PCA9509DP: Level translating I²C-bus/SMBus repeater

The PCA9509 is a level translating I²C-bus/SMBus repeater that enables processor low voltage 2-wire serial bus to interface with standard I²C-bus or SMBus I/O. While retaining all the operating modes and features of the I²C-bus system during the level shifts, it also permits extension of the I²C-bus by providing bidirectional buffering for both the data (SDA) and the clock (SCL) lines, thus enabling the I²C-bus or SMBus maximum capacitance of 400 pF on the higher voltage side. Port A allows a voltage range from 1.35 V to VCC(B) ‑ 1.0 V and requires no external pull-up resistors due to the internal current source. Port B allows a voltage range from 3.0 V to 5.5 V and is overvoltage tolerant. Both port A and port B SDA and SCL pins are high-impedance when the PCA9509 is unpowered.

For applications where Port A VCC(A) is less than 1.35 V or Port B VCC(B) is less than 3.0 V, use drop-in replacement PCA9509A.

The bus port B drivers are compliant with SMBus I/O levels, while port A uses a current sensing mechanism to detect the input or output LOW signal which prevents bus lock-up. Port A uses a 1 mA current source for pull-up and a 200 Ω pull-down driver. This results in a LOW on the port A accommodating smaller voltage swings. The output pull-down on the port A internal buffer LOW is set for approximately 0.2 V, while the input threshold of the internal buffer is set about 50 mV lower than that of the output voltage LOW. When the port A I/O is driven LOW internally, the LOW is not recognized as a LOW by the input. This prevents a lock-up condition from occurring. The output pull-down on the port B drives a hard LOW and the input level is set at 0.3 of SMBus or I²C-bus voltage level which enables port B to connect to any other I²C-bus devices or buffer.

The PCA9509 drivers are not enabled unless VCC(A) is above 0.8 V and VCC(B) is above 2.5 V. The enable (EN) pin can also be used to turn on and turn off the drivers under system control. Caution should be observed to change only the state of the EN pin when the bus is idle.

PCA9509DP: Product Block Diagram
Outline 3d SOT505-1

0 Hz to 400 kHz clock frequency

Remark: 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
Level translating I2C-bus/SMBus repeater (REV 7.0) PDF (302.0 kB) PCA950904 Nov 2014
Application Notes (3)
Name/DescriptionModified Date
PCA9500/PCA9501 provides simple card maintenance and control using I²C-bus (REV 1.0) PDF (90.0 kB) AN25623 Mar 2009
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 (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
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
Package Information (1)
Name/DescriptionModified Date
plastic thin shrink small outline package; 8 leads; body width 3 mm (REV 1.0) PDF (240.0 kB) SOT505-108 Feb 2016
Packing (1)
Name/DescriptionModified Date
TSSOP8; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or... (REV 1.0) PDF (214.0 kB) SOT505-1_11815 Apr 2013
Supporting Information (1)
Name/DescriptionModified Date
Reflow Soldering Profile (REV 1.0) PDF (34.0 kB) REFLOW_SOLDERING_PROFILE30 Sep 2013
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)
PCA9509DPActiveSOT505-1-40~852.7~3.6_tolerant_to_5.5 VDC0.9~5.511400
PCA9509DP/DGNo Longer ManufacturedSOT505-1-40~852.7~3.6_tolerant_to_5.5 VDC0.9~5.511400
Package Information
Product IDPackage DescriptionOutline VersionReflow/Wave SolderingPackingProduct StatusPart NumberOrdering code(12NC)MarkingChemical ContentRoHS / Pb Free / RHFLeadFree Conversion DateEFRIFR(FIT)MTBF(hour)MSLMSL LF
PCA9509DPSOT505-1Reflow_Soldering_ProfileReel 13" Q1/T1ActivePCA9509DP,118 (9352 822 26118)9509PCA9509DPAlways Pb-free0.02.05E811
PCA9509DP/DGSOT505-1Reflow_Soldering_ProfileReel 13" Q1/T1WithdrawnPCA9509DP/DG,118 (9352 934 08118)9509Always Pb-free0.02.05E811
Level translating I2C-bus/SMBus repeater pca9509gm
PCA9500/PCA9501 provides simple card maintenance and control using I²C-bus PCA9553
Level shifting techniques in I2C-bus design pca9685pw
I2C / SMBus Repeaters, Hubs and Expanders pca9600
I2C-bus specification and user manual pca9685pw
I2C-bus specification and user manual pca9685pw
PCA9600 demonstration board OM6293 pca9600
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
Extend the I2C-bus with advanced repeaters and hubs; NXP® 2-channel I2C-bus repeaters PCA9515x and... pca9600
plastic thin shrink small outline package; 8 leads; body width 3 mm pesd5v0l7bas
Reflow_Soldering_Profile Wave_Soldering_Profile LPC1112FD20
TSSOP8; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or... pesd5v0l7bas
PCA9509GM
PCT2075