistors?

No, LM3673TL-1.875/NOPB does not require external feedback resistors. It is a fixed-output variant with an internal resistor divider that sets VOUT to 1.875 V referenced to the 0.5 V internal bandgap. The FB pin is internally connected and must be tied directly to the output capacitor's VOUT node-no external components are permitted or needed on the FB net.

What is the thermal shutdown threshold for LM3673TL-1.875/NOPB?

The LM3673TL-1.875/NOPB activates thermal shutdown at a junction temperature of approximately 150°C (typical), and resumes normal operation once TJ cools to ~130°C (typical). This hysteresis prevents oscillation near the trip point. The DSBGA-5 package's RθJA of 181°C/W means sustained 350 mA operation at 5.5 V input requires careful PCB copper area design to avoid triggering shutdown in enclosed enclosures above 60°C ambient.

Can LM3673TL-1.875/NOPB operate from a 2.5 V input?

No, LM3673TL-1.875/NOPB cannot reliably operate from a 2.5 V input. Its absolute minimum recommended input voltage is 2.7 V per the datasheet's Recommended Operating Ratings. Below this, undervoltage lockout disables switching, and the internal reference and control circuits may not function correctly-resulting in unregulated output or failure to start. Systems must ensure VIN ≥ 2.7 V before asserting EN high.

What is the peak switch current limit of LM3673TL-1.875/NOPB?

The LM3673TL-1.875/NOPB has a typical peak switch current limit of 750 mA in open-loop testing, with a minimum of 590 mA and maximum of 855 mA across temperature and process variation. This limit protects the internal PFET and external inductor during output short-circuit or heavy transient events, and is factory-trimmed-no external adjustment is possible or required.