EL4089CS Intersil, EL4089CS Datasheet - Page 7

• Manufacturer Part Number: EL4089CS
• Manufacturer: Intersil

Specifications of EL4089CS

• Number Of Amplifiers: Single
• Single Supply Voltage (typ): Not RequiredV
• Single Supply Voltage (min): Not RequiredV
• Single Supply Voltage (max): Not RequiredV
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC
• Lead Free Status / RoHS Status: Not Compliant

component. Likewise for RX2. The 75Ω back terminating
resistor RXT is recommended when driving 75Ω cables.
The board layout should have a ground plane underneath
the EL4089, with the ground plane cut away from the vicinity
of the V
capacitance on pin 1.
Power supply bypassing is important, and a 0.1µF ceramic
capacitor, from each power pin to ground, placed very close
to the power pins, together with a 4.7µF tantalum bead
capacitor, is recommended.
When both digital and analog grounds are on the same
board, the EL4089 should be on the analog ground. The
digital ground can be connected to the Analog ground
through a 100Ω-300Ω resistor, near the EL4089. This allows
the digital signal a return path, while preventing the digital
noise from corrupting the analog ground.
NOTE: Basic formulae are: V (droop) = Ib+ * (Line time - Sample
time) / Capacitor and V (charge) = I
For best results the source impedance should be kept low,
using a buffer for example.
CAP VALUE
TABLE OF CHARGE STORAGE CAPACITOR VS DROOP
100
nF
10
33
IN
- pin, (pin 1). This helps to minimize the stray
CHARGING RATES (NOTE)
DROOP IN
60µs
mV
1.8
0.6
6
7
OUT
CHARGE IN
1.2µs
* Sample time / Capacitor
mV
3.6
36
11
CHARGE IN
4µs
mV
120
36
12
EL4089
FIGURE 1.
The S/H amplifier is current output and causes a small load
on the input source during sampling. When sampling is done
on the back porch with color burst there will be a small load
on the color burst. Therefore for best performance, the input
should be driven from an amplifier output or a 75Ω cable with
75Ω termination.