DG418 Datasheet, PDF (9/10 Pages) TEMIC Semiconductors – Precision CMOS Analog Switches

DG417/418/419
Test Circuits (Cont’d)
+5 V +15 V
C
C
V_L
V+
S
DG417/418
V, 2.4 V _IN
GND
D
V–
C
–15 V
+15 V NC
C
Meter
HP4192A
Impedance
Analyzer
or Equivalent
f = 1 MHz
V+ S₂
DG419
0 V, 2.4 V _IN
D₂
GND
S₁
D₁
V–
C
Figure 9. Source/Drain Capacitances
–15 V
Meter
HP4192A
Impedance
Analyzer
or Equivalent
f = 1 MHz
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 D₁ and
charges C₁. The charge stored on C₁ is used to power the
chip; operation is satisfactory because the switch requires
less than 1 mA of stand-by supply current. Loading of the
signal source is imperceptible. The DG419’s on-resistance
is a low 100 W for a 5-V input signal.
D₁
Input
Control
V+
D
V_L
S₁
S₂
IN
DG419
GND
V–
C₁
0.01 mF
V_OUT
R_L1
10 kW
R_L2
10 kW
Figure 10. Switched Signal Powers Remote
SPDT Analog Switch
Siliconix
9
S-52880—Rev. D, 28-Apr-97