Improved, 8-Channel/Dual 4-Channel,
CMOS Analog Multiplexers
DG408/DG409
______________________________________________________________Pin Description
PIN
DG408
1, 15, 16
—
2
3
4–7
—
8
—
9–12
—
13
14
DG409
—
1, 16
2
3
—
4–7
—
8, 9
—
10–13
14
15
NAME
A0, A2, A1
A0, A1
EN
V-
S1–S4
S1A–S4A
D
DA, DB
S8–S5
S4B–S1B
V+
GND
Address Inputs
Address Inputs
Enable Input
Negative Supply Voltage Input
Bidirectional Analog Inputs
Bidirectional Analog Inputs
Bidirectional Analog Output
Bidirectional Analog Outputs
Bidirectional Analog Inputs
Bidirectional Analog Inputs
Positive Supply Voltage Input
Ground
FUNCTION
__________Applications Information
Operation with
Supply Voltages Other than 15V
Using supply voltages less than ±15V reduces the ana-
log signal range. The DG408/DG409 switches operate
with ±4.5V to ±20V bipolar supplies or with a +4.5V to
+40V single supply. Connect V- to GND when operat-
ing with a single supply. Both device types can also
operate with unbalanced supplies, such as +24V and
-5V. The
Typical Operating Characteristics
graphs
show typical on-resistance with 20V, 15V, 10V, and 5V
supplies. (Switching times increase by a factor of two
or more for operation at 5V.)
V+
DG408
DG409
S
D
V
g
Overvoltage Protection
Proper power-supply sequencing is recommended for
all CMOS devices. Do not exceed the absolute maxi-
mum ratings, because stresses beyond the listed rat-
ings may cause permanent damage to the devices.
Always sequence V+ on first, then V-, followed by the
logic inputs, S or D. If power-supply sequencing is not
possible, add two small signal diodes in series with
supply pins for overvoltage protection (Figure 1).
Adding diodes reduces the analog signal range to 1V
below V+ and 1V above V-, but does not affect the
devices’ low switch resistance and low leakage charac-
teristics. Device operation is unchanged, and the differ-
ence between V+ and V- should not exceed +44V.
6
V-
Figure 1. Overvoltage Protection Using External Blocking
Diodes
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