The ISL59910 and ISL59913 are three-channel differential receivers and equalizers. They all have three high-speed differential receivers with five programmable poles. This then sums the outputs of these pole blocks into an output buffer. The equalization length is set to single needle. The ISL59910 and ISL59913 outputs can also be put into a high impedance state, allowing multiple devices to be connected in parallel for multiplexing applications. The gain of each channel can be adjusted up or down by 6dB using its VGAIN control signal. Plus, there's 6dB of gain that can be switched into the cable to provide a matched driver. The ISL59910 and ISL59913 have a bandwidth of 150MHz and consume only 108mA on ±5V supplies. A single input voltage is used to set the required cable length. The ISL59910 is a special version of the ISL59913 that decodes and encodes the three common modes of the synchronous EL4543 provided by the Category 5 cable pair. (Refer to the EL4543 datasheet for details.) The ISL59910 and ISL59913 are available in 28 Ld QFN packages and specified over the -40°C to +85°C temperature range.

feature

150MHz - 3dB Bandwidth Category 5 Compensation - 100MHz @ 600ft - 135MHz at 300ft

108mA supply current

Differential input range 3.2V

Common Mode Input Range -4V to +3.5V

±5V power supply

Output to the power supply within 1.5V

Available in 28 Ld QFN package

Lead-free plus annealed (RoHS compliant) available

application

Twisted pair receiver/equalizer

KVM (Keyboard/Video/Mouse)

VGA on twisted pair

safety video

Absolute Maximum Ratings (TA=+25°C) Operating Conditions Supply voltage between VS+ and VS-. 12 Volts maximum continuous output current per channel. 30mA power consumption. See curve pin voltage. VS--0.5V to VS++0.5V storage temperature. -65°C to +150°C ambient operating temperature. -40°C to +85°C die attach temperature. +150 degrees Celsius

CAUTION: Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a pressure rating and operation of the device under the above or any other conditions stated in the operating section of this specification is not implied.

IMPORTANT: Guaranteed all parameters with min/max specs. Type values are for informational purposes only. Unless otherwise stated, all tests are pulsed at the specified temperature, thus: TJ=TC=TA

Electrical Specifications VSA+=VA+=+5V, VSA-=VA-=-5V, TA=+25°C, Exposed Template=-5V unless otherwise specified

Electrical Specifications VSA+=VA+=+5V, VSA-=VA-=-5V, TA=+25°C, Exposed Template=-5V unless otherwise specified.

application information

logic control

The ISL59913 has two logic input pins, chip enable (enable) and switch gain (X2). Logic circuits all have a nominal threshold 1.1V above the logic potential reference pin (VREF). In most applications, the chip is expected to operate between 0V and +5V in +5V, 0V, -5V logic powered systems. In this case, the logic reference voltage should be tied to the 0V supply. If the logic refers to the -5V rail, then the logic reference should be connected to -5V. About 60 microamps, if all inputs are true, this will go up to about 200 microamps (positive). when the logic input is held at the logic reference level. When taken as a positive value, the input sink current depends on the high level, up to 50 microamps high and 5V above the reference level. If logic inputs are not used, they should be connected to the appropriate voltages to determine their state. Control Reference and Signal Reference to set equalizer and contrast. These signals are voltages in the range 0V to 1V, referenced to the Control REF pin. It is expected that the control reference pin will be connected to 0V. The control voltage goes from 0V to 1V, however, the control reference can be connected to any potential control voltage reference between -5V and 0V. The control voltage pin itself is high impedance. The control reference pin will be between 0µA and 200µA, depending on the applied control voltage. The necessity for the control reference and logic reference to effectively remove the 0V rail and operate at ±5V (or 0V only 10V) is possible. But we need to further define the reference signal of single-ended output 0V level. The output signal is referenced by the 0V pin. The output stage cannot pull the supply completely up or down, so it is important to position the reference to allow full output swing. The 0V reference should be tied to "Quiet Ground" as any noise on this pin will be transmitted directly to the output. The 0V pin is a high impedance pin that draws bias currents of a few microamps DC and similar levels of AC current.

balanced

High frequency (above 1MHz) information is found to be attenuated more significantly than low frequency information when transmitting signals over twisted pair. Attenuation is primarily due to resistive skin effect losses and has a loss curve that depends on conductor resistivity, wire surface condition and wire diameter. Cables for high performance twisted pair based 24awg copper wire (CAT-5 etc.). These cable types and, in general, cables with little variation in parameters exhibit the same frequency dependence as loss. (The equalization law equation in the ISL59913 on low loss cables is comparable to slightly longer cables. At pins VCTRL and VREF, the frequency dependence of equalization is as shown in Figure 8. The equalization matches cable losses up to 100 MHz. Above this, the system gain is rolled off quickly reducing the noise bandwidth. The more the rollover occurs, the higher the control voltage is quickly obtained, so the system (cable + equalizer) bandwidth decreases with increasing cable length. This is desirable of equalization increases as noise becomes a growing problem

The contrast ratio can be varied by a 4:1 ratio by changing the gain of the voltage signal path between pins VGAIN and VREF. This gain change is almost linear with the control voltage. For normal operation it is expected that the X2 mode output load will be reverse matched. The unity output load will be approximately 0.35V at the gain control voltage. This allows the gain to be adjusted up or down by 6dB to compensate for any contrast affecting the video signal. Figure 26 shows an example graph of the gain of the load at the gain control voltage

Common Mode Synchronous Decoding

The ISL59910 has a common mode decoding function that allows horizontal and vertical synchronization information, which is encoded by the EL4543 at the three differential inputs, to be decoded. Therefore, the entire RGB video signal can be transmitted, as well as the associated synchronization information, using only three twisted pairs. Decoding is based on the EL4543 encoding scheme, as shown in Figure 26 and Table 1. This scheme is divided into a three-level system designed such that the common mode voltage results in a fixed average DC level with no AC content. This eliminates the effects of EMI radiation on the common-mode signal on the twisted pair of the cable. The common-mode voltage is initially determined by the ISL59910 from the three input pairs. It is then passed to an internal logic decoding block that provides the horizontal and vertical sync output signals (HOUT and VOUT)

Power consumption

The ISL59910 and ISL59913 are designed for a 5V supply voltage. Supply current is guaranteed to be less than 39mA/channel at output. Operating from a ±5V supply, the total power dissipation is:

PDMAX = maximum power consumption

VS=power supply voltage=5V

IMAX=maximum quiescent supply current channel=39mA

VOUTMAX = maximum output voltage swing PDMAX = 1.29W

Application = 2VRL = Load Resistance = 150Ω θJA Calculations required for long-term reliable operation. This is done via Equation 3:

Tj is the maximum junction temperature (+150°C)

Ta is the maximum ambient temperature (+85°C)

+37°C/WθJA thermal resistance is achievable for the QFN 28 package copper area in a well-placed PCB thermal dissipation. To dissipate heat, the heat sink on the bottom must be soldered to the PCB. The heat passes through the heat spreader to the circuit board copper and then disperses into air. Therefore, the PCB copper plane becomes the heat sink. This proved to be a very effective technique. A separate application note details the 28 Ld QFN. Printed circuit boards have design considerations.