WT2605-28SS

Features

A 32-bit high-performance CPU with DSP instructions, with a main frequency of up to 120MHz.
External 26MHz crystal oscillator.
Three 32bit general timers.
1 main system watchdog.
Sample rates of 8, 11.025, 12, 16, 22.05,32, 44.1 and 48KHz are supported.
High-performance audio DAC with 9dB SNR and ADC with 90dB SNR.
Compliant with bluetooth 5.0 specification: BR/EDR
Modulation mode: GFSK, π/4 DQPSK,8DPSK
Transmit power: +2dBm
Occupied bandwidth: ≤2MHz
GPIO has internal pull-up and pull-down resistors, which can be mapped as functional io.
GPIO wake-up interrupt is supported.

Description

Overview

WT2605 has ADC and DAC peripherals with high signal-to-noise ratio, and the resolution is as high as 16bit. At the same time, it has standard UART, key control and other functions, and can store audio files by external USB flash, TF card, SPI Flash, etc. SPI Flash supports file management, and can realize file index playback, file name playback and other functions. Support standard MP3, WAV audio file playback and Bluetooth playback, and also decode and play audio files such as APE and FLAC (to be customized). Please refer to the scheme specification and schematic diagram for details.

Pin Description

Limited Parameters

Symbol	Description	Minimum	Typical Value	Maximum	Unit
VBAT	Pin voltage	3.0	3.7	5.0	V
IVBAT	External power supply current, without load	25	—	—	mA
T	Working temperature	-40	—	+85	℃
T	Storage temperature	-55	—	+125	℃

Application Circuit (Schematic)

Figure 2 WT2605-28SS Schematic of WT2605-28SS(MCU Part) — Figure 2 Schematic of WT2605-28SS(MCU Part)

Relevant requirements/specifications of Bluetooth circuit (including antenna):
It is recommended to adopt the standard package provided by Weichuang Zhiyin;
It is not allowed to walk at right angles with the antenna. If there is an inflection point in the design, please use circular arc connection.
The wiring and safety distance of the circuits around the Bluetooth chip should be more than 2mm as far as possible.
The distance from the Bluetooth chip to the antenna cannot exceed 1CM.
The Bluetooth chip should be isolated from the antenna by copper plating, and more than 1 row of vias should be added.
It is recommended to isolate the digital ground from the analog ground; Capacitors are required to be close to the periphery of several power supply pins.
When DACR and DACL are docked with the audio input port of power amplifier, analog ground should be used in parallel around the line to remove interference.
DACR and DACL should stay away from RF and heavy current power supply when wiring.

Figure 3 WT2605-28SS Crystal Oscillator Circuit — Figure 3 Crystal Oscillator Circuit

Crystal oscillator elated requirements/specifications:
crystal oscillator specification: 26M_9pF or 7.5pF load _+/-10ppm.
In PCB layout, the crystal oscillator should be far away from the antenna and isolated from the antenna by copper.
If the frequency offset of crystal oscillator is within +/-50K, it can be corrected by the frequency offset corrector provided by Waytronic. If it exceeds 50K, it can be handled by Waytronic.

Figure 4 WT2605-28SS Circuit of Lithium Battery — Figure 4 Circuit of Lithium Battery

Bluetooth chip battery assembly requirements:
When the battery is assembled, the antenna shall not be blocked.
When the battery is assembled, it should not be stuck between the high-frequency signal and digital information to avoid building an interference bridge.