Texas Instruments LM4961LQBD

Overview

LM4961LQBD from Texas Instruments is a mono ceramic speaker driver IC integrating a boost converter and BTL audio amplifier in a single WQFN-28 package. It delivers 15V_p-p output swing into a 2μF+30Ω capacitive load at 1% THD+N, operates from 3.0–5.0V supply, and features dual shutdown control (Shutdown 1 & Shutdown 2), Band-SW mode selection, and thermal shutdown protection - optimized for cellphone earpiece and ringer applications.

For engineers reviewing the LM4961LQBD datasheet, LM4961LQBD pinout, LM4961LQBD application, or LM4961LQBD equivalent, this page provides verified technical context on its integrated boost-converter–amplifier architecture, BTL voltage swing capability, shutdown logic states, Band-SW mode mapping (receiver vs. ringer), and thermal/power dissipation limits per TI SNAS242K Rev. May 2013.

Technical Context

The LM4961LQBD implements a two-stage BTL amplifier: first stage with externally configurable gain (via R_f/R_i), second stage fixed unity-gain inverting, yielding differential gain A_VD = 2×(R_f/R_i). Its integrated boost converter supplies up to 9.5V amplifier rail (V1) from 3.2–5.0V input, with programmable output via FB pin and external R2/R3 divider (V_FB = 1.23V).

Band-SW pin selects between receiver mode (Band-SW = GND, boost disabled, BW2 gain) and ringer mode (Band-SW = VDD, boost enabled, BW1 gain). Shutdown 1 and Shutdown 2 pins support independent logic-controlled disable; both low disables all circuitry, drawing only 0.1µA. Thermal shutdown activates at ≥125°C (θ_JA = 66°C/W).

Key Specifications

Pinout & Package

LM4961LQBD is housed in a 5 mm × 5 mm, 28-pin WQFN package with exposed thermal pad (Package Number NJB0028A). The exposed DAP must be soldered to PCB copper for thermal management (θ_JA = 66°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ceramic speaker driver applications.

Compared with LM4961LQBD, LM4960LQBD removes mode flexibility but simplifies design for fixed-gain ringer use, while TPA2010D1YZFR trades ceramic-speaker optimization for broader speaker compatibility and higher power - neither offers identical Band-SW–enabled dual-mode operation.

Availability

LM4961LQBD is available at Aetrix Electronics and suitable for cellphone earpiece, PDA audio output, portable media player speaker, and ringer applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LM4961LQBD 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 power management technologies, with decades of expertise in audio signal chain and portable power solutions.

The LM4961LQBD belongs to TI's Boomer® audio power amplifier family - engineered specifically for high-efficiency, low-component-count ceramic speaker drive in battery-powered mobile devices, emphasizing click/pop suppression, thermal robustness, and dual-mode flexibility.

FAQ

What is the maximum output voltage swing of the LM4961LQBD?

The LM4961LQBD delivers a typical 15 V_p-p output swing in BTL mode into a 2μF+30Ω ceramic speaker load at 1% THD+N, as specified in the TI SNAS242K datasheet. This high-voltage capability is enabled by its integrated boost converter, which generates up to 9.5V amplifier supply (Vamp) from a 3.2–5.0V input. The LM4961LQBD achieves this swing without external coupling capacitors due to its differential BTL architecture and mid-rail biasing.

How does the Band-SW pin function on the LM4961LQBD?

The Band-SW pin on the LM4961LQBD controls dual operational modes: applying logic high (VDD) enables ringer mode (boost converter active, BW1 gain path), while logic low (GND) selects receiver mode (boost disabled, BW2 gain path). This allows one LM4961LQBD to serve both earpiece and alert functions in cellphones. The pin has an internal 70kΩ pulldown resistor, and threshold voltages are VLH ≥1.5V and VLL ≤0.4V - confirmed in Electrical Characteristics tables for VDD = 4.2V and 3.2V.

What is the shutdown current specification for the LM4961LQBD?

The LM4961LQBD draws a typical shutdown current of 0.1 µA when both Shutdown 1 and Shutdown 2 pins are driven low, as measured under VDD = 4.2V and VDD = 3.2V conditions per SNAS242K. This ultra-low leakage enables extended battery life in always-on mobile devices. The shutdown state disables the boost converter, amplifier stages, and internal bias circuits - verified by quiescent current measurements in the Electrical Characteristics section.

Which package type does the LM4961LQBD use, and what are its thermal requirements?

The LM4961LQBD uses a 5 mm × 5 mm, 28-pin WQFN package with exposed die attach paddle (DAP), designated NJB0028A. Its thermal resistance is θ_JA = 66°C/W, and it requires the DAP to be soldered to a PCB copper plane for effective heat dissipation. The device includes thermal shutdown at ≥125°C junction temperature. Proper PCB layout - including thermal vias under the DAP and connection to ground plane - is essential to maintain TJ ≤125°C under continuous 15V_p-p output conditions.

Can the LM4961LQBD drive standard dynamic speakers, or is it limited to ceramic loads?

The LM4961LQBD is specifically optimized for capacitive ceramic speakers (e.g., 2μF+30Ω), not resistive dynamic speakers. Its BTL output stage is designed for high-voltage, low-current drive into capacitive impedance profiles, and its feedback architecture assumes ceramic load behavior. Driving an 8Ω dynamic speaker would violate output current limits and likely cause instability or thermal shutdown. For dynamic speakers, TI recommends alternatives like the TPA2010D1 - the LM4961LQBD's design intent and validation are strictly for ceramic transducers.