Datasheet
MAX4641/MAX4642/MAX4643
High-Speed, Low-Voltage, 4Ω, Dual SPST
CMOS Analog Switches
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Applications Information
The MAX4641/MAX4642/MAX4643 operate from a sin-
gle supply ranging from +1.8V to +5.5V. The devices
are guaranteed to be functional over that supply range,
but TTL/CMOS compatibility is only valid for operation
using a +5V supply. All voltage levels are referenced to
GND. Positive and negative DC analog inputs or AC
signals can be accommodated by shifting V+ and
GND.
ESD-protection diodes are internally connected be-
tween each analog-signal pin and both V+ and GND.
One of these diodes conducts if any analog signal
exceeds V+ or GND (Figure 1). Virtually all of the ana-
log leakage current comes from the ESD diodes to V+
or GND. Although the ESD diodes on a given signal pin
are identical, and therefore fairly well balanced, they
are reverse biased differently. Each is biased by either
V+ or GND and the analog signal. This means their
leakages will vary as the signal varies. The difference in
the two diode leakages to the V+ and GND pins consti-
tutes the analog-signal-path leakage current. All analog
leakage current flows between each pin and one of the
supply terminals, not to the other switch terminal. This
is why both sides of a given switch can show leakage
currents of the same or opposite polarity.
There is no normal current path between the analog-
signal paths and V+ or GND. V+ and GND also power
the internal logic and logic-level translators. The logic-
level translators convert the logic level into switched V+
and GND signals to drive the analog signal gates.
V+
NO_, NC_
GND
COM
Figure 1. Overvoltage Protection Using External Blocking
Diodes
MAX4641
IN_
0
1
NO_
MAX4641
OFF
ON
COM2
IN2
NO2
GND
1
2
8
7
V+
IN1
COM1
NO1
TOP VIEW
3
4
6
5
MAX4642
IN_
0
1
NC_
MAX4642
ON
OFF
COM2
IN2
NC2
GND
1
2
8
7
V+
IN1
COM1
NC1
3
4
6
5
MAX4643
IN_
0
1
NO1
MAX4643
OFF
ON
NC2
ON
OFF
COM2
IN2
NC2
GND
1
2
8
7
V+
IN1
COM1
NO1
3
4
6
5
QFN
QFN
QFN
Pin Configurations/Functional Diagrams/Truth Tables (continued)