7

FN7122.2

March 26, 2007

Applications Information

Product Description

The EL1510 is a dual operational amplifier designed for line

driving in DMT ADSL solutions. It is a dual current mode

feedback amplifier with low distortion while drawing

moderately low supply current. It is built using Elantec's

proprietary complimentary bipolar process and is offered in

industry standard pin-outs. Due to the current feedback

architecture, the EL1510 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 1.0µF tantalum capacitor in parallel with a 0.01µF 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 25. TRANSIMPEDANCE vs TEMPERATURE

FIGURE 26. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 27. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 28. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

3.5

0

2

3

1

0.5

1.5

2.5

DIE TEMPERATURE (°C)

-50

100

150

-25

0

50

125

25

75

1.136W

θ

10°

C/W

SO

8

1.8

1.6

1.4

0.8

0.6

0.2

0

0

25

50

75

100

150

AMBIENT TEMPERATURE (°C)

125

85

JEDEC JESD51-7 HIGH EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

0.4

1

1.2

JEDEC JESD51-7 HIGH EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD - DFN EXPOSED

DIEPAD SOLDERED TO PCB PER JESD51-5

4.5

4

3

2

1

0.5

0

0

25

50

75

100

150

AMBIENT TEMPERATURE (°C)

125

85

θ

3°C/

W

DF

N8

2.907W

3.5

2.5

1.5

781mW

θ

160

°C

/W

SO

8 &

DF

N8

1.2

1

0.8

0.6

0.2

0

0

25

50

75

100

150

AMBIENT TEMPERATURE (°C)

125

85

JEDEC JESD51-3 LOW EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

0.4

EL1510