Serially Controlled, Low-Voltage,

8-Channel/Dual 4-Channel Multiplexers

18

______________________________________________________________________________________

Pin Configurations/Functional Diagrams (continued)

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

CS

TOP VIEW

RESET

DOUT

V-

GND

DIN

V+

SCLK

N.C.

N.C.

NO7

NO6

NO2

NO1

NO0

COM

12

11

9

10

NO5

NO4

N.C.

NO3

SSOP

MAX349

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

CS

RESET

DOUT

V-

GND

DIN

V+

SCLK

N.C.

N.C. = NOT INTERNALLY CONNECTED

COMB

NO0B

NO1B

NO2A

NO1A

NO0A

COMA

12

11

9

10

NO2B

NO3B

N.C.

NO3A

SSOP

LOGIC

LOGIC

MAX350

Bipolar Supplies

The MAX349/MAX350 operate with bipolar supplies

from ±3.0V and ±8V. The V+ and V- supplies need not

be symmetrical, but their sum cannot exceed the

absolute maximum rating of 17V. Do not connect the

MAX349/MAX350 V+ to +3V and connect the logic-

level pins to TTL logic-level signals. This exceeds

the absolute maximum ratings and can damage the

part and/or external circuits.

Single Supply

The MAX349/MAX350 operate from single supplies

between +3V and +16V when V- is connected to GND.

All of the bipolar precautions must be observed.

High-Frequency Performance

In 50

Ω systems, signal response is reasonably flat up

to 50MHz (see

Typical Operating Characteristics).

Above 20MHz, the on response has several minor

peaks that are highly layout dependent. The problem is

not turning the switch on, but turning it off. The off-state

switch acts like a capacitor and passes higher frequen-

cies with less attenuation. At 10MHz, off-isolation is

about -45dB in 50

Ω systems, becoming worse (approx-

imately 20dB per decade) as frequency increases.

Higher circuit impedances also make off-isolation

worse. Adjacent channel attenuation is about 3dB

above that of a bare IC socket, and is entirely due to

capacitive coupling.