DG611 Vishay Siliconix, DG611 Datasheet - Page 7

• Manufacturer Part Number: DG611
• Description: High-Speed / Low-Glitch D/CMOS Analog Switches
• Manufacturer: Vishay Siliconix

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
V
2 V
g
5 V
R
g
S
IN
GND
+5 V
V
L
FIGURE 3. Charge Injection
S
IN
GND
+5 V
V
L
+15 V
V+
V–
V–
D
+15 V
–3 V
V+
V–
R
300
D
L
C
V
L
C
1 nF
O
V
L
O
FIGURE 2. Switching Time
X
C = RF bypass
Switch Output
TALK
Logic Input
V
Isolation = 20 log
S
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 S
it off, –8 V are applied via S
driver is especially suited for applications that require a large
number of RF switches, such as phased array radars.
=
5 V
0 V
0 V
2 V
V
S
R
g
= 50
1 V, 4 V
1 V, 4 V
NC
V
V
S
O
C
C
t
ON
L
(includes fixture and stray capacitance)
50%
S
IN
S
IN
+5 V
1
2
V
V
1
2
GND
O
L
FIGURE 4. Crosstalk
20%
= V
www.vishay.com FaxBack 408-970-5600
2
S
. This high-speed, low-power
DG611/612/613
Vishay Siliconix
–3 V
R
V–
+15 V
t
L
OFF
V+
+ r
R
D
D
1
2
L
DS(on)
C
1
90%
, whereas to turn
C
t
t
r
f
< 10 ns
< 10 ns
50
R
V
O
L
4-7