MAX349 Maxim, MAX349 Datasheet - Page 18

• Manufacturer Part Number: MAX349
• Description: The MAX349/MAX350 are 8-channel and dual 4-channel serially controlled multiplexers (muxes)
• Manufacturer: Maxim

Serially Controlled, Low-Voltage,
8-Channel/Dual 4-Channel Multiplexers
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.
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.
18
N.C. = NOT INTERNALLY CONNECTED
______________________________________________________________________________________
SCLK
COM
GND
NO0
NO1
NO2
NO3
N.C.
DIN
V+
10
1
2
3
4
5
6
7
9
8
MAX349
SSOP
LOGIC
Pin Configurations/Functional Diagrams (continued)
13
20
19
18
17
16
15
14
12
11
Bipolar Supplies
CS
RESET
DOUT
V-
N.C.
N.C.
NO7
NO6
NO5
NO4
Single Supply
TOP VIEW
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.
COMA
SCLK
NO0A
NO1A
NO2A
NO3A
GND
N.C.
DIN
V+
High-Frequency Performance
10
1
2
3
4
5
6
7
9
8
SSOP
MAX350
LOGIC
20
19
18
17
14
13
12
16
15
11
CS
RESET
DOUT
V-
N.C.
COMB
NO0B
NO1B
NO2B
NO3B