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PCA9509P: Low power level translating I²C-bus/SMBus repeater

The PCA9509P is a level translating I²C-bus/SMBus repeater with two voltage supplies 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 0.8 V to 1.5 V and is overvoltage tolerant. Port B allows a voltage range from 2.3 V to 5.5 V and is overvoltage tolerant. Both port A and port B SDA and SCL pins are high-impedance when the PCA9509P is unpowered.

The bus port B drivers are compliant with SMBus I/O levels, while port A uses an offset LOW which prevents bus lock-up and allows the bidirectional nature of the device. The output pull-down on the port A internal buffer LOW is set for approximately 0.2 VCC(A), while the input threshold of the internal buffer is set about 0.1 VCC(A) 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 PCA9509P drivers are not enabled unless VCC(A) is above 0.7 V and VCC(B) is above 1.7 V. The enable (EN) pin can also be used to turn the drivers on and off under system control. Caution should be observed to only change the state of the EN pin when the bus is idle.

The PCA9509P is the same as the PCA9509A but without the port A internal current source to allow high value pull-up resistors to reduce current consumption in portable applications.

The PCA9509P should be used if an external A-port pull-up resistor is required to adjust current for noise margin considerations or to reduce operating current consumption.

Concern

Recommended device

PCA9509

PCA9509A

PCA9509P

A-port — lowest voltage

1.0 V

0.85 V

0.85 V

A-port — current source [1]

yes—1 mA

yes—270 μA

no—external pull-up

operating current [2]

< 6.1 mA

< 1.9 mA

< 0.95 mA

standby current EN = LOW

< 2 mA

< 22 μA max.

< 22 μA max.

Outline 3d SOT902-2

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)

Package Information (2)

Packing (2)

Supporting Information (1)

Ordering Information

Package Information

Product ID	Package Description	Outline Version	Reflow/Wave Soldering	Packing	Product Status	Part NumberOrdering code(12NC)	Marking	Chemical Content	RoHS / Pb Free / RHF	LeadFree Conversion Date	EFR	IFR(FIT)	MTBF(hour)	MSL	MSL LF
PCA9509PGM		SOT902-2		Reel 7" Q3/T4, Reverse	Active	PCA9509PGM,125 (9352 979 54125)	Standard Marking	PCA9509PGM		Always Pb-free	0.0	2.0	5E8	1	1
PCA9509PDP		SOT505-1	Reflow_Soldering_Profile	Reel 13" Q1/T1	Active	PCA9509PDP,118 (9352 979 55118)	9509P	PCA9509PDP		Always Pb-free	0.0	2.0	5E8	1	1