Application information

TS4604

18/31

Doc ID 17913 Rev 1

6.2

Use of ceramic capacitors

We advise using ceramic capacitors for the decoupling, flying or tank capacitors because of

their low ESR properties. The rated voltage of the ceramic capacitor, however, is an

important parameter to take into consideration.

A 1 µF/6.3 V capacitor used at 4.8 V DC typically loses about 40% of its value. In fact, with a

4.8 V power supply voltage, the decoupling value is about 0.6 µF instead of 1 µF. Because

the decoupling capacitor influences the THD+N in the medium-to-high frequency region, this

capacitor variation becomes decisive. In addition, less decoupling means higher overshoots,

which can be problematic if they reach the power supply's AMR value (5.5 V).

This is why it is recommend to use a 1 µF/10 V/X5R or a 2.2 µF/6.3 V/X5R, or a new kind of

ceramic capacitor with a low DC bias variation rated at 6.3 V.

If a 1 µF/10 V ceramic capacitor is used, at 4.8 V the capacitance will be 0.82 µF.

If a 2.2 µF/6.3 V ceramic capacitor is used, at 4.8 V the capacitance will be 1.1 µF.

6.3

Flying and tank capacitor for the internal negative supply

The TS4604 embeds two independent internal negative supplies as shown in Figure 1.

Each of them requires two capacitors to work properly (a flying and a tank capacitor). The

internal negative supply capacitor must be correctly selected to generate an efficient

negative voltage.

Two flying capacitors (CHP and CLD) of 1 µF each with low ESR are recommended for

internal negative power supply operation.

●

CHP between pins 8 and 21.

●

CLD between pins 7 and 22.

Two tank capacitors (CPvss_HP and CPvss_LD) of 1 µF each with low ESR are

recommended for internal negative power supply energy storage.

●

CPvss_HP between pin 9 and ground.

●

CPvss_LD between pin 6 and ground.

An X5R dielectric for capacitor tolerance should be used. In order to take into consideration

the

ΔC/ΔV variation of this type of dielectric (see Section 6.2 above), we also recommend:

●

a 10 V DC rating voltage for 4.8 V power supply operation.

●

a 6.3 V DC rating operation for 3.3 V power supply operation.

These capacitors must be placed as close as possible to the TS4604 to minimize parasitic

inductance and resistance that have a negative impact on the audio performance.

6.4

Power supply decoupling capacitor (Cs)

A 1 µF decoupling capacitor (Cs) with low ESR is mandatory for the positive power supply

X5R dielectric for capacitor tolerance behavior. In order to take into consideration the

ΔC/ΔV

variation of this type of dielectric (see Section 6.2 above), it is also recommended to use:

●

a 10 V DC rating voltage for 4.8 V power supply operation.

●

a 6.3 V DC rating operation for 3.3 V power supply operation.