Serially Controlled, Low-Voltage,

8-Channel SPST Switch

12

______________________________________________________________________________________

Addressable Serial Interface

When several serial devices are configured as slaves,

addressable by the processor, DIN pins of each

decode logic individually control CS of each slave

device. When a slave is selected, its CS pin is driven

low, data is shifted in, and CS is driven high to latch the

data. Typically, only one slave is addressed at a time.

DOUT is not used.

__________Applications Information

Multiplexers

The MAX395 can be used as a multiplexer, but to

obtain the same electrical performance with slightly

improved programming speed, use the MAX349 8-

channel mux or the MAX350 dual 4-channel mux, both

in 18-pin packages.

D7 D6

D5 D4 D3 D2 D1 D0

DATA BITS FROM PREVIOUS DATA INPUT

D7 D6 D5 D4 D3 D2 D1

D0

DOUT

DIN

SCLK

SWITCHES

UPDATED

CS

D0

DATA BITS

Figure 2. Three-Wire Interface Timing

RESET

X

0

0

1

X

1

1

1

Switch 7 open (off)

Switch 6 open (off)

Switch 7 closed (on)

All switches open, D7–D0 = 0

FUNCTION

X

1

X

1

X

1

X

1

Switch 5 open (off)

Switch 4 open (off)

Switch 5 closed (on)

Switch 6 closed (on)

X

1

X

1

X

1

X

1

Switch 3 open (off)

Switch 2 open (off)

Switch 3 closed (on)

Switch 4 closed (on)

X

1

X

1

X

1

X

1

Switch 1 open (off)

Switch 0 open (off)

Switch 1 closed (on)

Switch 2 closed (on)

D7

X

0

X

X

X

X

X

1

X

X

X

X

X

X

X

X

D6

X

X

X

X

X

X

X

X

0

X

X

X

X

X

1

X

X

X

X

D4

X

0

X

1

X

X

X

X

X

X

X

X

X

D5

X

X

X

X

X

X

X

X

X

X

X

X

0

X

X

X

X

X

1

D2

X

X

X

X

X

X

X

DATA BITS

X

X

X

X

X

X

X

X

X

X

X

0

X

X

X

D0

X

X

X

X

X

X

X

X

X

X

0

X

1

X

D1

X

0

X

1

X

X

X

X

X

D3

X

X

X

X

X

1

1

X

Switch 0 closed (on)

X

Table 1. Serial-Interface Switch Programming