DG408 Datasheet, PDF (11/12 Pages) Intersil Corporation – Single 8-Channel/Differential 4-Channel, CMOS Analog Multiplexers

DG408/409
Vishay Siliconix
APPLICATIONS HINTS
Overvoltage Protection
A very convenient form of overvoltage protection consists of
adding two small signal diodes (1N4148, 1N914 type) in
series with the supply pins (see Figure 10). This
arrangement effectively blocks the flow of reverse currents.
It also floats the supply pin above or below the normal V+ or
V- value. In this case the overvoltage signal actually
becomes the power supply of the IC. From the point of view
of the chip, nothing has changed, as long as the difference
VS - (V-) doesn’t exceed + 44 V. The addition of these diodes
will reduce the analog signal range to 1 V below V+ and 1 V
above V-, but it preserves the low channel resistance and low
leakage characteristics.
V+
1N4148
S_X
V_g
D
DG408
1N4148
V-
Figure 10. Overvoltage Protection Using Blocking Diodes
8-Channel Sequential Multiplexer/Demultiplexer
Differential 4-Channel Sequential Multiplexer/Demultiplexer
+ 15 V
- 15 V
+ 15 V
- 15 V
Analog
Inputs
(Outputs)
+ 15 V
V+ GND V-
S₁
S₂
S₃
S_{4 DG408 D}
S₅
S₆
S₇
S₈
A₀ A₁ A₂ EN
Analog
Output
(Input)
Differential
Analog
Inputs
(Outputs)
+ 15 V
V+ GND V-
S_1a
S_2a
S_3a
D_a
S_4a
DG409
S_1b
S_2b
S_3b
S_4b
A₀
D_b
A₁ EN
Differential
Analog
Outputs
(Inputs)
Clock
In
NC
DM7493 Q_B
B_IN
Q_C
Q_D
A_IN
Q_A
NC
r₀₁ r_{02 GND}
+ 15 V
Enable In
(MUX On-Off Control)
Clock
In
J
Q
1/2 MM74C73
CLK
K
Q
NC
CLEAR GND
Reset Enable
Figure 11.
J
Q
1/2 MM74C73
CLK
K
Q
NC
CLEAR
6
Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon
Technology and Package Reliability represent a composite of all qualified locations. For related documents such as package/tape drawings, part marking, and
reliability data, see http://www.vishay.com/ppg?70062.
Document Number: 70062
S-71155–Rev. G, 11-Jun-07
www.vishay.com
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