Texas Instruments LM3677LEE-1.82/NOPB

Overview

LM3677LEE-1.82/NOPB from Texas Instruments is a 3 MHz, 600 mA synchronous step-down DC-DC converter optimized for ultra-low-voltage circuits powered by a single Li-Ion cell (2.7V–5.5V input). It delivers a fixed 1.82 V output with ±2.5% regulation accuracy, 16 µA typical quiescent current in PFM mode, and internal PFET/NFET synchronous rectification. It serves as the primary core voltage regulator in mobile phone baseband processors.

For engineers reviewing the LM3677LEE-1.82/NOPB datasheet, LM3677LEE-1.82/NOPB pinout, LM3677LEE-1.82/NOPB application, or LM3677LEE-1.82/NOPB equivalent, key selection considerations include its 5-bump DSBGA package footprint, automatic PFM/PWM mode transition at ~42 mA (VIN = 3.6 V), 0.5 V internal reference, and thermal shutdown activation at 150°C.

Technical Context

The LM3677LEE-1.82/NOPB implements a voltage-mode PWM controller with input voltage feed-forward compensation to maintain stable line regulation across its 2.7V–5.5V input range. Its 3 MHz (typ.) fixed-frequency operation enables use of sub-1 µH inductors and compact 0603/0805 ceramic capacitors.

It integrates dual MOSFETs - a 350 mΩ (typ.) PFET high-side switch and a 150 mΩ (typ.) NFET synchronous rectifier - enabling >90% efficiency at 300 mA load and 1.82 V output. Mode control logic automatically transitions between PWM (≥80 mA), PFM (light load), and shutdown (<0.4 V on EN) based on real-time load and feedback voltage thresholds.

Key Specifications

Pinout & Package

LM3677LEE-1.82/NOPB uses a lead-free 5-bump DSBGA package (YZR0005), 1.2 mm × 1.2 mm × 0.55 mm, with 0.5 mm bump pitch and bottom-side thermal pad. The package is optimized for high-density portable PCB layouts and requires no external heatsink under typical 600 mA loads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM3677LEE-1.82/NOPB, TPS62231DRVR offers identical functionality in a larger but more manufacturable package, while RT8059GJ6 sacrifices PFM efficiency for lower BOM cost and simpler layout - making LM3677LEE-1.82/NOPB optimal for space- and battery-life-critical portable designs.

Availability

LM3677LEE-1.82/NOPB is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, portable audio players, and WLAN modules requiring stable component supply with guaranteed long-term sourcing.

Supply support for LM3677LEE-1.82/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 specializing in analog, embedded processing, and connectivity technologies, with decades of leadership in power management ICs.

The LM3677 product line was designed specifically for ultra-low-voltage, high-efficiency power conversion in space-constrained portable electronics, emphasizing minimal external components, low quiescent current, and robust thermal performance.

FAQ

What is the recommended input capacitor for LM3677LEE-1.82/NOPB?

A 4.7 µF, 6.3 V X5R/X7R ceramic capacitor placed directly at the VIN pin is recommended. TI specifies this value ensures stable operation across the full 2.7V–5.5V input range and suppresses high-frequency switching noise. The LM3677LEE-1.82/NOPB datasheet further advises using 0603 or 0805 case sizes and avoiding Y5V dielectrics due to DC bias derating. Minimum capacitance is 2.2 µF at 3 V DC bias.

Does LM3677LEE-1.82/NOPB require an external feedback resistor network?

No. The LM3677LEE-1.82/NOPB is a fixed-output variant with internal resistor divider set to 1.82 V; no external FB resistors are needed. This simplifies layout and eliminates resistor tolerance errors. Only three external components are required: input capacitor, output capacitor, and inductor. The LM3677-ADJ version would require external resistors, but LM3677LEE-1.82/NOPB does not.

What is the thermal performance of LM3677LEE-1.82/NOPB in its DSBGA package?

The LM3677LEE-1.82/NOPB has a junction-to-ambient thermal resistance (θ_JA) of 117°C/W on a standard 4-layer board per JEDEC standards. At 600 mA output and 3.6 V input, power dissipation is ~360 mW, resulting in ~42°C junction rise above ambient. Thermal shutdown activates at 150°C (typ.), providing ample safety margin. The DSBGA's bottom thermal pad must be soldered to a solid copper pour for optimal performance.

Can LM3677LEE-1.82/NOPB operate from a 2.5 V input source?

No. The LM3677LEE-1.82/NOPB has a minimum input voltage of 2.7 V per its Absolute Maximum Ratings and Operating Ratings tables. Operation below 2.7 V risks undervoltage lockout activation and unstable regulation. For 2.5 V input systems, consider the LM3677-ADJ with adjusted feedback or alternate converters rated down to 2.3 V, such as the TPS62237.

How does the soft-start function work in LM3677LEE-1.82/NOPB?

The LM3677LEE-1.82/NOPB implements hardware-based soft-start by ramping the internal current limit in four discrete steps: 200 mA → 400 mA → 600 mA → 1220 mA (typical). This occurs only when EN transitions from low to high after VIN exceeds 2.7 V. Startup time depends on output capacitance and load; with 10 µF C_OUT and 300 mA load, typical startup is 300 µs. The LM3677LEE-1.82/NOPB does not require external soft-start components.