ST TDA7850A User Manual

TDA7850A

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 @ 14.4 V, 1 kHz, 10 %

■MOSFET output power stage

■Excellent 2 Ω driving capability

■Hi-fi class distortion

■Low output noise

■Standby 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

Flexiwatt27

(vertical)

Flexiwatt27

(horizontal)

■ ESD

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

Table 1. Device summary

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/N- Channel 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.

Order code	Package	Packing
TDA7850A	Flexiwatt27 (vertical)	Tube
TDA7850AH	Flexiwatt27 (horizontal	Tube
November 2008	Rev 3	1/16
		www.st.com

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

3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.4 Electrical characteristic curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4	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

TDA7850A	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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Table 5. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3/16

List of figures	TDA7850A

List of figures

Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2. Standard test and application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 3. Pin connections (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 4. Quiescent current vs. supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 5. Output power vs. supply voltage (RL = 4 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 6. Output power vs. supply voltage (RL = 2 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 7. Distortion vs. output power (RL = 4 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 8. Distortion vs. output power (RL = 2 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 9. Distortion vs. frequency (RL = 4 Ω). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 10. Distortion vs. frequency (RL = 2 Ω). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 11. Crosstalk vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 12. Supply voltage rejection vs. frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 13. Output attenuation vs. supply voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 14. Power dissipation and efficiency vs. output power (RL = 4 Ω, SINE) . . . . . . . . . . . . . . . . . 11 Figure 15. Power dissipation and efficiency vs. output power (RL = 2 Ω, SINE) . . . . . . . . . . . . . . . . . 11 Figure 16. Power dissipation vs. output power (RL = 4Ω, audio program simulation) . . . . . . . . . . . . . 11 Figure 17. Power dissipation vs. output power (RL = 2Ω, audio program simulation) . . . . . . . . . . . . . 11 Figure 18. ITU R-ARM frequency response, weighting filter for transient pop. . . . . . . . . . . . . . . . . . . 11 Figure 19. Flexiwatt27 (vertical) mechanical data and package dimensions . . . . . . . . . . . . . . . . . . . . 13 Figure 20. Flexiwatt27 (horizontal) mechanical data and package dimensions. . . . . . . . . . . . . . . . . . 14

4/16

TDA7850A	Block diagram and application circuit

1 Block diagram and application circuit

1.1Block diagram

Figure 1.	Block diagram
	Vcc1		Vcc2
					470μF	100nF
	ST-BY
					OFF DET
	MUTE			HSD	HSD/OFF DET
					OUT1+
	IN1				OUT1-
	0.1μF				PW-GND
					OUT2+
	IN2				OUT2-
	0.1μF				PW-GND
					OUT3+
	IN3				OUT3-
	0.1μF				PW-GND
					OUT4+
	IN4				OUT4-
	0.1μF				PW-GND
	AC-GND	SVR	TAB	S-GND
	0.47μF	47μF
					D03AU1467

1.2Standard test and application circuit

Figure 2.	Standard test and application circuit
		C8	C7
		0.1μF	2200μF
			Vcc1-2	Vcc3-4
	R1			7	21
	ST-BY	5				10
	10K	C9				9	OUT1
		1μF
	R2					8
		23
	MUTE
	47K	C10
	C1	1μF				6
						3	OUT2
	IN1	12
						4
	0.1μF
	IN2	13				18
	C2 0.1μF					19	OUT3
	IN3	16				20
	C3 0.1μF					22
	IN4	15				25	OUT4
	C4 0.1μF	S-GND				24
		14				2	OFF DET
		17	11	26
						1, 27
		C5	SVR	HSD/OFF DET		TAB
			C6
		0.47μF	47μF
							D03AU1469

5/16