WW DUAL BRIDGE AMPLIFIER WIDE SUPPLY VOLTAGE RANGE (VV) MINIMUM EXTERNAL COMPONENTS NO SWR CAPACITOR NO BOOTSTRAP NO BOUCHEROT CELLS INTERNALLY FIXED GAIN STANDBY & MUTE FUNCTIONS SHORT CIRCUIT PROTECTION THERMAL OVERLOAD PROTECTION TECHNOLOGY BIII CLIPWATT5 ORDERING NUMBER: TDA797SA DESCRIPTION The TDA797SA is a dual bridge amplifier specially designed for TV and Portable Radio applications. Pin to pin compatible with: TDA797, TDA7B, TDA7SA, TDA7M, TDA7MA, TDA7, & TDA7S. BLOCK AND APPLICATION DIAGRAM V CC IN.µF 3 3 OUT 7µF nf STBY 7 IN.µF SGND 9 Vref 5 OUT OUT MUTE PWGND OUT D9AU75B September 3 /
ABSOLUTE MAXIMUM RATINGS Symbol Parameter Value Unit V s Supply Voltage V I O Output Peak Current (internally limited) A Ptot Total power dissipation (T case = 7 C) 3 W T op Operating Temperature to 7 C T stg, T j Storage and Junction Temperature to 5 C THERMAL DATA Symbol Parameter Value Unit R th jcase Thermal Resistance Junctioncase Typ. =.; Max. =.5 C/W R th jamb Thermal Resistance Junction to ambient C/W PIN CONNECTION (Top view) 5 3 9 7 5 3 OUT OUT VCC IN N.C. N.C. SGND PWGND STBY MUTE N.C. IN V CC OUT OUT D3AU3 ELECTRICAL CHARACTERISTCS (V CC = 3V, R L = Ω, f = KHz, T amb = 5 C unless otherwise specified) Symbol Parameter Test Condition Min. Typ. Max. Unit V CC Supply Range.5 V I q Total Quiescent Current R L = 5 5 ma V OS Output Offset Voltage mv P O Output Power THD %.3 W THD Total Harmonic Distortion P O = W..3 % P O =.W to W f = Hz to 5KHz % SVR Supply Voltage Rejection f = Hz, V R =.5V 5 db CT Crosstalk db A MUTE Mute Attenuation db T w Thermal Threshold 5 C G V Closed Loop Voltage Gain 3 3 33 db G V Voltage Gain Matching.5 db /
ELECTRICAL CHARACTERISTCS (continued) (V CC = 3V, R L = Ω, f = KHz, T amb = 5 C unless otherwise specified) Symbol Parameter Test Condition Min. Typ. Max. Unit R i Input Resistance 5 3 KΩ VT MUTE Mute Threshold Vo = 3dB.3.9. V VT STBY Stby Threshold..3. V I STBY Stby Current V = GND µa e N Total Output Voltage A Curve; f = Hz to KHz 5 5 µv µv APPLICATION SUGGESTION STANDBY AND MUTE FUNCTIONS (A) Microprocessor Application In order to avoid annoying "PopNoise" during TurnOn/Off transients, it is necessary to guarantee the right Stby and mute signals sequence. It is quite simple to obtain this function using a microprocessor (Fig. and ). At first Stby signal (from µp) goes high and the voltage across the Stby terminal (Pin 7) starts to increase exponentially. The external RC network is intended to turnon slowly the biasing circuits of the amplifier, this to avoid "POP" and "CLICK" on the outputs. When this voltage reaches the Stby threshold level, the amplifier is switchedon 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 ms between Stby and mute signals is suitable for a proper operation. Figure. Microprocessor Application VCC IN C.µF 3 3 C5 7µF OUT C nf STBY R K 7 C µf µp SGND 9 IN C3.µF Vref 5 OUT OUT MUTE R K C µf PWGND OUT D95AU5A 3/
Figure. Microprocessor Driving Signals V S (V) V IN (mv) V STBY pin 7..3. V MUTE pin..9.3 I q (ma) V OUT (V) OFF STBY MUTE PLAY MUTE STBY OFF D9AU59/mod B) Low Cost Application In low cost applications where the µp is not present, the suggested circuit is shown in fig.3. The Stby and mute terminals are tied together and they are connected to the supply line via an external voltage divider. The device is switchedon/off from the supply line and the external capacitor C is intended to delay the Stby and mute threshold exceeding, avoiding "Popping" problems. /
Figure 3. Standalone lowcost Application VCC R 7K IN C3.µF STBY 7 3 3 C 7µF OUT C nf R 7K C µf SGND 9 IN C5.µF Vref 5 OUT OUT MUTE PWGND OUT D95AUA Figure. Distortion vs Output Power. THD(%) Figure 5. Distortion vs Frequency THD(%) Vcc = V Rl = ohm Vcc =.5V Rl = ohm. f = 5KHz f = 5KHz. Pout = mw f = KHz Pout = 5W.. Pout (W). k k k frequency (Hz) 5/
Figure. Frequency Response Level(dBr) 5.. 3...... 3.. Vcc =.5V Rl = ohm Pout = W 5. k k k frequency (Hz) Figure 9. Mute Attenuation vs Vpin Attenuation (db) 3 5 7 9.5.5 3 3.5.5 5 Vpin.(V) Figure 7. Output Power vs Supply Voltage Figure. StandBy attenuation vs Vpin 7 Po (W) Rf=Ω f=khz d=% d=% D99AU 7 9 Vs(V) Attenuation (db) 3 5 7 9.......... Vpin.7 (V) Figure. Ptot & Efficiency vs Ouput Power Ptot(W) Ptot.5 3 5 7 9 µ Vcc = V RL = Ω (both channel) f = KHz x Pout (W) µ (%) Figure. Quiescent Current vs Supply Voltage Iq (ma) 7 5 55 5 5 35 3 7 9 3 5 7 Vsupply(V) /
Figure. PC Board Component Layout Figure 3. Evaluation Board Top Layer Layout Figure. Evaluation Board Bottom Layer Layout 7/
HEAT SINK DIMENSIONING: In order to avoid the thermal protection intervention, that is placed approximatively at T j = 5 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 jc ) Max. ambient temperature T amb max Quiescent current I q (ma) Example: V CC = 3V, R load = ohm, R Th jc =.5 C/W, T amb max = 5 C V P dmax = (N channels) cc Π R I q V cc load P dmax = (. ).5 = 9 W (Heat Sinker) 5 T R amb max Th ca = R P Th jc = 5 5.5 =. C/W d max 9 In figure 5 is shown the Power derating curve for the device. Figure 5. Power derating curve 35 3 Pd (W) 5 5 (c) (b) (a) a) Infinite Heatsink b) 3.5 C/ W c) 5. C/ W d) 7. C/ W (d) 5 Tamb ( C) /
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. A thermal grease can be used in order to reduce the additional thermal resistance of the contact between package and heatsink. A pressing force of 7 Kg gives a good contact and the clip must be designed in order to avoid a maximum contact pressure of 5 Kg/mm between it and the plastic body case. As example, if a 5Kg force is applied by the clip on the package, the clip must have a contact area of mm at least. Figure. Example of right placement of the clip 9/
mm inch DIM. MIN. TYP. MAX. MIN. TYP. MAX. A 3.. OUTLINE AND MECHANICAL DATA B.5. C.5. D.55. Weight:.9gr E.9.55.9. F.7.73..9 G..7..5.5.55 G 7.57 7.7 7.9.9.7.75 H. H..73 H3 9.5.7 L 7.95.77 L.5.59 L.7...33. L3 5.5.7 M.5. Clipwatt5 M.5. 53 /
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