LY8661

Rev. 1.8

Dual 2.0W/CH Stereo Audio Amplifier include Headphone Function

5F, No. 2, lndustry E . Rd. IX, Science-Based Industrial Park, Hsinchu 300, Taiwan

TEL: 886-3-6668838

FAX: 886-3-6668836

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This enables the headphone function, turns off Amp A (+out) and Amp B (+out) which mutes the bridged

speaker. The amplifier then drives the headphones, whose impedance is in parallel with resistors R5 and R6.

These resistors have negligible effect on the LY8661’s output drive capability since the typical impedance of

headphones is 32Ω.

Figure 5 also shows the suggested headphone jack electrical connections. The jack is designed to mate with

a four wire (or three wire)plug. The plug’s tip and ring should each carry one of the two stereo output signals,

whereas the sleeve should carry the ground return. The headphone jack with one control pin contact is

sufficient to drive the HP Sense pin when connecting headphones.

As outlined above driving the Speaker (BTL) and Headphone (SE) loads simultaneously using LY8661 is

simple and easy. However this configuration will only work if the HP Logic pin is used to control the BTL/SE

operation and HP Sense pin is connected to GND(Figure 6).

FIGURE 5. With Headphone Circuit (QFN Type)

FIGURE 6. Without Headphone Circuit (QFN Type)