ST TDA7850 User Manual

4 x 50 W MOSFET quad bridge power amplifier

Features

■ High output power capability:

–4 x 50 W/4 Ω max.
–4 x 30 W/4 Ω @ 14.4 V, 1 kHz, 10 %
–4 x 80 W/2 Ω max.
–4 x 55 W/2 Ω @ 14.4V, 1 kHz, 10 %

■ MOSFET output power stage

■ Excellent 2 Ω driving capability

■ Hi-Fi class distortion

■ Low output noise

■ ST-BY function

■ Mute function

■ Automute at min. supply voltage detection

■ 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 V

load

■ Very inductive loads

■ Overrating chip temperature with soft thermal

limiter

■ Output DC offset detection

■ Load dump voltage

■ Fortuitous open gnd

■ Reversed battery

Table 1. Device summary

, across the

s

TDA7850

Flexiwatt25

(Vertical)

Flexiwatt25

(Horizontal)

■ ESD

Description

The TDA7850 is a breakthrough MOSFET
technology class AB audio power amplifier in
Flexiwatt 25 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 TDA7850 integrates a DC offset detector.

Order code Package Packing

TDA7850 Flexiwatt25 (Vertical) Tube

TDA7850H Flexiwatt25 (Horizontal Tube

November 2008 Rev 5 1/18

www.st.com

1

Contents TDA7850

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

3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.4 Electrical characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4 Application hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.1 SVR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.2 Input stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.3 Standby and muting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.4 DC offset detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.5 Heatsink definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2/18

TDA7850 List of tables

List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Table 2. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Table 3. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Table 4. Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Table 5. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3/18

List of figures TDA7850

List of figures

Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 2. Standard test and application circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 3. Pin connection (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 4. Components and top copper layer of the Figure 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 5. Bottom copper layer Figure 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 6. Quiescent current vs. supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 7. Output power vs. supply voltage (R
Figure 8. Output power vs. supply voltage (R
Figure 9. Distortion vs. output power (R
Figure 10. Distortion vs. output power (R
Figure 11. Distortion vs. frequency (R
Figure 12. Distortion vs. frequency (R

= 4Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

L

= 2Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

L

Figure 13. Crosstalk vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 14. Supply voltage rejection vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 15. Output attenuation vs. supply voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 16. Power dissipation and efficiency vs. output power (R
Figure 17. Power dissipation and efficiency vs. output power (R
Figure 18. Power dissipation vs. output power (R
Figure 19. Power dissipation vs. output power (R

Figure 20. ITU R-ARM frequency response, weighting filter for transient pop. . . . . . . . . . . . . . . . . . . 13

Figure 21. Flexiwatt25 (vertical) mechanical data and package dimensions . . . . . . . . . . . . . . . . . . . . 15

Figure 22. Flexiwatt25 (horizontal) mechanical data and package dimensions. . . . . . . . . . . . . . . . . . 16

= 4Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

L

= 2Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

L

= 4Ω). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

L

= 2Ω). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

L

= 4Ω, SINE) . . . . . . . . . . . . . . . . . 12

L

= 2Ω, SINE) . . . . . . . . . . . . . . . . . 12

= 4Ω, audio program simulation) . . . . . . . . . . . . . 13

L

= 2Ω, audio program simulation) . . . . . . . . . . . . . 13

L

L

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TDA7850 Block diagram and application circuit

C

1 Block diagram and application circuit

1.1 Block diagram

Figure 1. Block diagram

Vcc1 Vcc2

ST-BY

MUTE

IN1

0.1μF

IN2

0.1μF

IN3

0.1μF

IN4

0.1μF

AC-GND

0.47μF47μF

SVR TAB S-GND

1.2 Standard test and application circuit

Figure 2. Standard test and application circuit

ST-BY

MUTE

IN1

IN2

IN3

IN4

R1

10K

R2

47K

C1

0.1μF

C2 0.1μF

C3 0.1μF

C4 0.1μF

C8

0.1μF

4

C9

1μF

22
C10
1μF

11

12

15

S-GND

14

13

16 10 25 1

C5

0.47μF

*) R3 = 10kΩ to be placed when pin 25 is used as offset detector.

C7

2200μF

Vcc1-2

SVR TAB

C6

47μF

Vcc3-4

620

HSD/OD

R3

100nF470μF

HSD

*)

HSD/V

OFF_DET

OUT1+

OUT1-

PW-GND

OUT2+

OUT2-

PW-GND

OUT3+

OUT3-

PW-GND

OUT4+

OUT4-

PW-GND

D94AU158D

9

8

7

5

2

3

17

18

19

21

24

23

OUT1

OUT2

OUT3

OUT4

D95AU335

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Pin description TDA7850

2 Pin description

Figure 3. Pin connection (top view)

TAB

P-GND2

OUT2-

ST-BY

OUT2+

V

OUT1-

P-GND1

OUT1+

SVR

IN1

IN2

S-GND

IN4

IN3

AC-GND

OUT3+

P-GND3

OUT3-

V

OUT4+

MUTE

OUT4-

P-GND4

HSD

TAB

P-GND2

OUT2-

ST-BY

OUT2+

V

OUT1-

P-GND1

OUT1+

SVR

IN1

IN2

S-GND

IN4

IN3

AC-GND

OUT3+

P-GND3

OUT3-

V

OUT4+

MUTE

OUT4-

P-GND4

HSD

1

CC

Vertical

CC

25

D94AU159A

1

CC

Horizontal

CC

25

D06AU1655

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