PCA9518AD: Expandable 5-channel I2C-bus hub

The PCA9518A is a CMOS integrated circuit intended for application in I²C-bus and SMBus systems.

While retaining all the operating modes and features of the I²C-bus system, it permits extension of the I²C-bus by buffering both the data (SDA) and the clock (SCL) lines, thus enabling virtually an unlimited number of buses of 400 pF.

The I²C-bus capacitance limit of 400 pF restricts the number of devices and bus length. Using the PCA9518A enables the system designer to divide the bus into an unlimited number of segments off of a hub where any segment to segment transition sees only one repeater delay and is multiple master capable on each segment.

Using multiple PCA9518A parts, any width hub (in multiples of five)1can be implemented using the expansion pins.

The PCA9518A is a wider voltage range (2.3 V to 3.6 V) version of the PCA9518 and also improves partial power-down performance, keeping I²C-bus I/O pins in high-impedance state when VDD is below 2.0 V.

A PCA9518 cluster cannot be put in series with a PCA9515/16 or with another PCA9518 cluster. Multiple PCA9518 devices can be grouped with other PCA9518 devices into any size cluster thanks to the EXPxxxn pins that allow the I²C-bus signals to be sent/received from/to one PCA9518 to/from another PCA9518 within the cluster. Since there is no direction pin, slightly different 'legal' low voltage levels are used to avoid lock-up conditions between the input and the output of individual repeaters in the cluster. A 'regular LOW' applied at the input of any of the PCA9518 devices will then be propagated as a 'buffered LOW' with a slightly higher LOW value to all enabled outputs in the PCA9518 cluster. When this 'buffered LOW' is applied to a PCA9515 and PCA9516 or separate PCA9518 cluster (not connected via the EXPxxxn pins) in series, the second PCA9515 and PCA9516 or PCA9518 cluster will not recognize it as a 'regular LOW 'and will not propagate it as a 'buffered LOW' again. The PCA9510/9511/9513/9514 and PCA9512 cannot be used in series with the PCA9515 and PCA9516 or PCA9518 either, but can be used in series with themselves since they use shifting instead of static offsets to avoid lock-up conditions. This note is applicable to the 'A' versions of these devices also.

1

PCA9518AD: Product Block Diagram
SOT163-1

2. The maximum system operating frequency may be less than 400 kHz because of the delays added by the repeater.

Data Sheets (1)
Name/DescriptionModified Date
Expandable 5-channel I2C-bus hub (REV 3.0) PDF (127.0 kB) PCA9518A03 Dec 2008
Application Notes (3)
Name/DescriptionModified Date
Single card I2C bus buffers (REV 1.0) PDF (238.0 kB) AN1041916 Nov 2010
Level shifting techniques in I2C-bus design (REV 1.0) PDF (52.0 kB) AN1044120 Jun 2007
I2C / SMBus Repeaters, Hubs and Expanders (REV 2.0) PDF (1.0 MB) AN25519 Dec 2002
Users Guides (4)
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
PCA9600 demonstration board OM6293 (REV 1.0) PDF (130.0 kB) UM1032315 Dec 2008
I2C Demonstration Board 2005-1 Quick Start Guide (REV 1.0) PDF (261.0 kB) UM1020613 Jun 2006
Brochures (4)
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
I2C/SMBus buffers for backplane multi-point and hot-swap applications; NXP® Level-shifting and... (REV 1.0) PDF (773.0 kB) 7501653001 Jul 2008
Extend the I2C-bus with advanced repeaters and hubs; NXP® 2-channel I2C-bus repeaters PCA9515x and... (REV 1.0) PDF (740.0 kB) 7501653201 Jul 2008
Accommodate more I2C-bus devices on a single bus; NXP® expandable 5-channel I2C-bus hub PCA9518A (REV 1.0) PDF (232.0 kB) 7501608301 Aug 2007
Package Information (1)
Name/DescriptionModified Date
plastic small outline package; 20 leads; body width 7.5 mm (REV 1.0) PDF (335.0 kB) SOT163-108 Feb 2016
Packing (1)
Name/DescriptionModified Date
SO20; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or J Ordering... (REV 2.0) PDF (246.0 kB) SOT163-1_11815 Apr 2013
Supporting Information (2)
Name/DescriptionModified Date
Reflow Soldering Profile (REV 1.0) PDF (34.0 kB) REFLOW_SOLDERING_PROFILE30 Sep 2013
Wave Soldering Profile (REV 1.0) PDF (20.0 kB) WAVE_SOLDERING_PROFILE30 Sep 2013
IBIS Model
Ordering Information
ProductStatusPackage versionApplicationEnableFunctionOperating Temperature (Cel)Number of bitsVoltage Translation Range (V)Operating voltage (VDC)Operating voltage 2 (V)InputsOutputsTTL Drive (mA)GTL Drive (mA)I2C-bus (kHz)
PCA9518ADEnd of LifeSOT163-1-40~852.3~3.6 tolerant to 5.514400
Package Information
Product IDPackage DescriptionOutline VersionReflow/Wave SolderingPackingProduct StatusPart NumberOrdering code(12NC)MarkingChemical ContentRoHS / Pb Free / RHFLeadFree Conversion DateMSLMSL LF
PCA9518ADSOT163-1Reflow_Soldering_Profile Wave_Soldering_Profile
Reflow_Soldering_Profile Wave_Soldering_Profile
Reel 13" Q1/T1WithdrawnPCA9518AD,118 (9352 842 53118)PCA9518ADAlways Pb-free11