SLOS438F December   2004  – March 2017 TPA2012D2

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Dissipation Rating Table
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Fixed Gain Setting
      2. 9.3.2 Short-Circuit Protection
      3. 9.3.3 Operation With DACs and CODECs
      4. 9.3.4 Filter-Free Operation and Ferrite Bead Filters
    4. 9.4 Device Functional Modes
      1. 9.4.1 Shutdown Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 TPA2012D2 With Differential Input Signal
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Surface Mount Capacitors
          2. 10.2.1.2.2 Decoupling Capacitor (CS)
          3. 10.2.1.2.3 Input Capacitors (CI)
        3. 10.2.1.3 Application Curves
      2. 10.2.2 TPA2012D2 With Single-Ended Input Signal
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
        3. 10.2.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Decoupling Capacitor
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Pad Side
      2. 12.1.2 Component Location
      3. 12.1.3 Trace Width
    2. 12.2 Layout Examples
    3. 12.3 Efficiency and Thermal Considerations
  13. 13Device and Documentation Support
    1. 13.1 Receiving Notification of Documentation Updates
    2. 13.2 Community Resources
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

10 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.

10.1 Application Information

These typical connection diagrams highlight the required external components and system level connections for proper operation of the device. Each of these configurations can be realized using the evaluation modules (EVMs) for the device. These flexible modules allow full evaluation of the device in the most common modes of operation. Any design variation can be supported by TI through schematic and layout reviews. Visit e2e.ti.com for design assistance and join the audio amplifier discussion forum for additional information.

10.2 Typical Applications

10.2.1 TPA2012D2 With Differential Input Signal

TPA2012D2 Differential_los348.gif Figure 37. Typical Application Schematic With Differential Input Signals

10.2.1.1 Design Requirements

For this design example, use the parameters listed in Table 2.

Table 2. Design Parameters

PARAMETER VALUE
Power supply 5 V
Enable inputs High > 1.3 V
Low < 0.35 V
Speaker 8 Ω

10.2.1.2 Detailed Design Procedure

10.2.1.2.1 Surface Mount Capacitors

Temperature and applied DC voltage influence the actual capacitance of high-K materials. Table 3 shows the relationship between the different types of high-K materials and their associated tolerances, temperature coefficients, and temperature ranges. Notice that a capacitor made with X5R material can lose up to 15% of its capacitance within its working temperature range.

In an application, the working capacitance of components made with high-K materials is generally much lower than nominal capacitance. A worst-case result with a typical X5R material might be –10% tolerance, –15% temperature effect, and –45% DC voltage effect at 50% of the rated voltage. This particular case would result in a working capacitance of 42% (0.9 × 0.85 × 0.55) of the nominal value.

Select high-K ceramic capacitors according to the following rules:

  1. Use capacitors made of materials with temperature coefficients of X5R, X7R, or better.
  2. Use capacitors with DC voltage ratings of at least twice the application voltage. Use minimum 10-V capacitors for the TPA2012D2.
  3. Choose a capacitance value at least twice the nominal value calculated for the application. Multiply the nominal value by a factor of 2 for safety. If a 10-µF capacitor is required, use 20 µF.

The preceding rules and recommendations apply to capacitors used in connection with the TPA2012D2. The TPA2012D2 cannot meet its performance specifications if the rules and recommendations are not followed.

Table 3. Typical Tolerance and Temperature Coefficient of Capacitance by Material

MATERIAL COG/NPO X7R X5R
Typical tolerance ±5% ±10% 80% to –20%
Temperature ±30 ppm ±15% 22% to –82%
Temperature range (°C) –55°C to 125°C –55°C to 125°C –30°C to 85°C

10.2.1.2.2 Decoupling Capacitor (CS)

The TPA2012D2 is a high-performance Class-D audio amplifier that requires adequate power supply decoupling to 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, typically
1 µF, placed as close as possible to the device PVDD lead works best. Placing this decoupling capacitor close to the TPA2012D2 is important for the efficiency of the Class-D amplifier, because any resistance or inductance in the trace between the device and the capacitor can cause a loss in efficiency. For filtering lower-frequency noise signals, a 4.7 µF or greater capacitor placed near the audio power amplifier would also help, but it is not required in most applications because of the high PSRR of this device.

10.2.1.2.3 Input Capacitors (CI)

The TPA2012D2 does not require input coupling capacitors if the design uses a differential source that is biased from 0.5 V to VDD – 0.8 V. If the input signal is not biased within the recommended common-mode input range, if high-pass filtering is needed (see Figure 37), or if using a single-ended source (see Figure 38), input coupling capacitors are required.

The input capacitors and input resistors form a high-pass filter with the corner frequency, fc, determined in Equation 1.

Equation 1. TPA2012D2 q_fc_los438.gif

The value of the input capacitor is important to consider as it directly affects the bass (low frequency) performance of the circuit. Speakers in wireless phones cannot usually respond well to low frequencies, so the corner frequency can be set to block low frequencies in this application. Not using input capacitors can increase output offset.

Equation 2 is used to solve for the input coupling capacitance.

Equation 2. TPA2012D2 q_ci_los438.gif

If the corner frequency is within the audio band, the capacitors should have a tolerance of ±10% or better, because any mismatch in capacitance causes an impedance mismatch at the corner frequency and below.

10.2.1.3 Application Curves

For application curves, see the figures listed in Table 4.

Table 4. Table of Graphs

DESCRIPTION FIGURE NO.(1)
THD+N vs Output power Figure 1
THD+N vs Frequency Figure 5
Power dissipation vs Output power Figure 24
Output power vs Supply voltage Figure 32
(1) All figure numbers have a hyperlink to a figure in the Typical Characteristics.

10.2.2 TPA2012D2 With Single-Ended Input Signal

TPA2012D2 Single_ended_los438.gif Figure 38. Typical Application Schematic With Single-Ended Input Signal

10.2.2.1 Design Requirements

For this design example, use the parameters listed in Table 2.

10.2.2.2 Detailed Design Procedure

For the design procedure, see Detailed Design Procedure from the previous example.

10.2.2.3 Application Curves

For application curves, see the figures listed in Table 4.