FAN7040M

Overview

The FAN7040M is a mono Bridge-Tied Load (BTL) output amplifier featuring integrated DC volume control, housed in a 20-lead Small Outline Package (20SOP). It operates within a supply voltage range of 4.5V to 18V and delivers up to 3.5W of output power into a 16Ω load at THD+N=10%. The device provides a maximum voltage gain of 37dB with a control range from +37dB to -52dB. Key electrical characteristics include a typical supply current of 5mA, input impedance of 20kΩ, and a DC output offset voltage of 210mV max. It incorporates thermal protection, short-circuit proofing, and a Missing Current Limiter (MCL) activated at 130mA differential current.

Feature Summary

• Integrates DC volume control directly into the input stage, eliminating the need for external AC coupling capacitors while maintaining low DC offset voltage.
• Features a Mono BTL output architecture that reduces peak supply current ripple frequency and allows for higher output power with lower supply voltages.
• Includes built-in thermal protection that shuts down output power if junction temperature exceeds 150°C, and short-circuit protection against ground, VCC, and load shorts.
• Incorporates a Missing Current Limiter (MCL) circuit that activates when output current difference exceeds 130mA, suitable for single-ended headphone applications.

Applications

• Televisions and monitors
• Portable computers
• Desktop computers
• Low voltage audio systems

Procurement Notes

Verify the specific ordering suffix to confirm packaging format. The 'M' suffix indicates tube packaging, while 'MX' indicates tape and reel. Ensure the component matches the original Fairchild Semiconductor specifications, as onsemi has acquired relevant assets. Confirm the operating temperature range is -40°C to +85°C for the standard variant. Cross-reference pin assignments with the 20SOP mechanical drawing to ensure compatibility with existing PCB footprints.

Selection Notes

Select this component for designs requiring a single-chip solution for mono audio amplification with precise DC volume adjustment. The BTL configuration is optimal for maximizing output power efficiency in battery-fed portable devices or low-voltage systems. Consider the 20SOP package constraints for thermal management, as the device relies on board-level heat dissipation. Verify that the application does not require stereo output, as this is a mono amplifier. Ensure the load impedance matches the design assumptions for optimal power delivery and distortion performance.

Part Context

The FAN7040 series was originally developed by Fairchild Semiconductor as a specialized audio amplifier for consumer electronics. It addresses the need for compact, high-efficiency audio solutions in TVs and portable devices. The integration of DC volume control simplifies system design by removing bulky coupling capacitors. Although now part of onsemi's portfolio following corporate acquisitions, the technical specifications remain consistent with the original Fairchild datasheet documentation.

Replacement Considerations

The FAN7040MX serves as the tape and reel version of the FAN7040M. No other direct substitute part numbers are documented in the official datasheet. Verify functional equivalence if considering alternative manufacturers, specifically checking BTL topology, DC volume control interface, and 20SOP package dimensions.

FAQ

How is the mute mode activated?

The device switches to mute mode when the DC volume control voltage (VC) drops below 0.3V.

What is the function of the Missing Current Limiter (MCL)?

The MCL circuit protects the amplifier by shutting it off if the current difference between the two output terminals exceeds 130mA, which supports single-ended headphone applications.

Does the FAN7040 require external coupling capacitors for the volume control?

No, the DC volume control stage is integrated into the input stage, allowing for direct DC coupling without the need for external AC coupling capacitors.