PCA9561: Quad 6-bit multiplexed I²C-bus EEPROM DIP switch

The PCA9561 is a 20-pin CMOS device consisting of four 6-bit non-volatile EEPROM registers, six hardware pin inputs and a 6-bit multiplexed output. It is used for DIP switch-free or jumper-less system configuration and supports Mobile and Desktop VID Configuration, where five preset values (four sets of internal non-volatile registers and one set of external hardware pins) set processor voltage for operation in various performance or battery conservation sleep modes. The PCA9561 is also useful in server and telecommunications/networking applications when used to replace DIP switches or jumpers, since the settings can be easily changed via I²C-bus/SMBus without having to power down the equipment to open the cabinet. The non-volatile memory retains the most current setting selected before the power is turned off.

The PCA9561 typically resides between the CPU and Voltage Regulator Module (VRM) when used for CPU VID (Voltage IDentification code) configuration. It is used to bypass the CPU-defined VID values and provide a different set of VID values to the VRM, if an increase in the CPU voltage is desired. An increase in CPU voltage combined with an increase in CPU frequency leads to a performance boost of up to 7.5 %. Lower CPU voltage reduces power consumption. The main advantage of the PCA9561 over older devices, such as the PCA9559 or PCA9560, is that it contains four internal non-volatile EEPROM registers instead of just one or two, allowing five independent settings which allows a more accurate CPU voltage tuning depending on specific applications.

The PCA9561 has two address pins, allowing up to four devices to be placed on the same I²C-bus or SMBus.

PCA9561: Product Block Diagram
Outline 3d SOT360-1
Data Sheets (1)
Name/DescriptionModified Date
Quad 6-bit multiplexed I2C-bus EEPROM DIP switch (REV 4.0) PDF (708.0 kB) PCA956106 Nov 2012
Application Notes (4)
Name/DescriptionModified Date
Level shifting techniques in I2C-bus design (REV 1.0) PDF (52.0 kB) AN1044120 Jun 2007
I2C manual (REV 1.0) PDF (4.2 MB) AN1021627 Mar 2003
I2C 2002-1A Evaluation Board (REV 2.0) PDF (2.2 MB) AN1014626 Feb 2003
PCA8550 4-bit multiplexed/1-bit latched 5-bit I2C EEPROM (REV 1.0) PDF (60.0 kB) AN250_101 Oct 1998
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
Evaluate the I2C-bus with a comprehensive kit; NXP® I2C 2002-1A evaluation board kits OM6285 and OM6278 (REV 1.0) PDF (1.8 MB) 7501653101 Jul 2008
Package Information (1)
Name/DescriptionModified Date
plastic thin shrink small outline package; 20 leads; body width 4.4 mm (REV 1.0) PDF (304.0 kB) SOT360-108 Feb 2016
Packing (1)
Name/DescriptionModified Date
TSSOP20; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or... (REV 4.0) PDF (225.0 kB) SOT360-1_11815 Apr 2013
Reports or Presentations (1)
Name/DescriptionModified Date
design_con_2003_tecforum_i2c_b_1 (REV 0.1) PDF (4.2 MB) DESIGN_CON_2003_TECFORUM_I2C_B_127 Jan 2003
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
ProductStatusPackage versionOperating Temperature (Cel)I2C-bus (kHz)Operating voltage (VDC)Max Sink Current, per package (mA)Max Sink Current per bit (mA)No of AddressesNo of Outputs/Latched Outputs/Internal EEPROM Registers
PCA9561PWActiveSOT360-10~704003.0~3.61002546?0?2
Package Information
Product IDPackage DescriptionOutline VersionReflow/Wave SolderingPackingProduct StatusPart NumberOrdering code(12NC)MarkingChemical ContentRoHS / Pb Free / RHFLeadFree Conversion DateEFRIFR(FIT)MTBF(hour)MSLMSL LF
PCA9561PWSOT360-1SSOP-TSSOP-VSO-WAVEReel 13" Q1/T1ActivePCA9561PW,118 (9352 717 09118)PCA9561PCA9561PWweek 12, 20050.02.05E811
Bulk PackActivePCA9561PW,112 (9352 717 09112)PCA9561PCA9561PWweek 12, 20050.02.05E811
Quad 6-bit multiplexed I2C-bus EEPROM DIP switch pca9561d
Level shifting techniques in I2C-bus design pca9685pw
I2C manual se98apw
I2C 2002-1A Evaluation Board lm75a
PCA8550 4-bit multiplexed/1-bit latched 5-bit I2C EEPROM pca9558pw
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
Evaluate the I2C-bus with a comprehensive kit; NXP® I2C 2002-1A evaluation board kits OM6285 and OM6278 lm75a
design_con_2003_tecforum_i2c_b_1 lm75a
PCA9561 IBIS model PCA9561PW
SOT360-1 LPC1112FDH20
SSOP-TSSOP-VSO-WAVE LPC1114FDH28
Reel 13" Q1/T1 LPC824M201JDH20
PCA9561
PCA9634