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TPA2025D1
SLOS717B – AUGUST 2011 – REVISED DECEMBER 2014
TPA2025D1 2-W Constant Output Power Class-D Audio Amplifier With Class-G Boost
Converter and Battery Tracking AGC
1 Features
3 Description
•
The TPA2025D1 is a high efficiency Class-D audio
power amplifier with battery tracking AGC technology
and an integrated Class-G boost converter that
enhances efficiency at low output power. It drives up
to 1.9 W into an 8-Ω speaker (1% THD+N). With 85%
typical efficiency, the TPA2025D1 helps extend
battery life when playing audio.
1
•
•
•
•
•
•
•
Built-In Enhanced Battery Tracking Automatic
Gain Control (AGC)
– Limits Battery Current Consumption
1.9 W into 8-Ω Load from 3.6-V Supply (1%
THD+N)
Integrated Adaptive Boost Converter
– Increases Efficiency at Low Output Power
Low Quiescent Current of 2 mA From 3.6 V
Thermal and Short-Circuit Protection With Auto
Recovery
20-dB Fixed Gain
Similar Performance to TPA2015D1
Available in 1.53-mm × 1.982-mm,
0.5-mm Pitch 12-Ball WCSP Package
2 Applications
•
•
•
The built-in boost converter generates a 5.75-V
supply voltage for the Class-D amplifier. This
provides a louder audio output than a stand-alone
amplifier directly connected to the battery. The battery
tracking AGC adjusts the Class-D gain to limit battery
current at lower battery voltage.
The TPA2025D1 has an integrated low-pass filter to
improve the RF rejection and reduce DAC out-ofband noise, increasing the signal-to-noise ratio
(SNR).
The TPA2025D1 is available in a space saving
1.53 mm × 1.982 mm, 0.5 mm pitch DSBGA package
(YZG).
Cell Phones
PDA, GPS
Portable Electronics and Speakers
Device Information(1)
PART NUMBER
TPA2025D1
PACKAGE
BODY SIZE (NOM)
DSBGA (12)
1.53 mm x 1.982 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Battery Tracking Auto Gain Control
4 Simplified Application Diagram
2.2 mH
Connected to Supply
2.2 mF
VBAT
+
Audio
Input
-
6.8 mF - 22 mF
PVDD
BGND
INEnable
SW
IN+
TPA2025D1
OUT+
EN
OUT-
AGC
AGC AGND
PGND
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
TPA2025D1
SLOS717B – AUGUST 2011 – REVISED DECEMBER 2014
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Simplified Application Diagram............................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
1
2
3
3
4
8.1
8.2
8.3
8.4
8.5
8.6
8.7
4
4
4
4
5
5
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics...........................................
Operating Characteristics..........................................
Typical Characteristics ..............................................
9 Parameter Measurement Information ................ 11
10 Detailed Description ........................................... 11
10.1
10.2
10.3
10.4
Overview ...............................................................
Functional Block Diagram .....................................
Feature Description...............................................
Device Functional Modes......................................
11
11
12
13
11 Application and Implementation........................ 15
11.1 Application Information.......................................... 15
11.2 Typical Application ................................................ 15
12 Power Supply Recommendations ..................... 20
12.1 Power Supply Decoupling Capacitors................... 20
13 Layout................................................................... 20
13.1 Layout Guidelines ................................................. 20
13.2 Layout Example .................................................... 22
14 Device and Documentation Support ................. 23
14.1 Trademarks ........................................................... 23
14.2 Electrostatic Discharge Caution ............................ 23
14.3 Glossary ................................................................ 23
15 Mechanical, Packaging, and Orderable
Information ........................................................... 23
5 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision A (February 2012) to Revision B
•
Page
Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional
Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device
and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .............................. 1
Changes from Original (August 2011) to Revision A
Page
•
Changed Operating quiescent current TYP value from "3.5" to "2.0" for VBAT = 3.6 V; and, TYP value from "4" to
2.5" for VBAT = 5.2 V ............................................................................................................................................................. 5
•
Changed Shutdown quiescent current MAX value from "3" to "1" ........................................................................................ 5
•
Changed from "110 ms" to "1.6 seconds" in the SHORT CIRCUIT AUTO-RECOVERY description. ................................. 13
•
Changed from "within 200 ms" to "1.6 seconds" in the Speaker Load Limitation description.............................................. 18
2
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6 Device Comparison Table
DEVICE NAME
TPA2025D1
DESCRIPTION
2 W Constant Output Power Class-D Audio Amplifier with Class-G Boost Converter and Battery Tracking AGC
7 Pin Configuration and Functions
12-PIN
YZG PACKAGE
(TOP VIEW)
A1
A2
A3
PVDD
SW
BGND
B1
B2
B3
OUT+
AGC
VBAT
C1
C2
C3
OUT-
EN
IN+
D1
D2
D3
PGND
AGND
IN-
Pin Functions
PIN
NAME
WCSP
INPUT/ OUTPUT/
POWER (I/O/P)
PVDD
A1
O
Boost converter output and Class-D power stage supply voltage.
SW
A2
I
Boost converter switch input; connect boost inductor between VBAT and SW.
BGND
A3
P
Boost converter power ground.
OUT+
B1
O
Positive audio output.
AGC
B2
I
AGC inflection point select. Connect to VDD, GND or Float. Voltage at AGC pin is
only read at device power-up. A power cycle is required to change inflection points.
DESCRIPTION
VBAT
B3
P
Supply voltage.
OUT–
C1
O
Negative audio output.
EN
C2
I
Device enable; set to logic high to enable.
IN+
C3
I
Positive audio input.
PGND
D1
P
Class-D power ground.
AGND
D2
P
Analog ground.
IN–
D3
I
Negative audio input.
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8 Specifications
8.1 Absolute Maximum Ratings
Over operating free–air temperature range, TA= 25°C (unless otherwise noted) (1)
Supply voltage
VBAT
Input Voltage, VI
IN+, IN–
Output continuous total power dissipation
MIN
MAX
UNIT
–0.3
6
V
–0.3
VBAT + 0.3
V
See Thermal Information
Operating free-air temperature range, TA
–40
85
°C
Operating junction temperature range, TJ
–40
150
°C
Minimum load resistance
3.2
2
VRMS
150
°C
Maximum input voltage swing
Storage temperature range, Tstg
(1)
Ω
EN = 0 V
–65
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.
8.2 ESD Ratings
VALUE
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001
V(ESD)
(1)
(2)
Electrostatic discharge
(1)
UNIT
±2000
Charged-device model (CDM), per JEDEC specification JESD22C101 (2)
±500
Machine model (MM)
±100
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
8.3 Recommended Operating Conditions
MIN
MAX
Supply voltage, VBAT
2.5
5.2
UNIT
VIH
High–level input voltage, EN
1.3
VIL
Low–level input voltage, EN
0.6
V
TA
Operating free-air temperature
–40
85
°C
TJ
Operating junction temperature
–40
150
°C
V
V
8.4 Thermal Information
TPA2025D1
THERMAL METRIC
(1)
YZG
UNITS
12 PINS
RθJA
Junction-to-ambient thermal resistance
97.3
RθJC(top)
Junction-to-case(top) thermal resistance
36.7
RθJB
Junction-to-board thermal resistance
55.9
ψJT
Junction-to-top characterization parameter
13.9
ψJB
Junction-to-board characterization parameter
49.5
(1)
4
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
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8.5 Electrical Characteristics
VBAT = 3.6 V, TA = 25°C, RL = 8 Ω + 33 μH (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
VBAT supply voltage range
Class-D supply voltage
range
5.2
5.75
Boost converter disabled (in bypass mode)
2.5
5.2
2.2
UNIT
V
V
V
EN = VBAT = 3.6 V
2.0
5
EN = VBAT = 5.2V
2.5
6
0.2
1
μA
1.3
V
10
ms
Shutdown quiescent current VBAT = 2.5 V to 5.2 V, EN = GND
Input common-mode
voltage range
MAX
2.5
EN = VBAT, boost converter active
Supply under voltage
shutdown
Operating quiescent current
TYP
IN+, IN–
0.6
Start-up time
6
mA
8.6 Operating Characteristics
VBAT= 3.6 V, EN = VBAT, AGC = GND, TA = 25°C, RL = 8 Ω + 33 μH (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
5.4
5.75
6.4
UNIT
BOOST CONVERTER
PVDD
Boost converter output voltage range
Boost converter input current limit
IL
fBOOST
IBOOST = 0 mA
IBOOST = 700 mA
5.6
Power supply current
V
1800
Boost converter starts up from full shutdown
Boost converter start-up current limit
V
600
Boost converter wakes up from auto-pass through
mode
mA
1000
Boost converter frequency
1.2
MHz
CLASS-D AMPLIFIER
PO
Output power
THD = 1%, VBAT = 2.5 V, f = 1 kHz
1440
THD = 1%, VBAT = 3.0 V, f = 1 kHz
1750
THD = 1%, VBAT = 3.6 V, f = 1 kHz
1900
THD = 1%, VBAT = 2.5 V, f = 1 kHz,
RL = 4 Ω + 33 µH
1460
THD = 1%, VBAT = 3.0 V, f = 1 kHz,
RL = 4 Ω + 33 µH
1800
THD = 1%, VBAT = 3.6 V, f = 1 kHz,
RL = 4 Ω + 33 µH
2280
THD = 1%, VBAT = 3.6 V, f = 1 kHz, 6 dB crest
factor sine burst, no clipping
5.45
mW
VO
Peak output voltage
AV
Voltage gain
20
20.5
dB
|VOOS |
Output offset voltage
2
10
mV
Short-circuit protection threshold
current
2
19.5
Input impedance (per input pin)
AV = 20 dB
RIN
Input impedance in shutdown (per
input pin)
EN = 0 V
ZO
Output impedance in shutdown
Boost converter auto-pass through
threshold
fCLASS-D
Class-D switching frequency
η
Class-D and boost combined
efficiency
A
24
kΩ
1300
Class-D output voltage threshold when boost
converter automatically turns on
275
PO = 1 W, VBAT = 3.6 V
V
2
kΩ
2
VPK
300
325
82%
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Operating Characteristics (continued)
VBAT= 3.6 V, EN = VBAT, AGC = GND, TA = 25°C, RL = 8 Ω + 33 μH (unless otherwise noted)
PARAMETER
EN
Noise output voltage
SNR
Signal-to-noise ratio
TEST CONDITIONS
MIN
A-weighted
49
Unweighted
65
1.7 W, RL = 8 Ω + 33 µH. A-weighted
97
1.7 W, RL = 8 Ω + 33 µH. Unweighted
95
2 W, RL = 4 Ω + 33 µH. A-weighted
95
2 W, RL = 4 Ω + 33 µH. Unweighted
Total harmonic distortion plus
noise (1)
THD+N
TYP
MAX
UNIT
μVRMS
dB
93
PO = 100 mW, f = 1 kHz
0.06%
PO = 500 mW, f = 1 kHz
0.07%
PO = 1.7 W, f = 1 kHz, RL = 8 Ω + 33 µH
0.07%
PO = 2 W, f = 1 kHz, RL = 4 Ω + 33 µH
0.15%
THD+N added to other audio signal
connected at amplifier input during
shutdown
0.02%
AC PSRR
AC-Power supply ripple rejection
(output referred)
200 mVPP square ripple, VBAT = 3.8 V, f = 217 Hz
62.5
200 mVPP square ripple, VBAT = 3.8 V, f = 1 kHz
62.5
AC CMRR
AC-Common mode rejection ratio
(output referred)
200 mVPP square ripple, VBAT = 3.8 V, f = 217 Hz
71
200 mVPP square ripple, VBAT = 3.8 V, f = 1 kHz
71
dB
dB
AUTOMATIC GAIN CONTROL
(1)
6
AGC maximum attenuation
10
dB
AGC attenuation resolution
0.5
dB
AGC attack time (gain decrease)
20
µs/dB
AGC release time (gain increase)
1.6
s/dB
7.5
dB/V
Gain vs VBAT slope
VBAT < inflection point
AGC inflection point
(Note: AGC pin voltage is read only
at device powerup. A device power cycle is
required to change AGC inflection
points.)
AGC = Float
3.25
AGC = GND
3.55
AGC = VBAT
3.75
V
A-weighted
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8.7 Typical Characteristics
VBAT = 3.6 V, CI = 1 µF, CBOOST = 22 µF, LBOOST = 2.2 µH, EN = VBAT, and Load = 8 Ω + 33 µH, no ferrite bead unless otherwise
specified.
Figure 1. Output Power vs Supply Voltage
Figure 2. Output Power vs Supply Voltage
Figure 3. Total Supply Current vs Output Power
Figure 4. Total Supply Current vs Output Power
Figure 5. Total Harmonic Distortion + Noise vs Frequency
Figure 6. Total Harmonic Distortion + Noise vs Frequency
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Typical Characteristics (continued)
VBAT = 3.6 V, CI = 1 µF, CBOOST = 22 µF, LBOOST = 2.2 µH, EN = VBAT, and Load = 8 Ω + 33 µH, no ferrite bead unless
otherwise specified.
8
Figure 7. Total Harmonic Distortion + Noise vs Output
Power
Figure 8. Total Harmonic Distortion + Noise vs Output
Power
Figure 9. Gain vs Supply Voltage
Figure 10. Gain vs Supply Voltage
Figure 11. Maximum Peak Output Voltage vs Supply Voltage
Figure 12. Maximum Peak Output Voltage vs Supply Voltage
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Typical Characteristics (continued)
VBAT = 3.6 V, CI = 1 µF, CBOOST = 22 µF, LBOOST = 2.2 µH, EN = VBAT, and Load = 8 Ω + 33 µH, no ferrite bead unless
otherwise specified.
Figure 13. Supply Current vs Supply Voltage
Figure 14. Supply Current vs Supply Voltage
Figure 15. Total Efficiency vs Output Power
Figure 16. Total Efficiency vs Output Power
Figure 17. Total Power Dissipation vs Output Power
Figure 18. Total Power Dissipation vs Output Power
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Typical Characteristics (continued)
VBAT = 3.6 V, CI = 1 µF, CBOOST = 22 µF, LBOOST = 2.2 µH, EN = VBAT, and Load = 8 Ω + 33 µH, no ferrite bead unless
otherwise specified.
Figure 19. Quiescent Supply Current vs Supply Voltage
Figure 20. Supply Ripple Rejection vs Frequency
Figure 21. Common Mode Rejection Ratio vs Frequency
10
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9 Parameter Measurement Information
All parameters are measured according to the conditions described in the Specifications section.
Many audio analyzers will not give the correct readings on a Class-D amplifier without additional filtering, even if
they have an internal low-pass filter. A RC 30kHz low-pass filter (100-Ω, 47n-F) is implemented to reduce the
remaining noise frequencies from the PWM carrier signal. This filter was used on each output for the data sheet
graphs.
10 Detailed Description
10.1 Overview
The TPA2025D1 is a constant output, high efficiency Class-D audio amplifier with battery tracking AGC
technology and an integrated Class-G boost converter. This features give the device a great performance and
enhances efficiency at low output power. The TPA2025D1 can drive up to 1.9 W into an 8-Ω speaker (1%
THD+N).
The built-in boost converter operates from a battery supply voltage and generates a higher output voltage PVDD
at 5.75 V that drives the supply voltage of the Class-D amplifier. This provides a louder audio output than a
stand-alone amplifier directly connected to the battery.
The battery tracking AGC adjusts the Class-D gain to limit battery current at lower battery voltage. This lets the
device to extend the battery life while playing audio, typically with 85% efficiency. When the battery voltage is
below a certain threshold voltage, The TPA2025D1 lowers the audio loudness. The threshold is selectable with
an external pin.
The TPA2025D1 has an integrated low-pass filter to improve the RF rejection and reduce DAC out-of-band
noise, increasing the signal-to-noise ratio (SNR). The features included in this device allow it to be used in a wide
range of portable applications.
10.2 Functional Block Diagram
EN
Bias
Control
VBAT
SW
VBAT
Monitor
Adaptive
Boost
Converter
PVDD
Oscillator
AGC
PVDD
IN+
+
AGC
IN-
PWM
–
AGND
HBridge
OUT+
OUTPGND
BGND
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10.3 Feature Description
10.3.1 Battery Tracking Automatic Gain Control (AGC)
TPA2025D1 monitors the battery voltage and automatically reduces the gain when the battery voltage is below a
certain threshold voltage, which is defined as inflection point. Although battery tracking AGC lowers the audio
loudness, it prevents high battery current at end-of-charge battery voltage. The inflection point is selectable at
AGC pin. When the amplifier is turned on, the gain is set according to battery voltage and selected inflection
point.
Figure 22 shows the plot of gain as a function of battery supply voltage. The default slope is 7.5 dB/V. When
battery voltage drops below inflection point by 1 V, AGC reduces the gain by 7.5 dB. The TPA2025D1 can only
operate at one slope.
Figure 22. Gain vs Battery voltage
10.3.2 Boost Converter Auto Pass Through (APT)
The TPA2025D1 consists of an adaptive boost converter and a Class-D amplifier. The boost converter operates
from the supply voltage, VBAT, and generates a higher output voltage PVDD at 5.75 V. PVDD drives the supply
voltage of the Class-D amplifier. This improves loudness over non-boosted solutions. The boost converter has a
“Pass Through” mode in which it turns off automatically and PVDD is directly connected to VBAT through an
internal bypass switch.
The boost converter is adaptive and operates between pass through mode and boost mode depending on the
output audio signal amplitude. When the audio output amplitude exceeds the “auto pass through” (APT)
threshold, the boost converter is activated automatically and goes to boost mode. The transition time from normal
mode to boost mode is less than 3 ms. TPA2025D1’s APT threshold is fixed at 2 Vpk. When the audio output
signal is below APT threshold, the boost converter is deactivated and goes to pass through mode. The adaptive
boost converter maximizes system efficiency in lower audio output level.
The battery AGC is independent of APT threshold. The AGC operates in both boost-active and APT modes.
Figure 23 shows how the adaptive boost converter behaves with a typical audio signal.
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Feature Description (continued)
Figure 23. Adaptive Boost Converter with Typical Music Playback
10.3.3 Short Circuit Auto-Recovery
When a short circuit event happens, the TPA2025D1 goes to low duty cycle mode and tries to reactivate itself
every 1.6 seconds. This auto-recovery continues until the short circuit event stops. This feature protects the
device without affecting its long term reliability.
10.3.4 Thermal Protection
It is important to operate the TPA2025D1 at temperatures lower than its maximum operating temperature. The
maximum ambient temperature depends on the heat-sinking ability of the PCB system. Given θJA of 97.3°C/W,
the maximum allowable junction temperature of 150°C, and the internal dissipation of 0.5 W for 1.9 W, 8 Ω load,
3.6 V supply, the maximum ambient temperature is calculated as:
TA,MAX = TJ,MAX – θJA PD = 150°C – (97.3°C/W × 0.5W) = 101.4°C
The calculated maximum ambient temperature is 101.4°C at maximum power dissipation at 3.6 V supply and 8 Ω
load. The TPA2025D1 is designed with thermal protection that turns the device off when the junction temperature
surpasses 150°C to prevent damage to the IC.
10.3.5 Operation with DACS and Codecs
Large noise voltages can be present at the output of ΔΣ DACs and CODECs, just above the audio frequency
(e.g: 80 kHz with a 300 mVP-P). This out-of-band noise is due to the noise shaping of the delta-sigma modulator
in the DAC. Some Class-D amplifiers have higher output noise when used in combination with these DACs and
CODECs. This is because out-of-band noise from the CODEC/DAC mixes with the Class-D switching
frequencies in the audio amplifier input stage. The TPA2025D1 has a built-in low-pass filter with cutoff frequency
at 55 kHz that reduces the out-of-band noise and RF noise, filtering out-of-band frequencies that could degrade
in-band noise performance. This built-in filter also prevents AGC errors due to out-of-band noise. The
TPA2025D1 AGC calculates gain based on input signal amplitude only. If driving the TPA2025D1 input with 4thorder or higher ΔΣ DACs or CODECs, add an R-C low pass filter at each of the audio inputs (IN+ and IN-) of the
TPA2025D1 to ensure best performance. The recommended resistor value is 100 Ω and the capacitor value of
47 nF.
10.4 Device Functional Modes
10.4.1 Operation Below AGC Threshold
When the battery power supply voltage is below a certain threshold voltage, the TPA2025D1 starts reducing the
gain automatically. This AGC threshold is selected by external AGC pin at 3.25 V, 3.55 V and 3.75 V for FLOAT,
LOW and HIGH levels respectively.
Figure 24 shows the operation of AGC in time domain.
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Device Functional Modes (continued)
Battery Voltage
Inflection point voltage
0.5 dB
Gain
10 µs
Attack Time
20 µs/ dB
Release Time
1.6 s/ dB
Release time counter starts
Phase 1
Phase 2
Phase 3
Phase 4
Phase 5
Phase 6
Phase 7
Phase 8
Zoom -in time scale
Figure 24. Relationship Between Supply Voltage and Gain in Time Domain
Phase 1
Battery discharging normally; supply voltage is above inflection point; audio gain remains at 20 dB.
Phase 2
Battery voltage decreases below inflection point. AGC responds in 10 μs and reduces gain by one
step (0.5 dB)
Phase 3
Battery voltage continues to decrease. AGC continues to reduce gain. The rate of gain decrease is
defined as attack time. TPA2025D1’s attack time is 20 µs/dB.
Phase 4
Battery voltage is constant. AGC stops reducing gain.
Phase 5
Battery voltage decreases suddenly. AGC reduces gain multiple steps. (time scale from this phase
is longer) Release time counter resets every end of attack event.
Phase 6
Release time has elapsed. Battery voltage returns to previous level. AGC increases gain by one
step. TPA2025D1’s release time is 1.6 s/dB
Phase 7
Battery voltage remains constant. AGC continues to increase gain until it reaches steady state gain
value defined in Figure 22.
Phase 8
Battery voltage is recharged to above inflection point. AGC continues to increase gain until it
reaches 20 dB.
10.4.2 Shutdown Mode
The TPA2025D1 can be put in shutdown mode when asserting EN pin to a logic LOW. While in shutdown mode,
the device output stage is turned off and the current consumption is very low. The device exits shutdown mode
when a HIGH logic level is applied to EN pin.
14
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11 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
11.1 Application Information
The TPA2025D1 is a Class D amplifier with integrated automatic gain control and boost converter. This device is
capable of drive up to 1.9W to 8-Ω Speaker (1% THD+N). TPA2025D1 starts operating when setting EN pin to
HIGH level. The device enters in shutdown mode when asserting EN to LOW level. AGC pin connection sets the
threshold where the device will start reducing the output amplitude. The selectable threshold voltages are
specified in the Operating Characteristics section. In order to measure the TPA2025D1 output with an analyzer, a
30KHz Low pass filter should be implemented.
11.2 Typical Application
(1)
The 1-µF input capacitors on IN+ and IN- were shorted for input common-mode voltage measurements.
(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 R-C low-pass filter
(100 Ω, 47 nF) is used on each output for the data sheet graphs.
Figure 25. Typical Application Schematic
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Typical Application (continued)
11.2.1 Design Requirements
For this design example, use the parameters listed in Table 1.
Table 1. Design Parameters
PARAMETER
VALUE
Supply voltage range
2.5 V - 5.2 V
Input voltage range
0V-5V
Peak output voltage
5.45 V
Max output current
1.8 A
11.2.2 Detailed Design Procedure
11.2.2.1 Boost Converter Component Section
The critical external components are summarized in the following table:
PARAMETER
TEST CONDITIONS
Boost converter inductor
At 30% rated DC bias current of the inductor
MIN
1.5
Boost converter input
capacitor
Boost converter output
capacitor
Working capacitance biased at boost output voltage, if 4.7µH inductor is chosen,
then minimum capacitance is 10 µF
TYP MAX
2.2
UNIT
4.7
µH
4.7
10
µF
4.7
22
µF
11.2.2.1.1 Inductor Equations
Inductor current rating is determined by the requirements of the load. The inductance is determined by two
factors: the minimum value required for stability and the maximum ripple current permitted in the application. Use
Equation 1 to determine the required current rating. Equation 1 shows the approximate relationship between the
average inductor current, IL, to the load current, load voltage, and input voltage (IPVDD, PVDD, and VBAT,
respectively). Insert IPVDD, PVDD, and VBAT into Equation 1 and solve for IL. The inductor must maintain at least
90% of its initial inductance value at this current.
PVDD
æ
ö
IL = IPVDD ´ ç
÷
è VBAT ´ 0.8 ø
(1)
Ripple current, ΔIL, is peak-to-peak variation in inductor current. Smaller ripple current reduces core losses in the
inductor and reduces the potential for EMI. Use Equation 2 to determine the value of the inductor, L. Equation 2
shows the relationship between inductance L, VBAT, PVDD, the switching frequency, fBOOST, and ΔIL. Insert the
maximum acceptable ripple current into Equation 2 and solve for L.
VBAT ´ (PVDD - VBAT)
L=
DIL ´ ¦BOOST ´ PVDD
(2)
ΔIL is inversely proportional to L. Minimize ΔIL as much as is necessary for a specific application. Increase the
inductance to reduce the ripple current. Do not use greater than 4.7 μH, as this prevents the boost converter
from responding to fast output current changes properly. If using above 3.3 µH, then use at least 10 µF
capacitance on PVDD to ensure boost converter stability.
The typical inductor value range for the TPA2025D1 is 2.2 μH to 3.3 µH. Select an inductor with less than 0.5 Ω
dc resistance, DCR. Higher DCR reduces total efficiency due to an increase in voltage drop across the inductor.
16
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Table 2. Sample Inductors
L
(µH)
SIZE
(LxWxH mm)
DCR
TYP
(mΩ)
ISAT
MAX
(A)
1239AS-H-2R2N=P2
2.5 x 2.0 x 1.2
96
2.3
XFL4020-222MEC
4.0 x 4.0 x 2.15
22
3.5
Toko
1239AS-H-3R3N=P2
2.5 x 2.0 x 1.2
160
2.0
Coilcraft
XFL4020-332MEC
4.0 x 4.0 x 2.15
35
2.8
SUPPLIER
COMPONENT CODE
2.2
Toko
2.2
Coilcraft
3.3
3.3
C RANGE
4.7 - 22 µF / 16 V
6.8 - 22 µV / 10 V
10 - 22 µF / 10 V
11.2.2.1.2 Boost Converter Capacitor Selection
The value of the boost capacitor is determined by the minimum value of working capacitance required for stability
and the maximum voltage ripple allowed on PVDD in the application. Working capacitance refers to the available
capacitance after derating the capacitor value for DC bias, temperature, and aging. Do not use any component
with a working capacitance less than 4.7 µF. This corresponds to a 4.7 μF/16 V capacitor, or a 6.8 μF/10 V
capacitor.
Do not use above 22 μF capacitance as it will reduce the boost converter response time to large output current
transients.
Equation 3 shows the relationship between the boost capacitance, C, to load current, load voltage, ripple voltage,
input voltage, and switching frequency (IPVDD, PVDD, ΔV, VBAT, and fBOOST respectively).
Insert the maximum allowed ripple voltage into Equation 3 and solve for C. The 1.5 multiplier accounts for
capacitance loss due to applied dc voltage and temperature for X5R and X7R ceramic capacitors.
I
´ (PVDD - VBAT)
C = 1.5 ´ PVDD
DV ´ ¦BOOST ´ PVDD
(3)
11.2.2.1.3 Boost Terms
The following is a list of terms and definitions used in the boost equations.
C
Minimum boost capacitance required for a given ripple voltage on PVDD.
L
Boost inductor
fBOOST
Switching frequency of the boost converter.
IPVDD
Current pulled by the Class-D amplifier from the boost converter.
IL
Average current through the boost inductor.
PVDD
Supply voltage for the Class-D amplifier. (Voltage generated by the boost converter output)
VBAT
Supply voltage to the IC.
ΔIL
Ripple current through the inductor.
ΔV
Ripple voltage on PVDD.
11.2.2.2 Input Capacitors
Input audio DC decoupling capacitors are recommended. The input audio DC decoupling capacitors prevents the
AGC from changing the gain due to audio DAC output offset. The input capacitors and TPA2025D1 input
impedance form a high-pass filter with the corner frequency, fC, determined in Equation 4.
Any mismatch in capacitance between the two inputs will cause a mismatch in the corner frequencies. Severe
mismatch may also cause turn-on pop noise. Choose capacitors with a tolerance of ±10% or better.
1
fc =
2
p
x
x RICI )
(
(4)
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11.2.2.3 Speaker Load Limitation
Speakers are non-linear loads with varying impedance (magnitude and phase) over the audio frequency. A
portion of speaker load current can flow back into the boost converter output via the Class-D output H-bridge
high-side device. This is dependent on the speaker's phase change over frequency, and the audio signal
amplitude and frequency content. Most portable speakers have limited phase change at the resonant frequency,
typically no more than 40 or 50 degrees. To avoid excess flow-back current, use speakers with limited phase
change. Otherwise, flow-back current could drive the PVDD voltage above the absolute maximum recommended
operational voltage.
Confirm proper operation by connecting the speaker to the TPA2025D1 and driving it at maximum output swing.
Observe the PVDD voltage with an oscilloscope. In the unlikely event the PVDD voltage exceeds 6.5 V, add a
6.8 V Zener diode between PVDD and ground to ensure the TPA2025D1 operates properly. The amplifier has
thermal overload protection and deactivates if the die temperature exceeds 150°C. It automatically reactivates
once die temperature returns below 150°C. Built-in output over-current protection deactivates the amplifier if the
speaker load becomes short-circuited. The amplifier automatically restarts 1.6 seconds after the over-current
event. Although the TPA2025D1 Class-D output can withstand a short between OUT+ and OUT-, do not connect
either output directly to GND, VDD, or VBAT as this could damage the device.
11.2.3 Application Curve
18
Figure 26. Input Impedance vs Gain
Figure 27. Boost Startup Current vs Time
Figure 28. A-Weighted Noise vs Frequency
Figure 29. Startup Timing
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Figure 30. Shutdown Timing
Figure 31. EMC Performance Po = 750 mW with 2 Inch
Speaker Cable
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12 Power Supply Recommendations
The TPA2025D1 is designed to operate from an input voltage supply range between 2.5-V and 5.2-V. Therefore,
the output voltage range of power supply should be within this range and well regulated. The current capability of
upper power should not exceed the maximum current limit of the power switch.
12.1 Power Supply Decoupling Capacitors
The TPA2025D1 is a high-performance Class-D audio amplifier that requires adequate power supply decoupling.
Adequate power supply decoupling to ensures that the efficiency is high and total harmonic distortion (THD) is
low.
Place a low equivalent-series-resistance (ESR) ceramic capacitor, typically 0.1 µF, within 2 mm of the VBAT ball.
This choice of capacitor and placement helps with higher frequency transients, spikes, or digital hash on the line.
Additionally, placing this decoupling capacitor close to the TPA2025D1 is important, as any parasitic resistance
or inductance between the device and the capacitor causes efficiency loss. In addition to the 0.1 μF ceramic
capacitor, place a 2.2 µF to 10 µF capacitor on the VBAT supply trace. This larger capacitor acts as a charge
reservoir, providing energy faster than the board supply, thus helping to prevent any droop in the supply voltage.
13 Layout
13.1 Layout Guidelines
Decoupling capacitors should be placed as close to the supply voltage pin as possible. For this device a 10-µF
high-quality ceramic capacitor is recommended.
Table 3. Land Pattern Dimensions (1)
SOLDER PAD
DEFINITIONS
COPPER
PAD
Nonsolder mask
defined (NSMD)
275 μm
(+0.0, -25 μm)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
20
SOLDER MASK
OPENING
(5)
375 μm (+0.0, -25 μm)
(2) (3) (4)
COPPER
THICKNESS
STENCIL (6) (7)
OPENING
STENCIL
THICKNESS
1 oz max (32 μm)
275 μm x 275 μm Sq.
(rounded corners)
125 μm thick
Circuit traces from NSMD defined PWB lands should be 75 μm to 100 μm wide in the exposed area inside the solder mask opening.
Wider trace widths reduce device stand off and impact reliability.
Best reliability results are achieved when the PWB laminate glass transition temperature is above the operating the range of the
intended application.
Recommend solder paste is Type 3 or Type 4.
For a PWB using a Ni/Au surface finish, the gold thickness should be less 0.5 mm to avoid a reduction in thermal fatigue performance.
Solder mask thickness should be less than 20 μm on top of the copper circuit pattern
Best solder stencil performance is achieved using laser cut stencils with electro polishing. Use of chemically etched stencils results in
inferior solder paste volume control.
Trace routing away from WCSP device should be balanced in X and Y directions to avoid unintentional component movement due to
solder wetting forces.
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Copper Trace Width
Solder Pad Width
Solder Mask Opening
Copper Trace Thickness
Solder Mask Thickness
M0200-01
Figure 32. Land Pattern Dimensions
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13.2 Layout Example
Figure 33. TPA2025D1 Layout Example
22
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14 Device and Documentation Support
14.1 Trademarks
All trademarks are the property of their respective owners.
14.2 Electrostatic Discharge Caution
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.
14.3 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
15 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
TPA2025D1YZGR
ACTIVE
DSBGA
YZG
12
3000
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
TPA2025D1
TPA2025D1YZGT
ACTIVE
DSBGA
YZG
12
250
RoHS & Green
SNAGCU
Level-1-260C-UNLIM
-40 to 85
TPA2025D1
(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)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of