LY8006

1.4 W Mono Filterless Class D Audio power Amplifier (MSOP / DFN)

Rev. 1.7

－

Compatible with LY8890/8891/8891B Single-Ended Input

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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APPLICATION INFORMATION

Input Resistors (Ri) and Gain

+ Ri )] x 2

The resistor matching is very important in the amplifiers. Balance of the output on the reference voltage

depends on matched ratio of the resistors. CMRR, PSRR, and cancellation of the second harmonic distortion

if resistor mismatch occurs. Therefore, it is recommended to use 1% tolerance resistors or better to keep the

performance optimized. Matching is more important than overall tolerance.

Resistor arrays with 1% matching can be used with a tolerance greater than 1%.Place the input resistors very

close to the LY8006 to limit noise injection on the high-impedance nodes. For optimal performance the gain

should be set to 2 V/V or lower. Lower gain allows the LY8006 to operate at its best,

For example

Rf (KΩ)

150

150

150

150

150

150

Ri (KΩ)

300

150

100

75

50

37.5

Pre AMP. Gain

1

2

3

4

6

8

Total Gain

2

4

6

8

12

16

6.02

12.04

15.56

18.06

21.58

24.08

Input Capacitors (Ci)

The LY8006 using a single-ended source, So the input coupling capacitors are required. The input capacitors

fc = 1 / ( 2πRi Ci )

The value of the input capacitor is important to consider as it directly affects the bass (low frequency)

performance of the circuit. Speakers in wireless phones cannot usually respond well to low frequencies, so

the corner frequency can be set to block low frequencies in this application. Equation is reconfigured to solve

for the input coupling capacitance.

Ci = 1 / ( 2πRi fc )

If the corner frequency is within the audio band, the capacitors should have a tolerance of

±10% or better,

because any mismatch in capacitance causes an impedance mismatch at the corner frequency and below.