TS4601B datasheet(17/28 Pages) STMICROELECTRONICS

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TS4601B

Application information

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Application information

4.1

Common-mode sense

The TS4601B implements a common-mode sense to correct the voltage differences that

might occur between the headphone jack return and the GND of the device, thus creating

parasitic noise in the headphone and/or line-out.

The solution to strongly reduce and practically eliminate this noise, is to connect the

headphone jack ground to the CMS of the device that is a common-mode sense pin. It will

sense the difference of potential (voltage noise) between the TS4601B ground and

headphone ground. Thanks to CMS frequency response (refer to Figure 46 on page 16),

this noise is removed from the TS4601B outputs. Figure 1: Typical application schematics

for the TS4601B illustrates this connection.

4.2

I²C bus interface

In compliance with the I²C protocol, the TS4601B uses a serial bus to control the chip’s

functions with two wires: Clock (SCL) and Data (SDA). The clock line and the data line are

bi-directional (open-collector) with an external chip pull-up resistor (typically 10 k

Ω). The

maximum clock frequency in fast-mode specified by the I²C standard is 400 kHz, which

TS4601B supports. In this application, the TS4601B is always the slave device and the

controlling microcontroller MCU is the master device.

The slave address of the TS4601B is 1100 000x (C0h).

An SDZ pin is available to shut down the circuit from a master MCU.

Table 7 summarizes the pin descriptions for the I²C bus interface.

4.2.1

I²C bus operation

The host MCU can write into the TS4601B control register to control the TS4601B, and read

from the control register to get a configuration from the TS4601B. The TS4601B is

addressed by the byte consisting of the 7-bit slave address and R/W bit.

There are five control registers (see Table 9) named CR0 to CR4. In read mode, all the

control registers can be accessed. In write mode, only CR1 and CR2 can be addressed.

Table 7.

I²C bus interface pin descriptions

Functional description

SDA

Serial data pin

SCL

Clock input pin

SDZ

Master standby of the TS4601B

Table 8.

The first byte after the START message for addressing the device

R/W

000

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