STMICROELECTRONICS TDA7571

TDA7571
STPDACsw - Fully digital high efficiency power audio amplifier
Features
■
Output power 2 x 70W / 1 x 250W @ THD<1%
■
I2S input (FS = 38 to 48kHz)
■
PWM output (FPWM = FS x 8)
■
MCLK input = 256 x FS
■
Operation on 24bit
■
±30V supply voltage (Max.)
■
St-by
■
Mute
■
Stereo/bridge operation selection
■
Protections against short circuit across the load
■
Chip thermal protection
■
External temperature sensor possibility
■
Thermal warning pins
■
Adjustable clip detector pin
HiQUAD-64
Description
The TDA7571 i is a fully digital switchmode power
audio amplifier with I2S digital input and PWM
output.
Table 1.
The maximum output current and voltage swing
are depending by the output circuitry (power
supply, external power transistors and sensing
resistors). The device can work as a stereo
single-ended channels or a mono bridge power
amplifier.
Device summary
Order code
Package
Packing
TDA7571
HiQUAD-64
Tray
September 2007
Rev 1
1/21
www.st.com
21
Contents
TDA7571
Contents
1
Block and simplified application diagram . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2
Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4
Notes on the electrical schematic shown in Figure 3 and 4 . . . . . . . . . . . 13
3.4.1
4
Main characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Functions, pins and components description . . . . . . . . . . . . . . . . . . . 14
4.1
Short circuit protection current calculation . . . . . . . . . . . . . . . . . . . . . . . . 14
4.2
External thermal protection network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3
Internal thermal protection network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4
Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.5
Gate driving network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.6
PLL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.7
Dither . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.8
External connections description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.9
4.8.1
CD, THWEXT, THWINT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.2
MUTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.3
ST-BY - St-By pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.4
+Vs-low - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.5
DATA, SEL, SCK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.6
MCLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.7
DGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.8.8
BRIDGE and L/R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Components with critical placement and type . . . . . . . . . . . . . . . . . . . . . 18
5
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2/21
TDA7571
Block and simplified application diagram
1
Block and simplified application diagram
Figure 1.
Block and simplified application diagram
R9
R8
C1
L/R BRIDGE
MCLK
MASTER CLOCK
SD DATA
WS WORD SEL
SCK CLOCK
R10 RFS
33
Feed Lin
40
+Vs-Vref1
28
+Vs
9
12
PGND
CD SEL1
CD SEL2
CD
5V DIG
THW EXT
THW INT
C2
49
CHANNEL LEFT
HSD+
PROTECTIONS
I2S
LEFT
DIGITAL
SIGNAL
PROCESSING
50
35
DGND
MUTE
F
C3
2.5V
-2.5V
SGND C4
DGND
Spl1
14
Spl2
17
CHANNEL LEFT
LSD+
PROTECTIONS
10
21
23
29
24
CLIP
31
37
36
THERMAL
PROTECTIONS
CHANNEL RIGHT
HSD+
PROTECTIONS
56
55
RIGHT
DIGITAL
SIGNAL
PROCESSING
REF
39
OUTPUT
LOWPASS
FILTER
Gpls
Gnls
R6
Snl1
+Vs-5
15
-Vs+5
8
Spr1
7
Spr2
4
Gpr
5
Gprs
63
Gnrs
-25V
+25V
R5
M2
OUTPUT
LOWPASS
FILTER
Gpr
OUT
RIGHT
M1
Snr2
54
OUT
LEFT
M3
Gnl
6
CHANNEL RIGHT 64
LSD+
62
PROTECTIONS
INTERFACE
R4
52
P/O
M4
Gpl
Snl2
30
32
+25V
R7
18
22
38
ST-BY
13
INTERFACE
NTC
NTC
+Vs-low
42
48
OSC
SGND
R1
46
34
C7
5V dig
61
41
43
D1
45
44
D2
t1
53
47
t2
SGND
25
57
Feed Rin
-Vs+Vrefl
26,27,58,59
-Vs
Snr1
-25V
60
-Vs+Vrefr
C5
D01AU1271A
5V
R2
R3
3/21
Pin description
Pin description
sgnd
+2.5V
MUTE
N.C.
1
52
-2.5V
N.C.
2
51
N.C.
N.C.
3
50
SCK
Gpr
4
49
WS
Gprs
5
48
SD
+Vs-5
6
47
t2
Spr2
7
46
MCLK
Spr1
8
45
t1
+Vs-Vref1
9
44
d2
pgnd
10
43
d1
N.C.
11
42
+Vs-low
P/O
+Vs
12
41
Spl1
13
40
5Vdig
Spl2
14
39
f
-Vs+5
15
38
NTC
N.C.
16
37
THWext
Gpls
17
36
THWint
Gpl
18
35
Rfs
N.C.
19
34
L/R
N.C.
20
33
bridge
dgnd
CD
CDsel2
CDsel1
-Vs
Feed L in
27 28 29 30 31 32
-Vs
-Vs+Vrefl
Snl1
Snl2
Gnl
Gnls
21 22 23 24 25 26
4/21
ST-BY
58 57 56 55 54 53
64 63 62 61 60 59
Table 2.
Feed R in
-Vs
-Vs
-Vs+Vrefr
Snr1
Snr2
Pins connection diagram (top view)
Gnr
Figure 2.
Gnrs
2
TDA7571
AC00242
Pins description
Pin
number
Name
Voltage limit
(low)
Voltage limit
(high)
1
N.C.
Not connected
2
N.C.
Not connected
3
N.C.
Not connected
4
Gpr
Gate PMOS, right channel
+Vs-12V
30V
5
Gprs
Sense gate PMOS, right channel
+Vs-12V
30V
6
+Vs-5
7
Spr2
Sensing 2 PMOS, right channel
30V
8
Spr1
Sensing 1 PMOS, right channel
30V
9
+Vs-Vref1
10
pgnd
Power ground
11
N.C.
Not connected
Function
+Vs-6
Supply drivers PMOS
+Vs-12V
0 (ref.)
30V
TDA7571
Pin description
Table 2.
Pins description (continued)
Pin
number
Name
12
+Vs
Positive power supply
30V
13
Spl1
Sensing 1 PMOS, left channel
30V
14
Spl2
Sensing 2 PMOS, left channel
30V
15
-Vs+5
16
N.C.
Not connected
17
Gpls
Sense gate PMOS, left channel
+Vs-12V
30V
18
Gpl
Gate PMOS, left channel
+Vs-12V
30V
19
N.C.
Not connected
20
N.C.
Not connected
21
Gnl
Gate NMOS, left channel
-30V
-Vs+12V
22
Gnls
Gate NMOS, left channel
-30V
-Vs+12V
23
Snl2
Sensing 2 NMOS, left channel
-30V
24
Snl1
Sensing 1 NMOS, left Channel
-30V
25
-Vs+Vrefl
Supply drivers NMOS. left channel
-30V
26
-Vs
Negative power supply
-30V
27
-Vs
Negative power supply
-30V
28
Feed L in
Feedback network left channel
-5V
29
CDsel1
Clip detector selection 1
5.5V
30
CD sel2
Clip detector selection 2
5.5V
31
CD
Clip detector output
5.5V
32
dgnd
Digital ground
33
bridge
Stereo / bridge selection pin
0 = Stereo; 1 = Bridge
6V
34
L/R
Bridge Left/Right Selection
1 = Right; 0 = Left
6V
35
Rfs
pcm-pwm gain conversion resistor
6V
36
THWint
Internal thermal warning output
5.5V
37
THWext
External thermal warning output
5.5V
38
NTC
Sensing resistors network
5.5V
39
f
40
5Vdig
41
P/O
42
+Vs-low
43
44
Function
Voltage limit
(low)
Voltage limit
(high)
-Vs+6
-Vs+12V
5V
0 (ref)
6V
Digital 5V supply output
6V
PLL/FREE running osc. option
6V
Positive voltage supply low power
30
d1
Dither 1
6V
d2
Dither 2
6V
5/21
Pin description
Table 2.
6/21
TDA7571
Pins description (continued)
Pin
number
Name
45
t1
46
MCLK
47
t2
48
SD
I2S serial data
6V
49
WS
I2S word select
6V
50
SCK
I2S serial clock
6V
51
N.C.
Not connected
52
-2.5V
Signal -2.5V supply output
-2.75V
53
sgnd
Signal ground
0 (ref)
54
+2.5V
Signal 2.5V supply output
2.75V
55
MUTE
Mute input
5.5V
56
ST-BY
Stand by input
57
Feed R in
58
-Vs
Negative voltage supply
-30V
59
-Vs
Negative voltage supply
-30V
60
-Vs+Vrefr
Supply drivers NMOS. Right channel
-30V
61
Snr1
Sensing 2 NMOS, right channel
-30V
62
Snr2
Sensing 1 NMOS, right channel
-30V
63
Gnrs
Sense gate NMOS, right channel
-30V
-Vs+12V
64
Gnr
Gate NMOS, right channel
-30V
-Vs+12V
Function
Voltage limit
(low)
Voltage limit
(high)
6V
Master clock input (256 x fs)
6V
6V
Feedback network right channel
6V
-5
5V
-Vs+12V
TDA7571
Electrical specifications
3
Electrical specifications
3.1
Absolute maximum ratings
Table 3.
Absolute maximum ratings
Symbol
±Vs
3.2
Parameter
Operating supply voltage
Value
Unit
±30
V
Tj
Junction temperature, operating range
-40 to 150
°C
Tstg
Storage temperature, operating range
-55 to 150
°C
Value
Unit
3
°C/W
Thermal data
Table 4.
Thermal data
Symbol
Rth j-case
Parameter
Thermal resistance junction to case
3.3
Electrical characteristics
Table 5.
Electrical characteristics
(VS = ±25V, RL = 4Ω, f = 1kHz, Tj = 25°C, FS = 44.1kHz, Single-Ended, application circuit shown
in Figure 3, 2 x 65W/1 x 130W system, unless otherwise specified.)
Symbol
±VS
Iq
Ist-by
Parameter
Test condition
Min.
Operating supply voltage
Quiescent supply current
Quiescent supply current
Typ.
±12
Max.
Unit
±30
V
Vst-by = 5V
from +VS
25
mA
Vst-by = 5V
from +VS-low
20
mA
Vst-by = 5V
from -VS
25
mA
Vst-by = 0
from +VS
0.3
mA
Vst-by = 0
from +VS-low
0.2
mA
Vst-by = 0
from -VS
0.3
mA
Vos
Output offset voltage
Output-GND (single-ended)
250
mV
Vos
Output offset voltage
Output L - Output R (bridge)
250
mV
Po
Output power
Single-ended, @ THD = 1%
2 x 70W system
70
W
Po
Output power
Bridge, @ THD = 1%
1 x 250W system
250
W
Pd
Power dissipation of the
TDA7571
@ Pout = 25 W, bridge
configuration
1.75
W
7/21
Electrical specifications
Table 5.
Electrical characteristics (continued)
(VS = ±25V, RL = 4Ω, f = 1kHz, Tj = 25°C, FS = 44.1kHz, Single-Ended, application circuit shown
in Figure 3, 2 x 65W/1 x 130W system, unless otherwise specified.)
Symbol
Parameter
Pdt
Power dissipation of the external
power transistors
THD
Vohs
En
DR
TDA7571
Total harmonic distortion
Test condition
Min.
Typ.
Max.
Unit
@ Pout = 25W, bridge
configuration, 1x250W system
10
W
@ Pout = 10 W, single ended
0.1
%
@ Pout = 40 W, bridge
0.05
%
Half scale output voltage
single-ended, output voltage
@ IN = −6dBFS
10
Vrms
Output noise @ IN = -999dBFS
"A" weighted, single-ended
“A” weighted, bridge
180
100
µV
“A” weighted, -60dBFS, Singleended PLL option circuit
85
dB
“A” weighted, -60dBFS, Bridge
free running oscillation option
96
dB
100
110
dB
Dynamic range
S/N
Signal-to-noise ratio (noise floor)
"A" weighted, single-ended
“A” weighted, bridge
Ge
Gain error
f = 1kHz
1.5
dB
ΔGe
Delta gain error between
channels
f = 1kHz
0.2
dB
Crosstalk
f = 1kHz, Vo = 1Vrms
ct
60
dB
Vgspth
Threshold voltage of the
Pchannel Vgs sensor
(VSpx1 - VGpxs)
2.5
3
3.5
V
Vgsnth
Threshold voltage of the
Pchannel Vgs sensor
(VSnxs - VSnx1)
2.5
3
3.5
V
Am
Mute attenuation
Vo = 1Vrms
80
90
dB
SVR
Supply voltage rejection
f = 100Hz, Vr = 0.5V
50
60
dB
FSW
Switching frequency
FS x 8
KHz
Vil
3.3V Logic inputs low level
voltage
Vih
3.3V Logic inputs high level
voltage
Vil
5V Logic inputs low level voltage
Vih
8/21
1.5
V
pin: ST-BY, MUTE, SD, WS,
SCK, MCLK bridge
pin: L/R, CD SEL1, CD SEL2, P/O,
D1, D2. (these pins are typically
5V Logic inputs high level voltage connected to the DGND or 5V
dig pins)
2.3
V
1.5
3.5
V
V
TDA7571
Electrical specifications
Table 5.
Electrical characteristics (continued)
(VS = ±25V, RL = 4Ω, f = 1kHz, Tj = 25°C, FS = 44.1kHz, Single-Ended, application circuit shown
in Figure 3, 2 x 65W/1 x 130W system, unless otherwise specified.)
Symbol
Parameter
Test condition
Min.
Typ.
Max.
Unit
Clip detector
Vcd
Clip detector pin operating
voltage (open drain)
10
V
CDl
Clip detector pin leakage current CD off
1
μA
CDs
Clip detector pin saturation voltage CD on, 1mA
1
V
0.5
%
CDsel1=0, CDsel2=0
(near clipping detection)
CDi
Clip detector THD intervention
CDsel1=0, CDsel2=1
1
%
CDsel1=1, CDsel2=0
5
%
CDsel1=1, CDsel2=1
8
%
Protections
Thwc
Chip thermal warning
intervention
135
150
165
°C
Tsdc
Thermal shut-down chip
145
160
175
°C
Tsdch
Thermal shut-down chip
hysteresis
7
10
13
°C
Thws
External thermal warning
intervention
5Vdig
x 0.45
5Vdig
x 0.48
5Vdig
x 0.51
V
Tsds
External shut-down intervention
5Vdig
x 0.37
5Vdig
x 0.4
5Vdig
x 0.43
V
Tsdsh
External thermal shut-down
hysteresis
5Vdig
x 0.037
5Vdig
x 0.04
5Vdig
x 0.043
V
Vpp
Protection intervention voltage
Pchannel (Vspx1-Vspx2)
85
100
120
mV
Vpn
Protection intervention voltage
Nchannel (Vsnx2-Vsnx1)
85
100
120
mV
Ispx1
Current input pins 7, 13
150
200
260
μA
Isnx1
Current output pins 7, 13
150
200
260
μA
Drivers
Vhgp
High level output voltage (Gpl, Gpr)
+Vs
-10
V
Vlgp
Low level output voltage (Gpl, Gpr)
+Vs
V
Vhgn
High level output voltage (Gnl, Gnr)
-Vs
V
Vlgn
Low level output voltage (Gnl, Gnr)
-Vs
+10
V
Ihgp
High level output sink current
(Gpl, Gpr, peak)
2.2
A
9/21
Electrical specifications
Table 5.
Symbol
TDA7571
Electrical characteristics (continued)
(VS = ±25V, RL = 4Ω, f = 1kHz, Tj = 25°C, FS = 44.1kHz, Single-Ended, application circuit shown
in Figure 3, 2 x 65W/1 x 130W system, unless otherwise specified.)
Parameter
Test condition
Min.
Typ.
Max.
Unit
Ilgp
Low level output source current
(Gpl, Gpr, peak)
2.7
A
Ihgn
High level output sink current
(Gnl, Gnr, peak)
2.5
A
Ilgn
Low level output source current
(Gnl, Gnr, peak)
1.7
A
Internal power supply
5Vdig
5Vdig pin output voltage
Reference: dgnd pin
5
V
2.5V
2.5V pin output voltage
Reference: sgnd pin
2.5
V
-2.5V
-2.5V pin output voltage
Reference: sgnd pin
-2.5
V
Vref1
Vref1 pin output voltage
Reference: + Vs pin
-10
V
Reference: - Vs pin
10
V
Vrefl/Vrefr Vrefl, Vrefr pin output voltage
10/21
TDA7571
Figure 3.
Electrical specifications
PLL option diagram
11/21
Electrical specifications
Figure 4.
12/21
Free running oscillator option diagram
TDA7571
TDA7571
Electrical specifications
3.4
Notes on the electrical schematic shown in Figure 3 and 4
3.4.1
Main characteristics
●
2 channels single-ended or 1 channel bridge PWM amplifier
●
Power output: see Table 5
●
Figure 3: PLL option
●
Figure 4: free running oscillator option
●
Output voltage @ input = -6Bfs:
–
Figure 3: 10Vrms (single ended) - 20Vrms (bridge)
–
Figure 4: 9.5Vrms (single ended) - 19Vrms (bridge)
●
Clip detector settled at THD=10%
●
No dithering selected
The schematic is depicted showing the suggested structure of the printed circuit board
tracks (star points, high current path, components placement).
To avoid malfunctioning due to the parasitic inductance, short connections lengths are
recommended.
Table 6.
Component characteristics
Components
(See schematic of Figure 3 & 3)
Minimum load:
2 x 4 Ohm single-ended
or 8 Ohm bridge
(2 x 65W / 1 x 130W)
(power supply = ±25V)
Minimum load:
2 x 2 Ohm single-ended
or 4Ohm bridge
(2 x 125W / 1 x 250W)
(power supply = ±25V)
P-MOS-L
P-MOS-R
STP12PF06
2 x STP12PF06
in parallel
N-MOS-L
N-MOS-R
STP14NF06
2 x STP14NF06
in parallel
Rp-N-L2
RP-P-L2
Rp-N-R2
Rp-P-R2
Not present
4.7K
13/21
Functions, pins and components description
TDA7571
4
Functions, pins and components description
4.1
Short circuit protection current calculation
Figure 5.
Short circuit protection current diagram
TDA7571
Imos
Rp1 (typ=4.7kOhm)
Rsens
(not inductive resistor)
Typ. Values = 10 – 30 mOhm
Cfil (typ 2.2nF)
SPx2 pin
Rp2
Vp=100mV Typ
comparator
Rfil (typ. 100 Ohm)
to -Vs
SPx1 pin
Vrfil = Ispx1 x Rfil = 20mV Typ
1
Vpx ⋅ ( Rp1 + Rp2 )
I lim = ------------------ ⎛ -------------------------------------------------- + Vfil⎞
⎠
Rsens ⎝
Rp2
1
I lim = ------------------ ( Vpx + Vfil )
Rsens
4.2
← if Rp2 is not used
External thermal protection network
The purpose of this function is to sense critical points of the amplifier system, as example
the heatsink of the power transistors, avoiding too high temperature.
Through the external thermal warning pin (THWEXT, pin 37), a signal useful to reduce the
power dissipation reducing (as example) the output power and/or, in a system provided of
regulated power supply, reducing the voltage supply of the amplifier (±VS) is present.
Example of external thermal protection circuitry
●
●
14/21
Components:
–
type: B57621 C621/100k/+
–
Text = 10K
Results (simulations):
–
External thermal warning temperature intervention: 90 °C
–
External thermal shut down temperature intervention: 100 °C
–
External thermal shut down hysteresis: 6°C
TDA7571
4.3
Functions, pins and components description
Internal thermal protection network
The purpose of this function is to sense the chip temperature. Because of the power
dissipation of this device is almost constant (is not dependent by the output power), the
system must be designed to avoid chip temperature higher than 140 °C.
The internal thermal protection is intended to avoid dangerous situations due to, as
example, damaged power transistors (gate-source shorted) or bad environments conditions.
Through the internal thermal warning pin (THWINT, pin 36), a signal useful to switch-off the
system or, at least, reduce the power dissipation reducing (as example) the output power
and/or, in a system provided of regulated power supply, reducing the voltage supply of the
amplifier (±Vs) is present.
4.4
Feedback
The resistors Rgain-L1, Rgain-L2 for the Left channel and Rgain-R1, Rgain-R2 for the Right
channel defines the output AC voltage with a specific input digital data.
In the example, with 3.9Kohm and 1kohm, as shown in the schematic, the output voltage @
input = -6dBFS, is indicated in the Main characteristics description. These values are
needed to reach the clipping with 0dBFS input digital data and Vs = ±25V.
If different power supply values are used, different resistors can be used to guarantee the
clipping (then the output power), optimizing the signal to noise ratio.
If Vsmax is the maximum power supply at which the amplifier must goes into clipping
condition, the value of Rgain-X1 is given by:
( V smax ⋅ R gain – X2 – 5.1 ⋅ R gain – X2 )
R gain – X1 – --------------------------------------------------------------------------------------------------5.1
Considering Rgain-X2 = 1kohm, the relation become:
( V smax – 5.1 )
R gain – X1 = -----------------------------------5.1
As example, if Vsmax = ±20V, Rgain - L1 = Rgain - R1 = 2.92kohm ~= 3kohm
4.5
Gate driving network
The main purpose of the 27 ohm resistors Rd-N-L, Rd-P-L, Rd-N-R and Rd-P-R are the
following:
1.
Dumping of the L-C equivalent circuit done by the parasitic inductance and capacitance
present in the circuit
2.
Reduction of the dv/dt of the Vgs and then reduction of the di/dt of the drain current of
the power MOS.
The R-C snubber network done by:
Rs-N-L, Cs-N-L
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Functions, pins and components description
TDA7571
Rs-P-L, Cs-P-L
Rs-N-R, Cs-N-R
Rs-P-R, Cs-P-R
Are in the direction to increase the dumping (point 1) and reduce the dv/dt (point 2).
The value of these components is also depending on the layout structure. With a reduction
of the parasitic inductance present in the P.C. board layout, in the region around the power
transistors, the value of these components can be reduced, giving advantage in terms of
THD, mainly at mid-high power levels, due to the reduction of the "dead zone".
The minimum suggested value of Rd-x-x is around 10 Ohm, while, is some cases, Rs-x-x
and Cs-x-x can be removed.
4.6
PLL
In case of the schematic shown in Figure 3, the internal oscillator is locked by a PLL circuit
at the Master Clock input frequency (MCLK).
The loop filter of this PLL is externally connected to the pin F (39). It consists in a lag-lead
filter (Cpll1, Rpll). The output resistance of the pin F is a 10K (typ) resistor.
The typical suggested values of Cpll1 and Rpll are the following:
Cpll1 = 10Kpf
Rpll = 1Kohm.
In some cases, in a system with few clock interactions and a good MCLK signal, a parallel
capacitor Cpll2 of 2.2nF-4.7nF can help to decrease the noise at the pin F.
With the PLL option, the A.C. output amplitude is not dependant by the resistor Rosc,
because the voltage across Rosc is defined by the PLL itself, Moreover, the output A.C.
voltage is independent also from the clock of the PCM signal (32kHz, 44.1kHz, 48kHz).
Vice versa, if the free running oscillation is selected, the output signal is dependant by the
Rosc value and from the input PCM frequency.
4.7
Dither
With the pins D1 (43) and D2 (44) 4 types of digital dithering is achievable:
Table 7.
4 types of digital dithering
D1
D2
Dithering
1
0
0
Low
2
0
1
Mid-low
3
1
0
Mid-high
4
1
1
High
Because of the recorded signals (music or speech) already contains some amount of noise,
the dithering is generally not needed.
For high quality signals, it is suggested do not use the cases 3 and 4, that can be useful only
in case of low resolution signals without noise added.
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TDA7571
Functions, pins and components description
4.8
External connections description
4.8.1
CD, THWEXT, THWINT
These pins, if used, it must be connected to a pull-up resistor (>10kOhm) connected to a
supply voltage referred to the receiver device (as example, a µP).
Maximum voltage = 6V.
4.8.2
MUTE
Mute pin
4.8.3
ST-BY - St-By pin.
To avoid pop noise due to multiple ST-BY parasitic pulses, an R-C network must be added
(as example 47kOhm, 0.1µF)
4.8.4
+Vs-low This pin supply the low voltage circuits. It can be connected to the +Vs or to a reference
voltage comprising between 12V to +Vs.
A connection to +Vs through a 100Ohm resistor, together a 1uF capacitor placed from +Vslow and GND is possible too.
4.8.5
DATA, SEL, SCK
I2S digital inputs
4.8.6
MCLK
Master clock input. Must be F(MCLK) = 256 x Fs (11289.6kHz in case of Fs = 44.1 kHz)
4.8.7
DGND
Digital ground
4.8.8
BRIDGE and L/R
With this pin, the mode of working of the device (bridge or single-ended) can be selected.
If it is connected to the pin 32 (DGND) the device works in single-ended mode
If it is connected to the pin 40 (5Vdig) the device works in bridge mode.
In case of bridge mode, the pin 34 (L/R) makes the channel selection. If connected to
DGND, the Left channel is selected. If connected to 5Vdig, is selected the Right channel.
These pins must be selected with the device in ST-BY condition.
In case of single-ended operation, it is suggested to put the L/R pin at 5V.
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Functions, pins and components description
4.9
18/21
TDA7571
Components with critical placement and type
●
Ci-L1, Ci-L2, Ci-R1, Ci-R2 must be placed as near as possible to the sources of the
respective power MOS. If 2 power MOS in parallel are needed, can be useful to place a
couple of capacitors for each couple of power MOS. These capacitors are needed to
absorb the high di/dt current present during the Pchannel/Nchannel and
Nchannel/Pchannel transition that can cause high peak voltages on the power supply
wiring connection due to their parasitic inductance.
●
The capacitors placed between +Vs to GND and to -Vs are distributed along the power
lines. With P.C. board with very short connections, some of these capacitors can be
avoided (Cvs-1, Cvs-2, Cd3, Cd4, Cd8, Cd7).
●
The current sensing resistors Rsens-N-L, Rsens-P-L, Rsens-P-R and Rsens-N-R must
be not inductive components, as example, made by a constant an wire.
TDA7571
Package information
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect. The category of
second Level Interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
Figure 6.
HiQUAD-64 mechanical data and package dimensions
mm
DIM.
MIN.
TYP.
A
inch
MAX.
MIN.
TYP.
0.124
A1
0
0.25
0
0.010
A2
2.50
2.90
0.10
0.114
A3
0
0.10
0
0.004
b
0.22
0.38
0.008
0.015
0.012
c
0.23
0.32
0.009
D
17.00
17.40
0.669
D1 (1)
13.90
14.00
14.10
0.547
0.551
D2
2.65
2.80
2.95
0.104
0.110
E
17.00
17.40
0.669
E1 (1)
13.90
14.10
0.547
e
14.00
0.65
0.685
0.555
0.116
0.685
0.551
0.555
0.025
E2
2.35
2.65
0.092
E3
9.30
9.50
9.70
0.366
0.374
0.382
E4
13.30
13.50
13.70
0.523
0.531
0.539
0.104
F
0.10
0.004
G
0.12
0.005
L
0.80
OUTLINE AND
MECHANICAL DATA
MAX.
3.15
1.10
0.031
N
10°(max.)
S
0°(min.), 7˚(max.)
0.043
HiQUAD-64
(1): "D1" and "E1" do not include mold flash or protusions
- Mold flash or protusions shall not exceed 0.15mm(0.006inch) per side
N
E2
A2
A
c
A
b
BOTTOM VIEW
⊕
F M A B
33
53
E3
e
D2
(slug tail width)
5
Package information
B
E1
E3
E
Gauge Plane
slug
(bottom side)
C
0.35
A3
S
SEATING PLANE
L
21
64
G
C
COPLANARITY
1
E4 (slug lenght)
A1
D1
D
POQU64ME
19/21
Revision history
6
TDA7571
Revision history
Table 8.
20/21
Document revision history
Date
Revision
3-Sep-2007
1
Changes
Initial release.
TDA7571
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