Philips (Now NXP) TDA8947J Schematic [ru]

TDA8947J

4-channel audio ampliﬁer (SE: 1 W to 25 W; BTL: 4 W to 50 W)

Rev. 01 — 06 February 2004 Preliminary data

1. General description

The TDA8947J contains four identical audio power ampliﬁers. The TDA8947J can be used as: four Single-Ended (SE) channels with a ﬁxed gain of 26 dB, two times Bridge-Tied Load (BTL) channelswith a ﬁxed gain of 32 dB or two times SE channels (26 dB gain) plus one BTL channel (32 dB gain) operating as a 2.1 system.

The TDA8947J comes in a 17-pin Dil-Bent-Sil (DBS) power package. The TDA8947J is pin compatible with the TDA8944AJ and TDA8946AJ.

The TDA8947J contains a unique protection circuit that is solely based on multiple temperature measurements inside the chip. This gives maximum output power for all supply voltages and load conditions with no unnecessary audio holes. Almost any supply voltage and load impedance combination can be made as long as thermal boundary conditions (number of channels used, external heatsink and ambient temperature) allow it.

2. Features

3. Applications

■ SE: 1 W to 25 W, BTL: 4 W to 50 W operation possibility (2.1 system)

■ Soft clipping

■ Standby and mute mode

■ No on/off switching plops

■ Low standby current

■ High supply voltage ripple rejection

■ Outputs short-circuit protected to ground, supply and across the load

■ Thermally protected

■ Pin compatible with TDA8944AJ and TDA8946AJ.

■ Television

■ PC speakers

■ Boom box

■ Mini and micro audio receivers.

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4. Quick reference data

Table 1: Quick reference data

Symbol Parameter Conditions Min Typ Max Unit

stb

o(SE)

o(BTL)

THD total harmonic distortion SE; P

v(max)

SVRR supply voltage ripple

TDA8947J

4-channel audio ampliﬁer

supply voltage operating 9 18 26 V

[1]

no (clipping) signal quiescent supply current VCC=18V; RL= ∞ - 100 145 mA standby supply current - - 10 µA SE output power THD = 10 %; RL=4Ω

=18V 7 8.5 - W

=22V - 14 - W

BTL output power THD = 10 %; RL=8Ω

=18V 16 18 - W

=22V - 29 - W

= 1 W - 0.1 0.5 %

BTL; P

= 1 W - 0.05 0.5 %

maximum voltage gain SE 25 26 27 dB

BTL 31 32 33 dB

SE; f = 1 kHz - 60 - dB rejection

BTL; f = 1 kHz - 65 - dB

--28V

[1] The ampliﬁer can deliver output power with non clipping output signals into nominal loads as long as

the ratings of the IC are not exceeded.

5. Ordering information

Table 2: Ordering information

Type number

TDA8947J DBS17P plastic DIL-bent-SIL power package; 17 leads

Package Name Description Version

SOT243-1

(lead length 12 mm)

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6. Block diagram

TDA8947J

4-channel audio ampliﬁer

IN1+

IN2+

IN3+

IN4+

CIV

SVR

SGND

MODE1

MODE2

CC1

60 kΩ

0.5V

ref

STANDBY ALL

MUTE ALL

ON 1+2

MUTE 3+4

ON 3+4

CC2

SHORT-CIRCUIT

AND

TEMPERATURE

PROTECTION

OUT1+

OUT2−

OUT3−

OUT4+

TDA8947J

215

GND1 GND2

MDB014

Fig 1. Block diagram.

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7. Pinning information

7.1 Pinning

OUT1

GND1 V

CC1

OUT2

MODE2

IN2

SGND

IN1 IN3

MODE1

SVR IN4

CIV

OUT3

GND2 V

CC2

OUT4

−

+ +

−

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17

TDA8947J

4-channel audio ampliﬁer

TDA8947J

MDB015

Fig 2. Pin conﬁguration.

7.2 Pin description

Table 3: Pin description

Symbol Pin Description

OUT1+ 1 non inverted loudspeaker output of channel 1 GND1 2 ground of channels 1 and 2 V

CC1

OUT2− 4 inverted loudspeaker output of channel 2 MODE2 5 mode selection 2 input: mute and on for channels 3 and 4 IN2+ 6 input channel 2 SGND 7 signal ground IN1+ 8 input channel 1 IN3+ 9 input channel 3 MODE1 10 mode selection 1 input: standby, mute and on for all channels SVR 11 half supply voltage decoupling (ripple rejection) IN4+ 12 input channel 4

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3 supply voltage channels 1 and 2

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TDA8947J

4-channel audio ampliﬁer

Table 3: Pin description

Symbol Pin Description

CIV 13 common input voltage decoupling OUT3− 14 inverted loudspeaker output of channel 3 GND2 15 ground of channels 3 and 4 V

CC2

OUT4+ 17 non inverted loudspeaker output of channel 4 TAB - back side tab or heats spreader has to be connected to

8. Functional description

8.1 Input conﬁguration

The input cut-off frequency is:

i cut off–()

For SE application Ri= 60 kΩ and Ci= 220 nF:

…continued

16 supply voltage channels 3 and 4

ground

---------------------------- -

2π RiCi×()

(1)

i cut off–()

---------------------------------------------------------------- -

2π 60 103220 109–×××()

12 Hz==

For BTL application Ri= 30 kΩ and Ci= 470 nF:

i cut off–()

---------------------------------------------------------------- -

2π 30 103470 109–×××()

11 Hz==

As shown in Equation 2 and Equation 3, large capacitor values for the inputs are not necessary, so the switch-on delay during charging of the input capacitors can be minimized. This results in a good low frequency response and good switch-on behavior.

8.2 Power ampliﬁer

The power ampliﬁer is a BTL and/or SE ampliﬁer with an all-NPN output stage, capable of delivering a peak output current of 4 A.

Using the TDA8947J as a BTL ampliﬁer offers the following advantages:

• Low peak value of the supply current

• Ripple frequency on the supply voltage is twice the signal frequency

• No expensive DC-blocking capacitor

• Good low frequency performance.

(2)

(3)

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8.2.1 Output power measurement

The output power as a function of the supply voltage is measured on the output pins at THD = 10 %; see Figure 8.

The maximum output power is limited by the supply voltage (VCC= 26 V) and the maximum output current (Io= 4 A repetitive peak current).

For supply voltages VCC> 22 V, a minimum load is required; see Figure 5:

TDA8947J

4-channel audio ampliﬁer

• SE: R

• BTL: R

8.2.2 Headroom

Typical CD music requires at least 12 dB (factor 15.85) dynamic headroom, compared to the average power output, for transferring the loudest parts without distortion.

The Average Listening Level (ALL) music power, without any distortion, yields:

• SE at P

oALL()SE

• BTL at P

oALL()BTL

The power dissipation can be derived from Figure 9 (SE and BTL) for a headroom of 0 dB and 12 dB, respectively.

=3Ω

=6Ω.

=5W, VCC=18V, RL=4Ω and THD = 0.2 %:

o(SE)

510

⋅

---------------

15.85

o(BTL)

10 103⋅

------------------

15.85

315 mW==

=10W, VCC=18V, RL=8Ω and THD = 0.1 %:

630 mW==

(4)

(5)

Table 4: Power rating as function of headroom

Headroom Power output Power dissipation

SE BTL

0dB P 12 dB P

=5W Po=10W PD=17W

= 315 mW P

o(ALL)

= 630 mW PD=9W

o(ALL)

(all channels driven)

For heatsink calculation at the average listening level, a power dissipation of 9 W can be used.

8.3 Mode selection

The TDA8947J has three functional modes which can be selected by applying the proper DC voltage to pin MODE1.

Standby — The current consumption is very low and the outputs are ﬂoating. The device is in the standby mode when V grounded. In the standby mode, the function of pin MODE2 has been disabled.

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< 0.8 V, or when the MODE1 pin is

MODE1

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Mute — The ampliﬁer is DC-biased, but not operational (no audio output). This allows

the input coupling capacitors to be charged to avoid pop-noise. The device is in the mute mode when 4.5V<V

On — The ampliﬁer is operating normally. The on mode is activated at V

MODE1

mode. The output channels 3 and 4 can be switched on/off by applying a proper DC voltage

to pin MODE2, under the condition that the output channels 1 and 2 are in the on mode (see Figure 3).

Table 5: Mode selection

Voltage on pin Channel 1 and 2 Channel 3 and 4 MODE1 MODE2

0 to 0.8 V 0 to V

4.5 to (V (V

TDA8947J

4-channel audio ampliﬁer

<(VCC− 3.5 V).

MODE1

>(VCC− 2.0 V). The output of channels 3 and 4 can be set to mute or on

(sub woofer)

standby standby mute mute

on on

− 2.0 V) to V

− 3.5 V) 0 to V 0 to (VCC− 3.5 V) on mute

CC CC

− 2 V) to V

all standby

0.8 4.5 VCC−3.5

channels 3+4: mute

MDB016

all mute

VCC−3.5 V

channels 1+2: on channels 3+4: on or mute

VCC−2.0

MODE1

channels 3+4: on

MODE2

Fig 3. Mode selection.

8.4 Supply voltage ripple rejection

The Supply Voltage Ripple Rejection (SVRR) is measured with an electrolytic capacitor of 150 µF on pin SVR using a bandwidth of 20 Hz to 22 kHz. Figure 11 illustrates the SVRR as function of the frequency. A larger capacitor value on pin SVR improves the ripple rejection behavior at the lower frequencies.

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8.5 Built-in protection circuits

The TDA8947J contains two types of detection sensors: one measures local temperatures of the power stages and one measures the global chip temperature. At a local temperature of approximately 185 °C or a global temperature of approximately 150 °C, this detection circuit switches off the power stages for 2 ms. High impedance of the outputs is the result. After this time period the power stages switch on automatically and the detection will take place again; still a too high temperature switches off the power stages immediately. This protects the TDA8947J against shorts to ground, to the supply voltage and across the load, and against too high chip temperatures.

The protection will only be activated when necessary, so even during a short-circuit condition, a certain amount of (pulsed) current will still be ﬂowing through the short, just as much as the power stage can handle without exceeding the critical temperature level.

9. Limiting values

TDA8947J

4-channel audio ampliﬁer

Table 6: Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter Conditions Min Max Unit

ORM

stg

amb

tot

CC(sc)

[1] The ampliﬁer can deliver output power with non clipping output signals into nominal loads as long as

supply voltage operating −0.3 +26 V

input voltage −0.3 VCC+ 0.3 V repetitive peak output

current storage temperature non-operating −55 +150 °C ambient temperature −40 +85 °C total power dissipation - 69 W supply voltage to guarantee

short-circuit protection

the ratings of the IC are not exceeded.

10. Thermal characteristics

Table 7: Thermal characteristics

Symbol Parameter Conditions Value Unit

th(j-a)

th(j-c)

thermal resistance from junction to ambient

thermal resistance from junction to case

[1]

no (clipping) signal

in free air 40 K/W

all channels driven 1.3 K/W

−0.3 +28 V

-4 A

-24V

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