Datasheet
MAX349/MAX350
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 50Ω 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 50Ω 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.