DG611 Datasheet, PDF (7/8 Pages) Vishay Siliconix – High-Speed, Low-Glitch D/CMOS Analog Switches

DG611/612/613
Vishay Siliconix
TEST CIRCUITS
+5 V
+15 V
V_L
V+
"2 V
S
D
IN
GND
V–
V–
V_O
R_L
C_L
300 W
5V
Logic Input
0V
V_S= "2 V
Switch Output
0V
FIGURE 2. Switching Time
50%
t_r < 10 ns
t_f < 10 ns
90%
20%
t_ON
t_OFF
C_L (includes fixture and stray capacitance)
V_O = V_S
R_L
R_L + r_DS(on)
R_g
V_g
5V
+5 V
V_L
S
IN
GND
+15 V
V+
D
V–
–3 V
V_O
C_L
1 nF
FIGURE 3. Charge Injection
+5 V
C
V_S
R_g = 50 W
1 V, 4 V
NC
1 V, 4 V
X_TALK Isolation = 20 log
V_S
V_O
C = RF bypass
V_L
S₁
IN₁
S₂
IN₂
GND
+15 V
C
V+
D₁
D₂
V–
C
–3 V
FIGURE 4. Crosstalk
50 W
V_O
R_L
APPLICATIONS
High-Speed Sample-and-Hold
In a fast sample-and-hold application, the analog switch
characteristics are critical. A fast switch reduces aperture
uncertainty. A low charge injection eliminates offset (step)
errors. A low leakage reduces droop errors. The CLC111, a fast
input buffer, helps to shorten acquisition and settling times. A
low leakage, low dielectric absorption hold capacitor must
be used. Polycarbonate, polystyrene and polypropylene
are good choices. The JFET output buffer reduces droop
due to its low input bias current. (See Figure 5.)
Pixel-Rate Switch
Windows, picture-in-picture, title overlays are economically
generated using a high-speed analog switch such as the
DG613. For this application the two video sources must be
sync locked. The glitch-less analog switch eliminates halos.
(See Figure 6.)
Document Number: 70057
S-00399—Rev. G, 13-Sep-99
GaAs FET Drivers
Figure 7 illustrates a high-speed GaAs FET driver. To turn the
GaAs FET on 0 V are applied to its gate via S₁, whereas to turn
it off, –8 V are applied via S₂. This high-speed, low-power
driver is especially suited for applications that require a large
number of RF switches, such as phased array radars.
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