TI TPA3002D2

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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
FEATURES
D 9-W/Ch Into an 8-Ω Load From 12-V Supply
D Efficient, Class-D Operation Eliminates
D
D
D
D
D
DESCRIPTION
The TPA3002D2 is a 9-W (per channel) efficient, Class-D
audio amplifier for driving bridged-tied stereo speakers.
The TPA3002D2 can drive stereo speakers as low as 8 Ω.
The high efficiency of the TPA3002D2 eliminates the need
for external heatsinks when playing music.
Heatsinks and Reduces Power Supply
Requirements
32-Step DC Volume Control From −40 dB to
36 dB
Line Outputs For External Headphone
Amplifier With Volume Control
Regulated 5-V Supply Output for Powering
TPA6110A2
Space-Saving, Thermally-Enhanced
PowerPAD Packaging
Thermal and Short-Circuit Protection
Stereo speaker volume is controlled with a dc voltage
applied to the volume control terminal offering a range of
gain from –40 dB to 36 dB. Line outputs, for driving external
headphone amplifier inputs, are also dc voltage controlled
with a range of gain from –56 dB to 20 dB.
An integrated 5-V regulated supply is provided for
powering an external headphone amplifier.
APPLICATIONS
D LCD Monitors and TVs
D Powered Speakers
10 µF
Cs
0.1 µF
Cs
0.1 µF
RINN
RINP
Crinn
Crinp 1 µF
1 µF
Clinp
LINP
LINN
1 µF
C2p5
1 µF
Clinn
10 nF
Cbs
VREF
Ccpr
VCLAMPR
MODE_OUT
RINN
RINP
MODE
V2P5
AVCC
LINP
1 µF
MODE_OUT
MODE
VAROUTR
LINN
1 µF
BSRP
PVCCR
PVCCR
ROUTN
PGNDR
Cs
PGNDR
PVCCR
SD
ROUTN
BSRN
SDZ
PVCCR
Cs
PVCC
ROUTP
Cbs
10 µF
ROUTP
PVCC
10 nF
RLINE_OUT
VAROUTL
TPA3002D2
AVDDREF
AGND
VREF
AVDD
VARDIFF
VARDIFF
COSC
VARMAX
VARMAX
ROSC
Cs
Cbs
10 nF
PVCC
BSLP
PVCCL
PVCCL
LOUTP
LOUTP
PGNDL
PGNDL
LOUTN
LOUTN
VCLAMPL
PVCCL
AGND
REFGND
PVCCL
VOLUME
BSLN
VOL
REFGND
AVCC
Cs
0.1 µF
Cvcc
10 µF
LLINE_OUT
AVDD
Cvdd
Cosc
100 nF
220 pF
Rosc
120 kΩ
Ccpl
1 µF
10
kΩ
10
kΩ
Cs
0.1 µF
Cs
0.1 µF
10 µF
10 µF
Cs
Cbs
10 nF
PVCC
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments.
! "#$ ! %#&'" ($) (#"!
" !%$""! %$ *$ $! $+! !#$! !(( ,-)
(#" %"$!!. ($! $"$!!'- "'#($ $!. '' %$$!)
Copyright  2002−2004, Texas Instruments Incorporated
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during
storage or handling to prevent electrostatic damage to the MOS gates.
AVAILABLE OPTIONS
PACKAGED DEVICE
TA
48-PIN HTQFP (PHP)(1)
−40°C to 85°C
TPA3002D2PHP
(1) The PHP package is available taped and reeled. To order a taped and
reeled part, add the suffix R to the part number (e.g., TPA3002D2PHPR).
PIN ASSIGNMENTS
PHP PACKAGE
BSRP
PVCCR
ROUTP
ROUTP
PGNDR
ROUTN
ROUTN
PGNDR
43 42
41 40 39 38
37
SD
1
36
VCLAMPR
RINN
2
35
MODE_OUT
RINP
3
34
MODE
V2P5
4
33
AVCC
LINP
5
32
VAROUTR
LINN
6
31
VAROUTL
AVDDREF
7
30
AGND
VREF
8
29
AVDD
VARDIFF
9
28
COSC
VARMAX
10
27
ROSC
VOLUME
11
26
AGND
REFGND
12
25
VCLAMPL
BSLP
PVCCL
LOUTP
PVCCL
PGNDL
LOUTP
24
PGNDL
20 21 22 23
LOUTN
18 19
LOUTN
PVCCL
BSLN
15 16 17
PVCCL
TPA3002D2
13 14
2
46 45 44
PVCCR
48 47
PVCCR
PVCCR
BSRN
(TOP VIEW)
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
FUNCTIONAL BLOCK DIAGRAM
V2P5
PVCC
V2P5
VAROUTR
VClamp
Gen
V2P5
VCLAMPR
BSRN
Gain
Adj.
PVCCR(2)
Gate
Drive
Cint2
RINN
Gain
Adj.
Rfdbk2
RINP
Deglitch &
PGNDR
Modulation
Logic
BSRP
PVCCR(2)
Rfdbk2
V2P5
VREF
Gate
Drive
Cint2
VOLUME
Gain
Control
VARDIFF
VARMAX
PGNDR
Blocks
OC
Detect
V2P5
ROSC
Ramp
Generator
Biases
Startup
Protection
Logic
&
COSC
References
AVDDREF
ROUTP(2)
To Gain Adj.
REFGND
Thermal
VDD
VDDok
AVCC
AVDD
VCCok
AVDD
5V LDO
PVCC
TTL Input
Buffer
SD
MODE
MODE_OUT
AVCC
AGND
VClamp
Gen
VCLAMPL
BSLN
Mode
PVCCL(2)
Control
Gate
Drive
Cint2
V2P5
LINN
ROUTN(2)
PGNDL
Deglitch &
Gain
Adj.
Rfdbk2
BSLP
Modulation
Logic
LINP
LOUTN(2)
PVCCL(2)
Rfdbk2
V2P5
Cint2
Gain
Adj.
Gate
Drive
LOUTP(2)
PGNDL
VAROUTL
3
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Terminal Functions
TERMINAL
NO.
NAME
I/O
DESCRIPTION
AGND
26, 30
−
Analog ground for digital/analog cells in core
AVCC
AVDD
33
−
High-voltage analog power supply (8.5 V to 14 V)
29
O
5-V Regulated output capable of 100-mA output
AVDDREF
BSLN
7
O
5-V Reference output—provided for connection to adjacent VREF terminal.
13
I/O
Bootstrap I/O for left channel, negative high-side FET
BSLP
24
I/O
Bootstrap I/O for left channel, positive high-side FET
BSRN
48
I/O
Bootstrap I/O for right channel, negative high-side FET
BSRP
37
I/O
Bootstrap I/O for right channel, positive high-side FET
COSC
28
I/O
I/O for charge/discharging currents onto capacitor for ramp generator triangle wave biased at V2P5
LINN
6
I
Negative differential audio input for left channel
LINP
5
I
Positive differential audio input for left channel
LOUTN
16, 17
O
Class-D 1/2-H-bridge negative output for left channel
LOUTP
20, 21
O
Class-D 1/2-H-bridge positive output for left channel
MODE
34
I
Input for MODE control. A logic high on this pin places the amplifier in the variable output mode and the Class-D
outputs are disabled. A logic low on this pin places the amplifier in the Class-D mode and Class-D stereo outputs
are enabled. Variable outputs (VAROUTL and VAROUTR) are still enabled in Class-D mode to be used as
line-level outputs for external amplifiers.
MODE_OUT
35
O
Output for control of the variable output amplifiers. When the MODE pin (34) is a logic high, the MODE_OUT
pin is driven low. When the MODE pin (34) is a logic low, the MODE_OUT pin is driven high. This pin is intended
for MUTE control of an external headphone amplifier. Leave unconnected when not used for headphone
amplifier control.
PGNDL
18, 19
−
Power ground for left channel H-bridge
PGNDR
42, 43
−
Power ground for right channel H-bridge
PVCCL
14, 15
−
Power supply for left channel H-bridge (tied to pins 22 and 23 internally), not connected to PVCCR or AVCC.
PVCCL
22, 23
−
Power supply for left channel H-bridge (tied to pins 14 and 15 internally), not connected to PVCCR or AVCC.
PVCCR
38,39
−
Power supply for right channel H-bridge (tied to pins 46 and 47 internally), not connected to PVCCL or AVCC.
PVCCR
46, 47
−
Power supply for right channel H-bridge (tied to pins 38 and 39 internally), not connected to PVCCL or AVCC.
REFGND
12
−
Ground for gain control circuitry. Connect to AGND. If using a DAC to control the volume, connect the DAC
ground to this terminal.
RINP
3
I
Positive differential audio input for right channel
RINN
2
I
Negative differential audio input for right channel
ROSC
27
I/O
Current setting resistor for ramp generator. Nominally equal to 1/8*VCC
ROUTN
44, 45
O
Class-D 1/2-H-bridge negative output for right channel
ROUTP
40, 41
O
Class-D 1/2-H-bridge positive output for right channel
SD
1
I
Shutdown signal for IC (low = shutdown, high = operational). TTL logic levels with compliance to VCC.
VARDIFF
9
I
DC voltage to set the difference in gain between the Class-D and VAROUT outputs. Connect to GND or
AVDDREF if VAROUT outputs are unconnected.
VARMAX
10
I
DC voltage that sets the maximum gain for the VAROUT outputs. Connect to GND or AVDDREF if VAROUT
outputs are unconnected.
VAROUTL
31
O
Variable output for left channel audio. Line level output for driving external HP amplifier.
VAROUTR
32
O
Variable output for right channel audio. Line level output for driving external HP amplifier.
VCLAMPL
25
−
Internally generated voltage supply for left channel bootstrap capacitors.
VCLAMPR
36
−
Internally generated voltage supply for right channel bootstrap capacitors.
VOLUME
11
I
DC voltage that sets the gain of the Class-D and VAROUT outputs.
VREF
8
I
Analog reference for gain control section.
V2P5
4
O
2.5-V Reference for analog cells, as well as reference for unused audio input when using single-ended inputs.
Thermal
Pad
−
Connect to AGND and PGND—should be center point for both grounds.
—
4
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted(1)
UNIT
Supply voltage range:
AVCC, PVCC
MODE, VREF, VARDIFF, VARMAX, VOLUME
Input voltage range, VI
SD
−0.3 V to 15 V
0 V to 5.5 V
−0.3 V to VCC + 0.3 V
RINN, RINP, LINN, LINP
−0.3 V to 7 V
AVDD
AVDDREF
120 mA
Supply current
Output current,
VAROUTL, VAROUTR
20 mA
10 mA
Continuous total power dissipation
See Dissipation Rating Table
Operating free-air temperature range, TA
−40°C to 85°C
Operating junction temperature range, T
−40°C to 150°C
Storage temperature range, Tstg
−65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds
260°C
(1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
PACKAGE DISSIPATION RATINGS
PACKAGE
PHP
TA ≤ 25°C
4.3 W
DERATING FACTOR
34.7 mW/°C(1)
TA = 70°C
2.7 W
TA = 85°C
2.2 W
(1) The PowerPAD must be soldered to a thermal land on the printed circuit board. Please refer to the PowerPAD
Thermally Enhanced Package application note (SLMA002).
RECOMMENDED OPERATING CONDITIONS
Supply voltage, VCC
Volume reference voltage
PVCC, AVCC
VREF
Volume control pins, input voltage
VARDIFF, VARMAX, VOLUME
SD
High-level input voltage, VIH
MODE
MIN
MAX
UNIT
8.5
14
V
3.0
5.5
V
5.5
V
2
SD
Low-level input voltage, VIL
MODE
High-level output voltage, VOH
MODE_OUT, IOH = 1 mA
Low-level output voltage, VOL
MODE_OUT, IOL = −1 mA
High-level input current, IIH
Low-level input current, IIL
V
3.5
0.8
2
AVDD−100mV
MODE, VI= 5 V, VCC = 14 V
SD, VI= 14 V, VCC = 14 V
MODE, VI= 0 V, VCC = 14 V
SD, VI= 0 V, VCC = 14 V
V
V
AGND+100mV
V
1
uA
30
uA
1
uA
1
uA
Oscillator frequency, fOSC
225
275
kHz
Operating free-air temperature, TA
−40
85
°C
5
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
DC ELECTRICAL CHARACTERISTICS
TA = 25°C, VCC = 12 V, RL = 8 Ω (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
| VOS |
Class-D Output offset voltage
(measured differentially)
INN and INP connected together,
Gain = 36 dB
V2P5 (terminal 4)
2.5-V Bias voltage
No load
AVDD
5-V Regulated output
PSRR
Class-D power supply rejection ratio
IO = 0 to 100 mA, SD = 2 V,
VCC = 8 V to 14 V
VCC = 11.5 V to 12.5 V
ICC(class-D)
ICC(varout)
Class-D mode quiescent current
MODE = 2 V, SD = 2 V
16
28.5
mA
Variable output mode quiescent current
MODE = 3.5 V, SD = 2 V
7
9
mA
ICC(class-D – max power)
Class-D mode RMS current at max
power
RL = 8 Ω, PO = 9 W
2
ICC(SD)
Supply current in shutdown mode
SD = 0.8 V
1
rds(on)
Drain-source on-state resistance
VCC = 12 V,
IO = 1 A,
TJ = 25°C
25 C
10
0.45x
AVDD
4.5
65
0.5x 0.55x
AVDD AVDD
5.0
5.5
−80
mV
V
V
dB
A
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ÑÑÑÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑÑÑÑÑÑ
ÑÑÑÑÑÑÑÑÑÑÑ
ÑÑÑÑÑ
ÑÑÑÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑÑÑÑÑÑ
ÑÑÑÑÑÑÑÑÑÑÑ
ÑÑÑÑÑ
ÑÑÑÑÑ
ÑÑÑ
Ñ
ÑÑ
ÑÑÑ
ÑÑÑ
ÑÑÑ
High side
300
Low side
250
Total
550
10
uA
mΩ
590
AC ELECTRICAL CHARACTERISTICS FOR CLASS-D OUTPUTS
TA = 25°C, VCC = 12 V, RL = 8 Ω (unless otherwise noted)
PARAMETER
kSVR
Supply ripple rejection ratio
PO
Continuous output power
TEST CONDITIONS
MIN
SNR
MAX
UNITS
VCC = 11.5 V to 12.5 V from 10 Hz to 1 kHz,
Gain = 36 dB
−67
dB
THD+N = 1%, f = 1 kHz, RL = 8 Ω
7.5
W
9
W
THD+N = 10%, f = 1 kHz, RL = 8 Ω
79
µV
−82
dBV
20 Hz to 22 kHz, A-weighted filter,
Gain = 13.2 dB
100
µV
−80
dBV
Crosstalk, Class-D−Left → Class-D−Right
Gain = 13.2 dB, PO = 1 W, RL = 8 Ω
−77
dB
Crosstalk, Class-D → VAROUT
Maximum output at THD < 0.5%, Gain = 36 dB
−63
dB
Signal-to-noise ratio
Maximum output at THD+N < 0.5%,
f= 1 kHz, Gain = 36 dB
96
dB
Thermal trip point
150
°C
Thermal hystersis
20
°C
20 Hz to 22 kHz, No filter, Gain = 0.5 dB
Vn
TYP
Output integrated noise floor
CHARACTERISTICS FOR VAROUT OUTPUTS
PARAMETER
TEST CONDITIONS
Measured between V2P5 and VAROUT,
Gain = 20 dB, RL = 10 kΩ
MIN
TYP
UNITS
|VOS|
Output offset voltage
THD+N
Total harmonic distortion + noise
PSRR
DC power supply rejection ratio
AV = 7.3 dB, f = 1 kHz, PO = 6 mW, RL = 32 Ω
AV = 7.3 dB, f = 1 kHz, RL = 2 kΩ, VO = 1 Vrms
Gain = 20 dB
−74
dB
kSVR
Supply ripple rejection ratio
Gain = 20 dB, f = 1 kHz
−95
dB
Crosstalk, VAROUTL → VAROUTR
Maximum output at THD < 0.5%, Gain = 20 dB
−60
dB
Crosstalk, VAROUT → Class-D
Maximum output at THD < 0.5%, Gain = 20 dB
−74
dB
Vn
6
Output integrated noise floor
10
MAX
mV
0.025%
0.002%
20 Hz to 22 kHz, Gain = 20 dB
75
20 Hz to 22 kHz, Gain = −0.3 dB
15
µV
V
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Table 1. DC Volume Control for Class-D Outputs
VOLTAGE ON THE
VOLUME PIN AS A
PERCENTAGE OF VREF
(INCREASING VOLUME
OR FIXED GAIN)
VOLTAGE ON THE
VOLUME PIN AS A
PERCENTAGE OF
VREF (DECREASING
VOLUME)
GAIN OF CLASS-D
AMPLIFIER
%
%
dB
0 − 4.5
0 − 2.9
−75(1)
4.5 − 6.7
2.9 − 5.1
−40.0
6.7 − 8.91
5.1 − 7.2
−37.5
8.9 − 11.1
7.2 − 9.4
−35.0
11.1 − 13.3
9.4 − 11.6
−32.4
13.3 − 15.5
11.6 − 13.8
−29.9
15.5 − 17.7
13.8 − 16.0
−27.4
17.7 − 19.9
16.0 − 18.2
−24.8
19.9 − 22.1
18.2 − 20.4
−22.3
22.1 − 24.3
20.4 − 22.6
−19.8
24.3 − 26.5
22.6 − 24.8
−17.2
26.5 − 28.7
24.8 − 27.0
−14.7
28.7 − 30.9
27.0 − 29.1
−12.2
30.9 − 33.1
29.1 − 31.3
−9.6
33.1 − 35.3
31.3 − 33.5
−7.1
35.3 − 37.5
33.5 − 35.7
−4.6
37.5 − 39.7
35.7 − 37.9
39.7 − 41.9
37.9 − 40.1
−2.0
0.5†
41.9 − 44.1
40.1 − 42.3
3.1
44.1 − 46.4
42.3 − 44.5
5.6
46.4 − 48.6
44.5 − 46.7
8.1
48.6 − 50.8
46.7 − 48.9
10.7
50.8 − 53.0
48.9 − 51.0
13.2
53.0 − 55.2
51.0 − 53.2
15.7
55.2 − 57.4
53.2 − 55.4
18.3
57.4 − 59.6
55.4 − 57.6
20.8
59.6 − 61.8
57.6 − 59.8
23.3
61.8 − 64.0
59.8 − 62.0
25.9
64.0 − 66.2
62.0 − 64.2
28.4
66.2 − 68.4
64.2 − 66.4
30.9
68.4 − 70.6
66.4 − 68.6
> 70.6
>68.6
33.5
36.0(1)
(1) Tested in production. Remaining steps are specified by design.
7
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Table 2. DC Volume Control for VAROUT Outputs
VAROUT_VOLUME (V) −
FROM FIGURE 35 − AS
A PERCENTAGE OF
VREF (INCREASING
VOLUME OR FIXED
GAIN)
VAROUT_VOLUME (V)
− FROM FIGURE 35 −
AS A PERCENTAGE OF
VREF (DECREASING
VOLUME)
GAIN OF VAROUT
AMPLIFIER
%
%
dB
0 − 4.5
0 − 2.9
−66(1)
4.5 − 6.7
2.9 − 5.1
−56.0
6.7 − 8.91
5.1 − 7.2
−53.5
8.9 − 11.1
7.2 − 9.4
−50.9
11.1 − 13.3
9.4 − 11.6
−48.4
13.3 − 15.5
11.6 − 13.8
−45.9
15.5 − 17.7
13.8 − 16.0
−43.3
17.7 − 19.9
16.0 − 18.2
−40.8
19.9 − 22.1
18.2 − 20.4
−38.3
22.1 − 24.3
20.4 − 22.6
−35.7
24.3 − 26.5
22.6 − 24.8
−33.2
26.5 − 28.7
24.8 − 27.0
−30.7
28.7 − 30.9
27.0 − 29.1
−28.1
30.9 − 33.1
29.1 − 31.3
−25.6
33.1 − 35.3
31.3 − 33.5
−23.1
35.3 − 37.5
33.5 − 35.7
−20.5
37.5 − 39.7
35.7 − 37.9
−18.0
39.7 − 41.9
37.9 − 40.1
41.9 − 44.1
40.1 − 42.3
−15.5
−13.0(1)
44.1 − 46.4
42.3 − 44.5
−10.4
46.4 − 48.6
44.5 − 46.7
−7.9
48.6 − 50.8
46.7 − 48.9
−5.3
50.8 − 53.0
48.9 − 51.0
−2.8
53.0 − 55.2
51.0 − 53.2
−0.3
55.2 − 57.4
53.2 − 55.4
2.3
57.4 − 59.6
55.4 − 57.6
4.8
59.6 − 61.8
57.6 − 59.8
7.3
61.8 − 64.0
59.8 − 62.0
9.9
64.0 − 66.2
62.0 − 64.2
12.4
66.2 − 68.4
64.2 − 66.4
14.9
68.4 − 70.6
66.4 − 68.6
17.5
20.0(1)
> 70.6
>68.6
(1) Tested in production. Remaining steps are specified by design.
8
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
TYPICAL CHARACTERISTICS
TABLE OF GRAPHS
FIGURE
Class-D Efficiency
vs Output power
1
PO
Class-D Output power
vs Load resistance
2
vs Supply voltage
3
ICC
Class-D Supply current
vs Supply voltage
4
vs Output Power
5
Shutdown supply current
vs Supply voltage
6
Class-D Input resistance
vs Gain
IO(sd)
vs Frequency
THD+N
Class-D Total harmonic distortion + noise
kSVR
Class-D Supply ripple rejection ratio
vs Output power
vs Frequency
Class-D Closed loop response
12
14
Class-D Input offset voltage
vs Common-mode input voltage
15
Class-D Crosstalk
vs Frequency
16
Class-D Mute attenuation
Class-D Shutdown attenuation
17
vs Frequency
18
Class-D Common-mode rejection ratio
vs Frequency
19
VAROUT Input resistance
vs Gain
20
VAROUT Noise
vs Frequency
21
VAROUT Closed Loop Response
kSVR
10, 11
13
Class-D Intermodulation performance
THD+N
7
8, 9
22
VAROUT Common-mode rejection ratio
vs Frequency
23
VAROUT Crosstalk
vs Frequency
24
vs Output power
25
vs Output voltage
26
vs Frequency
27
vs Frequency
28
VAROUT Total harmonic distortion + noise
VAROUT Supply ripple rejection ratio
9
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
EFFICIENCY
vs
OUTPUT POWER
OUTPUT POWER
vs
LOAD RESISTANCE
100
16
RL = 8 Ω
90
f = 1 kHz,
LC Filter,
Class-D,
Resistive Load,
TA = 25°C
14
80
12
PO − Output Power − W
Efficiency − %
70
60
50
40
30
VCC = 12 V,
Class-D,
LC Filter,
Resistive Load
20
10
2
4
6
PO − Output Power − W
8
VCC = 12 V,
THD = 1%
10
8
6
4
2
0
0
VCC = 12 V,
THD = 10%
VCC = 8.5 V,
THD = 10%
0
10
8
10
12
14
RL − Load Resistance − Ω
Figure 1
16
Figure 2
OUTPUT POWER
vs
SUPPLY VOLTAGE
SUPPLY CURRENT
vs
SUPPLY VOLTAGE
17
14
16
I CC− Supply Current − mA
12
PO − Output Power − W
VCC = 8.5 V,
THD = 1%
10
8 Ω Speaker
10% THD+N
8
6
8 Ω Speaker
1% THD+N
4
SD = 2 V,
MODE = 2 V,
Class-D,
No Load
15
14
13
12
11
TA = 25°C
2
8.5
9
10
11
12
VCC − Supply Voltage − V
Figure 3
10
13
14
10
8.5
9
10
11
12
VCC − Supply Voltage − V
Figure 4
13
14
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
SUPPLY CURRENT
vs
OUTPUT POWER
SHUTDOWN SUPPLY CURRENT
vs
SUPPLY VOLTAGE
2.5
2.2
I CC − Supply Current − A
2.0
I CC(sd)− Shutdown Supply Current − µ A
VCC = 12 V,
MODE = 2 V,
Class-D,
Stereo,
TA = 25°C
1.5
8Ω
1.0
16 Ω
0.5
0
0
5
10
15
SD = 0 V
No Load
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
8.5
20
PO − Output Power − W
13
14
TOTAL HARMONIC DISTORTION + NOISE
vs
FREQUENCY
INPUT RESISTANCE
vs
GAIN
1
THD+N − Total Harmonic Distortion + Noise − %
120
Class-D
100
RL − Input Resistance − k Ω
12
10
11
VCC − Supply Voltage − V
Figure 6
Figure 5
80
60
40
20
0
−50
9
−30
−10
10
Gain − dB
Figure 7
30
50
VCC = 8 V
RL = 8 Ω
Gain = +36 dB
Class-D
PO = 3 W
0.1
PO = 0.25 W
PO = 1.5 W
0.01
20
100
1k
10k
f − Frequency − Hz
Figure 8
11
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
TOTAL HARMONIC DISTORTION + NOISE
vs
OUTPUT POWER
TOTAL HARMONIC DISTORTION + NOISE
vs
FREQUENCY
10
VCC = 12 V
RL = 8 Ω
Gain = +36 dB
Class-D
PO = 0.5 W
PO = 5 W
0.1
THD+N − Total Harmonic Distortion + Noise − %
THD+N − Total Harmonic Distortion + Noise − %
1
PO = 2.5 W
0.01
10
100
1k
10k
VCC = 8 V
RL = 8 Ω
Gain = +13.2 dB
Class-D
1
f = 1 kHz
0.1
0.01
10 m
f = 20 Hz
100 m
Figure 9
SUPPLY RIPPLE REJECTION RATIO
vs
FREQUENCY
−40
VCC = 12 V
RL = 8 Ω
Gain = +13.2 dB
Class-D
1
f = 20 Hz
f = 1 kHz
0.1
1
PO − Output Power − W
Figure 11
12
k SVR − Supply Ripple Rejection Ratio − dB
THD+N − Total Harmonic Distortion + Noise − %
10
100 m
10
Figure 10
TOTAL HARMONIC DISTORTION + NOISE
vs
OUTPUT POWER
0.01
10 m
1
PO − Output Power − W
f − Frequency − Hz
10
−45
RL = 8 Ω,
C2P5 = 1 µF,
Class-D
−50
−55
VCC = 8 V
−60
−65
VCC = 12 V
−70
−75
−80
20
100
1k
f − Frequency − Hz
Figure 12
10 k 20 k
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
INTERMODULATION PERFORMANCE
CLOSED LOOP RESPONSE
100
Gain
50
−20
50
0
−40
−50
−100
−100
−150
−150
VCC = 12 V,
Gain = +36 dB,
RL = 8 Ω
Class-D
−200
−250
10
100
FFT − dBr
−50
Phase − Deg
0
Phase
Gain − dB
0
100
100 k
−60
−80
−100
−120
−200
1k
10 k
f − Frequency − Hz
VCC = 12 V, 19 kHz, 20 kHz,
1:1, PO = 1 W, RL = 8 Ω
Gain = +13.2 dB,
BW =20 Hz to 22 kHz,
Class-D
No Filter
−140
50
−250
1M
100
1k
f − Frequency − Hz
Figure 13
Figure 14
INPUT OFFSET VOLTAGE
vs
COMMON-MODE INPUT VOLTAGE
CROSSTALK
vs
FREQUENCY
6
0
VCC = 12 V
Class-D
5
−10
−20
4
Crosstalk − dB
VIO − Input Offset Voltage − mV
10 k
3
2
−30
VCC = 12 V,
C2P5 = 1 µF,
PO = 1 W,
Gain = +13.2 dB,
Class-D,
RL = 8 Ω
−40
−50
−60
1
−70
0
−80
−1
0
1
2
3
4
VICM − Common-Mode Input Voltage − V
Figure 15
5
−90
20
100
1k
10 k 20 k
f − Frequency − Hz
Figure 16
13
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
MUTE ATTENUATION
vs
FREQUENCY
SHUTDOWN ATTENUATION
vs
FREQUENCY
−30
Mute Attenuation − dB
−50
−85
Shutdown Attenuation − dB
−40
−80
VCC = 12 V,
RL = 8 Ω,
VI = 1 Vrms
Class-D,
VOLUME = 0 V
−60
−70
−80
−90
−100
−90
−95
−100
−105
−110
−115
−110
−120
−120
−125
−130
10
100
1k
VCC = 12 V,
RL = 8 Ω,
VI = 1 Vrms
Gain = +13.2 dB,
Class-D
−130
10
10 k
100
f − Frequency − Hz
f − Frequency − Hz
Figure 17
Figure 18
INPUT RESISTANCE
vs
GAIN
COMMON-MODE REJECTION RATIO
vs
FREQUENCY
160
VAROUT
VCC = 12 V,
RL = 8 Ω,
C2P5 = 1 µF,
Class-D
140
RL − Input Resistance − k Ω
CMRR − Common-Mode Rejection Ratio − dB
−40
−50
−60
−70
−80
−90
−100
10
120
100
80
60
40
20
0
−50
100
10 k
1k
f − Frequency − Hz
Figure 19
14
10 k
1k
100 k
−30
−10
Gain − dB
Figure 20
10
30
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
NOISE
vs
FREQUENCY
CLOSED LOOP RESPONSE
0
12.9
VCC = 12 V,
Gain = +20 dB,
RL = 8 Ω
Inputs AC Coupled to GND,
VAROUT,
No Filter
−40
150
125
Gain − dB
−80
−100
−120
−140
5.8
100
2.2
75
−1.3
50
25
Phase
−4.8
0
−8.4
−25
−50
−11.9
−75
VCC = 12 V,
Gain = +7.9
dB,
RL = 8 Ω
VAROUT
−160
−15.4
−180
−19.0
−200
−22.5
10
20
100
1k
f − Frequency − Hz
10 k
100
−175
10 k
CROSSTALK (VAROUTL-TO-VAROUTR)
vs
FREQUENCY
0
VCC = 12 V,
RL = 8 Ω ,
C2P5 = 1 µF,
VAROUT
VO = 1 Vrms,
RL = 10 kΩ,
VAROUT
−10
−20
−46
G = 20 dB
G = 10 dB
G = 0 dB
Crosstalk − dB
−30
−48
−50
−52
−40
G = −10 dB
−50
−60
−54
−70
−56
−80
−58
−90
−60
20
−150
Figure 22
−40
−44
−125
f − Frequency − Hz
COMMON-MODE REJECTION RATIO
vs
FREQUENCY
−42
−100
1k
Figure 21
CMRR − Common-Mode Rejection Ratio − dBv
Noise FFT − dBV
−60
9.3
Phase − Deg
−20
175
Gain
−100
100
1k
f− Frequency − Hz
Figure 23
10 k
20
100
1k
10 k
f − Frequency − Hz
Figure 24
15
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
TOTAL HARMONIC DISTORTION + NOISE
vs
OUTPUT POWER
TOTAL HARMONIC DISTORTION + NOISE
vs
OUTPUT VOLTAGE
VCC = 12 V
RL = 32 Ω,
Gain = +6 dB,
VAROUT
10
2
THD+N −Total Harmonic Distortion + Noise − %
THD+N −Total Harmonic Distortion + Noise − %
20
1
0.2
f = 1 kHz
0.1
f = 20 kHz
0.02
0.01
f = 20 Hz
0.001
20 µ
100 µ 200 µ
1m
2m
10 m 20 m
20
10
2
VCC = 12 V
RL = 10 kΩ,
Gain = +6 dB
VAROUT
1
0.2
0.1
f = 1 kHz
0.02
0.01
0.001
20 m
100 m
PO − Output Power − W
Figure 25
k SVR − Supply Ripple Rejection Ratio − dB
THD+N −Total Harmonic Distortion + Noise − %
0.1
0.02
0.01
100
1k
f − Frequency − Hz
Figure 27
16
−40
VCC = 12 V
RL = 32 Ω,
PO = 5 mW,
Gain = +7.9 dB,
VAROUT
0.2
0.005
20
2
SUPPLY RIPPLE REJECTION RATIO
vs
FREQUENCY
10
1
1
Figure 26
TOTAL HARMONIC DISTORTION + NOISE
vs
FREQUENCY
2
100 m
VO − Output Voltage − VRMS
10 k
−50
VCC = 12 V
VAROUT
−60
−70
−80
−90
−100
−110
20
100
1k
f − frequency − Hz
Figure 28
10 k
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
C22
1 nF
VCC
ROUT+
GND
VCC
ROUT−
APPLICATION INFORMATION
C23
1 nF
L1
(Bead)
L2
(Bead)
10 µF
PGND
10 nF
C15
0.1uF
0.1uF
C9
C10
10 nF
1 µF
1 µF C5
C3
1 µF
1 µF C4
LIN−
1 µF
MODEB
BSRP
PVCCR
ROUTP
ROUTP
PGNDR
PGNDR
ROUTN
ROUTN
MODE
V2P5
AVCC
LINP
VAROUTR
VAROUTR
LINN
VAROUTL
VAROUTL
TPA3002D2
AVDDREF
AGND
VREF
AVDD
VARDIFF
COSC
VARMAX
ROSC
T6
T5
VOLUME
AGND
REFGND
VCLAMPL
MODE
C13
0.1 µF
C16
10 µF
C11
AVDD
220pF
100 nF
10 µF
R1
120 kΩ
AGND
BSLP
PVCCL
PVCCL
LOUTP
10 nF
PGND
L3
(Bead)
L4
(Bead)
C25
1nF
GND
C24
1nF
VCC
C21
0.1 µF
10 µF
LOUT−
PGND
VCC
10 nF
GND
1 µF
C12
0.1 µF
C17
LOUT+
C20
LOUTP
PGNDL
PGNDL
LOUTN
LOUTN
PVCCL
AGND
VCC
C14
C6
C8
GND
PVCCL
P1
50 kΩ
GND
RINP
T7
P2
50 kΩ
PGND
1 µF
MODE_OUT
BSLN
P3
50k
C7
VCLAMPR
RINN
C2
AGND
PVCCR
SD
C1
RIN−
PVCCR
BSRN
SHUTDOWN
PVCCR
C19
C18
Figure 29. Stereo Class-D With Single-Ended Inputs
17
18
AGND
REFGND
VOLUME
VARMAX
VARDIFF
VREF
AVDDREF
LINN
BSRN
T5
1 µF
LINP
V2P5
PGNDL
LOUTN
LOUT−
VCC
PVCCR
PVCCL
VCC
PVCCR
PVCCL
10 nF
LOUTN
C24
1 nF
L3
(Bead)
C25
1 nF
L4
(Bead)
PGND
PGNDL
10 µ F
0.1 µ F
C12
LOUTP
C11
VCLAMPR
VCLAMPL
AGND
ROSC
COSC
AVDD
AGND
VAROUTL
VAROUTR
AVCC
MODE
MODE_OUT
10 nF
C21
PVCCL
0.1 µ F
C17
C19
PVCCR
C20
C10
10 nF
VCC
PVCCR
PVCCL
VCC
ROUT+
ROUTP
LOUTP
LOUT+
TPA3002D2
ROUTN
GND
C4
1 µF
RINP
RINN
PGNDR
P1
50 kΩ
T6
C5
1 µF
1 µF
PGNDR
P2
50 kΩ
T7
C3
C1
1 µF
C9
0.1 µ F
PGND
ROUTP
P3
50 kΩ
LIN−
AGND
C2
SD
ROUTN
C18
C15
0.1 µ F
10 µ F
L2
(Bead)
C23
1 nF
BSRP
RIN−
SHUTDOWN
ROUT−
10 nF
GND
L1
(Bead)
C22
1 nF
1 µF
C8
220 pF
C6
120 kΩ
R1
100 nF
C14
C16
10 µ F
PGND
C13
0.1µ F
1 µF
AVDD
AVCC
C7
1 µF
Cin2
1 µF
Cin1
10 kΩ (T3)
Rhps2
0.47µ F
Cvcc
10 kΩ
Rhps1
Rout1 1 kΩ
Rout2 1 kΩ
R3
120 kΩ
AVDD
Cout2
BYP IN1
10 kΩ
Rhpf2
IN2 Vo2
SD VDD
GND Vo1
Rhpf1
10 kΩ
220 µF
TPA6110A2
Cout1
AVDD
(T4)
220 µ F
SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
www.ti.com
10 µF
BSLP
GND
BSLN
Figure 30. Stereo Class-D With Single-Ended Inputs and Stereo Headphone Amplifier Interface
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
CLASS-D OPERATION
This section focuses on the class-D operation of the TPA3002D2.
Traditional Class-D Modulation Scheme
The traditional class-D modulation scheme, which is used in the TPA032D0x family, has a differential output
where each output is 180 degrees out of phase and changes from ground to the supply voltage, VCC. Therefore,
the differential prefiltered output varies between positive and negative VCC, where filtered 50% duty cycle yields
0 V across the load. The traditional class-D modulation scheme with voltage and current waveforms is shown
in Figure 31. Note that even at an average of 0 V across the load (50% duty cycle), the current to the load is
high, causing high loss, thus causing a high supply current.
OUTP
OUTN
+12 V
Differential Voltage
Across Load
0V
−12 V
Current
Figure 31. Traditional Class-D Modulation Scheme’s Output Voltage and
Current Waveforms Into an Inductive Load With No Input
TPA3002D2 Modulation Scheme
The TPA3002D2 uses a modulation scheme that still has each output switching from 0 to the supply voltage.
However, OUTP and OUTN are now in phase with each other with no input. The duty cycle of OUTP is greater
than 50% and OUTN is less than 50% for positive output voltages. The duty cycle of OUTP is less than 50%
and OUTN is greater than 50% for negative output voltages. The voltage across the load sits at 0 V throughout
most of the switching period, greatly reducing the switching current, which reduces any I2R losses in the load.
19
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
OUTP
OUTN
Differential
Voltage
Across
Load
Output = 0 V
+12 V
0V
−12 V
Current
OUTP
OUTN
Differential
Voltage
Output > 0 V
+12 V
0V
Across
Load
−12 V
Current
Figure 32. The TPA3002D2 Output Voltage and Current Waveforms Into an Inductive Load
Efficiency: LC Filter Required With the Traditional Class-D Modulation Scheme
The main reason that the traditional class-D amplifier needs an output filter is that the switching waveform
results in maximum current flow. This causes more loss in the load, which causes lower efficiency. The ripple
current is large for the traditional modulation scheme, because the ripple current is proportional to voltage
multiplied by the time at that voltage. The differential voltage swing is 2 × VCC, and the time at each voltage
is half the period for the traditional modulation scheme. An ideal LC filter is needed to store the ripple current
from each half cycle for the next half cycle, while any resistance causes power dissipation. The speaker is both
resistive and reactive, whereas an LC filter is almost purely reactive.
The TPA3002D2 modulation scheme has very little loss in the load without a filter because the pulses are very
short and the change in voltage is VCC instead of 2 × VCC. As the output power increases, the pulses widen,
making the ripple current larger. Ripple current could be filtered with an LC filter for increased efficiency, but
for most applications the filter is not needed.
An LC filter with a cutoff frequency less than the class-D switching frequency allows the switching current to
flow through the filter instead of the load. The filter has less resistance than the speaker, which results in less
power dissipation, therefore increasing efficiency.
Effects of Applying a Square Wave Into a Speaker
Audio specialists have advised for years not to apply a square wave to speakers. If the amplitude of the
waveform is high enough and the frequency of the square wave is within the bandwidth of the speaker, the
square wave could cause the voice coil to jump out of the air gap and/or scar the voice coil. A 250-kHz switching
frequency, however, does not significantly move the voice coil, as the cone movement is proportional to 1/f2
for frequencies beyond the audio band.
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Damage may occur if the voice coil cannot handle the additional heat generated from the high-frequency
switching current. The amount of power dissipated in the speaker may be estimated by first considering the
overall efficiency of the system. If the on-resistance (rds(on)) of the output transistors is considered to cause the
dominant loss in the system, then the maximum theoretical efficiency for the TPA3002D2 with an 8-Ω load is
as follows:
ǒ
Efficiency (theoretical, %) + R ń R ) r
L
ds(on)
L
Ǔ
100% + 8ń(8 ) 0.58)
100% + 93.24%
(1)
The maximum measured output power is approximately 7.5 W with an 12-V power supply. The total theoretical
power supplied (P(total)) for this worst-case condition would therefore be as follows:
P
(total)
+ P ńEfficiency + 7.5 W ń 0.9324 + 8.04 W
O
(2)
The efficiency measured in the lab using an 8-Ω speaker was 89%. The power not accounted for as dissipated
across the rds(on) may be calculated by simply subtracting the theoretical power from the measured power:
Other losses + P
(total)
(measured) * P
(total)
(theoretical) + 8.43 * 8.04 + 0.387 W
(3)
The quiescent supply current at 14 V is measured to be 14.3 mA. It can be assumed that the quiescent current
encapsulates all remaining losses in the device, i.e., biasing and switching losses. It may be assumed that any
remaining power is dissipated in the speaker and is calculated as follows:
P
(dis)
+ 0.387 W * (14 V
14.3 mA) + 0.19 W
(4)
Note that these calculations are for the worst-case condition of 7.5 W delivered to the speaker. Since the 0.19 W
is only 2.5% of the power delivered to the speaker, it may be concluded that the amount of power actually
dissipated in the speaker is relatively insignificant. Furthermore, this power dissipated is well within the
specifications of most loudspeaker drivers in a system, as the power rating is typically selected to handle the
power generated from a clipping waveform.
When to Use an Output Filter
Design the TPA3002D2 without the filter if the traces from amplifier to speaker are short (< 1 inch). Powered
speakers, where the speaker is in the same enclosure as the amplifier, is a typical application for class-D without
a filter.
Most applications require a ferrite bead filter. The ferrite filter reduces EMI around 1 MHz and higher (FCC and
CE only test radiated emissions greater than 30 MHz). When selecting a ferrite bead, choose one with high
impedance at high frequencies, but very low impedance at low frequencies.
Use a LC output filter if there are low frequency (<1 MHz) EMI sensitive circuits and/or there are long wires from
the amplifier to the speaker.
33 µH
OUTP
L1
33 µH
OUTN
L2
C1
C2
0.1 µF
0.47 µF
C3
0.1 µF
Figure 33. Typical LC Output Filter, Cutoff Frequency of 27 kHz, Speaker Impedance = 8 Ω
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Ferrite
Chip Bead
OUTP
1 nF
Ferrite
Chip Bead
OUTN
1 nF
Figure 34. Typical Ferrite Chip Bead Filter (Chip bead example: Fair-Rite 2512067007Y3)
VOLUME CONTROL OPERATION
Three pins labeled VOLUME, VARDIFF, and VARMAX control the class-D volume when driving speakers and
the VAROUT volume. All of these pins are controlled with a dc voltage, which should not exceed VREF.
When driving speakers in class-D mode, the VOLUME pin is the only pin that controls the gain. Table 1 lists
the gain in class-D mode as determined by the voltage on the VOLUME pin in reference to the voltage on VREF.
If using a resistor divider to fix the gain of the amplifier, the VREF terminal can be directly connected to
AVDDREF and a resistor divider can be connected across VREF and REFGND. (See Figure 29 in the
Applications Section). For fixed gain, calculate the resistor divider values necessary to center the voltage
between the two percentage points given in the first column of Table 1. For example, if a gain of 10.7 dB is
desired, the resistors in the divider network can both be 10 kΩ. With these resistor values, a voltage of 50%
× VREF will be present at the VOLUME pin and result in a class-D gain of 10.7 dB.
If using a DAC to control the class-D gain, VREF and REFGND should be connected to the reference voltage
for the DAC and the GND terminal of the DAC, respectively. For the DAC application, AVDDREF would be left
unconnected. The reference voltage of the DAC provides the reference to the internal gain circuitry through the
VREF input and any fluctuations in the DAC output voltage will not affect the TPA3002D2 gain. The percentages
in the first column of Table 1 should be used for setting the voltages of the DAC when the voltage on the
VOLUME terminal is increased. The percentages in the second column should be used for the DAC voltages
when decreasing the voltage on the VOLUME terminal. Two lookup tables should be used in software to control
the gain based on an increase or decrease in the desired system volume. This is explained further in a section
below.
If using an analog potentiometer to control the gain, it should be connected between VREF and REFGND.
VREF can be connected to AVDDREF or an external voltage source, if desired. The first and second column
in Table 1 should be used to determine the point at which the gain changes depending on the direction that the
potentiometer is turned. If the voltage on the center tap of the potentiometer is increasing, the first column in
Table 1 should be referenced to determine the trip points. If the voltage is decreasing, the trip points in the
second column should be referenced.
The trip point, where the gain actually changes, is different depending on whether the voltage on the VOLUME
terminal is increasing or decreasing as a result of hysteresis about each trip point. The hysteresis ensures that
the gain control is monotonic and does not oscillate from one gain step to another. A pictorial representation
of the volume control can be found in Figure 36. The graph focuses on three gain steps with the trip points
defined in the first and second columns of Table 1 for class-D gain. The dotted lines represent the hysteresis
about each gain step.
VARDIFF AND VARMAX OPERATION
The TPA3002D2 allows the user to specify a difference between the class-D gain and VAROUT gain. This is
desirable to avoid any listening discomfort when plugging in headphones. When interfacing with the variable
outputs, the VARDIFF and VARMAX pins control the VAROUT channel gain proportional to the gain set by the
voltage on the VOLUME pin. When VARDIFF = 0 V, the difference between the class-D gain and the VAROUT
gain is 16 dB. As the voltage on the VARDIFF terminal is increased, the VAROUT channel gain decreases.
Internal to the TPA3002D2 device, the voltage on the VARDIFF terminal is subtracted from the voltage on the
VOLUME terminal and this value is used to determine the VAROUT gain.
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Some audio systems require that the gain be limited in the VAROUT mode to a level that is comfortable for
headphone listening. The VARMAX terminal controls the maximum gain for the VAROUT channels.
The functionality of the VARDIFF and VARMAX pin are combined to fix the VAROUT channel gain. A block
diagram of the combined functionality is shown in Figure 35. The value obtained from the block diagram for
VAROUT_VOLUME is a DC voltage that can be used in conjunction with Table 2 to determine the VAROUT
channel gain. Table 2 lists the gain in VAROUT mode as determined by the VAROUT_VOLUME voltage in
reference to the voltage on VREF.
The timing of the volume control circuitry is controlled by an internal 30 Hz clock. This clock determines the rate
at which the gain changes when adjusting the voltage on the external volume control pins. The gain updates
every 4 clock cycles (nominally 133 ms based on a 30Hz clock) to the next step until the final desired gain is
reached. For example, if the TPA3002D2 is currently in the +0.53 db class-D gain step and the VOLUME pin
is adjusted for maximum gain at +36 dB, the time required for the gain to reach 36dB is 14 steps x 133 ms/step
= 1.862 seconds. Referencing Table 1, there are 14 steps between the +0.53 dB gain step and the maximum
gain step of +36 dB.
VARDIFF (V)
VARMAX (V)
−
VOLUME (V)
VOLUME−VARDIFF
Is VARMAX>
YES
(VOLUME−VARDIFF)
VAROUT_VOLUME (V) = VOLUME (V) − VARDIFF (V)
?
NO
VAROUT_VOLUME (V) = VARMAX (V)
Figure 35. Block Diagram of VAROUT Volume Control
Decreasing Voltage on VOLUME Terminal
5.6
Class-D Gain − dB
+
3.1
Increasing Voltage on VOLUME Terminal
0.5
2.00
(40.1%*VREF)
2.21
2.10 2.11
(44.1%*VREF)
(41.9%*VREF) (42.3%*VREF)
Voltage on VOLUME Pin − V
Figure 36. DC Volume Control Operation, VREF = 5 V
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MODE OPERATION
The MODE pin is an input for controlling the output mode of the TPA3002D2. A logic HIGH on this pin disables
the Class-D outputs. A logic LOW on this pin enables the class-D outputs. The VAROUT outputs are active in
both modes and can be used as line level inputs to an external powered subwoofer while driving internal stereo
speakers with the class-D outputs. The trip levels are defined in the specifications table.
For interfacing with an external headphone amplifier like the TPA6110A2, the MODE pin can be connected to
the switch on a headphone jack. When configured like Figure 30, the class-D outputs will be disabled when a
headphone plug is inserted into the headphone jack.
MODE_OUT OPERATION
for controlling the SHUTDOWN pin on an external headphone amplifier like the TPA6110A2 or for interfacing
with other logic. The output voltages for a given load condition are given in the specifications table.
This output is controlled by the MODE pin logic. When the MODE input is driven to a logic low, the MODE_OUT
output drives to a logic high. Conversely, when the MODE pin is driven to a logic high, the MODE_OUT output
drives LOW. The MODE_OUT output is simply the inverted state of the MODE input.
It is designed in this manner because the TPA6110A2 SHUTDOWN input is active high. This allows the
TPA3002D2 to place the TPA6110A2 into the shutdown state when driving internal speakers in the Class-D
mode. Conversely, the MODE_OUT pin drives low to enable the TPA6110A2 headphone amplifier when
headphones are plugged into the headphone jack and the MODE input is driven high.
SELECTION OF COSC AND ROSC
The switching frequency is determined using the values of the components connected to ROSC (pin 27) and
COSC (pin 28) and may be calculated with the following equation:
fOSC = 6.6 / (ROSC * COSC)
INTERNAL 2.5-V BIAS GENERATOR CAPACITOR SELECTION
The internal 2.5-V bias generator (V2P5) provides the internal bias for the preamplifier stages on both the
class-D amplifiers and the variable amplifiers. The external input capacitors and this internal reference allow
the inputs to be biased within the optimal common-mode range of the input preamplifiers.
The selection of the capacitor value on the V2P5 terminal is critical for achieving the best device performance.
During startup or recovery from the shutdown state, the V2P5 capacitor determines the rate at which the
amplifier starts up. When the voltage on the V2P5 capacitor equals 0.75xV2P5, or 75% of its final value, the
device turns on and the class-D outputs start switching. The startup time is not critical for the best depop
performance since any pop sound that is heard is the result of the class-D outputs switching on and not the
startup time. However, at least a 0.47-µF capacitor is recommended for the V2P5 capacitor.
A secondary function of the V2P5 capacitor is to filter high frequency noise on the internal 2.5-V bias generator.
INPUT RESISTANCE
Each gain setting is achieved by varying the input resistance of the amplifier, which can range from its smallest
value to over six times that value. As a result, if a single capacitor is used in the input high-pass filter, the −3 dB
or cutoff frequency also changes by over six times.
Zf
Ci
Input
Signal
IN
Zi
The −3-dB frequency can be calculated using equation 5. Input impedance (Zi) vs Gain can be found in
Figure 7.
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
f *3dB +
1
2p Z iC i
(5)
INPUT CAPACITOR, CI
In the typical application an input capacitor (Ci) is required to allow the amplifier to bias the input signal to the
proper dc level (V2P5)for optimum operation. In this case, Ci and the input impedance of the amplifier (Zi) form
a high-pass filter with the corner frequency determined in equation 6.
−3 dB
(6)
1
fc +
2 p Zi C i
fc
The value of Ci is important, as it directly affects the bass (low frequency) performance of the circuit. Consider
the example where Zi is 20 kΩ and the specification calls for a flat bass response down to 20 Hz. Equation 6
is reconfigured as equation 7.
Ci +
1
2p Z i f c
(7)
In this example, Ci is 0.4 µF, so one would likely choose a value in the range of 0.47 µF to 1 µF. If the gain is
known and will be constant, use Zi from Figure 7 (Input Impedance vs Gain) to calculate Ci. Calculations for
Ci should be based off the impedance at the lowest gain step intended for use in the system. A further
consideration for this capacitor is the leakage path from the input source through the input network (Ci) and the
feedback network to the load. This leakage current creates a dc offset voltage at the input to the amplifier that
reduces useful headroom, especially in high gain applications. For this reason a low-leakage tantalum or
ceramic capacitor is the best choice. When polarized capacitors are used, the positive side of the capacitor
should face the amplifier input in most applications as the dc level there is held at 2.5 V, which is likely higher
than the source dc level. Note that it is important to confirm the capacitor polarity in the application.
Power Supply Decoupling, CS
The TPA3002D2 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling
to ensure the output total harmonic distortion (THD) is as low as possible. Power supply decoupling also
prevents oscillations for long lead lengths between the amplifier and the speaker. The optimum decoupling is
achieved by using two capacitors of different types that target different types of noise on the power supply leads.
For higher frequency transients, spikes, or digital hash on the line, a good low equivalent-series-resistance
(ESR) ceramic capacitor, typically 0.1 µF placed as close as possible to the device VCC lead works best. For
filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 µF or greater placed near
the audio power amplifier is recommended. The 10-µF capacitor also serves as local storage capacitor for
supplying current during large signal transients on the amplifier outputs.
BSN and BSP Capacitors
The full H-bridge output stages use only NMOS transistors. They therefore require bootstrap capacitors for the
high side of each output to turn on correctly. A 10-nF ceramic capacitor, rated for at least 25 V, must be
connected from each output to its corresponding bootstrap input. Specifically, one 10-nF capacitor must be
connected from xOUTP to xBSP, and one 10-nF capacitor must be connected from xOUTN to xBSN. (See the
application circuit diagram in Figure 29.)
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The bootstrap capacitors connected between the BSxx pins and corresponding output function as a floating
power supply for the high-side N-channel power MOSFET gate drive circuitry. During each high-side switching
cycle, the bootstrap capacitors attempt to hold the gate-to-source voltage high enough to keep the high-side
MOSFETs turned on. However, there is a leakage path and the voltage on the bootstrap capacitors slowly
decrease while the high-side is conducting.
By driving the outputs into heavy clipping with a sine wave of less than 50 Hz, the bootstrap voltage can
decrease below the minimum Vgs required to keep the high-side output MOSFET turned on. When this occurs,
the output transistor becomes a source-follower and the output drops from VCC to approximately Vclamp (voltage
on pins 25 and 36).
For the majority of applications, driving a square wave at low frequencies is not a design consideration and the
recommended bootstrap capacitor value of 10 nF is acceptable. However, if this is a concern, increasing the
bootstrap capacitors holds the gate voltage for a longer period of time and the drop in the output voltage does
not occur. A value of 220 nF is recommended with a 51 Ω resistor placed in series between the outputs and
bootstrap pins. The 51 Ω series resistor is necessary to limit the current charging and discharging the bootstrap
capacitors.
VCLAMP Capacitors
To ensure that the maximum gate-to-source voltage for the NMOS output transistors is not exceeded, two
internal regulators clamp the gate voltage. Two 1-µF capacitors must be connected from VCLAMPL (pin 25)
and VCLAMPR (pin 36) to ground and must be rated for at least 25 V. The voltages at the VCLAMP terminals
vary with VCC and may not be used for powering any other circuitry.
Internal Regulated 5-V Supply (AVDD)
The AVDD terminal (pin 29) is the output of an internally-generated 5-V supply, used for the oscillator,
preamplifier, and volume control circuitry. It requires a 0.1-µF to 1-µF capacitor, placed very close to the pin,
to ground to keep the regulator stable. The regulator may be used to power an external headphone amplifier
or other circuitry, up to a current limit specified in the specification table. When powering external circuitry, like
the TPA6110A2 headphone amplifier, an additional 10 µF or larger capacitor should be added to the AVDD
terminal.
AVDD − POWER-UP RESPONSE
Power−Up
Ch1
(AVDD)
AVDD
(pin 29)
Ch2
(AVCC)
AVCC
(pin 33)
Ch1 2 V/div
Ch2 5 V/div
M 10.0 µs
Figure 37. Power-Up Response
Differential Input
The differential input stage of the amplifier cancels any noise that appears on both input lines of the channel.
To use the TPA3002D2 EVM with a differential source, connect the positive lead of the audio source to the INP
input and the negative lead from the audio source to the INN input. To use the TPA3002D2 with a single-ended
source, ac ground the INP input through a capacitor equal in value to the input capacitor on INN and apply the
audio source to the INN input. In a single-ended input application, the INP input should be ac-grounded at the
audio source instead of at the device input for best noise performance.
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SD OPERATION
The TPA3002D2 employs a shutdown mode of operation designed to reduce supply current (ICC) to the
absolute minimum level during periods of nonuse for power conservation. The SD input terminal should be held
high (see specification table for trip point)during normal operation when the amplifier is in use. Pulling SD low
causes the outputs to mute and the amplifier to enter a low-current state, ICC(SD) = 10 µA. SD should never be
left unconnected, because amplifier operation would be unpredictable.
POWER-OFF POP REDUCTION
For the best power-off pop performance, the amplifier should be placed in the shutdown mode prior to removing
the power supply voltage.
Another method to reduce power-off pop can be implemented in the hardware. A 100-µF − 150-µF capacitor
can be added to the AVDD terminal in parallel with the 100-nF capacitor shown in Figure 29. The additional
capacitance holds up the regulator voltage for a longer period of time and results in smaller power-off pop.
USING LOW-ESR CAPACITORS
Low-ESR capacitors are recommended throughout this application section. A real (as opposed to ideal)
capacitor can be modeled simply as a resistor in series with an ideal capacitor. The voltage drop across this
resistor minimizes the beneficial effects of the capacitor in the circuit. The lower the equivalent value of this
resistance the more the real capacitor behaves like an ideal capacitor.
SHORT-CIRCUIT PROTECTION
The TPA3002D2 has short circuit protection circuitry on the outputs that prevents damage to the device during
output-to-output shorts, output-to-GND shorts, and output-to-VCC shorts. When a short-circuit is detected on
the outputs, the part immediately disables the output drive. This is a latched fault and must be reset by cycling
the voltage on the SD pin to a logic low and back to the logic high state for normal operation. This will clear the
short-circuit flag and allow for normal operation if the short was removed. If the short was not removed, the
protection circuitry will again activate.
The trip-point for the short-circuit protection is nominally set at 8 A. However, this trip point can vary with PCB
layout and the separation of AVCC and PVCC. It is important to connect the AVCC pin as close as possible to
all of the PVCC pins with a wide (>20 mils) trace. This minimizes the inductance between the two pins and allows
the short-circuit protection to trip at the nominal current. If the inductance between these two pins is large, the
short-circuit protection may inadvertently trip when drive low impedance loads into heavy clipping.
THERMAL PROTECTION
Thermal protection on the TPA3002D2 prevents damage to the device when the internal die temperature
exceeds 150°C. There is a ±15 degree tolerance on this trip point from device to device. Once the die
temperature exceeds the thermal set point, the device enters into the shutdown state and the outputs are
disabled. This is not a latched fault. The thermal fault is cleared once the temperature of the die is reduced by
20°C. The device begins normal operation at this point with no external system interaction.
THERMAL CONSIDERATIONS: OUTPUT POWER AND MAXIMUM AMBIENT TEMPERATURE
To calculate the maximum ambient temperature, the following equation may be used:
TAmax = TJmax – ΘJAPDissipated
where: TJmax = 150°C
ΘJA = 19°C/W
(2-Layer PCB, 5 sq. in. copper, see Figure 38)
(8)
To estimate the power dissipation, the following equation may be used:
PDissipated = PO(average) x ((1 / Efficiency) – 1)
Efficiency = ~85% for an 8-Ω load
= ~75% for a 4-Ω load
(9)
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Example. What is the maximum ambient temperature for an application that requires the TPA3002D2 to drive
7.5 W into stereo 8-Ω speakers?
PDissipated = 15 W × ((1 / 0.85) – 1) = 2.65 W
(PO = 7.5 W × 2)
TAmax = 150°C – (19°C/W × 2.65 W) =
99.65°C
This calculation shows that the TPA3002D2 can drive 7.5 W into an 8-Ω speaker up to the absolute maximum
ambient temperature rating of 85°C, which must never be exceeded.
Figure 38 and Figure 39 show the results of several thermal experiments conducted with the TPA3002D2. Both
figures show that the best thermal performance can be achieved with more copper area for heat dissipation
and an adequate number of thermal vias.
Figure 38 shows two curves for a 2-layer and 4-layer PCB. The 2-layer PCB layout was tightly controlled with
a fixed amount of 2 oz. copper on the bottom layer of the PCB. The amount of copper is shown on the x-axis.
Nine thermal vias of 13 mil (0,33 mm) diameter were drilled under the PowerPad and connected to the bottom
layer. The top layer only consisted of traces for signal routing.
The 4-layer PCB layout was also tightly controlled with a fixed amount of 2 oz. copper in middle GND layer. The
top layer only consisted of traces for signal routing. The bottom and other middle layer were left blank. Nine
thermal vias of 0,33 mm diameter were drilled under the PowerPAD and connected to the middle layer.
Figure 39 shows the effect of the number of thermal vias drilled under the PowerPAD on the thermal
performance of the PCB. The experiment was conducted with a 2-layer PCB and 3 square inches of copper
on the bottom layer. For the best thermal performance, at least 16 vias in a 4x4 pattern should be used under
the PowerPAD. Refer to the TPA3002D2 EVM User’s Manual (SLOU151), for an example layout with a 4x4
via pattern. PCB gerber files are available at request.
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
PRINTED CIRCUIT BOARD (PCB) LAYOUT
Because the TPA3002D2 is a class-D amplifier that switches at a high frequency, the layout of the printed circuit
board (PCB) should be optimized according to the following guidelines for the best possible performance.
D Decoupling capacitors — As described on page 28, the high-frequency 0.1-µF decoupling capacitors
should be placed as close to the PVCC (pin 14, 15, 22, 23, 38, 39, 46, 47) and AVCC (pin 33) terminals
as possible. The V2P5 (pin 4) capacitor, AVDD (pin 29) capacitor, and VCLAMP (pins 25, 36) capacitor
should also be placed as close to the device as possible. Large (10 µF or greater) bulk power supply
decoupling capacitors should be placed near the TPA3002D2 on the PVCCL, PVCCR, and AVCC
terminals.
D Grounding — The AVCC (pin 33) decoupling capacitor, AVDD (pin 29) capacitor, V2P5 (pin 4) capacitor,
COSC (pin 28) capacitor, and ROSC (pin 27) resistor should each be grounded to analog ground (AGND,
pin 26 and pin 30). The PVCC (pin 9 and pin 16) decoupling capacitors should each be grounded to power
ground (PGND, pins 18, 19, 42, 43). Analog ground and power ground may be connected at the
PowerPAD, which should be used as a central ground connection or star ground for the TPA3002D2.
Basically, an island should be created with a single connection to PGND at the PowerPAD.
D Output filter — The ferrite EMI filter (Figure 34) should be placed as close to the output terminals as
possible for the best EMI performance. The LC filter (Figure 33 should be placed close to the outputs. The
capacitors used in both the ferrite and LC filters should be grounded to power ground.
D PowerPAD — The PowerPAD must be soldered to the PCB for proper thermal performance and optimal
reliability. The dimensions of the PowerPAD thermal land should be 5 mm by 5 mm (197 mils by 197 mils).
The PowerPAD size measures 4,55 x 4,55 mm. Four rows of solid vias (four vias per row, 0,3302 mm or
13 mils diameter) should be equally spaced underneath the thermal land. The vias should connect to a
solid copper plane, either on an internal layer or on the bottom layer of the PCB. The vias must be solid
vias, not thermal relief or webbed vias. For additional information, please refer to the PowerPAD Thermally
Enhanced Package application note (SLMA002).
For an example layout, refer to the TPA3002D2 Evaluation Module (TPA3002D2EVM) User Manual
(SLOU151). Both the EVM user manual and the PowerPAD application note are available on the TI web site
at http://www.ti.com.
THERMAL RESISTANCE
vs
COPPER AREA 2-LAYER PCB
THERMAL RESISTANCE
vs
COPPER AREA 4-LAYER PCB
35
θ JA − Thermal Resistance − °C/W
θ JA − Thermal Resistance − °C/W
35
30
25
20
15
1
1.5
2
2.5
3
3.5
4
Copper Area − sq. Inches
4.5
5
30
25
20
15
1
2
3
4
Copper Area − sq. Inches
5
Figure 38. Thermal Resistance
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
THERMAL RESISTANCE
vs
THERMAL VIA QUANTITY 2-LAYER PCB
θ JA − Thermal Resistance − °C/W
25
24
23
22
21
20
4
6
8
10
12
14
Thermal Via Quantity (13 Mil Diameter)
16
Figure 39. Thermal Resistance
BASIC MEASUREMENT SYSTEM
This application note focuses on methods that use the basic equipment listed below:
D Audio analyzer or spectrum analyzer
D Digital multimeter (DMM)
D Oscilloscope
D Twisted pair wires
D Signal generator
D Power resistor(s)
D Linear regulated power supply
D Filter components
D EVM or other complete audio circuit
Figure 40 shows the block diagrams of basic measurement systems for class-AB and class-D amplifiers. A sine
wave is normally used as the input signal since it consists of the fundamental frequency only (no other
harmonics are present). An analyzer is then connected to the APA output to measure the voltage output. The
analyzer must be capable of measuring the entire audio bandwidth. A regulated dc power supply is used to
reduce the noise and distortion injected into the APA through the power pins. A System Two audio measurement
system (AP-II) (Reference 1) by Audio Precision includes the signal generator and analyzer in one package.
The generator output and amplifier input must be ac-coupled. However, the EVMs already have the ac-coupling
capacitors, (CIN), so no additional coupling is required. The generator output impedance should be low to avoid
attenuating the test signal, and is important since the input resistance of APAs is not very high (about 10 kΩ).
Conversely the analyzer-input impedance should be high. The output impedance, ROUT, of the APA is normally
in the hundreds of milliohms and can be ignored for all but the power-related calculations.
Figure 40(a) shows a class-AB amplifier system. They take an analog signal input and produce an analog signal
output. These amplifier circuits can be directly connected to the AP-II or other analyzer input.
This is not true of the class-D amplifier system shown in Figure 40(b), which requires low pass filters in most
cases in order to measure the audio output waveforms. This is because it takes an analog input signal and
converts it into a pulse-width modulated (PWM) output signal that is not accurately processed by some
analyzers.
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SLOS402C − DECEMBER 2002 − REVISED JANUARY 2004
Power Supply
Signal
Generator
APA
RL
Analyzer
20 Hz − 20 kHz
(a) Basic Class-AB
Power Supply
Low-Pass RC
Filter
Signal
Generator
Class-D APA
RL†
Low-Pass RC
Filter
Analyzer
20 Hz − 20 kHz
† For efficiency measurements with filter-free class-D amplifiers, RL should be an inductive load like a
speaker.
(b) Filter-Free and Traditional Class-D
Figure 40. Audio Measurement Systems
The TPA3002D2 uses a modulation scheme that does not require an output filter for operation, but they do
sometimes require an RC low-pass filter when making measurements. This is because some analyzer inputs
cannot accurately process the rapidly changing square-wave output and therefore record an extremely high
level of distortion. The RC low-pass measurement filter is used to remove the modulated waveforms so the
analyzer can measure the output sine wave.
DIFFERENTIAL INPUT AND BTL OUTPUT
All of the class-D APAs and many class-AB APAs have differential inputs and bridge-tied load (BTL) outputs.
Differential inputs have two input pins per channel and amplify the difference in voltage between the pins.
Differential inputs reduce the common-mode noise and distortion of the input circuit. BTL is a term commonly
used in audio to describe differential outputs. BTL outputs have two output pins providing voltages that are 180
degrees out of phase. The load is connected between these pins. This has the added benefits of quadrupling
the output power to the load and eliminating a dc blocking capacitor.
A block diagram of the measurement circuit is shown in Figure 41. The differential input is a balanced input,
meaning the positive (+) and negative (−) pins will have the same impedance to ground. Similarly, the BTL output
equates to a balanced output.
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Evaluation Module
Audio Power
Amplifier
Generator
Analyzer
Low-Pass
RC Filter
CIN
VGEN
RGEN
RIN
ROUT
RIN
ROUT
CIN
RGEN
RL
Low-Pass
RC Filter
Twisted-Pair Wire
RANA
CANA
RANA
CANA
Twisted-Pair Wire
Figure 41. Differential Input—BTL output Measurement Circuit
The generator should have balanced outputs and the signal should be balanced for best results. An unbalanced
output can be used, but it may create a ground loop that will affect the measurement accuracy. The analyzer
must also have balanced inputs for the system to be fully balanced, thereby cancelling out any common mode
noise in the circuit and providing the most accurate measurement.
The following general rules should be followed when connecting to APAs with differential inputs and BTL
outputs:
D
D
D
D
D
Use a balanced source to supply the input signal.
Use an analyzer with balanced inputs.
Use twisted-pair wire for all connections.
Use shielding when the system environment is noisy.
Ensure the cables from the power supply to the APA, and from the APA to the load, can handle the large
currents (see Table 3).
Table 3 shows the recommended wire size for the power supply and load cables of the APA system. The real
concern is the dc or ac power loss that occurs as the current flows through the cable. These recommendations
are based on 12-inch long wire with a 20-kHz sine-wave signal at 25°C.
Table 3. Recommended Minimum Wire Size for Power Cables
POUT
(W)
RL
(Ω)
AWG SIZE
10
4
2
4
18
1
8
22
< 0.75
8
18
22
22
DC POWER LOSS
(MW)
AC POWER LOSS
(MW)
16
40
18
42
22
3.2
8.0
3.7
8.5
28
2.0
8.0
2.1
8.1
1.5
6.1
1.6
6.2
28
CLASS-D RC LOW-PASS FILTER
An RC filter is used to reduce the square-wave output when the analyzer inputs cannot process the pulse-width
modulated class-D output waveform. This filter has little effect on the measurement accuracy because the cutoff
frequency is set above the audio band. The high frequency of the square wave has negligible impact on
measurement accuracy because it is well above the audible frequency range and the speaker cone cannot
respond at such a fast rate. The RC filter is not required when an LC low-pass filter is used, such as with the
class-D APAs that employ the traditional modulation scheme (TPA032D0x, TPA005Dxx).
The component values of the RC filter are selected using the equivalent output circuit as shown in Figure 42.
RL is the load impedance that the APA is driving for the test. The analyzer input impedance specifications should
be available and substituted for RANA and CANA. The filter components, RFILT and CFILT, can then be derived
for the system. The filter should be grounded to the APA near the output ground pins or at the power supply
ground pin to minimize ground loops.
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Load
RC Low-Pass Filters
RFILT
AP Analyzer Input
CFILT
VL= VIN
RL
CANA
RANA
CANA
RANA
VOUT
RFILT
CFILT
To APA
GND
Figure 42. Measurement Low-Pass Filter Derivation Circuit—Class-D APAs
The transfer function for this circuit is shown in equation (10) where ωO = REQCEQ, REQ = RFILTRANA and
CEQ = (CFILT + CANA). The filter frequency should be set above fMAX, the highest frequency of the measurement
bandwidth, to avoid attenuating the audio signal. Equation (11) provides this cutoff frequency, fC. The value of
RFILT must be chosen large enough to minimize current that is shunted from the load, yet small enough to
minimize the attenuation of the analyzer-input voltage through the voltage divider formed by RFILT and RANA.
A rule of thumb is that RFILT should be small (~100 Ω) for most measurements. This reduces the measurement
error to less than 1% for RANA ≥ 10 kΩ.
ǒ Ǔ
V
OUT
V
IN
f
C
+ Ǹ2
ǒ
R
R
+
f
ANA
)R
ANA
FILT
Ǔ
ǒ Ǔ
1 ) j ww
O
(10)
MAX
(11)
An exception occurs with the efficiency measurements, where RFILT must be increased by a factor of ten to
reduce the current shunted through the filter. CFILT must be decreased by a factor of ten to maintain the same
cutoff frequency. See Table 4 for the recommended filter component values.
Once fC is determined and RFILT is selected, the filter capacitance is calculated using equation (12). When the
calculated value is not available, it is better to choose a smaller capacitance value to keep fC above the minimum
desired value calculated in equation (11).
C
FILT
+
1
2p
f
C
R
FILT
(12)
Table 4 shows recommended values of RFILT and CFILT based on common component values. The value of fC
was originally calculated to be 28 kHz for an fMAX of 20 kHz. CFILT, however, was calculated to be 57000 pF,
but the nearest values of 56000 pF and 51000 pF were not available. A 47000 pF capacitor was used instead,
and fC is 34 kHz, which is above the desired value of 28 kHz.
Table 4. Typical RC Measurement Filter Values
MEASUREMENT
Efficiency
All other measurements
RFILT
CFILT
1 000 Ω
5 600 pF
100 Ω
56 000 pF
33
PACKAGE OPTION ADDENDUM
www.ti.com
18-Apr-2006
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
TPA3002D2PHP
ACTIVE
HTQFP
PHP
48
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-4-260C-72 HR
TPA3002D2PHPG4
ACTIVE
HTQFP
PHP
48
250
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-4-260C-72 HR
TPA3002D2PHPR
ACTIVE
HTQFP
PHP
48
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-4-260C-72 HR
TPA3002D2PHPRG4
ACTIVE
HTQFP
PHP
48
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-3-260C-168 HR
Lead/Ball Finish
MSL Peak Temp (3)
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in
a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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