DG417, DG418, DG419
Vishay Siliconix
TEST CIRCUITS
+5V
C
V
L
+ 15 V
+ 15 V
C
V+
S
V+ S
2
Meter
S
1
Meter
HP4192A
Impedance
Analyzer
or Equivalent
f = 1 MHz
C
NC
DG417/418
0 V, 2.4 V
IN
HP4192A
Impedance
Analyzer
or Equivalent
C
f = 1 MHz
0 V, 2.4 V
DG419
IN
D
GND
V-
D
2
GND
V-
D
1
C
- 15 V
- 15 V
Figure 9. Source/Drain Capacitances
APPLICATIONS
Switched Signal Powers Analog Switch
The analog switch in Figure 10 derives power from its input
signal, provided the input signal amplitude exceeds 4 V and
its frequency exceeds 1 kHz.
This circuit is useful when signals have to be routed to either
of two remote loads. Only three conductors are required: one
for the signal to be switched, one for the control signal and a
common return.
A positive input pulse turns on the clamping diode D
1
and
charges C
1
. The charge stored on C
1
is used to power the
chip; operation is satisfactory because the switch requires
less than 1 µA of stand-by supply current. Loading of the
signal source is imperceptible. The DG419’s on-resistance is
a low 100
for a 5 V input signal.
D
1
V+
D
Input
S
2
V
L
S
1
C
1
0.01 µF
V
OUT
IN
Control
R
L2
10 k
DG419
GND
V-
R
L1
10 k
Figure 10. Switched Signal Powers Remote SPDT Analog Switch
Document Number: 70051
S10-1528-Rev. G, 19-Jul-10
www.vishay.com
9
VISHAY [ VISHAY TELEFUNKEN ]
