Serial-to-Parallel/Parallel-to-Serial Converters andLoad-Switch Controllers with SMBus InterfaceMAX1661/MAX1662/MAX1663______________________________________________________________Pin DescriptionPINNAMEFUNCTION 1 VCC Supply Voltage Input, 2.7V to 5.5V. 2 I/O1 Input 1 or Output 1 (open drain). This pin can tolerate up to 28V. 3 I/O2 Input 2 or Output 2 (open drain). This pin can tolerate up to 28V. 4 I/O3 Input 3 or Output 3 (open drain). This pin can tolerate up to 28V. 5 GND Ground 6 ADD SMBus Address Select Pin (see Table 1 for details). 7 SMBSUS SMBus Suspend-Mode Control Input. Drive low to select the suspend-mode register. Drive high to select the normal-mode register. (See Detailed Description.) 8 SMBDATA SMBus Serial-Data Input/Output (open drain) 9 SMBCLK SMBus Serial Clock Input 10 ALERT Interrupt Output, active low, open drain TRANSITION DETECTORS I/01 SMBCLK 8 INPUT SMB SMBDATA REGISTER I/02 MAX1661/ MAX1662/ I/03 MAX1663 ADD ADDRESS NORMAL DECODER NORMAL O1 MUX DATA REGISTER SUSPEND 7 CONTROL NORMAL ALERT RESPONSE O2 MUX REGISTER SUSPEND CONTROL NORMAL ALERT SUSPEND- R O3 MODE MUX FAULT S DATA SUSPEND LATCH REGISTER CONTROL THERMAL SHUTDOWN SMBSUS Figure 1. Functional Diagram _______________________________________________________________________________________5