WLT5856A Audio Bluetooth module Product specification V2.
1 2 3 4 5 6 7 Index Summary .......................................................................................................................... 3 Functional characteristics ................................................................................................ 3 Application area ............................................................................................................... 3 Electrical characteristics ......................................................................
1 Summary WLT5856A is an audio Bluetooth module developed by WLT , and a single chip audio Bluetooth solution based on RDA5856.
2 Electrical characteristics Basic characteristics Absolute Maximum Ratings Min Max Unit Power supply Voltage (LDOIN) –0.5 +5.0 V Voltage of I/O pins –0.5 +3.6 V Storage Temperature –55 +125 °C table 1. Absolute maximum Recommended Operating Conditions Min TYP Max Unit Power supply Voltage (LDOIN) 3.5 3.8 4.2 V 0 3.3 3.6 V -30 25 75 °C Voltage of I/O pins Operating Temperature table 2. Recommended working conditions Wireless Standard Bluetooth BR/EDR/LE Frequency 2.
Radio frequency performance Bluetooth BR table 4 BluetoothBR Receiving characteristics table 5 BluetoothBR Emission characteristics 2018-02-26 5 / 15
Bluetooth EDR table 6 BluetoothEDR Receiving characteristics 2018-02-26 6 / 15
table 7 BluetoothEDR Emission characteristics 2018-02-26 021-20255077 7 / 15
table 8 FM RF characteristics Audio characteristics Parameter Min Type Max Unit SNR - 93.5 - dB THD - -85.
3 Hardware introduction Functional block diagram figure 1. WLT5856A Block diagram of the module WLT5856A There are two main parts inside the module： 1. Bluetooth part：Contains the Bluetooth chip RDA5856，2.4GHzPCB Antenna and external interface. 2. Audio section：RDA5856 integrated Audio Codec, Provides analog audio input and output,Digital audio input and output,Headphone amplifier and so on, Support for Bluetooth HFP，A2DP（Source 和 Sink）Other audio applications.
Module size and pin arrangement figure2. WLT5856A Module Dimensions (Front) figure3.
维霖通(上海)通信技术有限公司 Wi-linktech Communication Technologies (Shanghai) Co.
Reference schematic diagram UART figure 4.
Module Schematic diagram figure 5. WLT5856A Module Schematic diagram Antenna circuit figure 6. WLT5856A Module Antenna circuit The PCB antenna on the design on 40-TMAX50-VFD2G is a PCB Antenna.( See Figure4-1) The PCB Antenna was designed to match an impedance of 50 ohm at 2.45 GHz. Antenna Gain ： 2.5dBi.
4 PCB Design Recommended weld plate size figure 7. WLT5856A Package size reference PCB layout Matters needing attention Bluetooth is working 2.4GHz Under the frequency,Should try to avoid the impact of various factors on the wireless transceiver, pay attention to the following points: 1. The part of the product enclosure that surrounds the module avoids the use of metal, and if the enclosure is metallic, consider using an external antenna. 2.
PCB Layout figure 8.
5 Reflux parameter recommendation Reflow parameters can refer to the following settings: figure 9. Reflow recommended curve Temperature range Time Key parameters Preheat zone(<150℃) 60-120S Ramp up rate:≤2S Uniform temperature zone(150-200℃) 60-120S Ramp up rate:<1S Recirculation zone(>217℃) 40-60S Peak:240-260℃ Cooling zone Ramp down rate:1℃/s≤Slope≤4℃/s table 11.
6 Antenna S11 Parameter figure 10. 7 Software application WLT5856A is an audio Bluetooth module that supports Audio Codec.The module integrates audio Bluetooth protocol stack, supports a variety of traditional Bluetooth applications and Bluetooth low energy applications.For example: HFP, A2DP, AVRCP and so on. WLT5856A module supports UART AT + command mode to configure and select the mode of operation, the specific command, please see the relevant WLT5856A module software application documentation.
8 FCC Statement Warning: Changes or modifications to this unit not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment. NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation.
