9

Applications Information

Product Description

The EL8108 is a dual current feedback operational amplifier

designed for video distribution solutions. It is a dual current

mode feedback amplifier with low distortion while drawing

moderately low supply current. It is built using Intersil’s

proprietary complimentary bipolar process and is offered in

industry standard pinouts. Due to the current feedback

architecture, the EL8108 closed-loop 3dB bandwidth is

dependent on the value of the feedback resistor. First the

desired bandwidth is selected by choosing the feedback

Performance Curves section show the effect of varying both

the power supply voltage.

Power Supply Bypassing and Printed Circuit

Board Layout

As with any high frequency device, good printed circuit

board layout is necessary for optimum performance. Ground

plane construction is highly recommended. Lead lengths

should be as short as possible, below ¼”. The power supply

pins must be well bypassed to reduce the risk of oscillation.

A 4.7µF tantalum capacitor in parallel with a 0.1µF ceramic

capacitor is adequate for each supply pin.

For good AC performance, parasitic capacitances should be

kept to a minimum, especially at the inverting input. This

implies keeping the ground plane away from this pin. Carbon

resistors are acceptable, while use of wire-wound resistors

should not be used because of their parasitic inductance.

Similarly, capacitors should be low inductance for best

performance.

FIGURE 36. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 37. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 38. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 39. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

JEDEC JESD51-7 HIGH EFFECTIVE THERMAL

CONDUCTIVITY (4-LAYER) TEST BOARD

3.5

3

0

AMBIENT TEMPERATURE (°C)

0

150

50

100

2

2.5

1

1.5

0.5

125

25

75 85

1.136W

110°C/

W

SO8

JEDEC JESD51-3 LOW EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

1.4

0

0.8

0.4

0.2

0.6

1.2

AMBIENT TEMPERATURE (°C)

0

1

25

50

75

100

150

125

85

781mW

θ

0°C/W

SO8

JEDEC JESD51-7 HIGH EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD - LPP EXPOSED

DIEPAD SOLDERED TO PCB PER JESD51-5

4.5

4

3

2

1

0.5

0

0

255075

100

150

AMBIENT TEMPERATURE (°C)

125

85

3.5

2.5

1.5

3.125W

QFN16

JEDEC JESD51-3 LOW EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

1.2

1

0.8

0.6

0.4

0.2

0

025

50

75

100

150

AMBIENT TEMPERATURE (°C)

833mW

QFN16

125

85

EL8108