SLOS660C January   2010  – October 2015 TPA2028D1

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 Operating Characteristics
    7. 7.7 I2C Timing Requirements
    8. 7.8 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 Automatic Gain Control
      2. 9.3.2 Operation With DACs and CODECs
      3. 9.3.3 Filter Free Operation and Ferrite Bead Filters
      4. 9.3.4 General I2C Operation
        1. 9.3.4.1 Single- and Multiple-Byte Transfers
        2. 9.3.4.2 Single-Byte Write
        3. 9.3.4.3 Multiple-Byte Write and Incremental Multiple-Byte Write
        4. 9.3.4.4 Single-Byte Read
        5. 9.3.4.5 Multiple-Byte Read
    4. 9.4 Device Functional Modes
      1. 9.4.1 Enable/Disable Amplifier
      2. 9.4.2 TPA2028D1 AGC and Start-Up Operation
        1. 9.4.2.1 AGC Startup Condition
      3. 9.4.3 Short Circuit Auto-Recovery
    5. 9.5 Programming
      1. 9.5.1 TPA2028D1 AGC Recommended Settings
    6. 9.6 Register Maps
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Decoupling Capacitor CS
        2. 10.2.2.2 Input Capacitors CI)
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Decoupling Capacitors
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Component Placement
      2. 12.1.2 Trace Width
      3. 12.1.3 Pad Size
    2. 12.2 Layout Example
    3. 12.3 Efficiency and Thermal Considerations
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    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

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12 Layout

12.1 Layout Guidelines

12.1.1 Component Placement

Place all the external components very close to the TPA2028D1. Placing the decoupling capacitor, CS, close to the TPA2028D1 is important for the efficiency of the Class-D amplifier. Any resistance or inductance in the trace between the device and the capacitor can cause a loss in efficiency.

12.1.2 Trace Width

Recommended trace width at the solder balls is 75 μm to 100 μm to prevent solder wicking onto wider PCB traces. For high current pins (PVDD (L, R), PGND, and audio output pins) of the TPA2028D1, use 100-μm trace widths at the solder balls and at least 500-μm PCB traces to ensure proper performance and output power for the device. For the remaining signals of the TPA2028D1, use 75-μm to 100-μm trace widths at the solder balls. The audio input pins (IN+ and IN–) must run side-by-side to maximize common-mode noise cancellation

12.1.3 Pad Size

In making the pad size for the DSBGA balls, TI recommends that the layout use non solder mask defined (NSMD) land. With this method, the solder mask opening is made larger than the desired land area, and the opening size is defined by the copper pad width. Figure 50 and Table 15 shows the appropriate diameters for a DSBGA layout. The TPA2028D1 evaluation module (EVM) layout is shown in the next section as a layout example.

TPA2028D1 land_pat_los524.gif Figure 50. Land Pattern Dimensions

Table 15. Land Pattern Dimensions(1) (2) (3) (4)

SOLDER PAD DEFINITIONS COPPER PAD SOLDER MASK(5) OPENING COPPER THICKNESS STENCIL(6) (7) OPENING STENCIL THICKNESS
Non solder mask defined (NSMD) 275 μm
(+0.0, –25 μm)		 375 μm
(+0.0, –25 μm)		 1 oz max (32 μm) 275 μm × 275 μm Sq. (rounded corners) 125 μm thick
(1) 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.
(2) Best reliability results are achieved when the PWB laminate glass transition temperature is above the operating the range of the intended application.
(3) Recommend solder paste is Type 3 or Type 4.
(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.
(5) Solder mask thickness should be less than 20 μm on top of the copper circuit pattern
(6) 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.
(7) Trace routing away from DSBGA device should be balanced in X and Y directions to avoid unintentional component movement due to solder wetting forces.

12.2 Layout Example

TPA2028D1 tpa2028d1_lyout_ex.gif Figure 51. TPA2028D1 Layout Example

12.3 Efficiency and Thermal Considerations

The maximum ambient temperature depends on the heat-sinking ability of the PCB system. The derating factor for the packages are shown in the dissipation rating table. Converting this to θJA for the DSBGA package:

Equation 7. TPA2028D1 eq_tja_los592.gif

Given θJA of 105°C/W, the maximum allowable junction temperature of 150°C, and the maximum internal dissipation of 0.4 W for 3 W output power, 4-Ω load, 5-V supply, from Figure 17, the maximum ambient temperature can be calculated with the following equation.

Equation 8. TPA2028D1 eq_tamax_los592.gif

Equation 8 shows that the calculated maximum ambient temperature is 108°C at maximum power dissipation with a 5-V supply and 4-Ω a load. The TPA2028D1 is designed with thermal protection that turns the device off when the junction temperature surpasses 150°C to prevent damage to the IC. Also, using speakers more resistive than 8-Ω dramatically increases the thermal performance by reducing the output current and increasing the efficiency of the amplifier.