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Download PCA9605 Simple 2-wire bus buffer
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PCA9605 NXP Semiconductors Simple 2-wire bus buffer 3.3 V SCL_IN VDD SCL_OUT SCL SDA SDA_IN SDA_OUT SDA U4 U5 VDD SCL SLAVE SDA U1 MASTER/ SLAVE VDD PCA9525 SCL SLAVE U6 up to 400 pF load (PCA9525) up to 400 pF load (PCA9525) or 4 nF load if only PCA9605's used (R1 and R2 = 110 Ω) R5 110 Ω R4 110 Ω SCL_IN VDD SCL_OUT SCL SDA_IN SDA_OUT SDA SLAVE U7 VDD U2 SCL PCA9605 VDD DIR SCL EN SDA VDD SCL SDA DIR SDA EN BUS MASTER U3 R4 1.1 kΩ SCL SDA VDD R3 1.1 kΩ R2 1.1 kΩ R1 1.1 kΩ SLAVE U8 up to 4 nF load (PCA9605) 002aaf342 Fig 14. PCA9605 typical buffer application Figure 15 shows the PCA9605 used with masters on both sides of the buffer. More than one master may be used on the Sxx_IN side of the IC. However, to locate a master on the Sxx_OUT side and have that master be able to communicate with devices on the Sxx_IN side, it must either have direct control over the direction pin (DIR) of the PCA9605, or it must request another controlling master to change the direction. In Figure 15, U4 uses an IRQ to signal to U2 that requests a direction change. Once in control, it could alternatively use the bus to signal ‘release of control’. PCA9605 Product data sheet All information provided in this document is subject to legal disclaimers. Rev. 1 — 28 February 2011 © NXP B.V. 2011. All rights reserved. 11 of 22
