TCA9509 Output Current Specification

David Escandon

Other Parts Discussed in Thread: TCA9509, TCA9517

TI Team,

I'm using the TCA9509 is a mixed voltage I2C bus. I have 3.3V on the B side and 2.5V on the A side. The datasheet specifies a 10uA low level output current. However, the datasheet says the A side has a strong pull down resistor of 200 ohms. For a low voltage output of ~.2V, wouldn't this imply a 1mA low level output current? How do you arrive at 10uA? Can you share the driver structure for both the A and B sides?

-David

over 12 years ago

0 Jeffery Pfarr over 12 years ago

TI__Genius 14317 points

David,

I think that the 10 uA is the max low level output current. Internal to the device, the sink current is 1 mA through the 200 ohm pulldown. See http://e2e.ti.com/support/interface/etc_interface/f/390/p/164518/602783.aspx#602783 for a discussion related to this.

0 David Escandon over 12 years ago in reply to Jeffery Pfarr

Expert 2175 points

Jeff,

Can you confirm that this is the case? According to the datasheet, the specification is listed as a low level output current.

http://www.ti.com/lit/ds/symlink/tca9509.pdf

0 Jeffery Pfarr over 12 years ago in reply to David Escandon

TI__Genius 14317 points

From Device Apps.:

The data sheet is correct … the A-side of the TCA9509 is intended to drive only a very small load ( typically just one CMOS Input). The TCA9517 is designed to drive the full 6mA load on both A and B side.. if the voltage levels are acceptable, it could be a suitable replacement.

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TCA9509 Output Current Specification