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
Philips Semiconductors
4. Quick reference data
Table 1. Quick reference data
VCC =18V; T
unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Unit
V
CC
I
q
I
CC(stb)
P
o
THD total harmonic
G
v(max)
∆G
v
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
V
I(VC)
V
CC
THD = 10 %; R
V
CC
P
o
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;
L
-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
TFA9843AJ_1 © Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Preliminary data sheet Rev. 01 — 28 April 2006 2 of 19
Philips Semiconductors
6. Block diagram
IN1
TFA9843AJ
20 W stereo power amplifier with volume control
V
CC
9
4
60
kΩ
8
OUT1
Fig 1. Block diagram
7. Pinning information
7.1 Pinning
IN2
CIV
VC
1
60
kΩ
3
V
REF
7
VOLUME
CONTROL
SHORT-CIRCUIT
AND
TEMPERATURE
PROTECTION
V
CC
0.5V
TFA9843AJ
5
GND
CC
001aae428
2
OUT2
6
SVR
1
IN2
2
OUT2
3
CIV
4
IN1
5
GND
SVR
VC
OUT1
V
CC
TFA9843AJ
6
7
8
9
001aae429
Fig 2. Pin configuration
TFA9843AJ_1 © Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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
CC
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:
f
i3dB–()
=
---------------------------- -
2π R
1
×()
iCi
Single-ended application: Ri=60kΩ and Ci= 220 nF:
f
i3dB–()
---------------------------------------------------------------- -
2π 60 10
1
3
× 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.
TFA9843AJ_1 © Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Preliminary data sheet Rev. 01 — 28 April 2006 4 of 19
Philips Semiconductors
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
P
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
o
= 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
V
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
CC
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.
TFA9843AJ_1 © Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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
V
CC
V
I
I
ORM
T
stg
T
amb
P
tot
V
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
R
R
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
TFA9843AJ_1 © Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Preliminary data sheet Rev. 01 — 28 April 2006 6 of 19
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