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PCA9548A

ACTIVE

8-channel 2.3- to 5.5-V I2C/SMBus switch with reset & voltage translation

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TCA9548A ACTIVE 8-channel 1.65- to 5.5-V I2C/SMBus switch with reset & voltage translation Performance enhancements for power-on reset and lower voltage operation.

Product details

Addresses 8 Supply voltage (max) (V) 5.5 Supply voltage (min) (V) 2.3 Features Reset pin Rating Catalog Frequency (max) (MHz) 0.4 Operating temperature range (°C) -40 to 85 Number of channels 8
Addresses 8 Supply voltage (max) (V) 5.5 Supply voltage (min) (V) 2.3 Features Reset pin Rating Catalog Frequency (max) (MHz) 0.4 Operating temperature range (°C) -40 to 85 Number of channels 8
SOIC (DW) 24 159.65 mm² 15.5 x 10.3 SSOP (DB) 24 63.96 mm² 8.2 x 7.8 TSSOP (PW) 24 49.92 mm² 7.8 x 6.4 TVSOP (DGV) 24 32 mm² 5 x 6.4 VQFN (RGE) 24 16 mm² 4 x 4
  • 1-of-8 Bidirectional Translating Switches
  • I2C Bus and SMBus Compatible
  • Active-Low Reset Input
  • Three Hardware Address Pins for Use of up to Eight PCA9548A Devices on the I2C Bus
  • Channel Selection Via I2C Bus
  • Power-Up with All Switch Channels Deselected
  • Low RON Switches
  • Allows Voltage-Level Translation Between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
  • No Glitch on Power Up
  • Supports Hot Insertion
  • Low Standby Current
  • Operating Power-Supply Voltage Range of 2.3 V to 5.5 V
  • 5-V Tolerant Inputs
  • 0-kHz to 400-kHz Clock Frequency
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)
  • 1-of-8 Bidirectional Translating Switches
  • I2C Bus and SMBus Compatible
  • Active-Low Reset Input
  • Three Hardware Address Pins for Use of up to Eight PCA9548A Devices on the I2C Bus
  • Channel Selection Via I2C Bus
  • Power-Up with All Switch Channels Deselected
  • Low RON Switches
  • Allows Voltage-Level Translation Between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
  • No Glitch on Power Up
  • Supports Hot Insertion
  • Low Standby Current
  • Operating Power-Supply Voltage Range of 2.3 V to 5.5 V
  • 5-V Tolerant Inputs
  • 0-kHz to 400-kHz Clock Frequency
  • Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)

The PCA9548A 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. Any individual SCx/SDx channel or combination of channels can be selected, determined by the contents of the programmable control register. These downstream channels can be used to resolve I2C slave address conflicts. For example, if eight identical digital temperature sensors are needed in the application, one sensor can be connected at each channel: 0-7.

The system master can reset the PCA9548A in the event of a time-out or other improper operation by asserting a low in the RESET input. Similarly, the power-on reset deselects all channels and initializes the I2C/SMBus state machine. Asserting RESET causes the same reset and initialization to occur without powering down the part. This allows recovery should once of the downstream I2C buses get stuck in a low state.

The pass gates of the switches are constructed so that the VCC pin can be used to limit the maximum high voltage, which is passed by the PCA9548A. This allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5-V tolerant.

The PCA9548A 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. Any individual SCx/SDx channel or combination of channels can be selected, determined by the contents of the programmable control register. These downstream channels can be used to resolve I2C slave address conflicts. For example, if eight identical digital temperature sensors are needed in the application, one sensor can be connected at each channel: 0-7.

The system master can reset the PCA9548A in the event of a time-out or other improper operation by asserting a low in the RESET input. Similarly, the power-on reset deselects all channels and initializes the I2C/SMBus state machine. Asserting RESET causes the same reset and initialization to occur without powering down the part. This allows recovery should once of the downstream I2C buses get stuck in a low state.

The pass gates of the switches are constructed so that the VCC pin can be used to limit the maximum high voltage, which is passed by the PCA9548A. This allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5-V tolerant.

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Technical documentation

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Type Title Date
* Data sheet PCA9548A Low Voltage 8-Channel I2C Switch with Reset datasheet (Rev. G) PDF | HTML 11 Mar 2021
Application note I2C Solutions for Hot Swap Applications (Rev. A) 31 Jan 2023
Application note I2C Dynamic Addressing 25 Apr 2019
Selection guide Logic Guide (Rev. AB) 12 Jun 2017
Application note Choosing the Correct I2C Device for New Designs PDF | HTML 07 Sep 2016
Application note Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) 02 Dec 2015
Application note Understanding the I2C Bus PDF | HTML 30 Jun 2015
Application note Maximum Clock Frequency of I2C Bus Using Repeaters 15 May 2015
Application note I2C Bus Pull-Up Resistor Calculation PDF | HTML 13 Feb 2015
Application note Programming Fun Lights With TI's TCA6507 30 Nov 2007
Application note Semiconductor Packing Material Electrostatic Discharge (ESD) Protection 08 Jul 2004

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

TCA9548AEVM — TCA9548A I2C 1-to-8 bidirectional translating switch evaluation module

The TCA9548AEVM is designed to evaluate and demonstrate the functionality of TI’s TCA954xA family of I2C switches. The TCA9548AEVM can be used as a standalone evaluation module to interface with an existing system or paired with the MSP430 Lauchpad which serves as the I2C master and power supply (...)

User guide: PDF
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Simulation model

PCA9548A IBIS Model

SCPM010.ZIP (130 KB) - IBIS Model
Design tool

I2C-DESIGNER — I2C designer tool

Use the I2C Designer tool to quickly resolve conflicts in addressing, voltage level and frequency in I2C based designs. Enter master and slave inputs to automatically generate an I2C tree or easily build a custom solution. This tool will help designers save time and comply with the I2C standard (...)
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
User guide: PDF
Package Pins CAD symbols, footprints & 3D models
SOIC (DW) 24 Ultra Librarian
SSOP (DB) 24 Ultra Librarian
TSSOP (PW) 24 Ultra Librarian
TVSOP (DGV) 24 Ultra Librarian
VQFN (RGE) 24 Ultra Librarian

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