TCA9548APWR Symbol, Features, Layout Guidelines and TCA9548APWR vs PCA9548APW-T
03 November 2023
Ⅲ. TCA9548APWR symbol, footprint and pin configuration
Ⅳ. What are the features of TCA9548APWR?
Ⅴ. Technical parameters of TCA9548APWR
Ⅵ. Layout guidelines for TCA9548APWR
Ⅶ. What are the differences between TCA9548APWR and PCA9548APW-T?
Ⅷ. What are the purposes of TCA9548APWR?
A multiplexer is an electronic device used to combine multiple input signals into a single output signal. It uses serial data transmission technology to combine data from multiple input channels into a sequence in a certain order and transmit it through a shared transmission medium. Input signals can be of various types such as data, audio, video, etc. Its output is a data stream with an identifier, which can be restored to the original individual input signals by a demultiplexer. Multiplexers are widely used in fields such as computer networks, modern communications, and digital circuits because of their efficient data transmission capabilities and reduced resource usage.
Multiplexers have the following functions.
1. Data transmission: It can transmit multiple input signals to the output end in a certain order, realize data transmission and distribution, and facilitate system data processing and exchange.
2. Signal multiplexing: It has the capability to merge and send multiple input signals to a single output terminal, achieving signal multiplexing and conserving signal lines and system hardware resources.
3. Signal selection: It can select different input signals for transmission according to the control signal, realize signal selection, and facilitate the system's processing and control of different signals.
The TCA9548APWR is an I²C multiplexer from Texas Instruments with eight bidirectional switches that can be controlled via the PC bus. The multiplexer operates stably over the operating temperature range of -40°C to 85°C and is environmentally RoHS compliant (lead-free). This type of multiplexer is widely used in various industries such as communications technology, data communications, defense, industrial, aerospace, personal computers and laptop computers.
The SCL/SDA upstream pair fans out eight downstream pairs or channels. We can select any individual SCn/SDn channel or combination of channels, depending on the settings of the programmable control register. For example, if the application requires eight identical digital temperature sensors, we can connect one sensor on each channel as directed by the programmable control register.
In the event of a timeout or other improper operation, the system host can reset the TCA9548APWR device by asserting a low level on the RESET input. Setting RESET to an active state enables reset and initialization without powering down the component, which allows recovery in the event of an abnormality on the downstream PC bus.
Replacements and equivalents:
The above figure shows the symbol, footprint and pin configuration of TCA9548APWR respectively. It has a total of 24 pins, each of which performs different tasks in working state.
• The indicator pins are there to show which channel is currently in use.
• When in its inactive state, the TCA9548APWR exhibits remarkably low current consumption. This device incorporates advanced energy-saving technology to maintain minimal power usage during idle periods, effectively mitigating energy wastage.
• It supports the I²C bus standard and can operate at frequencies up to 400 kHz.
• It supports a wide voltage range, from 1.65V to 5.5V, and is suitable for systems with many different power supply voltages.
• It has eight I²C channels that can be independently selected, allowing up to eight different I²C devices to be connected.
• It can be configured and controlled via commands on the I²C bus, selecting the corresponding channel, allowing dynamic switching of different I²C devices.
For the PCB layout of TCA9548APWR, we should follow common PCB layout practices. However, other issues associated with high-speed data transmission, such as matched impedances and differential pairs, are not caused by the speed of the I²C signal. Typically, there is a dedicated ground plane on the inner side of the board, and the pins connected to ground should have a low-impedance path in the form of a wide polygon layout with multiple vias. In addition, bypass and decoupling capacitors are often used to ensure voltage stability at the VCC pin. When encountering short-term power fluctuations, using larger capacitors can provide additional power, while using smaller capacitors can filter out high-frequency ripples.
In scenarios where voltage conversion is unnecessary, the VDPUX voltage and VCC can share the same potential. However, in situations necessitating voltage translation, VDPUM and VDPU0–VDPU7 can all reside on the same layer of the board, with separate planes designed to isolate distinct voltage potentials.
To reduce the problem of increased total I²C bus capacitance caused by PCB parasitics, the data lines (SCn and SDn) should be as short as possible and the trace width should be minimized.
• Power management: It can be used to manage the power supply of I²C devices. By switching a subbus to a disabled state, it can reduce the power consumption of devices associated with that subbus, thereby saving energy. This operating mode can effectively extend the battery life of the device without sacrificing performance, while also reducing the burden on the power grid and achieving more environmentally friendly power management.
• Saving I²C pins: If the microcontroller or microcontroller has a limited number of available I²C pins, we can use TCA9548APWR to connect multiple devices to the same I²C bus without assigning a separate I²C bus to each device.
• Expand I2C bus capacity: It can expand an I²C bus to 8 sub-buses, and each sub-bus can be connected to a different I²C device, thereby expanding the capacity of the I²C bus.
• Address conflict resolution: When multiple I²C devices have the same I²C address on the same I²C bus, it can be used to isolate these devices to different sub-buses to resolve address conflict issues.
• Industrial automation and medical equipment fields: It is an efficient multi-channel I²C controller with voltage conversion function, which allows devices with different voltage levels to communicate with each other.
Frequently Asked Questions
1. What is TCA9548A?
The TCA9548A device has eight bidirectional translating switches that can be controlled through the I2C bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels.
2. What is I2C connection?
I2C stands for Inter-Integrated Circuit. It is a bus interface connection protocol incorporated into devices for serial communication. It was originally designed by Philips Semiconductor in 1982.
3. What is the operating temperature range of TCA9548APWR?
The operating temperature of TCA9548APWR ranges from -40°C to 85 °C.
4. What is the replacement and equivalent of TCA9548APWR?
You can replace the TCA9548APWR with the PCA9548APWR, PCA9548APW or PCA9548APWRG4.
5. How does the TCA9548APWR work?
The TCA9548APWR has an I2C interface and can be controlled by sending specific commands through the I2C bus. These commands allow you to select which channel is active at any given time, effectively connecting one of the attached I2C devices to the bus.
