PCA9646: Buffered 4-channel 2-wire bus switch

The PCA9646 is a monolithic CMOS integrated circuit for 2-wire bus buffering and switching in applications including I²C-bus, SMBus, PMBus, and other systems based on similar principles.

Each of the four outputs may be independently enabled in any combination as determined by the contents of the programmable control register. Each I/O is impedance isolated from all others, thus allowing a total of five branches of 2-wire bus with the maximum specified load (e.g., 5 × 400 pF for Fm+ I²C-bus at 1 MHz, or 5 × 4 nF at lower frequencies) (Ref. 1). More than one PCA9646 may be used in series, providing a substantial fan-out capability.

The PCA9646 includes a unidirectional buffer for the clock signal, and a bidirectional buffer for the data signal. The direction of the clock signal may also be set by the contents of the programmable control register. Clock stretching and timing must always be under control of the master device.

The PCA9646 has excellent application to 2-wire bus address expansion and increasing of maximum load capacitance. Very large LED displays are a perfect example.

PCA9646: Product Block Diagram
Outline 3d SOT403-1
Data Sheets (1)
Name/DescriptionModified Date
Buffered 4-channel 2-wire bus switch (REV 2.0) PDF (162.0 kB) PCA964617 Jun 2015
Application Notes (3)
Name/DescriptionModified Date
Very large I2C-bus systems and long buses (REV 1.0) PDF (216.0 kB) AN1108426 Oct 2011
Level shifting techniques in I2C-bus design (REV 1.0) PDF (52.0 kB) AN1044120 Jun 2007
PCA954X FAMILY OF I²C / SMBus MULTIPLEXERS and SWITCHES (REV 2.0) PDF (807.0 kB) AN26201 Oct 2004
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 thin shrink small outline package; 16 leads; body width 4.4 mm (REV 1.0) PDF (300.0 kB) SOT403-108 Feb 2016
Packing (1)
Name/DescriptionModified Date
TSSOP16; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or... (REV 1.0) PDF (218.0 kB) SOT403-1_11808 Apr 2013
Supporting Information (1)
Name/DescriptionModified Date
Footprint for wave soldering (REV 1.0) PDF (16.0 kB) SSOP-TSSOP-VSO-WAVE08 Oct 2009
IBIS Model
Ordering Information
ProductStatus
PCA9646PWActive
Package Information
Product IDPackage DescriptionOutline VersionReflow/Wave SolderingPackingProduct StatusPart NumberOrdering code(12NC)MarkingChemical ContentRoHS / Pb Free / RHFLeadFree Conversion DateEFRIFR(FIT)MTBF(hour)MSLMSL LF
PCA9646PWSOT403-1SSOP-TSSOP-VSO-WAVEReel 13" Q1/T1ActivePCA9646PW,118 (9352 927 49118)PCA9646PCA9646PWAlways Pb-free0.05.02E811
Buffered 4-channel 2-wire bus switch pca9646d
Very large I2C-bus systems and long buses pca9601
Level shifting techniques in I2C-bus design pca9685pw
PCA954X FAMILY OF I²C / SMBus MULTIPLEXERS and SWITCHES pca9516apw
I2C-bus specification and user manual pca9685pw
I2C-bus specification and user manual pca9685pw
I2C Demonstration Board 2005-1 Quick Start Guide pca9685pw
NXP® I2C-bus solutions 2014: Smart, simple solutions for the 12 most common design concerns pca9685pw
Add design fl exibility with multi-channel I2C/SMBus muxes and switches; NXP® 2-, 4-, and 8-channel... pca9548a
PCA9646PW IBIS Model PCA9646PW
SOT403-1 LPC812M101JDH16
SSOP-TSSOP-VSO-WAVE LPC1114FDH28
Reel 13" Q1/T1 LPC812M101JDH16
PCA9646
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