Texas Instruments TPA2035D1 User manual

1
FEATURES APPLICATIONS
DESCRIPTION
APPLICATION CIRCUIT
_
+
IN−
IN+
PWM H−
Bridge
VO −
VO +
Internal
Oscillator
To Battery
VDD
GND
Bias
Circuitry
Differential
Input
TPA2035D1
SHUTDOWN
A1 A2 A3
B1 B2 B3
C1 C2 C3
IN+ GND VO−
VDD PVDD PGND
IN− SHUTDWN VO+
1,4 mm
9-BALL WAFER CHIP SCALE, YZF PACKAGE,
(TOP VIEW OF PCB)
Note: Pin A1 is marked with a “0” .
1,55 mm
1,4 mm
1,55 mm
TPA
2035D1
0402
~
2,5 mm
~1,7 mm
CS
CS
TPA2035D1
www.ti.com ................................................................................................................................................................................................ SLOS562 – AUGUST 2008
2.75-W FIXED GAIN MONO FILTER-FREE CLASS-D AUDIO POWER AMPLIFIER
•Wireless Handsets, PDAs, and other mobile2
•Maximize Battery Life and Minimize Heat
devices– 0.5- µA Shutdown Current– 3-mA Quiescent Current– High Efficiency Class-D
The TPA2035D1 is a 2.75-W high efficiency filter-free– 88% at 400mW at 8 Ω
class-D audio power amplifier in an approximately– 80% at 100mW at 8 Ω
1.5-mm × 1.5-mm wafer chip scale package (WCSP)that requires only one external component. The•Short Circuit Auto-recovery
pinout is the same as the TPA2010D1 (SLOS417 )•Gain of 2 V/V (6dB)
except that the external gain setting input resistors•Only One External Component Required
required by the TPA2010D1 are integrated into thefixed gain of the TPA2035D1.– Internal Matched Input Gain and FeedbackResistors for Excellent PSRR and CMRR
Features like – 75dB PSRR and improved– Optimized PWM Output Stage Eliminates RF-rectification immunity with a small PCB footprint(WCSP amplifier plus single decoupling cap) makeLC Output Filter
the TPA2035D1 ideal for wireless handsets. A fast– PSRR ( – 75 dB) and Wide Supply Voltage
start-up time of 3.2 ms with minimal pop makes the(2.5 V to 5.5 V) Eliminates Need for a
TPA2035D1 ideal for PDA applications.Dedicated Voltage Regulator
In wireless handsets, the earpiece, speaker phone,– Fully Differential Design Reduces RF
and melody ringer can each be driven by theRectification and Eliminates Bypass
TPA2035D1. The TPA2035D1 has a low 27- µV noiseCapacitor
floor, A-weighted.– CMRR ( – 69 dB)Eliminates Two InputCoupling Capacitors•Thermal and Short-Circuit Protection•Pinout Similar to the TPA2010D1•Wafer Chip Scale Packaging (WCSP)– NanoFree™ (YZF)
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2NanoFree is a trademark of Texas Instruments.
PRODUCTION DATA information is current as of publication date.
Copyright © 2008, Texas Instruments IncorporatedProducts conform to specifications per the terms of the TexasInstruments standard warranty. Production processing does notnecessarily include testing of all parameters.

ABSOLUTE MAXIMUM RATINGS
RECOMMENDED OPERATING CONDITIONS
PACKAGE DISSIPATION RATINGS
TPA2035D1
SLOS562 – AUGUST 2008 ................................................................................................................................................................................................ www.ti.com
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
ORDERING INFORMATION
T
A
PACKAGE (YZF)
(1)
PART NUMBER SYMBOL
9 balls, 1.5 mm × 1.5 mm WCSP– 40 ° C to 85 ° C TPA2035D1YZF
(2)
CGD(0.05/-0.1 mm tolerance)
(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TIwebsite at www.ti.com .(2) The YZF package is only available taped and reeled. To order add the suffix Rto the end of the part number for a reel of 3000, or addthe suffix Tto the end of the part number for a reel of 250 (e.g. TPA2035D1YZFR).
over operating free-air temperature range unless otherwise noted
(1)
TPA2035D1
In active mode – 0.3 V to 6 VV
DD
Supply voltage
In SHUTDOWN mode – 0.3 V to 7 VV
I
Input voltage – 0.3 V to V
DD
+ 0.3 VContinuous total power dissipation See Dissipation Rating TableT
A
Operating free-air temperature – 40 ° C to 85 ° CT
J
Operating junction temperature – 40 ° C to 125 ° CT
stg
Storage temperature – 65 ° C to 150 ° CESD Electro-Static Discharge Tolerance - Human Body Model (HBM) for all pins
(2)
2KV
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratingsonly, and functional operation of the device at these or any other conditions beyond those indicated under recommended operatingconditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.(2) The output pins Vo – and Vo+ are tolerant to 1.5KV HBM ESD
MIN NOM MAX UNIT
V
DD
Supply voltage 2.5 5.5 VV
IH
High-level input voltage SHUTDOWN 1.3 V
DD
VV
IL
Low-level input voltage SHUTDOWN 0 0.35 VV
IC
Common mode input voltage range V
DD
= 2.5 V, 5.5 V 0.5 V
DD
– 0.8 VT
A
Operating free-air temperature – 40 85 ° C
DERATING FACTOR T
A
≤25 ° C T
A
= 70 ° C T
A
= 85 ° CPACKAGE
(1 / θ
JA
) POWER RATING POWER RATING POWER RATING
YZF 4.8 mW/ ° C
(1)
480 mW 264 mW 192 mWYZF 7.5 mW/ ° C
(2)
750 mW 412 mW 300 mW
(1) Derating factor measured with JEDEC Low-K board; 1S0P - One signal layer and zero plane layers.(2) Derating factor measured with JEDEC High K board; 1S2P - One signal layer and two plane layers.Please see JEDEC Standard 51-3 for Low-K board, JEDEC Standard 51-7 for High-K board, and JEDEC Standard 51-12 for usingpackage thermal information.Please see JEDEC document page for downloadable copies: http://www.jedec.org/download/default.cfm.
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ELECTRICAL CHARACTERISTICS
OPERATING CHARACTERISTICS
TPA2035D1
www.ti.com ................................................................................................................................................................................................ SLOS562 – AUGUST 2008
T
A
= 25 ° C (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Output offset voltage|V
OS
| Inputs AC grounded, V
DD
= 2.5 V to 5.5 V 5 25 mV(measured differentially)PSRR Power supply rejection ratio V
DD
= 2.5 V to 5.5 V – 75 -61 dBV
DD
= 2.5 V – 69 -52CMRR Common mode rejection ratio V
IC
= 0.5 V to (V
DD
– 0.8 V) V
DD
= 3.6 V – 69 -52 dBV
DD
= 5.5 V – 69 -52|I
IH
| High-level input current V
DD
= 5.5 V, V
I
= 5.8 V 50 µA|I
IL
| Low-level input current V
DD
= 5.5 V, V
I
= – 0.3 V 5 µAV
DD
= 5.5 V, no load 4 5.7I
(Q)
Quiescent current V
DD
= 3.6 V, no load 3 mAV
DD
= 2.5 V, no load 2.2 3.7I
(SD)
Shutdown current V
( SHUTDOWN)
= 0.35 V, V
DD
= 2.5 V to 5.5 V 0.5 0.8 µAV
DD
= 2.5 V 550Static drain-source on-stater
DS(on)
V
DD
= 3.6 V 420 m Ωresistance
V
DD
= 5.0 V 350Output impedance in
V
( SHUTDOWN)
< = 0.35 V 2 k ΩSHUTDOWN
f
(sw)
Switching frequency V
DD
= 2.5 V to 5.5 V 240 300 400 kHzGain V
DD
= 2.5 V to 5.5 V 5.5 6 6.5 dBResistance of internal pulldownR
PD
resistor from shutdown pin to 300 k ΩGND
T
A
= 25 ° C, R
L
= 8 Ω(unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V
DD
= 5 V 2.75R
L
= 4 Ω, THD + N = 10%, f = 1 kHz V
DD
= 3.6 V 1.35 WV
DD
= 2.5 V 0.59V
DD
= 5 V 2.25R
L
= 4 Ω, THD + N = 1%, f = 1 kHz V
DD
= 3.6 V 1.12 WV
DD
= 2.5 V 0.48P
O
Output power
V
DD
= 5 V 1.68R
L
= 8 Ω, THD + N = 10%, f = 1 kHz V
DD
= 3.6 V 0.85 WV
DD
= 2.5 V 0.38V
DD
= 5 V 1.37R
L
= 8 Ω, THD + N = 1%, f = 1 kHz V
DD
= 3.6 V 0.68 WV
DD
= 2.5 V 0.31V
DD
= 5 V, P
O
= 1 W, R
L
= 8 Ω, f = 1 kHz 0.18%Total harmonic distortion plusTHD+N V
DD
= 3.6 V, P
O
= 0.5 W, R
L
= 8 Ω, f = 1 kHz 0.11%noise
V
DD
= 2.5 V, P
O
= 200 mW, R
L
= 8 Ω, f = 1 kHz 0.10%V
DD
= 3.6 V, Inputs AC grounded f = 217 Hz,k
SVR
Supply ripple rejection ratio – 73 dBwith C
I
= 1 µF V
(RIPPLE)
= 200 mV
pp
SNR Signal-to-noise ratio V
DD
= 5 V, P
O
= 1 W, R
L
= 8 Ω, A weighted noise 100 dBNo weighting 35V
DD
= 3.6 V, f = 20 Hz to 20 kHz,V
n
Output voltage noise µV
RMSInputs AC grounded with C
I
= 1 µF
A weighting 27V
DD
= 3.6 V, V
IC
= 1 V
pp
, V
Cm
= 1.8CMRR Common mode rejection ratio f = 217 Hz – 69 dBV
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FUNCTIONAL BLOCK DIAGRAM
Input
Buffer SC
300 KΩ
TPA2035D1
SLOS562 – AUGUST 2008 ................................................................................................................................................................................................ www.ti.com
OPERATING CHARACTERISTICS (continued)T
A
= 25 ° C, R
L
= 8 Ω(unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
R
I
Input impedance A
V
= 2 V/V 30.2 k Ω
Start-up time from shutdown V
DD
= 3.6 V 3.2 msShort circuit detection
V
DD
= 3.6 V 1.7 Athreshold
Terminal Functions
TERMINAL
I/O DESCRIPTIONNAME YZF
IN – C1 I Negative differential audio inputIN+ A1 I Positive differential audio inputV
O-
A3 O Negative BTL audio outputV
O+
C3 O Positive BTL audio outputAnalog ground terminal. Must be connected to same potential as PGND using a direct connectionGND A2 I
to a single point ground.High-current Analog ground terminal. Must be connected to same potential as GND using a directPGND B3
connection to a single point ground.Power supply terminal. Must be connected to same power supply as PV
DD
using a directV
DD
B1 I
connection. Voltage must be within values listed in Recommended Operating Conditions table.High-current Power supply terminal. Must be connected to same power supply as V
DD
using aPV
DD
B2 I direct connection. Voltage must be within values listed in Recommended Operating Conditionstable.SHUTDOWN C2 I Shutdown terminal. When terminal is low the device is put into Shutdown mode.
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TYPICAL CHARACTERISTICS
TABLE OF GRAPHS
TEST SET-UP FOR GRAPHS
TPA2035D1
IN+
IN −
OUT+
OUT −
VDD GND
CI
CI
Measurement
Output
+
−
1mF
+
−
VDD
Load
30 kHz
Low Pass
Filter
Measurement
Input
+
−
TPA2035D1
www.ti.com ................................................................................................................................................................................................ SLOS562 – AUGUST 2008
FIGURE
Efficiency vs Output power 1, 2P
D
Power dissipation vs Output power 3, 4Supply current vs Output power 5, 6I
DD
Supply current vs Supply voltage 7I
(SD)
Shutdown current vs Shutdown voltage 8vs Load resistance 9, 10P
O
Output power
vs Supply voltage 11vs Output power 12, 13THD+N Total harmonic distortion plus noise vs Frequency 14, 15, 16, 17vs Common-mode input voltage 1819, 20, 21, 22, 23, 24, 25,K
SVR
Supply voltage rejection ratio vs Frequency
26, 27vs Time 28GSM power supply rejection
vs Frequency 29K
SVR
Supply voltage rejection ratio vs Common-mode input voltage 30, 31, 32vs Frequency 33CMRR Common-mode rejection ratio
vs Common-mode input voltage 34
(1) C
I
was shorted for any common-mode input voltage measurement. All other measurements were taken with a 1- µF C
I(unless otherwise noted).(2) A 33- µH inductor was placed in series with the load resistor to emulate a small speaker for efficiency measurements.(3) The 30-kHz low-pass filter is required, even if the analyzer has an internal low-pass filter. An RC low-pass filter(100 Ω, 47-nF) is used on each output for the data sheet graphs.
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0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.5 1 1.5 2 2.5 3
P - Output Power - W
O
P - Power Dissipation - W
D
V = 5 V, R = 4
DD L W
Class AB 4 W
Class AB 8 W
V = 5 V, R = 8
DD L W
0
10
20
30
40
50
60
70
80
90
100
0 0.2 0.4 0.6 0.8 1 1.2 1.4
P - Output Power - W
O
Efficiency - %
R = 8
LW, 33 μH
V = 5 V
DD
V = 2.5 V
DD
V = 3.6 V
DD
Class AB
0
10
20
30
40
50
60
70
80
90
00.5 11.5 2 2.5
P - Output Power - W
O
Efficiency - %
V = 2.5 V
DD
V = 3.6 V
DD
V = 5 V
DD
Class AB
R = 4
LW, 33 μH
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
PO - Output Power - W
P - Power Dissipation - W
D
V = 3.6 V, R = 4
DD L W
V = 3.6 V, R = 8
DD L W
Class AB, 4 W
Class AB, 8 W
650
600
550
500
450
400
350
300
250
200
150
100
0
V = 3.6 V
DD
V = 2.5 V
DD
V = 5 V
DD
0 0.5 1 1.5 32.52
P - Output Power - W
O
I - Supply Current - mA
DD
R = 4 , 33 μH
LW
50
360
320
280
240
200
160
120
80
40
0
V = 3.6 V
DD
V = 2.5 V
DD
V = 5 V
DD
P - Output Power - W
O
I - Supply Current - mA
DD
R = 8 , 33 μH
LW
0 0.25 0.5 0.75 1 1.25 1.5 1.75
3.6
3.2
2.8
2.4
2
1.6
1.2
0.4
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
V = 2.5 V
DD
V = 5 V
DD
V = 3.6 V
DD
I - Supply Current - mA
DD
Shutdown Voltage - V
R = No Load
L
0.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
2.5 3 3.5 4 4.5 55.5
V - Supply Voltage - V
DD
I - Supply Current - mA
DD
R = 8 , 33 H
LW m
R = 8
LW
No Load
P - Output Power - W
O
0
0.5
1
1.5
2
2.5
3
3.5
4 9 14 19 24 29
R - Load Resistance -
LW
V = 3.6 V, 10%
DD
V = 2.5 V, 10%
DD
V = 5 V, 10%
DD
TPA2035D1
SLOS562 – AUGUST 2008 ................................................................................................................................................................................................ www.ti.com
EFFICIENCY EFFICIENCY POWER DISSIPATIONvs vs vsOUTPUT POWER OUTPUT POWER OUTPUT POWER
Figure 1. Figure 2. Figure 3.
POWER DISSIPATION SUPPLY CURRENT SUPPLY CURRENTvs vs vsOUTPUT POWER OUTPUT POWER OUTPUT POWER
Figure 4. Figure 5. Figure 6.
SUPPLY CURRENT SHUTDOWN CURRENT OUTPUT POWERvs vs vsSUPPLY VOLTAGE SHUTDOWN VOLTAGE LOAD RESISTANCE
Figure 7. Figure 8. Figure 9.
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20
0.05
0.1
1
10
310m 100m 1
P - Output Power - W
O
THD+N - Total Harmonic Distortion + Noise - %
V = 5 V
DD
V = 2.5 V
DD
V = 3 V
DD
V = 3.6 V
DD
R = 4
LW
0
0.5
1
1.5
2
2.5
3
2.5 3 3.5 4 4.5 5
V - Supply Voltage - V
DD
4 THD+N = 1%W
4 THD+N = 10%W
8 THD+N = 1%W
8 THD+N = 10%W
P- Output Power - W
O
0
0.5
1
1.5
2
2.5
4 9 14 19 24 29
R - Load Resistance -
LW
V = 2.5 V, 1%
DD
V = 3.6 V, 1%
DD
V = 5 V, 1%
DD
P- Output Power - W
O
20
0.05
0.1
1
210m 100m 1
P - Output Power - W
O
THD+N - Total Harmonic Distortion + Noise - %
V = 5 V
DD
V = 2.5 V
DD
V = 3 V
DD
V = 3.6 V
DD
R = 8
LW
10
1
0.01
0.1
f - Frequency - Hz
20k20 100 1k 10k
P = 500 mW
O
P = 25 mW
O
P = 125 mW
O
THD+N - Total Harmonic Distortion + Noise - %
RL= 8
V = 3.6 V
W
DD
1
0.01
0.1
f - Frequency - Hz
20k20 100 1k 10k
THD+N - Total Harmonic Distortion + Noise - %
P = 1 W
O
R = 8
V = 5 V
L
DD
W
P = 50 mW
O
P = 250 mW
O
1
0.01
0.1
f - Frequency - Hz
20k20 100 1k 10k
V = 2.5 V
DD
V = 5 V
DD
V = 4 V
DD
V = 3.6 V
DD
V = 3 V
DD
THD+N - Total Harmonic Distortion + Noise - %
R = 4
LW
1
0.005
0.01
0.1
f - Frequency - Hz
20k20 100 1k 10k
P = 200 mW
O
P = 15 mW
O
P = 75 mW
O
THD+N - Total Harmonic Distortion + Noise - %
R = 8
V = 2.5 V
L
DD
W
TPA2035D1
www.ti.com ................................................................................................................................................................................................ SLOS562 – AUGUST 2008
TOTAL HARMONIC DISTORTION +OUTPUT POWER OUTPUT POWER NOISEvs vs vsLOAD RESISTANCE SUPPLY VOLTAGE OUTPUT POWER
Figure 10. Figure 11. Figure 12.
TOTAL HARMONIC DISTORTION + TOTAL HARMONIC DISTORTION + TOTAL HARMONIC DISTORTION +NOISE NOISE NOISEvs vs vsOUTPUT POWER FREQUENCY FREQUENCY
Figure 13. Figure 14. Figure 15.
TOTAL HARMONIC DISTORTION + TOTAL HARMONIC DISTORTION + TOTAL HARMONIC DISTORTION +NOISE NOISE NOISEvs vs vsFREQUENCY FREQUENCY COMMON MODE INPUT VOLTAGE
Figure 16. Figure 17. Figure 18.
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-100
-90
-80
-70
-60
-50
-40
-30
10 100 1 k 100 k
f - Frequency - Hz
Supply Ripple Rejection Ratio - dB
10 k
Inputs ac-grounded,
C = 1 F,
R = 8 ,
Gain = 2 V/V
I
L
m
W
V = 5 V
DD
V = 2.5 V
DD
V = 3.6 V
DD
-100
-90
-80
-70
-60
-50
-40
-30
10 100 1 k 10 k 100 k
f - Frequency - Hz
Supply Ripple Rejection Ratio - dB
V = 3.6 V
DD
V = 2.5 V
DD
V = 5 V
DD
Inputs ac-grounded,
C = 1 F,
R = 4 ,
Gain = 2 V/V
I
L
m
W
-100
-90
-80
-70
-60
-50
-40
-30
10 100 1 k 10 k 100 k
f - Frequency - Hz
Supply Ripple Rejection Ratio - dB
V = 3.6 V
DD
V = 2.5 V
DD
V = 2.7 V
DD
V = 5 V
DD
Inputs Floating,
R = 8 ,
Gain = 2 V/V
LW
V
200 mV/div
DD
V
20 mV/div
OUT
t - Time - 2 mS/div
0
-140
-120
-100
-80
-60
-40
-20
02k 200 400 600 800 1k 1.2k 1.4k 1.6k1.8k
f - Frequency - Hz
V - Supply Voltage - dBV
DD
V - Output Voltage - dBV
O
V Shown in Figure 22
C = 1 F,
Inputs ac-Grounded
DD
Im
-150
-130
-110
-90
-70
-50
-30
10
-10
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
DC Common-Mode Voltage - V
Supply Ripple Rejection Ratio - dB
V = 2.5 V
DD V = 3.6 V
DD
V = 5 V
DD
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
DC Common-Mode Voltage - V
Supply Ripple Rejection Ratio - dB
V = 3.6 V
DD
V = 5 V
DD
V = 2.5 V
DD
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
DC Common-Mode Voltage - V
Supply Ripple Rejection Ratio - dB
V = 2.5 V
DD
V = 3.6 V
DD
V = 5 V
DD
TPA2035D1
SLOS562 – AUGUST 2008 ................................................................................................................................................................................................ www.ti.com
SUPPLY RIPPLE REJECTION RATIO SUPPLY RIPPLE REJECTION RATIO SUPPLY RIPPLE REJECTION RATIOvs vs vsFREQUENCY FREQUENCY FREQUENCY
Figure 19. Figure 20. Figure 21.
GSM POWER SUPPLY REJECTION GSM POWER SUPPLY REJECTIONvs vsTIME FREQUENCY
Figure 22. Figure 23.
SUPPLY RIPPLE REJECTION RATIO SUPPLY RIPPLE REJECTION RATIO SUPPLY RIPPLE REJECTION RATIOvs vs vsDC COMMON MODE VOLTAGE DC COMMON MODE VOLTAGE DC COMMON MODE VOLTAGE
Figure 24. Figure 25. Figure 26.
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-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
V - Common-Mode Input Voltage - V
IC
V = 2.5 V
DD
V = 5 V
DD
CMRR - Common-Mode Rejection Ratio - dB
V = 3.6 V
DD
-85
-80
-75
-70
-65
-60
10 100 1 k 10 k 100 k
f - Frequency - Hz
CMRR - Common Mode Rejection Ratio - dB
V = 3.6 V,
V = 1 Vpp,
R = 8
DD
IC
LW
TPA2035D1
www.ti.com ................................................................................................................................................................................................ SLOS562 – AUGUST 2008
COMMON-MODE REJECTION COMMON-MODE REJECTIONRATIO RATIOvs vsFREQUENCY COMMON-MODE INPUT VOLTAGE
Figure 27. Figure 28.
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APPLICATION INFORMATION
FULLY DIFFERENTIAL AMPLIFIER
Advantages of Fully Differential Amplifiers
SHORT CIRCUIT AUTO-RECOVERY
COMPONENT SELECTION
Decoupling Capacitor (C
S
)
Input Capacitors (C
I
)
TPA2035D1
SLOS562 – AUGUST 2008 ................................................................................................................................................................................................ www.ti.com
The device is a fully differential amplifier with differential inputs and outputs. The fully differential amplifierconsists of a differential amplifier and a common-mode amplifier. The differential amplifier ensures that theamplifier outputs a differential voltage on the output that is equal to the differential input times the gain. Thecommon-mode feedback specifies that the common-mode voltage at the output is biased around V
DD
/2regardless of the common-mode voltage at the input. The fully differential TPA2035D1 can still be used with asingle-ended input; however, the TPA2035D1 should be used with differential inputs when in a noisyenvironment, like a wireless handset, to ensure maximum noise rejection.
•Input-coupling capacitors not required:– The fully differential amplifier allows the inputs to be biased at voltage other than mid-supply. The inputs ofthe TPA2035D1 can be biased anywhere within the common mode input voltage range listed in theRecommended Operating Conditions table. If the inputs are biased outside of that range, input-couplingcapacitors are required.•Midsupply bypass capacitor, C
(BYPASS)
, not required:– The fully differential amplifier does not require a bypass capacitor. Any shift in the midsupply affects bothpositive and negative channels equally and cancels at the differential output.•Better RF-immunity:
– GSM handsets save power by turning on and shutting off the RF transmitter at a rate of 217 Hz. Thetransmitted signal is picked-up on input and output traces. The fully differential amplifier cancels the signalbetter than the typical audio amplifier.
When a short circuit event happens, the TPA2035D1 goes to shutdown mode and tries to reactivate itself after20 µs. This auto-recovery will continue until the short circuit event stops. This feature can protect the devicewithout affecting the device's long term reliability.
Figure 29 shows the TPA2035D1 typical schematic with differential inputs, while Figure 30 shows theTPA2035D1 with differential inputs and input capacitors. Figure 31 shows the TPA2035D1 with a single-endedinput.
The TPA2035D1 is a high-performance class-D audio amplifier that requires adequate power supply decouplingto ensure the efficiency is high and total harmonic distortion (THD) is low. For higher frequency transients,spikes, or digital hash on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor, typically1µF, placed as close as possible to the device V
DD
lead works best. Placing this decoupling capacitor close tothe TPA2035D1 is important for the efficiency of the class-D amplifier, because any resistance or inductance inthe trace between the device and the capacitor can cause a loss in efficiency. For filtering lower-frequency noisesignals, a 10 µF or greater capacitor placed near the audio power amplifier would also help, but it is not requiredin most applications because of the high PSRR of this device. Typically, the smaller the capacitor's case size, thelower the inductance and the closer it can be placed to the TPA2035D1.
The TPA2035D1 does not require input coupling capacitors if the design uses a differential source that is biasedwithin the common-mode input voltage range. That voltage range is listed in the Recommended OperatingConditions table. If the input signal is not biased within the recommended common-mode input range, such as inneeding to use the input as a high pass filter, shown in Figure 30 , or if using a single-ended source, shown inFigure 31 , input coupling capacitors are required. The same value capacitors should be used on both IN+ andIN – for best pop performance.
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