Explore the 69A2 IC with our detailed schematic diagram, Download The Datasheet, pinout information, And guide to all pins and their connections. Explore the 69A2 IC and 6969A2 IC with 16 pins. Find everything you need about the same circuit Diagram and its Pinout on this Page.
69A2 IC Circuit Diagram
Description of 69A2 IC Schematic Diagram
This schematic illustrates the connections for a 69A2 Bluetooth IC (AC6969A_SOP16 Package), detailing its pinout and associated components for Bluetooth functionality. The key components include capacitors, inductors, resistors, antennas, and a crystal oscillator. Here's a breakdown of the pins, their functions, and the role of each connected component, explaining step by step.
Pin Details of 69A2 IC and Connected Components
Pin 1: VDDIO
Function: This pin provides the operating voltage for the I/O pins of the IC.
Connection: It is connected to a 3.3V power source through decoupling capacitors (C1 and C4).
Component Details:
C1 (105): A 1µF capacitor, providing stability and noise filtering for the power supply.
C4 (105): Another 1µF capacitor that further filters the VDDIO line, reducing any high-frequency noise.
Pin 2: VBAT
Function: This pin supplies power to the internal battery management system of the IC.
Connection: Connected directly to the battery voltage (VBAT) line.
Component Details:
VBAT: Provides power to the IC when a battery is used as the primary power source. This is crucial for wireless/Bluetooth operation in portable devices.
Pin 3: LDO_IN/PB5
Function: Low-dropout (LDO) regulator input and Port B GPIO pin 5. It supplies regulated power to certain sections of the IC.
Connection:
This pin is tied to the +3.3V power rail through capacitors for smoothing.
Pin 4: BT_AVDD
Function: Bluetooth Analog Voltage Digital Domain. Supplies power to the Bluetooth section's analogue circuitry.
Connection: Also tied to VBAT for power, ensuring stable operation of Bluetooth circuits.
Pin 5: PB3/ADC6
Function: This pin serves dual purposes:
PB3: General-purpose input/output pin.
ADC6: Analog-to-digital converter pin for reading analog signals.
Connection: Can be used for various functions in conjunction with other components like buttons or sensors.
Pin 6: PB1/ADC5
Function: Another dual-purpose pin:
PB1: General-purpose I/O pin.
ADC5: Analog-to-digital converter pin for converting analogue signals to digital values.
Connection: Typically left floating or connected to external peripherals that need ADC functions.
Pin 7: BT_RF
Function: This is the Bluetooth RF (radio frequency) output pin, responsible for sending and receiving Bluetooth signals.
Connection: It connects directly to the Bluetooth antenna (BT_ANT) through the matching circuit, which includes:
L1 (NC): An inductor (not connected) that can be used for tuning purposes.
C3 (222/16V): A 2200pF capacitor that provides matching for the antenna and the RF circuit.
C8 (2.7P): A 2.7pF capacitor fine-tunes the antenna's impedance matching.
Working: The combination of these components ensures efficient RF transmission and reception, optimizing the Bluetooth communication range and signal integrity.
Pin 8: VSSIO (Ground)
Function: This is the ground pin for the I/O circuit.
Connection: It is tied to the common ground of the circuit, ensuring the proper return path for electrical current.
Component Details:
C2 (NC/10V): Not connected; in some designs, this can be used to stabilize ground signals.
Pin 9 & 10: BT_OSCO and BT_OSCI
Function: These pins are for the Bluetooth crystal oscillator, responsible for generating the clock frequency needed for Bluetooth operation.
Connection:
Y1 (24M): A 24 MHz crystal oscillator connected between these two pins.
Working: The crystal provides a stable reference clock for Bluetooth signal generation. The two pins, BT_OSCO (oscillator output) and BT_OSCI (oscillator input) drive and maintain this clock.
Pin 11: KEY0
Function: This is a general-purpose input pin used to connect buttons or keys.
Connection: Usually tied to a button to initiate functions like Bluetooth pairing or power control.
Component Role: It interacts with external switches that control user interactions like turning the device on/off, pairing Bluetooth, or switching modes.
Pin 12: MIC_BIAS/PA2/PA3/USB_DP
Function:
MIC_BIAS: Provides bias voltage for the microphone.
PA2/PA3: General-purpose I/O pins.
USB_DP: Data-positive pin for USB communication.
Connection: These can be connected to a microphone circuit or used for USB functionality if applicable.
Pin 13: DACR (Digital-to-Analog Converter Right)
Function: This pin provides the right channel audio output from the digital-to-analog converter (DAC).
Connection: It can be connected to the audio amplification circuit or directly to a speaker in stereo audio systems.
Pin 14: DACL (Digital-to-Analog Converter Left)
Function: Provides the left channel audio output.
Connection: Similar to the DACR pin, this connects to the left speaker or audio amplifier.
Pin 15: AGND (Analog Ground)
Function: Ground for analogue circuits within the IC.
Connection: Tied to the common ground for analogue sections, ensuring proper operation of sensitive analogue components like the DACs and ADCs.
Pin 16: MIC
Function: This pin is the microphone input.
Connection: Connected to an external microphone or audio input device.
Working: This pin accepts audio input, which can be processed by the IC and transmitted over Bluetooth or amplified for playback.
Components Explained
Bluetooth Antenna (BT_ANT):
This is crucial for wireless communication, transmitting and receiving signals over Bluetooth. The capacitors and inductors connected to it form a tuning circuit that matches the impedance between the antenna and the IC, optimizing signal strength.
Crystal Oscillator (Y1 - 24 MHz):
The crystal oscillator provides a precise clock signal needed for Bluetooth communication. A stable clock is essential for accurate data transmission and maintaining synchronization with paired devices.
Capacitors (C1, C3, C4, C8):
These capacitors are used for decoupling, filtering, and matching purposes. They ensure that power lines are clean from noise and that the RF signals are tuned correctly for optimal antenna performance.
Inductors (L1, L2):
Although labelled as "NC" (not connected) in this specific schematic, inductors are generally used in RF circuits for tuning and impedance matching, playing a role in ensuring the antenna's resonance frequency aligns with the Bluetooth signal.
Working Principle of the Circuit
Power Supply:
The circuit is powered via the VBAT and 3.3V lines. Capacitors C1 and C4 help stabilize the supply voltage, reducing ripples and ensuring smooth operation.
Bluetooth Signal Handling:
The BT_RF pin is the key for transmitting and receiving Bluetooth signals, connected to the antenna through a matching network. This ensures efficient signal propagation.
The crystal oscillator (Y1) generates a 24 MHz clock signal, crucial for timing and synchronization in Bluetooth communication.
Audio Processing:
The microphone input (MIC) and audio output pins (DACL, DACR) allow the IC to handle voice or audio signals. The DAC converts digital signals into analogue ones for playback through speakers.
Control & User Interaction:
The KEY0 pin provides an interface for external buttons, allowing user interaction like pairing, power control, and mode switching.
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