Application Information

TS4975

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4

Application Information

The TS4975 integrates 2 monolithic power amplifiers. The amplifier output can be configured

as either SE (single-ended) capacitively-coupled output or PHG (phantom ground) output.

This chapter gives information on how to configure the TS4975 in application.

4.1

I²C bus interface

The TS4975 uses a serial bus, which conforms to the I²C protocol (the TS4975 must be

powered when it is connected to I²C bus), to control the chip’s functions with two wires: Clock

and Data. The Clock line and the Data line are bi-directional (open-collector) with an external

chip pull-up resistor (typically 10 kOhm). The maximum clock frequency in Fast-mode specified

by the I²C standard is 400kHz, which TS4975 supports. In this application, the TS4975 is

always the slave device and the controlling micro controller MCU is the master device.

The ADD pin is allows one to set one of two possible 7-bit device addresses. This setting is

needed for when a number of chips are connected to the same bus (for example two TS4975

devices), to avoid address conflicts. The two possible TS4975 addresses are:

●

$CCh when the ADD pin is connected to logic low voltage,

●

$CEh when ADD pin is connected to logic high voltage.

Table 8.

I²C bus interface pin descriptions

4.1.1

I²C bus operation

The host MCU can write into the TS4975 control register to control the TS4975, and read from

the control register to get a configuration from the TS4975. The TS4975 is addressed by the

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

Table 9.

The first byte after the START message for addressing the device

In order to write data into the TS4975, after the “start” message, the MCU must send the

following data:

●

send byte with the I²C 7-bit slave address and with a low level for the R/W bit

●

send the data (control register setting)

Pin

Functional Description

SDA

This is the serial data pin

SCL

This is the clock input pin

ADD

User-setable portion of device’s I2C address

A6

A5

A4

A3

A2

A1

A0

R/W

110

0

1

1

A0

X