TDA7850A
4 x 50 W MOSFET quad bridge power amplifier
Datasheet production data
Features
■
High output power capability:
– 4 x 50 W/4 max.
– 4 x 30 W/4 @ 14.4 V, 1 kHz, 10 %
– 4 x 80 W/2 max.
– 4 x 55 W/2 @ 14.4 V, 1 kHz, 10 %
■
MOSFET output power stage
■
Excellent 2 driving capability
■
Hi-fi class distortion
■
Low output noise
■
Standby function
■
Mute function
■
Automute at min. supply voltage detection
'!0'03
Flexiwatt27
(Horizontal)
■
Low external component count:
– Internally fixed gain (26 dB)
– No external compensation
– No bootstrap capacitors
■
On board 0.35 A high side driver
■
Protections:
– Output short circuit to GND, to Vs, across
the load
– Very inductive loads
– Overrating chip temperature with soft
thermal limiter
– Output DC offset detection
– Load dump voltage
– Fortuitous open gnd
– Reversed battery
– ESD
Table 1.
'!0'03
Flexiwatt27
(VertIcal)
Description
The TDA7850A is a breakthrough MOSFET
technology class AB audio power amplifier in
Flexiwatt27 package designed for high power car
radio. The fully complementary P-Channel/NChannel output structure allows a rail to rail
output voltage swing which, combined with high
output current and minimized saturation losses
sets new power references in the car-radio field,
with unparalleled distortion performances.
The TDA7850A integrates a DC offset detector.
Device summary
Order code
Package
Packing
TDA7850A
Flexiwatt27 (vertical)
Tube
TDA7850AH
Flexiwatt27 (horizontal
Tube
September 2013
This is information on a product in full production.
Doc ID 13998 Rev 5
1/16
www.st.com
1
Contents
TDA7850A
Contents
1
Block diagram and application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2
Standard test and application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3
Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4
3.1
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2
Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4
Electrical characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Application hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.1
SVR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2
Input stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.3
Standby and muting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4
DC offset detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.5
Heatsink definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2/16
Doc ID 13998 Rev 5
TDA7850A
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Doc ID 13998 Rev 5
3/16
List of figures
TDA7850A
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
4/16
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Standard test and application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Pin connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Quiescent current vs. supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Output power vs. supply voltage (RL = 4 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Output power vs. supply voltage (RL = 2 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Distortion vs. output power (RL = 4 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Distortion vs. output power (RL = 2 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Distortion vs. frequency (RL = 4 ). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Distortion vs. frequency (RL = 2 ). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Crosstalk vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Supply voltage rejection vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Output attenuation vs. supply voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Power dissipation and efficiency vs. output power (RL = 4 , SINE) . . . . . . . . . . . . . . . . . 11
Power dissipation and efficiency vs. output power (RL = 2 , SINE) . . . . . . . . . . . . . . . . . 11
Power dissipation vs. output power (RL = 4, audio program simulation) . . . . . . . . . . . . . 11
Power dissipation vs. output power (RL = 2, audio program simulation) . . . . . . . . . . . . . 11
ITU R-ARM frequency response, weighting filter for transient pop. . . . . . . . . . . . . . . . . . . 11
Flexiwatt27 (horizontal) mechanical data and package dimensions. . . . . . . . . . . . . . . . . . 13
Flexiwatt27 (vertical) mechanical data and package dimensions . . . . . . . . . . . . . . . . . . . . 14
Doc ID 13998 Rev 5
TDA7850A
Block diagram and application circuit
1
Block diagram and application circuit
1.1
Block diagram
Figure 1.
Block diagram
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1.2
Standard test and application circuit
Figure 2.
Standard test and application circuit
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Doc ID 13998 Rev 5
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5/16
Pin description
2
TDA7850A
Pin description
Figure 3.
Pin connections (top view)
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6/16
Doc ID 13998 Rev 5
TDA7850A
Electrical specifications
3
Electrical specifications
3.1
Absolute maximum ratings
Table 2.
Absolute maximum ratings
Symbol
Value
Unit
Operating supply voltage
18
V
VS (DC)
DC supply voltage
28
V
VS (pk)
Peak supply voltage (for t = 50 ms)
50
V
Output peak current
repetitive (duty cycle 10 % at f = 10 Hz)
non repetitive (t = 100 s)
9
10
A
A
Power dissipation Tcase = 70 °C
80
W
Tj
Junction temperature
150
°C
Tstg
Storage temperature
-55 to 150
°C
Value
Unit
1
°C/W
VS
IO
Ptot
3.2
Parameter
Thermal data
Table 3.
Thermal data
Symbol
Rth j-case
3.3
Parameter
Thermal resistance junction-to-case
Max.
Electrical characteristics
Refer to the test and application diagram, VS = 14.4 V; RL = 4 ; Rg = 600 ; f = 1 kHz;
Tamb = 25 °C; unless otherwise specified.
Table 4.
Symbol
Iq1
VOS
Electrical characteristics
Parameter
Quiescent current
RL =
Output offset voltage
Play mode - Mute mode
During mute ON/OFF output
offset voltage
dVOS
Test condition
During St-By ON/OFF output
offset voltage
ITU R-ARM weighted
see Figure 18
Min.
Typ.
Max.
Unit
100
180
280
mA
-
-
±50
mV
-10
-
+10
mV
-10
-
+10
mV
Gv
Voltage gain
-
25
26
27
dB
dGv
Channel gain unbalance
-
-
-
±1
dB
Doc ID 13998 Rev 5
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Electrical specifications
Table 4.
Electrical characteristics (continued)
Symbol
Po
TDA7850A
Parameter
Output power
Test condition
Min.
Typ.
Max.
Unit
VS = 13.2 V; THD = 10 %
VS = 13.2 V; THD = 1 %
VS = 14.4 V; THD = 10 %
VS = 14.4 V; THD = 1 %
23
16
28
20
25
19
30
23
-
W
VS = 14.4 V; THD = 10 %, 2
50
55
W
Max. output power(1)
VS = 14.4 V; RL = 4
VS = 14.4 V; RL = 2
-
50
85
-
W
THD
Distortion
Po = 4 W
Po = 15 W; RL = 2
-
0.006
0.015
0.02
0.03
%
eNo
Output noise
"A" Weighted
Bw = 20 Hz to 20 kHz
-
35
50
50
70
V
SVR
Supply voltage rejection
f = 100 Hz; Vr = 1 Vrms
50
75
-
dB
fch
High cut-off frequency
PO = 0.5 W
100
300
-
KHz
Ri
Input impedance
80
100
120
K
CT
Cross talk
60
-
70
60
-
dB
-
20
Standby current consumption
VST-BY = 1.5 V
-
ISB
VST-BY = 0V
-
-
10
Ipin5
Standby pin current
VST-BY = 1.5V to 3.5V
-
-
±1
A
VSB out
Standby out threshold voltage
(Amp: ON)
2.75
-
-
V
VSB in
Standby in threshold voltage
(Amp: OFF)
-
-
1.5
V
Mute attenuation
POref = 4W
80
90
-
dB
VM out
Mute out threshold voltage
(Amp: Play)
3.5
-
-
V
VM in
Mute in threshold voltage
(Amp: Mute)
-
-
1.5
V
VS automute threshold
(Amp: Mute)
Att 80 dB; POref = 4 W
(Amp: Play)
Att < 0.1 dB; PO = 0.5 W
6.5
7
Po max.
AM
VAM in
Ipin23
f = 1 kHz; PO = 4 W
f = 10 kHz; PO = 4 W
A
V
7.5
8
VMUTE = 1.5 V
(Sourced Current)
7
12
18
A
VMUTE = 3.5 V
-5
-
18
A
Dropout voltage
IO = 0.35 A; VS = 9 to 16 V
-
0.25
0.6
V
Current limits
-
400
-
800
mA
Muting pin current
HSD section
Vdropout
Iprot
8/16
Doc ID 13998 Rev 5
TDA7850A
Electrical specifications
Table 4.
Electrical characteristics (continued)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
8
-
-
V
-
-
6
V
Offset detector (Pin 26)
VM_ON
Mute voltage for DC offset
detection enabled
VM_OFF
VST-BY = 5 V
VOFF
Detected differential output offset VST-BY = 5 V; Vmute = 8 V
±2
±3
±4
V
V26_T
Pin 26 voltage for detection =
TRUE
VST-BY = 5 V; Vmute = 8 V
VOFF > ±4 V
0
-
1.5
V
V26_F
Pin 26 voltage for detection =
FALSE
VST-BY = 5 V; Vmute = 8 V
VOFF > ±2 V
12
-
-
V
1. Saturated square wave output.
3.4
Electrical characteristic curves
Figure 4.
Quiescent current vs. supply
voltage
Figure 5.
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2, c
Output power vs. supply voltage
(RL = 4 )
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Figure 6.
Output power vs. supply voltage
(RL = 2 )
6S6
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Figure 7.
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Distortion vs. output power
(RL = 4 )
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2, 7
F +(Z
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2, 7
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Doc ID 13998 Rev 5
0O7
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9/16
Electrical specifications
Figure 8.
TDA7850A
Distortion vs. output power
(RL = 2 )
Figure 9.
4($
4($
63 6
2, 7
63 6
2, 7
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Distortion vs. frequency
(RL = 4 )
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Figure 11. Crosstalk vs. frequency
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2, 7
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Figure 10. Distortion vs. frequency
(RL = 2 )
2, 7
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2G 7
Figure 12. Supply voltage rejection vs.
frequency
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Figure 13. Output attenuation vs. supply
voltage
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10/16
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Doc ID 13998 Rev 5
6S6
'!0'03
TDA7850A
Electrical specifications
Figure 14. Power dissipation and efficiency
vs. output power (RL = 4 , SINE)
H
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Figure 15. Power dissipation and efficiency
vs. output power (RL = 2 , SINE)
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H
H
63 6
2, X7
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2, X7
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'!0'03
Figure 16. Power dissipation vs. output power Figure 17. Power dissipation vs. output power
(RL = 4, audio program simulation)
(RL = 2, audio program simulation)
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63 6
2, X7
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Figure 18. ITU R-ARM frequency response,
weighting filter for transient pop
/UTPUTATTENUATIOND"
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'!0'03
Doc ID 13998 Rev 5
11/16
Application hints
4
TDA7850A
Application hints
Ref. to the circuit of Figure 2.
4.1
SVR
Besides its contribution to the ripple rejection, the SVR capacitor governs the turn ON/OFF time
sequence and, consequently, plays an essential role in the pop optimization during ON/OFF
transients. To conveniently serve both needs, Its minimum recommended value is 10µF.
4.2
Input stage
The TDA7850A's inputs are ground-compatible and can stand very high input signals
(± 8Vpk) without any performance degradation.
If the standard value for the input capacitors (0.1µF) is adopted, the low frequency cut-off
will amount to 16 Hz.
4.3
Standby and muting
STANDBY and MUTING facilities are both CMOS compatible. In absence of true CMOS
ports or microprocessors, a direct connection to Vs of these two pins is admissible but a
470k equivalent resistance should be present between the power supply and the muting
and stand-by pins.
R-C cells have always to be used in order to smooth down the transitions for preventing any
audible transient noises.
About the stand-by, the time constant to be assigned in order to obtain a virtually pop-free
transition has to be slower than 2.5V/ms.
4.4
DC offset detector
The TDA7850A integrates a DC offset detector to avoid that an anomalous DC offset on the
inputs of the amplifier may be multiplied by the gain and result in a dangerous large offset on
the outputs which may lead to speakers damage for overheating.
The feature works with the amplifier unmuted and no signal at the inputs.
The DC offset detection can be available at 2 different pins:
–
–
4.5
Pin 2 (always enabled)
Pin 26. Only enabled if Vmute (pin23) is set higher than 8V. If not (Vmute < 6 V)
pin 26 will revert to the original HSD function.
Heatsink definition
Under normal usage (4 Ohm speakers) the heatsink's thermal requirements have to be
deduced from Figure 16, which reports the simulated power dissipation when real
music/speech programmes are played out. Noise with gaussian-distributed amplitude was
employed for this simulation. Based on that, frequent clipping occurrence (worst-case) will
cause Pdiss = 26W. Assuming Tamb = 70°C and TCHIP = 150°C as boundary conditions, the
heatsink's thermal resistance should be approximately 2°C/W. This would avoid any thermal
shutdown occurrence even after long-term and full-volume operation.
12/16
Doc ID 13998 Rev 5
TDA7850A
Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
Figure 19. Flexiwatt27 (horizontal) mechanical data and package dimensions
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