AD8139 AD [Analog Devices], AD8139 Datasheet - Page 23

• Manufacturer Part Number: AD8139
• Description: Low Noise Rail-to-Rail Differential ADC Driver
• Manufacturer: AD [Analog Devices]

Since this is a single-ended-to-differential application on a
single supply, the input common-mode voltage swing must be
checked. From Figure 62, β = 0.52, V
1.1 V p-p swinging about ground. Using Equation 16, V
calculated to be 0.53 V p-p swinging about a baseline of 1.25 V,
and the minimum negative excursion is approximately 1 V.
V
S
SIGNAL
SOURCE
50Ω
OCM
Figure 62. AD8139 Driving AD6645, 14-Bit, 80 MSPS/105 MSPS A/D Converter
= 2.4 V, and V
2V p-p
R
61.9Ω
T
226Ω
200Ω
V
2.4V
OCM
ICM
0.01µF
ACM
is
8
2
1
is
+
AD8139
–
Rev. A | Page 23 of 24
3
6
205Ω
205Ω
4
5
25Ω
25Ω
Exposed Paddle (EP)
The SOIC-8 and LFCSP packages have an exposed paddle on
the underside of its body. In order to achieve the specified
thermal resistance, it must have a good thermal connection to one
of the PCB planes. The exposed paddle must be soldered to a pad
on top of the board that is connected to an inner plane with several
thermal vias.
5V
AIN
AIN
GND C1
AV
CC
AD6645
0.1µF
0.01µF
C2
0.1µF
DV
3.3V
CC
VREF
0.01µF
AD8139