FN6406 Rev 1.00

Page 9 of 13

Sep 28, 2018

ISL59910, ISL59913

Applications Information

Logic Control

The ISL59913 has two logical input pins, Chip Enable

(ENABLE) and Switch Gain (X2). The logic circuits all have a

nominal threshold of 1.1V above the potential of the logic

reference pin (VREF). In most applications it is expected that

this chip runs from a +5V, 0V, -5V supply system with logic

being run between 0V and +5V. In this case, tie the logic

reference voltage to the 0V supply. If the logic is referenced to

the -5V rail, connect the logic reference to -5V. The logic

reference pin sources about 60µA and this rises to about

200µA if all inputs are true (positive).

The logic inputs all source up to 10µA when they are held at

the logic reference level. When taken positive, the inputs sink a

current dependent on the high level, up to 50µA for a high level

5V above the reference level.

If the logic inputs are not used, tie them to the appropriate

voltage to define their state.

Control Reference and Signal Reference

Analog control voltages are required to set the equalizer and

contrast levels. These signals are voltages in the range 0V to

1V, which are referenced to the control reference pin. It is

expected that the control reference pin is tied to 0V and the

control voltage varies from 0V to 1V. It is, however, acceptable

to connect the control reference to any potential between -5V

and 0V to which the control voltages are referenced.

The control voltage pins themselves are high impedance. The

control reference pin sources between 0µA and 200µA

depending on the control voltages being applied.

The control reference and logic reference effectively remove the

necessity for the 0V rail and operation from ±5V (or 0V and 10V)

only is possible. However, we still need a further reference to

define the 0V level of the single-ended output signal. The

reference for the output signal is provided by the 0V pin. The

output stage cannot pull fully up or down to either supply so it is

important that the reference is positioned to allow full output

swing. Tie the 0V reference to a quiet reference as any noise on

this pin is transferred directly to the output. The 0V pin is a high

impedance pin and draws DC bias currents of a few µA and

similar levels of AC current.

Equalizing

When transmitting a signal across a twisted pair cable, the high

frequency (above 1MHz) information is attenuated more

significantly than the information at low frequencies. The

attenuation is predominantly due to resistive skin effect losses

and has a loss curve which depends on the resistivity of the

conductor, surface condition of the wire, and the wire diameter.

For the range of high performance twisted pair cables based

on 24awg copper wire (CAT-5 etc), these parameters vary only

a little between cable types and in general cables exhibit the

same frequency dependence of loss. (The lower loss cables

can be compared with somewhat longer lengths of similar

cables.) This enables a single equalizing law equation to be

built into the ISL59913.

With a control voltage applied between pins VCTRL and VREF,

the frequency dependence of the equalization is shown in

Figure 8 on page 6. The equalization matches the cable loss

up to about 100MHz. Above this, system gain is rolled off

rapidly to reduce noise bandwidth. The roll-off occurs more

rapidly for higher control voltages, thus the system (cable +

equalizer) bandwidth reduces as the cable length increases.

This is desirable, as noise increases as the equalization

increases.

Typical Performance Curves (Continued)

FIGURE 23. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

FIGURE 24. PACKAGE POWER DISSIPATION vs AMBIENT

TEMPERATURE

JEDEC JESD51-7 HIGH EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD - QFN EXPOSED

DIEPAD SOLDERED TO PCB PER JESD51-5



JA =

37°C

/W

QF

N28

3.378W

0

50

85

150

4.5

3.5

2.5

1.5

0.5

0

AMBIENT TEMPERATURE (°C)

25

75

100

125

4

2

1

3

JEDEC JESD51-3 LOW EFFECTIVE THERMAL

CONDUCTIVITY TEST BOARD

893mW



JA =

140

°C/W

QF

N28

0

50

85

150

1.2

0.8

0.6

0.4

0.2

0

AMBIENT TEMPERATURE (°C)

25

75

100

125

1