STMicroelectronics TDA7491LP

Overview

TDA7491LP from STMicroelectronics is a dual-channel BTL Class-D audio amplifier IC designed for LCD TV and monitor audio output stages. It delivers 5 W + 5 W continuous output into 8 Ω at 9 V supply (THD = 10%), operates from a single 5–14 V supply, achieves 90% efficiency, supports four fixed gain settings (20–32 dB), and features filterless operation with differential inputs.

For engineers reviewing the TDA7491LP datasheet, TDA7491LP pinout, TDA7491LP application, or TDA7491LP equivalent, key selection considerations include its PowerSSO-36 EPD thermal package, dual-channel BTL architecture, gain-selectable differential input interface, and integrated standby/mute/thermal/short-circuit protection - all critical for compact, high-efficiency TV speaker amplification designs.

Technical Context

The TDA7491LP implements two fully independent Class-D BTL channels with unipolar PWM modulation, internal 320 kHz oscillator (±10% tolerance), and configurable master/slave clock synchronization via SYNCLK. Each channel uses differential analog inputs with 68 kΩ typical input resistance and supports external LC filtering or filterless operation using integrated modulation topology.

It integrates dual 3.3 V regulators (VDDPW for power stage, VDDS for signal blocks), diagnostic open-drain output (DIAG) for fault reporting, and programmable gain via GAIN0/GAIN1 logic inputs. Protection includes undervoltage lockout (4.5 V threshold), thermal shutdown at 150 °C, and overcurrent detection (3 A threshold).

Key Specifications

Pinout & Package

Package: PowerSSO-36 EPD (Exposed Pad Down), thermally enhanced surface-mount package with exposed copper pad soldered to PCB ground plane for direct heat conduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel Class-D audio amplifier applications.

Compared with TDA7491HV, the TDA7491LP trades maximum supply voltage headroom for optimized thermal performance in low-profile TV assemblies; versus TPA3110D2, it prioritizes integration and board-area savings over raw power - making it the preferred choice for mainstream LCD TV audio subsystems.

Availability

TDA7491LP is available at Aetrix Electronics and suitable for LCD TV manufacturing, monitor production, and set-top box assembly requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for TDA7491LP 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in analog, power, and microcontroller technologies for industrial, automotive, and consumer markets.

The TDA7491LP belongs to ST's high-efficiency audio amplifier product line, engineered specifically for cost-sensitive, space-constrained visual display applications where thermal management and EMI compliance are critical design constraints.

FAQ

What is the minimum recommended PCB copper area for thermal management?

The TDA7491LP's PowerSSO-36 EPD package relies on the exposed pad soldered to a minimum 200 mm² copper pour connected to ground. ST recommends ≥4 internal/external copper layers with thermal vias (≥12 × 0.3 mm diameter) under the EP pad to maintain junction temperature ≤125 °C at full 5 W/channel output in still air.

Can the TDA7491LP drive 4 Ω speakers?

Yes - the TDA7491LP delivers 5 W per channel into 4 Ω loads at 6.6 V supply (THD = 10%). Its 3 A overcurrent protection threshold and thermal shutdown ensure safe operation, but PCB layout must provide enhanced copper area and airflow to manage the higher power dissipation versus 8 Ω operation.

How does the DIAG pin indicate fault conditions?

The DIAG pin is an open-drain output pulled low during thermal shutdown, overcurrent, or undervoltage events. It remains high-impedance during normal operation. External pull-up (typically 10 kΩ to 3.3 V) enables microcontroller GPIO monitoring; pulse width or duration is not encoded - only asserted/unasserted state is used.

Is external clock synchronization mandatory for stable operation?

No - the TDA7491LP operates autonomously using its internal 320 kHz oscillator (set by ROSC resistor). SYNCLK is optional and used only when synchronizing multiple TDA7491LP devices to eliminate beat frequencies; in standalone applications, SYNCLK can be left unconnected or tied to VSS.