TPA005D12 ClassĆD Stereo Audio Power Amplifier Evaluation Module User’s Guide August 1999 Mixed-Signal Products SLOU051A
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.
Preface Related Documentation From Texas Instruments J J J J TI Plug-N-Play Audio Amplifier Evaluation Platform (TI Literature Number SLOU011) provides detailed information on the evaluation platform and its use with TI audio evaluation modules. TPA005D12 CLASS-D STEREO AUDIO POWER AMPLIFIER (TI Literature Number SLOS246) This is the data sheet for the TPA005D12 audio amplifier integrated circuit.
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Running Title—Attribute Reference Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.
Running Title—Attribute Reference Figures 1–1 1–2 2–1 3–1 3–2 3–3 3–4 3–5 3–6 3–7 3–8 3–9 3–10 3–11 3–12 3–13 3–14 3–15 3–16 3–17 3–18 3–19 3–20 3–21 3–22 3–23 3–24 The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Top View . . . . . . . . . 1-3 The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Bottom View . . . . . . 1-3 Quick Start Platform Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1 Introduction This chapter provides an overview of the Texas Instruments (TI) TPA005D12 class-D stereo audio power amplifier evaluation module (SLOP246). It includes a list of EVM features, a brief description of the module illustrated with a pictorial diagram, and a list of EVM specifications. Topic Page 1.1 Feature Highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1–2 1.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Feature Highlights 1.1 Feature Highlights The TI TPA005D12 class-D stereo audio power amplifier evaluation module and the TI plug-n-play audio amplifier evaluation platform include the following features: - - TPA005D12 Class-D Stereo Audio Power Amplifier Evaluation Module J J J J J J J J J J J J J - 1-2 Dual channel, bridge-tied load (BTL) only operation 5 V operation 2 W BTL output into 4 Ω at 5 V Low current consumption in shutdown/mute mode (50 µA/2.
Description 1.2 Description The TPA005D12 class-D stereo audio power amplifier evaluation module is a complete, 2-Watt per channel stereo audio power amplifier. It consists of the TI TPA005D12 class-D stereo audio power amplifier IC along with a small number of other parts mounted on a circuit board that measures approximately 2 ¼ inches by 2 ¼ inches (Figure 1–1 and 1–2).
TPA005D12 Class-D EVM Specifications Single in-line header pins extend from the underside of the module circuit board to allow the EVM to either be plugged into the TI plug-n-play audio Amplifier evaluation Platform, or to be wired directly into existing circuits and equipment when used stand-alone. The platform has room for a single TPA005D12 class-D evaluation module and is a convenient vehicle for demonstrating TI’s audio power amplifier and related evaluation modules.
Chapter 2 Quick Start Follow the steps in this chapter to quickly prepare the TPA005D12 class-D stereo audio amplifier EVM for use. Using the TPA005D12 class-D EVM with the TI plug-n-play audio amplifier evaluation platform is a quick and easy way to connect power, signal and control inputs, and signal outputs to the EVM using standard connectors.
Precautions 2.1 Precautions Power Supply Input Polarity and Maximum Voltage Always ensure that the polarity and voltage of the external power connected to VCC power input connector J1, J2, and/or VDD power input connector J6 are correct. Overvoltage or reverse-polarity power applied to these terminals can open onboard soldered-in fuses and cause other damage to the platform, installed evaluation modules, and/or the power source.
Quick Start List for Platform 2.2 Quick Start List for Platform Follow these steps when using the TPA005D12 class-D EVM with the TI plug-n-play audio amplifier evaluation platform (see the platform user’s guide, SLOU011, for additional details). Numbered callouts for selected steps are shown in Figure 2–1 and details appear in Chapter 3. - Platform Preparations 1) Ensure that all external power sources are set to OFF.
Quick Start List for Stand-Alone 2.3 Quick Start List for Stand-Alone Follow these steps to use the TPA005D12 class-D EVM stand-alone or to connect it into existing circuits or equipment. Connections to the TPA005D12 module header pins can be made via individual sockets, wire-wrapping, or soldering to the pins, either on the top or the bottom of the module circuit board. - Power supply 1) Ensure that all external power sources are set to OFF.
Chapter 3 Details This chapter provides details on the TPA005D12 IC, the evaluation module, and the steps in the Quick-Start list, a discussion of class-D amplifiers, additional application information, a parts list for the TPA005D12 class-D evaluation module, module performance graphs, and module PCB layer illustrations. Topic Page 3.1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 3.
Precautions 3.1 Precautions Power Supply Input Polarity and Maximum Voltage Always ensure that the polarity and voltage of the external power connected to VCC power input connector J1, J2, and/or VDD power input connector J6 are correct. Overvoltage or reverse-polarity power applied to these terminals can open onboard soldered-in fuses and cause other damage to the platform, installed evaluation modules, and/or the power source.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module 3.2 The TPA005D12 Class-D Audio Power Amplifier Evaluation Module The TPA005D12 class-D stereo audio power amplifier evaluation module is powered by a TPA005D12 class-D stereo power amplifier integrated circuit. The EVM is capable of delivering greater than 2 W of continuous average power per channel into 4-Ω loads at less than 0.6% THD+N over a 20-Hz to 20-kHz frequency range from a 5-V supply.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module TP11 Lout+ Lout– SD TP12 L3 Texas Instruments 1999 TP10 TP9 C18 L2 TP8 C19 U1 C13 C14 TP4 C4 SD S2 TP3 TP2 + TP6 TP5 TP7 C5 Mute S1 C3 + VDD GND L1 C2 SLOP246 TPA005D12 EVM Board VDD2 GND L4 Mute Rout– Rout+ Figure 3–2. The TI TPA005D12 Class-D Stereo Audio Power Amplifier EVM — Top View R2 R1 C1 TP1 GND +RIN– –LIN+GND Figure 3–3.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module Figure 3–4. TPA005D12 Class-D EVM Schematic Diagram VDD R2 100k R1 100k SD S2 SD Mute S1 Mute LIN+ C13 C9 C10 10µF 1µF C8 1µF VDD LOUT+ C20 C24 1µF 0.22µF C21 0.22µF L1 15µH L3 15µH LOUT– C15 1µF VDD C17 0.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module 3.2.2 Overview of Class-D Audio Amplifiers Class-D audio amplifiers are very similar in operation to switch-mode power supplies in that both compare an input signal with a reference to create an error voltage that controls a pulse-width modulator (PWM) circuit. The PWM circuit then produces an output signal at constant frequency and with a duty cycle that varies according to the input signal.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module Figure 3–6. Class-D Input and Output Waveforms VIN VRAMP VDD VOUT 0V The VRAMP signal must be at a much higher frequency than the highest frequency component of VIN to obtain an accurate representation at the low-pass filter output and allow greater attenuation of the switching component of VOUT. The TPA005D12 class-D EVM uses a 250 kHz VRAMP signal to sample VIN.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module 3.2.4 Class-D Differential Inputs The TPA005D12 EVM line inputs allow the use of a single-ended or differential audio source. The differential input stage of the amplifier cancels any noise that appears on both input lines of a channel. To use the EVM with a differential source, connect the positive lead of the audio source to the RIN+/LIN+ inputs and the negative lead to the RIN–/LIN– inputs.
The TPA005D12 Class-D Audio Power Amplifier Evaluation Module 3.2.6 TPA005D12 Class-D EVM Test Points Test points have been included on the TPA005D12 class-D EVM to facilitate user analysis of device performance and design adjustments. Table 3–2 lists each test point and its corresponding function. Table 3–2.
Class-D Amplifier Design Considerations 3.3 Class-D Amplifier Design Considerations Detailed information for proper design and implementation of TI class-D audio power amplifiers appears in the application report Design Considerations for Class-D Audio Power Amplifiers, TI Literature Number SLOA031, on the TI website (http://www.ti.com/sc/apa). This document provides background information, general equations, and component selection criteria for the topics listed below.
Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform 3.4 Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform The TPA005D12 class-D stereo audio amplifier evaluation module was designed to be used with the TI plug-n-play audio amplifier evaluation platform. It simply plugs into socket U2 and U3. The following paragraphs provide additional details for using the TPA005D12 class-D EVM with the platform. 3.4.
Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform 3.4.2 Module Switches The TPA005D12 class-D stereo audio amplifier evaluation module is equipped with two pushbutton switches that allow the module shutdown and mute functions to be manually activated. 3.4.2.1 S1 — Shutdown To have the module amplifier IC enter the shutdown mode, press the Shutdown switch (S2) on the module. S2 connects the amplifier IC SHUTDOWN pin to ground, forcing it into a low-power state.
Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform 3.4.3 Signal Routing Signal flow on the platform is controlled by two signal routing switches, as shown in Figure 3 – 7. Figure 3–7. Platform Signal Routing and Outputs Off + Audio Input R R R U1 Signal Conditioning S2 – U2/U3 TPA005D12 Amplifier EVM – L L L J7, J8, J9 Speaker Outputs + On U2 – U4 R U5 Stereo Headphone Amplifier R S3 + – J10 Headphone Output – GND L L + U5 3.4.3.
Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform 3.4.4 Shutdown The TPA005D12 class-D EVM is equipped with a shutdown control input pin. When this input is tied to GND, the TPA005D12 amplifier IC on the module enters the shutdown mode and dissipates very little power. When the EVM control input is tied to VDD or allowed to float, amplifier operation resumes.
Using The TPA005D12 Class-D EVM With the Plug-N-Play Platform 3.4.4.2 Mute/Mode Select (JP6) A 3-pin jumper header (JP6) on the platform, functioning as an SPDT switch, routes the control signal from the headphone jack to either the mute control input pin or the mode control input pin of the evaluation module. J J 3.4.4.3 Set jumper JP6 to MODE when a separate headphone amplifier is NOT installed in U5. Set jumper JP6 to MUTE when a separate headphone amplifier IS installed in U5.
Power Requirements 3.4.5 Power Requirements The TPA005D12 class-D stereo audio power amplifier evaluation module is designed to operate from a supply voltage between 4.5 V and 5.5 V. For best performance (highest output power with lowest distortion), the module should be operated at 5 V. The TI plug-n-play audio amplifier evaluation platform provides several options for powering the TPA005D12 class-D EVM.
Inputs and Outputs 3.4.6 Inputs and Outputs The TI plug-n-play audio amplifier evaluation platform is equipped with several standard conectors for audio inputs and outputs. 3.4.6.1 Inputs In most cases, audio signals enter the platform through either a pair of RCA phono jacks (J3 and J5) or a miniature (1/8″) stereo phone jack (J4). Certain signal conditioning and amplifier EVMs, however, may have additional signal input connectors mounted on the module circuit board.
Using The TPA005D12 Class-D EVM Stand-Alone 3.5 Using The TPA005D12 Class-D EVM Stand-Alone Using the TPA005D12 class-D stereo audio power amplifier evaluation module stand-alone is much the same as using it with the platform. The same 4.5-V to 5.5-V power supply range and the isolated out+ and out– lines for BTL operation (Section 3.2.3) requirements exist. Figure 3–10 shows the connections that are required for operation (with the exception of the fault monitor circuit, which is optional).
Using The TPA005D12 Class-D EVM Stand-Alone 3.5.2 Input Connections The class-D amplifier input signals can be connected in either of two ways: differential or single-ended. For differential operation, connect the two lines from the signal source to the positive and negative inputs of each channel (RIN+/RIN– and LIN+/LIN– module pins).
TPA005D12 Class-D EVM Performance Characteristics 3.6 TPA005D12 Class-D EVM Performance Characteristics The TPA005D12 class-D stereo audio power amplifier EVM was tested using an Audio Precision System II, model 2322, a 5-V regulated dc power supply, and the TI PNP audio power amplifier evaluation platform set up as described in Chapter 2. Results were obtained with 4-Ω and 8-Ω speaker loads. The results are shown in Figures 3–11 through 3–17.
TPA005D12 Class-D EVM Performance Characteristics THD+N – Total Harmonic Distortion Plus Noise – (%) Figure 3–12. Class-D Amplifier Distortion versus Output Power at 4 Ω TOTAL HARMONIC DISTORTION PLUS NOISE vs OUTPUT POWER 1 VDD = 5 V RL = 4 Ω TA = 25° C 1 kHz 0.1 0.02 0.01 0.1 1 2 PO – Output Power – W THD+N – Total Harmonic Distortion Plus Noise – (%) Figure 3–13.
TPA005D12 Class-D EVM Performance Characteristics Figures 3–14 and 3–15 show a frequency sweep for a 1-W output. The lower frequency distortion of the graphs is dominated by noise, while the distortion at higher frequencies is due primarily to the fast-changing duty cycle of the PWM output. Figure 3–14.
TPA005D12 Class-D EVM Performance Characteristics EVM crosstalk is shown in Figures 3–16 and 3–17. The frequency is swept from 20 Hz to 20 kHz for a constant 2-W output. Several factors affect crosstalk, such as component selection (especially the inductor), filter layout, grounding, and power supply decoupling. Figure 3–16.
TPA005D12 Class-D EVM Interconnects 3.7 TPA005D12 Class-D EVM Interconnects Table 3–4 shows the correlation between the TPA005D12 class-D amplifier IC pins, the EVM pins, and the plug-n-play (PNP) platform sockets. Table 3–4.
TPA005D12 Class-D EVM Bill of Materials 3.8 TPA005D12 Class-D EVM Bill of Materials The components in the bill of materials (Table 3–5) were selected for their common values, availability, and the smallest size available to meet these criteria. Table 3–5. TPA005D12 Class-D EVM Bill of Materials Reference Description Size EVM Qty. Manufacturer/ Part Number C17 Capacitor, Ceramic Chip, 0.
TPA005D12 Class-D EVM Schematic 3.9 TPA005D12 Class-D EVM Schematic The following schematic depicts the TPA005D12 class-D EVM. Note: C13 and C14 are optional and have been provided to allow flexibility of design. Figure 3–18. TPA005D12 Class-D EVM Schematic Diagram VDD R2 100k R1 100k SD S2 SD Mute S1 Mute LIN+ C13 C9 C10 10µF 1µF C8 1µF VDD LOUT+ C20 C24 1µF 0.22µF C21 0.22µF L1 15µH L3 15µH LOUT– C15 1µF VDD C17 0.
TPA005D12 Class-D EVM PCB Layers 3.10 TPA005D12 Class-D EVM PCB Layers The following illustrations depict the TPA005D12 class-D EVM PCB assembly and layers. These drawings are not to scale. Gerber plots can be obtained from any TI Sales Office. Figure 3–19. TPA005D12 Class-D EVM Top Assembly Figure 3–20.
TPA005D12 Class-D EVM PCB Layers Figure 3–21. TPA005D12 Class-D EVM Top Layer Figure 3–22.
TPA005D12 Class-D EVM PCB Layers Figure 3–23. TPA005D12 Class-D EVM Third Layer Figure 3–24.
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