DA7202

10 W Mono Class-D Amplifier for 2S Battery Devices

Company confidential

Datasheet

Revision 3a

20-Aug-2015

CFR0011-120-00 Rev 5

11 of 25

© 2015 Dialog Semiconductor

8.4

Gain

The DA7202 has a fixed gain of +18 dB.

Output volume is directly proportional to the input signal strength. It is assumed that any required

variation in output volume will be controlled by varying the DA7202 input signal. The input signal

amplitude can be reduced by the use of resistor dividers in conjunction with the known input

impedance.

8.5

Class D output stage

The class D output stage is connected directly to the PVDD (two cell battery pack) power supply.

High-efficiency operation is achieved by operating the output transistors as switches. The output

power transistors are either fully On or fully Off, providing a minimum resistance path for current from

the power supply to the load. The block’s outputs are connected directly to the speaker at OUT_P

and OUT_N.

Filterless operation is achieved by connecting a load (a speaker) between the output terminals of the

Class D ouput block. As a result, the voltage across the load represents a PWM (Pulse Width

Modulated) audio signal, while the output current in the load is a filtered, demodulated representation

of the input audio signal.

For filterless operation, the speaker load can be considered as a first order output filter with a cut-off

frequency well below the PWM carrier signal (the current in the load is a filtered version of the output

PWM voltage signal). See section 10.2 for further detail on speaker selection.

8.6

Power down (PDN_N)

The DA7202 is powered down by pulling the PDN_N pin low. When the device is powered down, a

controlled shutdown process is performed, thus ensuring that there are no audible artefacts (pops

and clicks) on the output path.

The time to disable the device is illustrated in Figure 16.

Table 7: Actions of the PDN_N pin

PDN_N Value

Description

0

Power Down

1

Active