ST TDA7491MV User Manual
25 W mono BTL class-D audio amplifier
Features
20 W continuous output power:
R
= 8 Ω, THD = 10% at V
L
25 W continuous output power:
R
= 6 Ω, THD = 10% at V
L
Wide range single supply operation (5 V - 18 V)
High efficiency (η = 90%)
Four selectable, fixed gain settings of
nominally 20 dB, 26 dB, 30 dB and 32 dB
Differential inputs minimize common-mode
noise
Filterless operation
No ‘pop’ at turn-on/off
Standby and mute features
Short-circuit protection
Thermal overload protection
Externally synchronizable
CC
CC
= 18 V
= 16 V
TDA7491MV
PowerSSO-36 with
exposed pad down
Description
The TDA7491MV is a mono BTL class-D audio
amplifier with single power supply designed for
LCD TVs and monitors.
Thanks to the high efficiency and an
exposed-pad-down (EPD) package no heatsink is
required.
Furthermore, the filterless operation allows a
reduction in the external component count.
The TDA7491MV is pin to pin compatible with the
TDA7491P, TDA7491LP and TDA7491HV for the
left channel as given in Section 6.1 on page 19.
Table 1. Device summary
Order code Operating temp. range Package Packaging
TDA7491MV 0 to 70 °C PowerSSO-36 EPD Tube
TDA7491MV13TR 0 to 70 °C PowerSSO-36 EPD Tape and reel
May 2009 Doc ID 14576 Rev 2 1/28
www.st.com
28
Contents TDA7491MV
Contents
1 Device block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Pin out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Pin list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Characterization curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Test board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6 Applications circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1 Compatibility with TDA7491 stereo BTL family . . . . . . . . . . . . . . . . . . . . 19
7 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.1 Mode selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
7.2 Gain setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.3 Input resistance and capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.4 Internal and external clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.4.1 Master mode (internal clock) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.4.2 Slave mode (external clock) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.5 Filterless modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.6 Output low-pass filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.7 Protection function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.8 Diagnostic output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.9 Heatsink requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2/28 Doc ID 14576 Rev 2
TDA7491MV List of tables
List of tables
Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 2. Pin description list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 3. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 4. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 5. Electrical specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 6. PowerSSO-36 slug down dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 7. Mode settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 8. Gain settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 9. How to set up SYNCLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 10. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Doc ID 14576 Rev 2 3/28
List of figures TDA7491MV
List of figures
Figure 1. Internal block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 2. Pin connection (top view, PCB view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 3. Output power vs supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 4. THD vs output power (1 kHz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5. THD vs output power (100 Hz) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 6. THD vs Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 7. Frequency Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 8. FFT (0 dB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 9. FFT (-60 dB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 10. Closed-loop gain vs frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 11. Power dissipation and efficiency vs output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 12. Attenuation vs mute voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 13. Current consumption vs voltage on pin STBY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 14. Attenuation vs voltage on pin STBY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 15. Power supply rejection ratio vs frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 16. Test board (TDA7491HV) layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 17. PowerSSO-36 slug down outline drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 18. Applications circuit for class-D amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 19. Standby and mute circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 20. Turn-on/off sequence for minimizing speaker “pop” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 21. Device input circuit and frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 22. Master and slave connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 23. Unipolar PWM output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 24. Typical LC filter for a 8-Ω speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 25. Typical LC filter for a 4-Ω speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 26. Behavior of pin DIAG for various protection conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 27. Power derating curves for PCB used as heatsink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4/28 Doc ID 14576 Rev 2
TDA7491MV Device block diagram
1 Device block diagram
Figure 1 shows the block diagram of the TDA7491MV.
Figure 1. Internal block diagram
Doc ID 14576 Rev 2 5/28
Pin description TDA7491MV
2 Pin description
2.1 Pin out
Figure 2. Pin connection (top view, PCB view)
SUB_GND
NC
NC
NC
NC
NC
NC
NC
NC
OUTN
OUTN
PVCC
PVCC
PGND
PGND
OUTP
OUTP
PGND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Exposed pad down
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
VSS
SVCC
VREF
SGND
VDDS
GAIN1
GAIN0
SVR
DIAG
SGND
VDDS
SYNCLK
ROSC
INN
INP
MUTE
STBY
VDDPW
6/28 Doc ID 14576 Rev 2
TDA7491MV Pin description
2.2 Pin list
Table 2. Pin description list
Number Name Type Description
1 SUB_GND POWER Connect to the frame
2,3 NC - No internal connection
4,5 NC - No internal connection
6,7 NC - No internal connection
8,9 NC - No internal connection
10,11 OUTN OUT Negative PWM output
12,13 PVCC POWER Power supply
14,15 PGND POWER Power stage ground
16,17 OUTP OUT Positive PWM output
18 PGND POWER Power stage ground
19 VDDPW OUT
3.3 V (nominal) regulator output referred to ground for power
stage
20 STBY INPUT Standby mode control
21 MUTE INPUT Mute mode control
22 INP INPUT Positive differential input
23 INN INPUT Negative differential input
24 ROSC OUT Master oscillator frequency-setting pin
25 SYNCLCK IN/OUT Clock in/out for external oscillator
26 VDDS OUT
3.3 V (nominal) regulator output referred to ground for signal
blocks
27 SGND POWER Signal ground
28 DIAG OUT Open-drain diagnostic output
29 SVR OUT Supply voltage rejection
30 GAIN0 INPUT Gain setting input 1
31 GAIN1 INPUT Gain setting input 2
32 VDDS POWER To be connected to VDDS (pin 26)
33 SGND POWER Signal ground
34 VREF OUT Half VDDS (nominal) referred to ground
35 SVCC POWER Signal power supply
36 VSS OUT 3.3 V (nominal) regulator output referred to power supply
Doc ID 14576 Rev 2 7/28
Electrical specifications TDA7491MV
3 Electrical specifications
3.1 Absolute maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
CC
T
op
T
j
T
stg
DC supply voltage for pins PVCCA, PVCCB, SVCC 24 V
Operating temperature 0 to 70 °C
Junction temperature -40 to 150 °C
Storage temperature -40 to 150 °C
3.2 Thermal data
Table 4. Thermal data
Symbol Parameter Min Typ Max Unit
R
th j-case
R
th j-amb
1. FR4 with vias to copper area of 9 cm2 (see also Section 7.9: Heatsink requirements on page 26).
Thermal resistance, junction to case - 2 3
Thermal resistance, junction to ambient
(mounted on recommended PCB)
3.3 Electrical specifications
Unless otherwise stated, the results in Ta bl e 5 below are given for the conditions:
V
=18V, RL (load) = 8 Ω, R
CC
Tamb = 25 °C.
Table 5. Electrical specifications
OSC
(1)
-24-
= R3 = 39 kΩ, C8 = 100 nF, f = 1 kHz, GV = 20 dB, and
°C/W
Symbol Parameter Condition Min Typ Max Unit
V
CC
I
q
I
qSTBY
V
OS
V
OS
I
OCP
T
R
V
j
i
OVP
Supply voltage for
pins PVCC, SVCC
Total quiescent Without LC filter - 26 35 mA
Quiescent current in standby - - 2.5 5.0 µA
Output offset voltage Play mode -150 - 150 mV
Output offset voltage Mute mode -60 - 60 mV
Overcurrent protection threshold RL = 0 Ω 35- A
Junction temperature at thermal
shut-down
Input resistance Differential input 55 60 - kΩ
Overvoltage protection threshold - 19 21 - V
8/28 Doc ID 14576 Rev 2
-5-18V
- - 150 - °C
TDA7491MV Electrical specifications
Table 5. Electrical specifications (continued)
Symbol Parameter Condition Min Typ Max Unit
V
R
P
P
P
P
UVP
dsON
o
o
o
D
Undervoltage protection
threshold
Power transistor on resistance
Output power
Output power
Output power
Dissipated power Po = 20 W THD = 10% - 2.0 - W
η Efficiency P
THD Total harmonic distortion P
G
V
Closed loop gain
- --4V
High side - 0.2 -
Ω
Low side - 0.2 -
THD = 10% - 20 -
W
THD = 1% - 16 -
R
= 8 Ω, THD = 10%
L
=12V
V
CC
= 8 Ω, THD = 1%
R
L
VCC=12V
R
= 6 Ω, THD = 10%
L
VCC=16V
-9.5-
W
-7.2-
-20-
W
= 6 Ω, THD = 1%
R
L
VCC=16V
= 20 W 80 90 - %
o
= 1 W - 0.1 0.2 %
o
-16-
GAIN0 = L, GAIN1 = L 18 20 22
GAIN0 = L, GAIN1 = H 24 26 28
dB
GAIN0 = H, GAIN1 = L 28 30 32
GAIN0 = H, GAIN1 = H 30 32 34
∆G
V
eN Total input noise
Gain matching - -1 - 1 dB
A Curve, G
= 20 dB - 20 -
V
µV
f = 22 Hz to 22 kHz - 25 35
SVRR Supply voltage rejection ratio
, T
T
r
f
SW
f
SWR
V
inH
V
inL
A
MUTE
Rise and fall times - - 50 - ns
f
Switching frequency Internal oscillator 290 310 330 kHz
Output switching frequency
Digital input high (H)
Digital input low (L) - - 0.8
Mute attenuation V
fr = 100 Hz, Vr = 0.5 V,
C
= 10 µF
SVR
With internal oscillator
With external oscillator
40 50 - dB
(1)
250 - -
(2)
250 - -
2.3 - -
-
= 1 V 60 80 - dB
MUTE
kHz
V
Doc ID 14576 Rev 2 9/28
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