WLT3266 Dual Mode Bluetooth Module

1 Summary

The WLT3266 is an audio Bluetooth module developed by WLT, utilizing the BK3266 chip. It features a built-in audio protocol stack and supports various Bluetooth applications and profiles. This module facilitates interconnection, data transmission, voice, and music applications for users' Bluetooth devices.

1.1 Functional Characteristics

• Supports Bluetooth HFP, A2DP, HID, AVRCP.
• Supports transparent/protocol data transfer mode with AT instruction set configuration.
• Supports UART communication interface with speeds up to 3Mbps.
• Built-in 16-bit audio DAC and 16-bit audio ADC.
• Built-Capless headphone amplifier.
• Built-in MIC bias and amplifier.
• Supports multiple analog audio inputs.
• Onboard PCB antenna; external antenna option available.
• Single-supply operation from 2.8V to 4.2V.
• Stamp hole pin design for easy and reliable welding.
• Compact size: 13 x 27.2 mm.
• Flexible software platform for customized services.

1.2 Application Areas

• Bluetooth Speaker
• Music Transponder
• Car Bluetooth
• Bluetooth Hands-free
• Health Care
• Wireless POS Machine
• Portable Printer

2 Electrical Characteristics

2.1 Basic Characteristics

Table 1: Absolute Maximum Ratings

Table 2: Recommended Working Conditions

2.2 Radio Frequency Performance

Table 4: Radio Frequency Performance

2.3 Audio Characteristics

Table 5: Audio Performance

3 Hardware Introduction

3.1 Functional Block Diagram

The WLT3266 module consists of two main parts:

• Bluetooth Part: Includes the BK3266 Bluetooth chip, a 2.4GHz PCB Antenna, and external interfaces.
• Audio Section: Features the WLT3266 integrated Audio Codec, providing analog audio input/output, digital audio input/output, and a headphone amplifier. It supports Bluetooth HFP, A2DP (Source and Sink), and other audio applications.

Diagram Description: A block diagram shows the BK3266 chip connected to various interfaces including UART, USB, SPI/SDIO, Mic IN, Line IN, and Line OUT. An antenna (ANT) and ground (GND) are also depicted.

3.2 Module Size and Pin Arrangement

Diagram Description:

• Figure 2 shows the WLT3266 Module Dimensions (Front) with a length of 13.0 mm and a width of 27.2 mm. Key dimensions include 7.5 mm for antenna area, 1.5 mm for pin spacing, 1.72 mm for the bottom edge, and 0.7 mm and 1.0 mm for side dimensions.
• Figure 3 illustrates the WLT3266 Module thickness, showing dimensions of 2.5 mm and 0.8 mm.

3.3 Pin Definition

Table 6: WLT3266 Pin Definition

Figure 4: Description of 26-Pin Package shows a visual representation of the pinout.

3.4 Reference Design

Figure 5: Reference Design illustrates a typical connection schematic between an MCU and the WLT3266 module. It details the connections for UART, GND, LINEIN, P15, NC, SD_CMD, SD_CLK, SD_DAT, RESET, VDD, and VCC5USB.

Note: GPIO14 serves as the amplifier enable pin (high level effective). When using an audio power amplifier, GPIO14 should be connected to the chip's enable pin, as shown in Figure 6: GPIO14 Reference Design.

4 PCB Design

4.1 Recommended Weld Plate Size

Figure 7: WLT3266 Package Size Reference provides dimensions for PCB layout, indicating a 13.0 mm width and 27.2 mm length for the module placement area.

4.2 PCB Layout Matters Needing Attention

When operating at the 2.4GHz frequency, it is crucial to minimize interference for the wireless transceiver. Consider the following points:

• Avoid using metal in the product enclosure surrounding the module. If the enclosure is metallic, consider using an external antenna.
• Keep metallic screws away from the RF part of the module.
• Position the module on the motherboard such that the antenna area is at the edge or corner. Ensure no copper traces or alignment features are present directly below the module's antenna area.

5 Reflow Parameter Recommendation

Figure 8: Reflow Recommended Curve displays the recommended temperature profile for reflow soldering:

• Preheat Zone: 150-200°C, Ramp up rate: Max 2°C/sec. Duration: 60-120 seconds.
• Peak Temperature: 240-260°C.
• Ramp Down Rate: 1°C/s to 4°C/s.
• Cooling Zone: Duration: 40-60 seconds.

Table 7: Reflow Recommended Parameters provides a detailed breakdown of temperature ranges, time, and key parameters for each reflow zone.

6 Software Application

The WLT3266 module supports Audio Codec and integrates an audio Bluetooth protocol stack. It is compatible with various traditional Bluetooth applications and Bluetooth Low Energy applications, including HFP, A2DP, and AVRCP.

The module supports UART AT+ command mode for configuration and mode selection. Refer to the relevant WLT3266 module software application documentation for specific commands.

For custom software development, please contact Wi-linktech.

7 Regulatory Module Integration Instructions

List of Applicable FCC Rules

This device complies with Part 15 of the FCC Rules.

Limited Module Procedures

Not applicable.

Summarize the Specific Operational Use Conditions

This module can be used in Bluetooth Speakers, Car Bluetooth systems, Bluetooth Hands-free devices, Wireless POS machines, and Portable Printers, as well as smart home devices. The typical input voltage is 3.3V DC (nominal 2.8-4.2V DC), and the ambient temperature should not exceed 80°C.

RF Exposure Considerations

• Module is limited to OEM installation ONLY.
• OEM integrators are responsible for ensuring that the end-user has no manual instructions to remove or install the module.
• The module is limited to installation in mobile or fixed applications, according to Part 2.1091(b).

FCC Radiation Exposure Statement

This module complies with FCC RF radiation exposure limits for an uncontrolled environment. The transmitter must not be co-located or operated in conjunction with any other antenna or transmitter.

Label and Compliance Information

If the FCC identification number is not visible on the module when installed inside another device, the exterior of the host device must display a label referring to the enclosed module. This label can state: "Contains Transmitter Module FCC ID: 2AOO6-WLT3266" or "Contains FCC ID: 2AOO6-WLT3266".

When the module is installed inside another device, the host device's user manual must include the following warning statements:

1. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any interference received, including interference that may cause undesired operation.
2. Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.

Devices must be installed and used in strict accordance with the manufacturer's instructions as described in the user documentation that accompanies the product.

Additional Testing, Part 15 Subpart B Disclaimer

The final host/module combination requires evaluation against FCC Part 15B criteria for unintentional radiators to be authorized as a Part 15 digital device. The host integrator must ensure the final composite product complies with FCC requirements through technical assessment or evaluation according to FCC rules, including transmitter operation, and should refer to guidance in KDB 996369.

Frequency Spectrum to be Investigated

For host products with a certified modular transmitter, the frequency range of investigation for the composite system is specified by rule in Sections 15.33(a)(1) through (a)(3) or the range applicable to the digital device, as shown in Section 15.33(b)(1), whichever is the higher frequency range of investigation.

FCC Statement

Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) This device must accept any interference received, including interference that may cause undesired operation.