PCA9549D: Octal bus switch with individually I2C-bus controlled enables

The PCA9549 provides eight bits of high speed TTL-compatible bus switching controlled by the I²C-bus. The low ON-state resistance of the switch allows connections to be made with minimal propagation delay. Any individual A to B channel or combination of channels can be selected via the I²C-bus, determined by the contents of the programmable Control register. When the I²C-bus bit is HIGH (logic 1), the switch is on and data can flow from Port A to Port B, or vice versa. When the I²C-bus bit is LOW (logic 0), the switch is open, creating a high-impedance state between the two ports, which stops the data flow.

An active LOW reset input (RESET) allows the PCA9549 to recover from a situation where the I²C-bus is stuck in a LOW state. Pulling the RESET pin LOW resets the I²C-bus state machine and causes all the bits to be open, as does the internal power-on reset function.

Three address pins allow up to eight devices on the same bus.

PCA9549D: Product Block Diagram
Outline 3d SOT137-1
Data Sheets (1)
Name/DescriptionModified Date
Octal bus switch with individually I2C-bus controlled enables (REV 2.0) PDF (140.0 kB) PCA954913 Jul 2009
Application Notes (1)
Name/DescriptionModified Date
Level shifting techniques in I2C-bus design (REV 1.0) PDF (52.0 kB) AN1044120 Jun 2007
Users Guides (3)
Name/DescriptionModified Date
I2C-bus specification and user manual (REV 6.0) PDF (1.4 MB) UM1020428 Apr 2014
I2C-bus specification and user manual (REV 5.0) PDF (1.6 MB) UM10204_JA03 Apr 2013
I2C Demonstration Board 2005-1 Quick Start Guide (REV 1.0) PDF (261.0 kB) UM1020613 Jun 2006
Brochures (2)
Name/DescriptionModified Date
NXP® I2C-bus solutions 2014: Smart, simple solutions for the 12 most common design concerns (REV 1.0) PDF (3.5 MB) 7501754001 Aug 2014
Add design fl exibility with multi-channel I2C/SMBus muxes and switches; NXP® 2-, 4-, and 8-channel... (REV 1.0) PDF (641.0 kB) 7501652901 Jul 2008
Package Information (1)
Name/DescriptionModified Date
plastic small outline package; 24 leads; body width 7.5 mm (REV 1.0) PDF (379.0 kB) SOT137-108 Feb 2016
Packing (1)
Name/DescriptionModified Date
SO24; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or J Ordering... (REV 4.0) PDF (235.0 kB) SOT137-1_11812 Apr 2013
Supporting Information (1)
Name/DescriptionModified Date
Footprint for wave soldering (REV 1.0) PDF (8.0 kB) SO-SOJ-WAVE08 Oct 2009
Ordering Information
ProductStatusPackage versionInterruptPower-on resetOperating Temperature (Cel)I2C-bus interfaceNo of AddressesI2C-bus (kHz)Operating voltage (VDC)Details
PCA9549DEnd of LifeSOT137-1SO24-40~8584002.3~5.5