PCA9509_1

© Koninklijke Philips Electronics N.V. 2006. All rights reserved.

Product data sheet

Rev. 01 — 27 June 2006

3 of 16

Philips Semiconductors

PCA9509

5.

Pinning information

5.1 Pinning

5.2 Pin description

[1]

Port A and port B can be used for either SCL or SDA.

6.

Functional description

Refer to Figure 1 “Functional diagram of PCA9509”.

without degradation of system performance. The PCA9509 contains 2 bidirectional

open-drain buffers specifically designed to support up-translation/down-translation

over-voltage tolerant to 5.5 V even when the device is unpowered.

The PCA9509 includes a power-up circuit that keeps the output drivers turned off until

any sequence at power-up. After power-up and with the EN pin HIGH, a LOW level on

port A (below approximately 0.15 V) turns the corresponding port B driver (either SDA or

SCL) on and drives port B down to about 0 V. When port A rises above approximately

0.15 V, the port B pull-down driver is turned off and the external pull-up resistor pulls the

and port A pulls down to 0.2 V (typical). The port B pull-down is not enabled unless the

Fig 2.

Pin configuration for TSSOP8

Fig 3.

Pin configuration for SO8

PCA9509DP

A1

B1

A2

B2

GND

EN

002aac126

1

2

3

4

6

5

8

7

PCA9509D

A1

B1

A2

B2

GND

EN

002aac127

1

2

3

4

6

5

8

7

Table 2.

Pin description

Symbol

Pin

Description

1

port A power supply

A1[1]

2

port A (lower voltage side)

A2[1]

3

port A

GND

4

ground (0 V)

EN

5

enable input (active HIGH)

B2[1]

6

B1[1]

7

port B

8

port B power supply