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DG408 Datasheet, PDF (8/16 Pages) Intersil Corporation – Single 8-Channel/Differential 4-Channel, CMOS Analog Multiplexers | |||
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DG408, DG409
Test Circuits and Waveforms (Continued)
5V +15V
VIN
S1 EN V+
SIGNAL
GENERATOR
VO
D
A2
A1
RL
A0
V-
GND
-15V
ANALYZER
INSERTION LOSS = 20 Log V----V-O---I--UN-----T--
3V OR 0V +15V
CHANNEL
SELECT
EN
A2
A1
V+
S1
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S8
A0
D
V-
GND
-15V
IMPEDANCE
ANALYZER
FIGURE 7. INSERTION LOSS
Typical Applications
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 9). This arrangement
effectively blocks the ï¬ow of reverse currents. It also ï¬oats
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 V+ - (V-) doesnât
exceed 44V. The addition of these diodes will reduce the
analog signal range to 1V below V+ and 1V above V-, but it
preserves the low channel resistance and low leakage
characteristics.
Typical application information is for Design Aid Only, not
guaranteed and not subject to production testing.
FIGURE 8. SOURCE/DRAIN CAPACITANCES
V+
1N4148
SX
VG
D
DG408
1N4148
V-
FIGURE 9. OVERVOLTAGE PROTECTION USING BLOCKING
DIODES
8
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