1. Product Overview: LM4663MT

️· Type: 2W Class D Amplifier
️· Package: TSSOP (24-pin)
️· Intended Application: Driving speakers (both headphones and standard speakers) in audio devices.
️· Life Support Policy: Specifically excluded from use in life-critical medical devices without express written approval from National Semiconductor.

2. Key Features & Design Considerations

️· Power Management:
- Shutdown Mode: Allows for reduced quiescent current during power-up, especially important for USB-powered devices or those with limited current capabilities. A circuit using the LP3740 is recommended for this.
- Power-up Sequence: The amplifier should be initially powered up in shutdown mode.
️· Input/Output:
- Stereo Input Channels: Two input channels (Channel 1 and Channel 1) are available.
- Speaker Outputs: Left (Lout+) and Right (Rout+) outputs for standard speakers, and HPL/HPR for headphones.
️· Control & Flexibility:
- Jumper Selection: Jumpers on the PC board provide control over the following:
■ Shutdown Mode (Normal vs. Shutdown)
■ Input Channel Selection (Channel 1 vs. Channel 2)
■ Active Amplifier (Headphone vs. Class D)
■ Headphone activation (when a headphone jack is plugged in)
️· PC Board Layout:
- Four-layer PCB recommended for optimal performance. Specifics regarding ground and supply planes are detailed in figures 3-7.
- Short connections between power reservoir capacitors, power amp outputs, and filter inductors are critical for minimizing EMI.
️· Bill of Materials: A table (Table 3) lists necessary components and footprints.

3. Figures & Tables (Highlights)

️· Figure 1: Overall block diagram (not explicitly detailed in the summary, but visually represented the amplifier setup).
️· Figures 2-7: Detailed PC board layouts (component side, inner layer ground/supply planes).
️· Figure 2: Circuit using the LP3740 for power-up shutdown.
️· Table 3: Jumper selection guide.
️· Table 2: Bill of Materials (BOM)

4. Ordering Information:

️· Order Number: LM4663MT
️· Package Number: MTC24



IMPORTANT NOTES ABOUT THIS DOCUMENT:

️· AGE & OBSOLESCENCE: This document is *very* old. National Semiconductor was acquired by Texas Instruments (TI) years ago. The LM4663MT is likely obsolete or has been replaced by a newer device. DO NOT USE THIS DOCUMENT AS A RELIABLE SOURCE FOR MODERN DESIGN PRACTICES or component availability.
️· LACK OF DETAIL: Many specific technical values (e.g., voltage levels, component values) are *not* provided in the summary. The document assumes a certain level of existing knowledge.
️· INCOMPLETE FIGURE DESCRIPTIONS: I'm summarizing from text *around* the figures, but I don't have the figures themselves in this text-only format.
️· NATIONAL SEMICONDUCTOR: The entire document is branded as National Semiconductor, not Texas Instruments.