TI TPA112D

TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
D
D
D
D
D
D OR DGN PACKAGE
(TOP VIEW)
150-mW Stereo Output
Wide Range of Supply Voltages
– Fully Specified for 3.3 V and 5 V
Operation
– Operational From 2.5 V to 5.5 V
Thermal and Short-Circuit Protection
Surface Mount Packaging
– PowerPAD MSOP
– SOIC
Standard Operational Amplifier Pinout
VO 1
IN1–
IN1+
GND
1
8
2
7
3
6
4
5
VDD
VO 2
IN2–
IN2+
description
The TPA112 is a stereo audio power amplifier packaged in an 8-pin PowerPAD MSOP package capable of
delivering 150 mW of continuous RMS power per channel into 8-Ω loads. Amplifier gain is externally configured
by means of two resistors per input channel and does not require external compensation for settings of 1 to 10.
THD+N when driving an 8-Ω load from 5 V is 0.1% at 1 kHz, and less than 2% across the audio band of 20 Hz
to 20 kHz. For 32-Ω loads, the THD+N is reduced to less than 0.06% at 1 kHz, and is less than 1% across the
audio band of 20 Hz to 20 kHz. For 10-kΩ loads, the THD+N performance is 0.01% at 1 kHz, and less than 0.02%
across the audio band of 20 Hz to 20 kHz.
functional block diagram
RF
VDD
8
VO1
1
Short-Circuit
Protection
CI
VDD
RI
LIN–
CI
RI
LIN+
2
IN1–
3
IN1+
CC
RC
RO
RF
To Headphone
Jack
(See TPA152)
VDD/2
CI
RIN–
CI
RI
RF
6
IN2–
5
IN2+
VO2
CC
7
RO
RI
RC
RIN+
Over-Temperature
Protection
4
RF
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  2000, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
1
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
AVAILABLE OPTIONS
PACKAGED DEVICES
TA
SMALL OUTLINE†
(D)
MSOP
Symbolization
MSOP†
(DGN)
– 40°C to 85°C
TPA112D
TPA112DGN
TI AAD
† The D and DGN package is available in left-ended tape and reel only (e.g., TPA112DR,
TPA112DGNR).
Terminal Functions
TERMINAL
NAME
I/O
NO.
DESCRIPTION
GND
4
I
GND is the ground connection.
IN1–
2
I
IN1– is the inverting input for channel 1.
IN1+
3
I
IN1+ is the noninverting input for channel 1.
IN2–
6
I
IN2– is the inverting input for channel 2.
IN2+
5
I
IN2+ is the noninverting input for channel 2.
VDD
VO1
8
I
1
O
VDD is the supply voltage terminal.
VO1 is the audio output for channel 1.
VO2
7
O
VO2 is the audio output for channel 2.
absolute maximum ratings over operating free-air temperature (unless otherwise noted)†
Supply voltage, VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V
Differential input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
Input current, II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±2.5 µA
Output current, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±250 mA
Continuous total power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . internally limited
Operating junction temperature range, TJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –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
† 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.
DISSIPATION RATING TABLE
PACKAGE
TA ≤ 25°C
POWER RATING
DERATING FACTOR
ABOVE TA = 25°C
TA = 70°C
POWER RATING
TA = 85°C
POWER RATING
377 mW
D
725 mW
5.8 mW/°C
464 mW
DGN
2.14 W‡
17.1 mW/°C
1.37 W
1.11 W
‡ Please see the Texas Instruments document, PowerPAD Thermally Enhanced Package Application Report
(literature number SLMA002), for more information on the PowerPAD package. The thermal data was
measured on a PCB layout based on the information in the section entitled Texas Instruments Recommended
Board for PowerPAD on page 33 of the before mentioned document.
recommended operating conditions
MIN
MAX
Supply voltage, VDD
2.5
5.5
V
Operating free-air temperature, TA
–40
85
°C
2
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
UNIT
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
dc electrical characteristics at TA = 25°C, VDD = 3.3 V
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
5
UNIT
VIO
PSRR
Input offset voltage
IDD(q)
IDD(SD)
Supply current
1.5
3
mA
Supply current in SHUTDOWN mode
10
50
µA
ZI
Input impedance
>1
Power supply rejection ratio
VDD = 3.2 V to 3.4 V
83
mV
dB
MΩ
ac operating characteristics, VDD = 3.3 V, TA = 25°C, RL = 8 Ω
PARAMETER
TEST CONDITIONS
PO
THD+N
Output power (each channel)
THD ≤ 0.1%
Total harmonic distortion + noise
BOM
Maximum output power BW
PO = 70 mW,
G = 10,
Phase margin
Open loop
Supply ripple rejection
f = 1 kHz
Channel/channel output separation
f = 1 kHz
Signal-to-noise ratio
PO = 100 mW
SVRR
SNR
MIN
TYP
70†
20–20 kHz
2%
THD <5%
>20
MAX
UNIT
mW
kHz
58°
Vn
Noise output voltage
† Measured at 1 kHz
68
dB
86
dB
100
dB
9.5
µV(rms)
dc electrical characteristics at TA = 25°C, VDD = 5 V
PARAMETER
VIO
PSRR
Input offset voltage
IDD(q)
IDD(SD)
Supply current
ZI
TEST CONDITIONS
MIN
TYP
MAX
UNIT
5
mV
1.5
3
mA
Supply current in SHUTDOWN mode
60
100
µA
Input impedance
>1
Power supply rejection ratio
VDD = 4.9 V to 5.1 V
76
dB
MΩ
ac operating characteristics, VDD = 5 V, TA = 25°C, RL = 8 Ω
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
PO
THD+N
Output power (each channel)
THD ≤ 0.1%
70†
Total harmonic distortion + noise
2%
BOM
Maximum output power BW
PO = 150 mW, 20–20 kHz
G = 10,
THD <5%
>20
Phase margin
Open loop
56°
Supply ripple rejection
f = 1 kHz
68
dB
Channel/channel output separation
f = 1 kHz
86
dB
Signal-to-noise ratio
PO = 150 mW
100
dB
9.5
µV(rms)
SVRR
SNR
Vn
Noise output voltage
† Measured at 1 kHz
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
mW
kHz
3
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
ac operating characteristics, VDD = 3.3 V, TA = 25°C, RL = 32 Ω
PARAMETER
TEST CONDITIONS
PO
THD+N
Output power (each channel)
THD ≤ 0.1%
Total harmonic distortion + noise
BOM
Maximum output power BW
PO = 30 mW,
G = 10,
Phase margin
Open loop
Supply ripple rejection
f = 1 kHz
Channel/channel output separation
f = 1 kHz
Signal-to-noise ratio
PO = 100 mW
SVRR
SNR
MIN
TYP
40†
20–20 kHz
0.5%
THD <2%
>20
MAX
UNIT
mW
kHz
58°
Vn
Noise output voltage
† Measured at 1 kHz
68
dB
86
dB
100
dB
9.5
µV(rms)
ac operating characteristics, VDD = 5 V, TA = 25°C, RL = 32 Ω
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
PO
THD+N
Output power (each channel)
THD ≤ 0.1%
Total harmonic distortion + noise
BOM
Maximum output power BW
PO = 60 mW,
G = 10,
Phase margin
Open loop
Supply ripple rejection
f = 1 kHz
68
dB
Channel/channel output separation
f = 1 kHz
86
dB
Signal-to-noise ratio
PO = 150 mW
SVRR
SNR
40†
20–20 kHz
0.4%
THD <2%
>20
Vn
Noise output voltage
† Measured at 1 kHz
4
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
mW
kHz
56°
100
dB
9.5
µV(rms)
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
Table of Graphs
FIGURE
THD+N
Total harmonic distortion plus noise
vs Frequency
vs Power output
1, 2, 4, 5, 7, 8,
10, 11, 13, 14,
16, 17, 34, 36
3, 6, 9,
12, 15, 18
PSSR
Power supply rejection ratio
vs Frequency
19, 20
Vn
Output noise voltage
vs Frequency
21, 22
Crosstalk
vs Frequency
23 – 26,
37, 38
Mute attenuation
vs Frequency
27, 28
Open-loop gain
vs Frequency
29, 30
Phase margin
vs Frequency
29, 30
Phase
vs Frequency
39 – 44
Output power
vs Load resistance
31, 32
ICC
Supply current
vs Supply voltage
33
SNR
Signal-to-noise ratio
vs Voltage gain
Closed-loop gain
vs Frequency
39 – 44
Power dissipation/amplifier
vs Output power
45, 46
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
35
5
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
10
VDD = 3.3 V
PO = 30 mW
CB = 1 µ F
RL = 32 Ω
1
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10
AV = 5
AV = 10
0.1
AV = 1
0.01
0.001
20
100
1k
1
VDD = 3.3 V
AV = 1 V/V
RL = 32 Ω
CB = 1 µ F
PO = 15 mW
0.1
PO = 10 mW
0.01
PO = 30 mW
0.001
20
10k 20k
100
f – Frequency – Hz
Figure 2
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
10
10
VDD = 3.3 V
RL = 32 Ω
AV = 1 V/V
CB = 1 µF
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10k 20k
f – Frequency – Hz
Figure 1
20 kHz
10 kHz
1
0.1
1 kHz
20 Hz
0.01
1
10
50
1
VDD = 5 V
PO = 60 mW
RL = 32 Ω
CB = 1 µF
AV = 10 mW
0.1
AV = 5 mW
0.01
AV = 1 mW
0.001
20
PO – Output Power – mW
100
1k
f – Frequency – Hz
Figure 3
6
1k
Figure 4
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
10k 20k
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
10
1
0.1
VDD = 5 V
RL = 32 Ω
AV = 1 V/V
CB = 1 µF
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10
PO = 30 mW
PO = 15 mW
0.01
PO = 60 mW
0.001
20
100
1k
VDD = 5 V
AV = 1 V/V
RL = 32 Ω
CB = 1 µF
20 kHz
1
10 kHz
0.1
1 kHz
20 Hz
0.01
0.002
10k 20k
0.01
Figure 5
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
10
VDD = 3.3 V
RL = 10 kΩ
PO = 100 µF
CB = 1 µF
AV = 5 mW
0.01
AV = 2 mW
0.001
20
100
1k
10k 20k
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10
0.1
0.2
Figure 6
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
1
0.1
PO – Output Power – W
f – Frequency – Hz
1
VDD = 3.3 V
RL = 10 kΩ
AV = 1 V/V
CB = 1 µF
0.1
PO = 45 µW
0.01
PO = 90 µW
PO = 130 µW
0.001
20
f – Frequency – Hz
100
1k
10k 20k
f – Frequency – Hz
Figure 7
Figure 8
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
7
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
10
VDD = 3.3 V
RL = 10 k Ω
AV = 1 V/V
CB = 1 µF
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10
1
0.1
20 Hz
10 kHz
0.01
20 Hz
1 kHz
0.001
5
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
10
100
1
VDD = 5 V
RL = 10 kΩ
PO = 300 µW
CB = 1 µF
0.1
AV = 5
AV = 1
0.01
AV = 2
0.001
20
200
PO – Output Power – µW
100
Figure 10
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
10
VDD = 5 V
RL = 10 kΩ
AV = 1 V/V
CB = 1 µF
PO = 300 µW
0.1
PO = 200 µW
0.01
PO = 100 µW
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10
0.001
20
VDD = 5 V
RL = 10 kΩ
AV = 1 V/V
CB = 1 µ F
1
0.1
20 Hz
20 kHz
0.01
10 kHz 1 kHz
0.001
100
1k
10k 20k
5
10
100
PO – Output Power – µW
f – Frequency – Hz
Figure 11
8
10k 20k
f – Frequency – Hz
Figure 9
1
1k
Figure 12
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
500
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
2
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
10
VDD = 3.3 V
PO = 75 mW
RL = 8 Ω
CB = 1 µF
1
AV = 5
AV = 2
0.1
AV = 1
0.01
0.001
100
20
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
THD+N –Total Harmonic Distortion + Noise – %
THD+N – Total Harmonic Distortion Plus Noise – %
TYPICAL CHARACTERISTICS
1k
VDD = 3.3 V
RL = 8 Ω
AV = 1 V/V
PO = 30 mW
1
PO = 15 mW
0.1
0.01
PO = 75 mW
0.001
20
10k 20k
f – Frequency – Hz
100
1k
10k 20k
f – Frequency – Hz
Figure 13
Figure 14
THD+N – Total Harmonic Distortion Plus Noise – %
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
OUTPUT POWER
THD+N –Total Harmonic Distortion + Noise – %
10
VDD = 3.3 V
RL = 8 Ω
AV = 1 V/V
20 kHz
10 kHz
1
1 kHz
0.1
20 Hz
0.01
10m
0.1
0.3
2
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
VDD = 5 V
PO = 100 mW
RL = 8 Ω
CB = 1 µF
1
AV = 2
AV = 5
0.1
AV = 1
0.01
0.001
20
100
1k
10k 20k
f – Frequency – Hz
PO – Output Power – W
Figure 15
Figure 16
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
9
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
POWER OUTPUT
10
THD+N –Total Harmonic Distortion + Noise – %
THD+N –Total Harmonic Distortion + Noise – %
10
VDD = 5 V
RL = 8 kΩ
AV = 1 V/V
PO = 30 mW
1
0.1
PO = 60 mW
0.01
PO = 10 mW
0.001
20
100
1k
VDD = 5 V
RL = 8 Ω
AV = 1 V/V
20 kHz
1
10 kHz
20 Hz
0.01
10m
10k 20k
0.1
f – Frequency – Hz
Figure 18
POWER SUPPLY REJECTION RATIO
vs
FREQUENCY
POWER SUPPLY REJECTION RATIO
vs
FREQUENCY
VDD = 3.3 V
RL = 8 Ω to 10 kΩ
CB = 0.1 µF
–30
CB = 1 µF
–40
–50
–60
CB = 2 µF
–70
Bypass = 1.65 V
–80
–90
–100
20
100
1k
10k 20k
0
PSRR – Power Supply Rejection Ratio – dB
PSRR – Power Supply Rejection Ratio – dB
0
–20
VDD = 5 V
RL = 8 Ω to 10 kΩ
–10
–20
CB = 0.1 µF
–30
CB = 1 µF
–40
–50
–60
CB = 2 µF
–70
–80
–90
–100
20
f – Frequency – Hz
Bypass = 2.5 V
100
1k
f – Frequency – Hz
Figure 19
10
1
PO – Output Power – W
Figure 17
–10
1 kHz
0.1
Figure 20
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
10k 20k
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
OUTPUT NOISE VOLTAGE
vs
FREQUENCY
OUTPUT NOISE VOLTAGE
vs
FREQUENCY
20
10
Vn – Output Noise Voltage – µV
Vn – Output Noise Voltage – µV
20
VDD = 3.3 V
BW = 10 Hz to 22 kHz
AV = 1 V/V
RL = 8 Ω to 10 kΩ
1
20
100
1k
10
VDD = 5 V
BW = 10 Hz to 22 kHz
RL = 8 Ω to 10 kΩ
AV = 1 V/V
1
20
10k 20k
100
f – Frequency – Hz
Figure 22
CROSSTALK
vs
FREQUENCY
CROSSTALK
vs
FREQUENCY
–60
Crosstalk – dB
–75
–50
PO = 25 mW
VDD = 3.3 V
RL = 32 Ω
CB = 1 µF
AV = 1 V/V
–60
–65
–80
IN 2 TO OUT 1
–85
–90
–95
–70
–75
IN 2 TO OUT 1
–80
–85
–100
IN 1 TO OUT 2
–105
–110
20
PO = 100 mW
VDD = 3.3 V
RL = 8 Ω
CB = 1 µF
AV = 1 V/V
–55
Crosstalk – dB
–70
10k 20k
f – Frequency – Hz
Figure 21
–65
1k
IN 1 TO OUT 2
–90
–95
100
1k
10k 20k
–100
20
f – Frequency – Hz
100
1k
10k 20k
f – Frequency – Hz
Figure 23
Figure 24
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
11
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
CROSSTALK
vs
FREQUENCY
CROSSTALK
vs
FREQUENCY
–60
–50
VDD = 5 V
PO = 25 mW
CB = 1 µF
RL = 32 Ω
AV = 1 V/V
–65
–65
–60
–65
Crosstalk – dB
Crosstalk – dB
–75
–55
–80
–85
IN 2 TO OUT 1
–90
–95
VDD = 5 V
PO = 100 mW
CB = 1 µF
RL = 8 Ω
AV = 1 V/V
–70
IN 2 TO OUT 1
–75
–80
–85
–100
–90
IN 1 TO OUT 2
IN 1 TO OUT 2
–105
–95
–110
20
100
1k
–100
20
10k 20k
100
f – Frequency – Hz
Figure 25
MUTE ATTENUATION
vs
FREQUENCY
0
–10
–20
–30
–40
–50
–60
–70
–40
–50
–60
–70
–80
–90
–90
100
1k
10k 20k
VDD = 5 V
CB = 1 µF
RL = 32 Ω
–30
–80
–100
20
12
0
VDD = 3.3 V
RL = 32 Ω
CB = 1 µF
Mute Attenuation – dB
Mute Attenuation – dB
–20
10k 20k
Figure 26
MUTE ATTENUATION
vs
FREQUENCY
–10
1k
f – Frequency – Hz
–100
20
100
1k
f – Frequency – Hz
f – Frequency – Hz
Figure 27
Figure 28
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
10k 20k
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
OPEN–LOOP GAIN AND PHASE MARGIN
vs
FREQUENCY
150°
100
VDD = 3.3 V
TA = 25°C
No Load
120°
Phase
60
φ m – Phase Margin
Open-Loop Gain – dB
80
90°
40
60°
Gain
20
30°
0
0°
–20
100
1k
10k
100k
1M
–30°
10M
f – Frequency – Hz
Figure 29
OPEN–LOOP GAIN AND PHASE MARGIN
vs
FREQUENCY
100
150°
Open-Loop Gain – dB
80
Phase
60
40
120°
90°
60°
Gain
20
30°
0
0°
–20
100
1k
10k
100k
1M
φ m – Phase Margin
VDD = 5 V
TA = 25°C
No Load
–30°
10M
f – Frequency – Hz
Figure 30
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
13
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
OUTPUT POWER
vs
LOAD RESISTANCE
OUTPUT POWER
vs
LOAD RESISTANCE
120
300
THD+N = 1 %
VDD = 3.3 V
AV = 1 V/V
250
PO – Output Power – mW
PO – Output Power – mW
100
THD+N = 1 %
VDD = 5 V
AV = 1 V/V
80
60
40
20
200
150
100
50
0
8
24
16
40
32
48
56
0
64
8
16
RL – Load Resistance – Ω
24
THD+N – Total Harmonic Distortion Plus Noise – %
1.4
I DD – Supply Current – mA
1.2
1
0.8
0.6
0.4
0.2
3
3.5
4
56
64
4.5
5
5.5
1
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
VI = 1 V
AV = 1 V/V
RL = 10 kΩ
CB = 1 µF
0.1
0.01
0.001
20
100
1k
f – Frequency – Hz
VDD – Supply Voltage – V
Figure 33
14
48
Figure 32
SUPPLY CURRENT
vs
SUPPLY VOLTAGE
2.5
40
RL – Load Resistance – Ω
Figure 31
0
32
Figure 34
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
10k 20k
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
104
THD+N – Total Harmonic Distortion Plus Noise – %
SIGNAL–TO–NOISE RATIO
vs
VOLTAGE GAIN
VI = 1 V
SNR – Signal–to–Ratio – dB
102
100
98
96
94
92
1
2
3
4
5
6
8
7
9
10
1
TOTAL HARMONIC DISTORTION PLUS NOISE
vs
FREQUENCY
VDD = 5 V
AV = 1
RL = 10 kΩ
CB = 1 µF
0.1
0.01
0.001
20
100
AV – Voltage Gain – V/V
Figure 35
VDD = 3.3 V
VO = 1 V
RL = 10 kΩ
CB = 1 µF
–80
VDD = 5 V
VO = 1 V
RL = 10 kΩ
CB = 1 µF
–70
–80
–90
Crosstalk – dB
Crosstalk – dB
CROSSTALK
vs
FREQUENCY
–60
–70
10k 20k
Figure 36
CROSSTALK
vs
FREQUENCY
–60
1k
f – Frequency – Hz
–100
IN2 to OUT1
–110
–120
–90
–100
IN2 to OUT1
–110
–120
–130
–130
IN1 to OUT2
–140
IN1 to OUT2
–140
–150
20
100
1k
10k 20k
–150
20
f – Frequency – Hz
100
1k
10k 20k
f – Frequency – Hz
Figure 37
Figure 38
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
15
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
CLOSED–LOOP GAIN AND PHASE
vs
FREQUENCY
200°
180°
Phase
140°
Phase
160°
Closed–Loop Gain – dB
120°
VDD = 3.3 V
RI = 20 kΩ
RF = 20 kΩ
RL = 32 Ω
CI = 1 µF
AV = –1 V/V
30
20
10
100°
80°
Gain
0
–10
10
100
1k
10k
100k
1M
f – Frequency – Hz
Figure 39
CLOSED–LOOP GAIN AND PHASE
vs
FREQUENCY
200°
180°
160°
140°
Closed–Loop Gain – dB
120°
VDD = 5 V
RI = 20 kΩ
RF = 20 kΩ
RL = 32 Ω
CI = 1 µF
AV = –1 V/V
30
20
10
100°
80°
Gain
0
–10
10
100
1k
10k
100k
f – Frequency – Hz
Figure 40
16
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
1M
Phase
Phase
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
CLOSED–LOOP GAIN AND PHASE
vs
FREQUENCY
200°
180°
Phase
140°
Phase
160°
Closed–Loop Gain – dB
120°
VDD = 3.3 V
RI = 20 kΩ
RF = 20 kΩ
RL = 8 Ω
CI = 1 µF
AV = –1 V/V
40
100°
80°
60°
Gain
20
0
–20
10
100
1k
10k
100k
1M
f – Frequency – Hz
Figure 41
CLOSED–LOOP GAIN AND PHASE
vs
FREQUENCY
200°
160°
140°
Phase
180°
Phase
Closed–Loop Gain – dB
120°
VDD = 3.3 V
RI = 20 kΩ
RF = 20 kΩ
RL = 10 kΩ
CI = 1 µF
AV = –1 V/V
30
20
10
100°
80°
Gain
0
–10
10
100
1k
10k
100k
1M
f – Frequency – Hz
Figure 42
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
17
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
CLOSED–LOOP GAIN AND PHASE
vs
FREQUENCY
200°
180°
Phase
Closed–Loop Gain – dB
140°
VDD = 5 V
RI = 20 kΩ
RF = 20 kΩ
RL = 8 Ω
CI = 1 µF
AV = –1 V/V
120°
Phase
160°
100°
80°
60°
40°
Gain
20
0
–20
10
100
1k
10k
100k
1M
f – Frequency – Hz
Figure 43
CLOSED–LOOP GAIN AND PHASE
vs
FREQUENCY
200°
180°
160°
140°
120°
VDD = 5 V
RI = 20 kΩ
RF = 20 kΩ
RL = 10 kΩ
CI = 1 µF
AV = –1 V/V
30
100°
80°
20
10
Gain
0
–10
10
100
1k
10k
100k
f – Frequency – Hz
Figure 44
18
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
1M
Phase
Closed–Loop Gain – dB
Phase
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
TYPICAL CHARACTERISTICS
POWER DISSIPATION/AMPLIFIER
vs
OUTPUT POWER
80
180
VDD = 3.3 V
VDD = 5 V
8Ω
70
8Ω
160
140
Amplifier Power – mW
60
Amplifier Power – mW
POWER DISSIPATION/AMPLIFIER
vs
OUTPUT POWER
50
40
16 Ω
30
32 Ω
20
120
100
16 Ω
80
60
32 Ω
40
64 Ω
10
64 Ω
20
0
0
20
40
60
80 100 120 140 160 180
200
0
0
20
40
Load Power – mW
60
80 100 120 140 160 180
200
Load Power – mW
Figure 45
Figure 46
APPLICATION INFORMATION
gain setting resistors, RF and RI
ǒǓ
The gain for the TPA112 is set by resistors RF and RI according to equation 1.
Gain
+*
RF
(1)
RI
Given that the TPA112 is a MOS amplifier, the input impedance is very high. Consequently input leakage
currents are not generally a concern, although noise in the circuit increases as the value of RF increases. In
addition, a certain range of RF values is required for proper start-up operation of the amplifier. Taken together
it is recommended that the effective impedance seen by the inverting node of the amplifier be set between
5 kΩ and 20 kΩ. The effective impedance is calculated in equation 2.
Effective Impedance
+ RRF)RRI
F
(2)
I
As an example, consider an input resistance of 20 kΩ and a feedback resistor of 20 kΩ. The gain of the amplifier
would be – 1 and the effective impedance at the inverting terminal would be 10 kΩ, which is within the
recommended range.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
19
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
APPLICATION INFORMATION
20
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
gain setting resistors, RF and RI (continued)
For high performance applications, metal film resistors are recommended because they tend to have lower
noise levels than carbon resistors. For values of RF above 50 kΩ, the amplifier tends to become unstable due
to a pole formed from RF and the inherent input capacitance of the MOS input structure. For this reason, a small
compensation capacitor of approximately 5 pF should be placed in parallel with RF. This, in effect, creates a
low-pass filter network with the cutoff frequency defined in equation 3.
f co(lowpass)
+ 2 p R1 C
(3)
F F
For example, if RF is 100 kΩ and CF is 5 pF then fco(lowpass) is 318 kHz, which is well outside the audio range.
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 for optimum operation. In this case, CI and RI form a high-pass filter with the corner frequency
determined in equation 4.
f co(highpass)
+ 2 p R1 C
(4)
I I
The value of CI is important to consider, as it directly affects the bass (low frequency) performance of the circuit.
Consider the example where RI is 20 kΩ and the specification calls for a flat bass response down to 20 Hz.
Equation 4 is reconfigured as equation 5.
CI
+ 2pR f
1
(5)
I co(highpass)
In this example, CI is 0.40 µF, so one would likely choose a value in the range of 0.47 µF to 1 µF. A further
consideration for this capacitor is the leakage path from the input source through the input network (RI, CI) and
the feedback resistor (RF) 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 (> 10). 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 VDD/2, which is
likely higher that the source dc level. It is important to confirm the capacitor polarity in the application.
power supply decoupling, CS
The TPA112 is a high-performance CMOS audio amplifier that requires adequate power supply decoupling to
ensure that 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 VDD lead, works best. For
filtering lower-frequency noise signals, a larger aluminum electrolytic capacitor of 10 µF or greater placed near
the power amplifier is recommended.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
21
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
APPLICATION INFORMATION
midrail voltage
The TPA112 is a single-supply amplifier, so it must be properly biased to accommodate audio signals. Normally,
the amplifier is biased at VDD/2, but it can actually be biased at any voltage between VDD and ground. However,
biasing the amplifier at a point other than VDD/2 will reduce the amplifier’s maximum output swing. In some
applications where the circuitry driving the TPA112 has a different midrail voltage, it might make sense to use
the same midrail voltage for the TPA112, and possibly eliminate the use of the dc-blocking caps.
There are two concerns with the midrail voltage source: the amount of noise present, and its output impedance.
Any noise present on the midrail voltage source that is not present on the audio input signal will be input to the
amplifier, and passed to the output (and increased by the gain of the circuit). Common-mode noise will be
cancelled out by the differential configuration of the circuit.
The output impedance of the circuit used to generate the midrail voltage needs to be low enough so as not to
be influenced by the audio signal path. A common method of generating the midrail voltage is to form a voltage
divider from the supply to ground, with a bypass capacitor from the common node to ground. This capacitor
improves the PSRR of the circuit. However, this circuit has a limited range of output impedances, so to achieve
very low output impedances, the voltage generated by the voltage divider is fed into a unity-gain amplifier to
lower the output impedance of the circuit.
VDD
VDD
R
R
+
_
Midrail
CBYPASS
TLV2460
R
CBYPASS
a) Midrail Voltage Generator Using a Simple
Resistor-Divider
Midrail
R
b) Buffered Midrail Voltage Generator to Provide
Low Output Impedance
Figure 47. Midrail Voltage Generator
If a voltage step is applied to a speaker, it will pop. To reduce popping, the midrail voltage should rise at a
sub-sonic rate; that is, a rate less than the rise time of a 20-Hz waveform. If the voltage rises faster than that,
there is the possibility of a pop from the speaker.
Pop can also be heard in the speaker if the midrail voltage rises faster than either the input coupling capacitor,
or the output coupling capacitor. If midrail rises first, then the charging of the input and output capacitors will
be heard in the speaker. To keep this noise as low as possible, the relationship shown in equation 6 should be
maintained.
ǒ
CB
1
R SOURCE
Ǔvǒ ǓƠ
1
CI RI
1
R LC C
(6)
Where CBYPASS is the value of the bypass capacitor, and RSOURCE is the equivalent source impedance of the
voltage divider (the parallel combination of the two resistors). For example, if the voltage divider is constructed
using two 20-kΩ resistors, then RSOURCE is 10 kΩ.
22
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
APPLICATION INFORMATION
midrail bypass capacitor, CB
The midrail bypass capacitor, CB, serves several important functions. During start-up, CB determines the rate
at which the amplifier starts up. This helps to push the start-up pop noise into the subaudible range (so slow
it can not be heard). The second function is to reduce noise produced by the power supply caused by coupling
into the output drive signal. This noise is from the midrail generation circuit internal to the amplifier. The capacitor
is fed from the resistor divider with equivalent resistance of RSOURCE. To keep the start-up pop as low as
possible, the relationship shown in equation 7 should be maintained.
ǒ
CB
1
R SOURCE
Ǔvǒ Ǔ
1
CI RI
(7)
As an example, consider a circuit where CB is 1 µF, RSOURCE = 160 kΩ, CI is 1 µF, and RI is 20 kΩ. Inserting
these values into the equation 9 results in:
6.25
v 50
which satisfies the rule. Bypass capacitor, CB, values of 0.1 µF to 1 µF ceramic or tantalum low-ESR capacitors
are recommended for the best THD and noise performance.
output coupling capacitor, CC
In the typical single-supply single-ended (SE) configuration, an output coupling capacitor (CC) is required to
block the dc bias at the output of the amplifier, thus preventing dc currents in the load. As with the input coupling
capacitor, the output coupling capacitor and impedance of the load form a high-pass filter governed by
equation 8.
f (out high)
+ 2 p R1 C
(8)
L C
The main disadvantage, from a performance standpoint, is that the typically small load impedances drive the
low-frequency corner higher. Large values of CC are required to pass low frequencies into the load. Consider
the example where a CC of 68 µF is chosen and loads vary from 32 Ω to 47 kΩ. Table 1 summarizes the
frequency response characteristics of each configuration.
Table 1. Common Load Impedances vs Low Frequency Output Characteristics in SE Mode
RL
CC
Lowest Frequency
32 Ω
68 µF
73 Hz
10,000 Ω
68 µF
0.23 Hz
47,000 Ω
68 µF
0.05 Hz
As Table 1 indicates, headphone response is adequate and drive into line level inputs (a home stereo for
example) is very good.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
23
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
APPLICATION INFORMATION
24
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
output coupling capacitor, CC (continued)
The output coupling capacitor required in single-supply SE mode also places additional constraints on the
selection of other components in the amplifier circuit. With the rules described earlier still valid, add the following
relationship:
output pull-down resistor, RC + RO
Placing a 100-Ω resistor, RC, from the output side of the coupling capacitor to ground insures the coupling
capacitor, CC, is charged before a plug is inserted into the jack. Without this resistor, the coupling capacitor
would charge rapidly upon insertion of a plug, leading to an audible pop in the headphones.
Placing a 20-kΩ resistor, RO, from the output of the IC to ground insures that the coupling capacitor fully
discharges at power down. If the supply is rapidly cycled without this capacitor, a small pop may be audible in
10-kΩ loads.
using low-ESR capacitors
Low-ESR capacitors are recommended throughout this application. A real 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.
5-V versus 3.3-V operation
The TPA112 was designed for operation over a supply range of 2.7 V to 5.5 V. This data sheet provides full
specifications for 5-V and 3.3-V operation since these are considered to be the two most common standard
voltages. There are no special considerations for 3.3-V versus 5-V operation as far as supply bypassing, gain
setting, or stability. Supply current is slightly reduced from 3.5 mA (typical) to 2.5 mA (typical). The most
important consideration is that of output power. Each amplifier in the TPA112 can produce a maximum voltage
swing of VDD – 1 V. This means, for 3.3-V operation, clipping starts to occur when VO(PP) = 2.3 V as opposed
when VO(PP) = 4 V while operating at 5 V. The reduced voltage swing subsequently reduces maximum output
power into the load before distortion begins to become significant.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
25
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
MECHANICAL DATA
D (R-PDSO-G**)
PLASTIC SMALL-OUTLINE PACKAGE
14 PINS SHOWN
0.050 (1,27)
0.020 (0,51)
0.014 (0,35)
14
0.010 (0,25) M
8
0.008 (0,20) NOM
0.244 (6,20)
0.228 (5,80)
0.157 (4,00)
0.150 (3,81)
Gage Plane
0.010 (0,25)
1
7
0°– 8°
A
0.044 (1,12)
0.016 (0,40)
Seating Plane
0.069 (1,75) MAX
0.010 (0,25)
0.004 (0,10)
PINS **
0.004 (0,10)
8
14
16
A MAX
0.197
(5,00)
0.344
(8,75)
0.394
(10,00)
A MIN
0.189
(4,80)
0.337
(8,55)
0.386
(9,80)
DIM
4040047 / D 10/96
NOTES: A.
B.
C.
D.
26
All linear dimensions are in inches (millimeters).
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion, not to exceed 0.006 (0,15).
Falls within JEDEC MS-012
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
TPA112
150-mW STEREO AUDIO POWER AMPLIFIER
SLOS212C – AUGUST 1998 – REVISED MARCH 2000
MECHANICAL DATA
DGN (S-PDSO-G8)
PowerPAD PLASTIC SMALL-OUTLINE PACKAGE
0,38
0,25
0,65
8
0,25 M
5
Thermal Pad
(See Note D)
0,15 NOM
3,05
2,95
4,98
4,78
Gage Plane
0,25
1
0°– 6°
4
3,05
2,95
0,69
0,41
Seating Plane
1,07 MAX
0,15
0,05
0,10
4073271/A 04/98
NOTES: A.
B.
C.
D.
All linear dimensions are in millimeters.
This drawing is subject to change without notice.
Body dimensions include mold flash or protrusions.
The package thermal performance may be enhanced by attaching an external heat sink to the thermal pad.
This pad is electrically and thermally connected to the backside of the die and possibly selected leads.
E. Falls within JEDEC MO-187
PowerPAD is a trademark of Texas Instruments.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
27
IMPORTANT NOTICE
Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgment, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
Customers are responsible for their applications using TI components.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright  2000, Texas Instruments Incorporated