Philips TFA9843AJ User Manual

TFA9843AJ

20 W stereo power ampliﬁer with volume control

Rev. 01 — 28 April 2006 Preliminary data sheet

1. General description

The TFA9843AJ contains two identical audio power ampliﬁers. The TFA9843AJ can be used as two Single-Ended (SE) channels with a volume control. The maximum gain is 26 dB.

The TFA9843AJcomes in a 9-pin DIL-bent-SIL (DBS9P) power package.The TFA9843AJ is pin compatible with the TFA9842AJ, TFA9843(B)J, TFA9842(B)J and TFA9841J. The difference between the TFA9843AJ and the TFA9843(B)J, TFA9842(B)J, TFA9841Jis the functionality of pin 7. The TFA9843AJ has a volume control on pin 7 (VC). The TFA9843(B)J, TFA9842(B)J and TFA9841J have a mode select on pin 7 (MODE).

The TFA9843AJ 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

n 2 channel SE: 1 W to 20 W operation possibility n Soft clipping n Input clamps n Volume control n Standby and Mute mode n No on or off switching plops n Low standby current n High supply voltage ripple rejection n Outputs short-circuit protected to ground, supply and across the load n Thermally protected n Pin compatible with the TFA9842AJ, TFA9843(B)J, TFA9842(B)J, TFA9841J

3. Applications

n CRT TV and LCD TV n Monitors n PC speakers n Boom box n Mini and micro audio receivers

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4. Quick reference data

Table 1. Quick reference data

VCC =18V; T unless otherwise speciﬁed.

Symbol Parameter Conditions Min Typ Max Unit

CC(stb)

THD total harmonic

v(max)

∆G

SVRR supply voltage ripple

amb

supply voltage operating quiescent current VCC=18V; RL= ∞ - 60 100 mA standby supply current VCC=18V;

output power THD = 10 %; RL=4Ω;

distortion maximum voltage gain V voltage gain range 1.5 V < V

rejection

=25°C; RL=4Ω; V

TFA9843AJ

20 W stereo power ampliﬁer with volume control

I(VC)=VCC

I(VC)

THD = 10 %; R V

I(VC)

f=1kHz

; Vi= 0 V; measured in test circuit of Figure 11;

[1]

9 1828V

- - 150 µA

< 0.8 V

7 8.5 - W

=18V

=4Ω;

-14-W

=22V

= 1 W - 0.1 0.5 %

> 5.0V 25 26 27 dB

< 5.0 V - 80 - dB

I(VC)

[2]

-60-dB

[1] A minimum load of 3 Ω is allowed at supply voltages > 22 V. [2] Supply voltage ripple rejection is measured at the output, with a source impedance ZS=0Ω at the input

and with a frequency range from 20 Hz to 22 kHz (unweighted). The ripple voltage is a sine wave with a frequency f

5. Ordering information

Table 2. Ordering information

Type number

TFA9843AJ DBS9P plastic DIL-bent-SIL power package; 9 leads (lead length

and an amplitude of 300 mV (RMS), which is applied to the positive supply rail.

ripple

Package Name Description Version

SOT523 -1

12/11 mm); exposed die pad

Preliminary data sheet Rev. 01 — 28 April 2006 2 of 19

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6. Block diagram

IN1

TFA9843AJ

20 W stereo power ampliﬁer with volume control

60 kΩ

OUT1

Fig 1. Block diagram

7. Pinning information

7.1 Pinning

IN2

CIV

60 kΩ

REF

VOLUME

CONTROL

SHORT-CIRCUIT

AND

TEMPERATURE

PROTECTION

0.5V

TFA9843AJ

GND

001aae428

OUT2

SVR

IN2

OUT2

CIV

IN1

GND

SVR

OUT1

TFA9843AJ

6 7 8 9

001aae429

Fig 2. Pin conﬁguration

Preliminary data sheet Rev. 01 — 28 April 2006 3 of 19

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7.2 Pin description

Table 3. Pin description

Symbol Pin Description

IN2 1 input 2 OUT2 2 loudspeaker terminal 2 CIV 3 common input voltage decoupling IN1 4 input 1 GND 5 ground SVR 6 half supply voltage decoupling (ripple rejection) VC 7 volume control input (standby, mute and volume control) OUT1 8 loudspeaker terminal 1 V

8. Functional description

TFA9843AJ

20 W stereo power ampliﬁer with volume control

9 supply voltage

8.1 Input conﬁguration

The input cut-off frequency is as follows:

i3dB–()

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

2π R

×()

iCi

Single-ended application: Ri=60kΩ and Ci= 220 nF:

i3dB–()

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

2π 60 10

× 220× 109–×()

12 Hz==

As shown in Equation 2, large capacitor values for the inputs are not necessary; therefore 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.

The TFA9843AJ has clamps on the inputs. In Standby mode the voltage on the input pins is clamped for voltages lower than −0.1 V. When the TFA9843AJ is in Mute, Volume control or Operating mode (maximum gain) the input clamp voltage is 1 V (RMS).

8.2 Power ampliﬁer

The power ampliﬁer is a single-ended ampliﬁer with an all NPN output stage, capable of delivering a peak output current of 4 A.

(1)

(2)

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%;seeFigure 7. The maximum output power is limited by the supply voltage of 26 V and the maximum availableoutput current is 4 A repetitive peak current. A minimum load of 3 Ω is required for supply voltages > 22 V; see Figure 4. The output power is measured with one channel driven.

Preliminary data sheet Rev. 01 — 28 April 2006 4 of 19

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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. At VCC= 18 V and Po= 6.5 W (SE with RL=4Ω) at THD < 0.5 % (see Figure 5), the Average Listening Level (ALL) music power without any distortion yields:

TFA9843AJ

20 W stereo power ampliﬁer with volume control

oALLSE,()

6.5

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

15.85

410 mW==

The power dissipation can be derived from Figure 8 (SE) for 0 dB respectively 12 dB headroom; see Table 4.

For the average listening level a power dissipation of 4.2 W can be used for a heatsink calculation.

Table 4. Power rating as function of headroom

Headroom Power output (THD < 0.5 %)

(SE)

0dB P 12 dB P

= 6.5 W 8.2 W

= 410 mW 4.2 W

o(ALL)

Power dissipation (P); both channels driven

8.3 Mode selection

The TFA9843AJ has four functional modes, which can be selected by applying the proper DC voltage to pin VC; see Table 5.

Table 5. Mode selection

I(VC)

0 V to 0.8 V Standby

1.2 V to 1.5 V Mute in this mode the ampliﬁer is DC-biased but not

1.5 V to 5.0 V Volume control in this mode the volume of the ampliﬁer can be

5.0 V to V

Status Deﬁnition

in this mode the current consumption is very low and the outputs are ﬂoating; the device is in Standby mode when V

I(VC)

< 0.8 V

operational (no audio output); this allows the input coupling capacitors to be charged to avoid plop noise; the device is in Mute mode when

1.2V<V

I(VC)

< 1.5 V

controlled; the gain can be adjusted between the range of 1.5V<V

On (maximum gain) in this mode the ampliﬁer has its maximum gain; the

Operating mode is activated at V

I(VC)

< 5.0 V

I(VC)

> 5.0 V

(3)

8.4 Supply voltage ripple rejection

The supply voltage ripple rejection (SVRR) is measured with an electrolytic capacitor of 150 µF connected to pin SVR with a bandwidth of 20 Hz to 22 kHz. The SVRR as a function of the frequency is illustrated in Figure 10. A larger capacitor value on pin SVR improves the ripple rejection behavior at the lower frequencies.

Preliminary data sheet Rev. 01 — 28 April 2006 5 of 19

Philips Semiconductors

8.5 Built-in protection circuits

The TFA9843AJ contains two types of temperature sensors; one measures the local temperatures of the power stages and one measures the global chip temperature. At a local temperature of the power stage of approximately 185 °C or a global temperature of approximately 150 °C this detection circuit switches off the power stages for 2 ms. When the outputs are switched off the voltage is measured on the outputs. In the event of a short-circuit to ground or to VCC the device will remain in Protection mode. In all other cases the power stages switch-on automatically and the detection will take place again; however a too high temperature will switch-off the power stages immediately. This can result in repetitive switching during too high junction temperature. This protects the TFA9843AJ against short-circuits to ground, to the supply voltage, across the load and 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 ﬂow through the short-circuit (as much as the power stage can handle without exceeding the critical temperature level).

9. Limiting values

TFA9843AJ

20 W stereo power ampliﬁer with volume control

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(scp)

supply voltage operating −0.3 +28 V input voltage −0.3 VCC+ 0.3 V repetitive peak output current - 4 A storage temperature non-operating −55 +150 °C ambient temperature operating −40 +85 °C total power dissipation - 35 W short-circuit protection supply

voltage

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

-26 V

in free air 40 K/W

both channels driven

2.0 K/W

Preliminary data sheet Rev. 01 — 28 April 2006 6 of 19

+ 13 hidden pages

Philips TFA9843AJ User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1. General description

2. Features

3. Applications

4. Quick reference data

5. Ordering information

6. Block diagram

7. Pinning information

7.1 Pinning

7.2 Pin description

8. Functional description

8.2.1 Output power measurement

8.2.2 Headroom

8.3 Mode selection

8.4 Supply voltage ripple rejection

8.5 Built-in protection circuits

9. Limiting values

10. Thermal characteristics