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TDA7297SA中文资料

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TDA7297SA

September 2003 s WIDE SUPPLY VOLTAGE RANGE (6V-18V)s

MINIMUM EXTERNAL COMPONENTS –NO SWR CAPACITOR –NO BOOTSTRAP –NO BOUCHEROT CELLS –INTERNALLY FIXED GAIN

s STAND-BY & MUTE FUNCTIONS s SHORT CIRCUIT PROTECTION s

THERMAL OVERLOAD PROTECTION

DESCRIPTION

The TDA7297SA is a dual bridge amplifier specially designed for TV and Portable Radio applications.Pin to pin compatible with: TDA7297, TDA7266B,TDA7266SA, TDA7266M, TDA7266MA, TDA7266,& TDA7266S.

10W+10W DUAL BRIDGE AMPLIFIER

TECHNOLOGY BI20II

TDA7297SA

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ABSOLUTE MAXIMUM RATINGS

THERMAL DATA

Symbol Parameter

Value Unit V s Supply Voltage

20V I O Output Peak Current (internally limited)2A Ptot Total power dissipation (T case = 70°C)30W T op Operating Temperature

0 to 70°C T stg, T j

Storage and Junction T emperature

-40 to 150

°C

Symbol Parameter

Value

Unit R th j-case Thermal Resistance Junction-case T yp. = 1.8; Max. = 2.5

°C/W R th j-amb

Thermal Resistance Junction to ambient

°C/W

ELECTRICAL CHARACTERISTCS

(V CC = 13V, R L = 8?, f = 1KHz, T amb = 25°C unless otherwise specified)

Symbol Parameter

Test Condition

Min. Typ.

Max.Unit V CC Supply Range

6.5

18V I q Total Quiescent Current R L = ∞

5065mA V OS Output Offset Voltage 120

mV P O Output Power

THD 10%8.3

10W THD

Total Harmonic Distortion

P O = 1W

0.1

0.3%P O = 0.1W to 2W f = 100Hz to 15KHz

%SVR Supply Voltage Rejection f = 100Hz, V R =0.5V

4056dB CT Crosstalk 4660dB A MUTE Mute Attenuation 60

80dB T w Thermal Threshold 150°C G V Closed Loop Voltage Gain 31

33dB ?G V

Voltage Gain Matching

0.5

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TDA7297SA

APPLICATION SUGGESTION STAND-BY AND MUTE FUNCTIONS

(A) Microprocessor Application

In order to avoid annoying "Pop-Noise" during Turn-On/Off transients, it is necessary to guarantee the right St-by and mute signals sequence. It is quite simple to obtain this function using a microprocessor (Fig. 1 and 2).At first St-by signal (from μP) goes high and the voltage across the St-by terminal (Pin 7) starts to increase ex-ponentially. The external RC network is intended to turn-on slowly the biasing circuits of the amplifier, this to avoid "POP" and "CLICK" on the outputs.

When this voltage reaches the St-by threshold level, the amplifier is switched-on and the external capacitors in series to the input terminals (C3, C5) start to charge.

It's necessary to mantain the mute signal low until the capacitors are fully charged, this to avoid that the device goes in play mode causing a loud "Pop Noise" on the speakers.

A delay of 100-200ms between St-by and mute signals is suitable for a proper operation.Figure 1. Microprocessor Application

R i Input Resistance 2530K ?VT MUTE Mute Threshold Vo = -30dB

2.3 2.9 4.1V VT ST -BY St-by Threshold 0.8

1.3

1.8V I ST -BY St-by Current V6 = GND 100μA e N

Total Output Voltage

A Curve;

f = 20Hz to 20KHz

150220

500μV μV

ELECTRICAL CHARACTERISTCS (continued)

(V CC = 13V, R L = 8?, f = 1KHz, T amb = 25°C unless otherwise specified)

Symbol Parameter

Test Condition

Min. Typ.Max.

Unit

TDA7297SA

Figure 2. Microprocessor Driving Signals

B) Low Cost Application

In low cost applications where the μP is not present, the suggested circuit is shown in fig.3.

The St-by and mute terminals are tied together and they are connected to the supply line via an external voltage divider.

The device is switched-on/off from the supply line and the external capacitor C4 is intended to delay the St-by and mute threshold exceeding, avoiding "Popping" problems.

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TDA7297SA Figure 3. Stand-alone low-cost Application

Figure 4. Distortion vs Output Power.Figure 5. Distortion vs Frequency

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TDA7297SA

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Figure 6. Frequency Response

Figure 7. Output Power vs Supply Voltage

Figure 8. Ptot & Efficiency vs Ouput Power

Figure 9. Mute Attenuation vs Vpin 6

Figure 10. Stand-By attenuation vs Vpin 7

Figure 11. Quiescent Current vs Supply

Voltage

TDA7297SA Figure 12. PC Board Component Layout

Figure 13. Evaluation Board Top Layer Layout

Figure 14. Evaluation Board Bottom Layer Layout

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TDA7297SA

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HEAT SINK DIMENSIONING:

In order to avoid the thermal protection intervention, that is placed approximatively at T j = 150°C, it is important the dimensioning of the Heat Sinker R Th (°C/W).The parameters that influence the dimensioning are:–Maximum dissipated power for the device (P dmax )–Max thermal resistance Junction to case (R Th j-c )–Max. ambient temperature T amb max –Quiescent current I q (mA)Example:

V CC = 13V, R load = 8ohm, R Th j-c = 2.5 °C/W , T amb max = 50°C P dmax = (N° channels) · P dmax = 2 · ( 4.28 ) + 0.5 = 9 W

(Heat Sinker) In figure 15 is shown the Power derating curve for the device.Figure 15. Power derating curve

V cc

Π2R load 2--------------?--------------------------I q V cc ?+R Th c-a 150T amb max

–P d max ----------------------------------------R Th j-c –15050–9---------------------- 2.5–8.6°C/W ===

TDA7297SA

Clipwatt Assembling Suggestions

The suggested mounting method of Clipwatt on external heat sink, requires the use of a clip placed as much as possible in the plastic body center, as indicated in the example of figure 16.

A thermal grease can be used in order to reduce the additional thermal resistance of the contact between pack-age and heatsink.

A pressing force of 7 - 10 Kg gives a good contact and the clip must be designed in order to avoid a maximum contact pressure of 15 Kg/mm2 between it and the plastic body case.

As example , if a 15Kg force is applied by the clip on the package , the clip must have a contact area of 1mm2 at least.

Figure 16. Example of right placement of the clip

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TDA7297SA

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TDA7297SA Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted

by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not

authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

The ST logo is a registered trademark of STMicroelectronics.

All other names are the property of their respective owners

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