OPA682N BURR-BROWN [Burr-Brown Corporation], OPA682N Datasheet - Page 14

• Manufacturer Part Number: OPA682N
• Description: Wideband, Fixed Gain BUFFER AMPLIFIER With Disable
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

FIGURE 4. Two-Channel Video Multiplexer.
FIGURE 3. Wideband, AC-Coupled, Single-Supply A/D Driver.
cies exceeding 5MHz. The high slew rate, exceptional out-
put swing and high linearity of the OPA682 make it an ideal
single-supply ADC driver. Figure 3 shows an example input
interface to a very high performance 10-bit, 60MSPS CMOS
converter.
The OPA682 in the circuit of Figure 3 provides 240MHz
bandwidth operating at a signal gain of +2 with a 2Vp-p
output swing. The non-inverting input bias voltage is refer-
enced to the midpoint of the ADC signal range by dividing
off the top and bottom of the internal ADC reference ladder.
With the gain resistor (R
has a gain of +1 to the output, centering the output voltage
V
DIS
®
OPA682
1Vp-p
0.1 F
Video 1
G
) AC-coupled, this bias voltage
Video 2
+5V
0.1 F
400
R
G
75
75
+2.5V DC Bias
+5V
OPA682
400
400
400
R
2k
2k
F
2Vp-p
DIS
14
OPA682
OPA682
+5V
–5V
+5V
–5V
50
2k
2k
swing as well. Tested performance at a 20MHz analog input
frequency and a 60MSPS clock rate on the converter gives
> 58dBc SFDR.
WIDEBAND VIDEO MULTIPLEXING
One common application for video speed amplifiers which
include a disable pin is to wire multiple amplifier outputs
together, then select which one of several possible video
inputs to source onto a single line. This simple “Wired-OR
Video Multiplexer” can be easily implemented using the
OPA682 as shown in Figure 4.
DIS
DIS
Clock
400
400
22pF
+3.5V
0.1 F
+1.5V
0.1 F
Input
Input
CM
REFT
REFB
+5V
|V
68.1
68.1
60MSPS
ADS823
OUT
10-Bit
| < 2.6V
75
RG-59
Cable
V
OUT