Sony TS 4974 Service Manual

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1W Differential Audio Power Amplifier

with Up/Down Digital Volume Control Pins

■ Operating from VCC = 2.5V to 5.5V

■ Zero pop&clickless circuit

■ 1.W output power @ Vcc=5V, THD=1%,

F=1kHz, with 8

■ Ultra low consum ption in sta ndby mode

(2µA max.)

■ 85dB PSRR @ 217Hz

■ 16 digital volume contro l st eps

■ Two up and down volume control discrete

pins

■ Gain range from -33dB to + 12dB

■ Integrated debouncing system

■ Ultra fast start up time: 15ms typ.

■ DFN10 3X3 mm pitch 0.5

Description

At 3.3v, the TS4974 is a dual power audio amplifier capable of delivering 380mW of continuous RMS ouput power into a 8 tied loads with 1% THD+N. An external standby mode control reduces the supply current to less than 2µA. An internal over-temperature shutdown protection is provided.

The TS4974 has been designed for high quality audio applications such as m obi le phones and for minimizing the number of external components.

The TS4974 features a 16 step digital volume control through two discrete control Up and Down pins. The start-up gain is internally fixed to -12dB. An integrated debou nce system prevents voltage pikes on UP/DOWN pins during volume control mode to be taken into account during a debounce time of 10ms (typ.).

Ω Load

Ω bridged-

PRODUCT PREVIEW

Pin Connections (top view)

TS4974IQ DFN Package

TS4974IQ - Pinout

VIN-

VIN+

BYPASS

STANDBY

GND

1 2

2 3

3 4

4 5

9 8

8 7

7 6

TS4974

VCC

VCC VOUT-

VOUTVOUT+

VOUT+

UP / DVC

UP / DVC DOWN / DVC

DOWN / DVC

Applications

■ Mobile phones (cellular / cordless)

■ PDAs

Order Codes

TS4974IQT -40, +85°C QFN Tape & Reel TBA

November 2004 Revision 1 1/8

This is preliminary information on a new product now in development. Details are subject to change without notice.

■ Laptop/no t ebook com pu te r s

■ Portable audio devices

Part Number Temperature Range Package Packaging Marking

TS4974 Absolute Maximum Ratings

1 Absolute Maximum Ra tings

Table 1: Key parameters and their absolute maximum ratings

Symbol Parameter Value Unit

Vcc

oper

stg

thja

ESD

Supply voltage Input Voltage

Operating Free Air Temperature Range

Storage Temperature Maximum Junction Temperature

Thermal Resistance Junction to Ambient Power Dissipation

Human Body Model

Internally Limited

ESD Machine Model ( min Value ) 200 V

Latch-up Latch-up Immunity 200 mA

Lead Temperature (soldering, 10sec ) 260 °C

1) All volta ges values are measured wi th respec t to the ground pin.

2) The magni tude of input signal must never exceed VCC + 0.3V / GND - 0.3V.

3) Device i s protected in case of over temperatur e by a thermal shutdown ac tive @ 150°C.

4) Exceed i ng the power derating curves during a long perio d, may involv e abnormal operating condition.

5) Human body model, 100pF discharged throu gh a 1. 5kOhm resist or, into pin to Vc c device.

Table 2: Operating Conditions

GND to V

-40 to + 85 °C

-65 to +150 °C 150 °C 200 °C/W

2kV

Symbol Parameter Value Unit

Vcc Supply Voltage 2.5 to 5.5 V

Standby Voltage Input :

VSTB

Device ON Device OFF

1.5

≤ V

GND ≤ V

STB

≤ V

≤ 0.4

Volume control UP/DOWN voltage input:

≤ V

VU/D

UP/DOWN mode ON UP/DOWN mode OFF

RL Load Resistor

40% of VCC ≤ V

≤ 30% of V

U/D

≤ VCC

≥ 8 Ω

TSD Thermal Shutd own Temperature 150 °C R

1) With He at Sink Surfac e = 125mm2.

Thermal Resistance Junction to Ambient

thja

80 °C/W

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Application Information TS4974

1 Application Information

Figure 1: Typical application schematics

VCC

1µF

Vin+

Vin-

BYPASS

330nF

1µF +

DIFFERENTIAL

DIFFERENTIAL INPUT STAGE

INPUT STAGE

TS4974

BIAS

STBY

TS4974

DIGITAL VOLUME

CONTROL

OUT1

OUT2

8 Ω

STDBY

GND

UP DOWN

Operation Mode

The TS4974 is a f ully differential power amplifier which enables better performances i n terms of noise immunity and PSRR.

The TS4974 features a digital volume control with an internal gain range from -33dB up to +12dB, by steps of 3dB. When the dev ice is firstly biased, an i nitial gain of -12dB is internal ly fixed. When standby mode is activated, the gain value is memorized and held until standby is released.

The volume is controlled by means of t wo pins UP and DOW N on which the applicatio n of a VIL voltage will activate the increase or decrease in gain. The TS4974 integrates a debouncing system w hich does not allow to take into account UP or DOWN pulse shorter than T

debounce

function is implemented. When a continuous voltage is applied on UP or DOWN pin, the gain is continuously increased or decreased after a certain time called T autorepeat sequence i s longer ( x1.5T

time is necessary to cover the whole gain range of the device.

range

) to avoid any parasitic activation. In this operat ional mode,

auto

time. Moreover an autorepeat

autorepeat

. The first period of each

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