参数资料
| 型号： | ISL59911IRZ |
| 厂商： | Intersil |
| 文件页数： | 2/17页 |
| 文件大小： | 0K |
| 描述： | IC RCVR/EQUALZR TRPL DIFF 32QFN |
| 标准包装： | 60 |
| 类型： | 接收器 |
| 驱动器/接收器数： | 0/3 |
| 规程： | 双绞线 |
| 电源电压： | 5V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 供应商设备封装： | 32-QFN 裸露焊盘（5x6） |
| 包装： | 管件 |
ISL59911
10
FN7548.0
September 2, 2011
Applications Information
ISL59911 Overview
Differential video signals sent over long distances of twisted pair
wire encounter are increasingly attenuated as frequency and
distance increase, resulting in loss of high frequency detail
(blurring). The exact loss characteristic is a function of the wire
gauge, whether the pairs are shielded or unshielded, the
dielectric of the insulation, and the length of the wire. The loss
mechanism is primarily skin effect.
The signal can be restored by applying a filter with the inverse
transfer function of the cable to the far end signal. The ISL59911
is designed to compensate for losses due to long cables, and
incorporates the functionality and flexibility to match a wide
variety of loss characteristics.
Power Supply Sequencing
Power to the ISL59911’s negative supply pins should be applied
before the positive supply ramps. As shown in Figure 11,
V- should reach -3V before V+ reaches 1V.
If this power supply sequence cannot be guaranteed, then the
ADDR1 pin must be held low during power-up until V- has crossed
-3V.
If this power supply sequencing requirement is not met and if
ADDR1 is high, there is a small chance that the ISL59911 factory
trim will become permanently corrupted.
Power Supply Bypassing
For best performance, all ICs need bypass capacitors across
some or all of their power supply pins. The best high-frequency
decoupling is achieved with a 0.1μF capacitor between each
power supply pin and GND. Adjacent supply pins (pins 2 and 3,
19 and 20, 22 and 23, and 25 and 26) can share the same
decoupling capacitor. Keep the path to both pins as short as
possible to minimize inductance and resistance. Pins 3 and 10
provide power to the internal equalizer, while supply pins
between pin 17 and pin 25 provide power to the analog output
buffers. For best performance, the equalizer supplies should be
somewhat isolated from the buffer supplies. A separate path
back to the power source should be adequate.
A 10μF capacitor on each of the V+ and V- supplies provides
sufficient low-frequency decoupling. The 10μF capacitors do not
need to be particularly close to the ISL59911 to be effective, but
should still have a low-impedance path to the supply rails.
In many mixed-signal ICs, separation of the analog and digital
supplies and grounds is critical to prevent digital noise from
appearing on the analog signals. Because the digital logic in the
ISL59911 is only active during a one-time configuration, the
analog and digital supply pins (and grounds) can be connected
together, simplifying PCB layout and routing.
Input Termination
The differential input signal from a Cat x cable should have a
characteristic impedance of 100
Ω and is therefore terminated by
the two 50
Ω resistors across the differential inputs, as shown in
Ω resistor and 0.1F capacitor
connected to the midpoint keep the AC impedance low at high
frequencies, providing common-mode AC termination while
allowing the low-frequency component of the common mode
(containing the embedded H and V sync signals) to move freely.
The 1k resistor provides a higher-impedance DC path to ground,
so the common mode voltage is set to 0V when no cable is
connected.
Device Initialization
To ensure that the ISL59911 functions properly, the following
steps must be taken after initial power-up:
1. Ensure that the ENABLE pin is high.
2. Through the serial interface, write 0x06 to register 0x13, then
write 0x00 to the same register. This ensures that the DC gain
of the device is accurate.
3. Perform an offset calibration by setting bit 0 of register 0x0C
to 1. The bit is automatically resets to 0 upon completion of
calibration. If offset calibration is not performed, the
ISL59911 may have large DC offsets.
Communicating with the ISL59911
The ISL59911 is controlled through the industry standard I2C
serial interface. Adjustments to the frequency response over five
distinct frequency bands, gain and offset fine-tuning, and several
other functions are made through this interface as described in
the Register Listing starting on page 8. This level of control
enables much more accurate and flexible response matching
than previous solutions.
The ISL59911 also has an external Chip Enable (ENABLE) pin,
allowing hardware control of whether the chip is operating or in a
low-power standby mode.
Programming the ISL59911 for a Specific
Cable and Length
Determining the optimum settings for the ISL59911’s multiple
equalizer frequencies, gain, and low pass filter can initially seem
quite challenging. To equalize any cable type of any length,
transmit a step (a pure white screen works well, since the video
in HSYNC region is black) and adjust the filters, starting at
200kHz and working up to 100MHz, so that the response at the
receive end is as flat as possible. Once the response is flat, the
gain should be adjusted as necessary to compensate for the DC
losses.
This technique is not usually practical in the field, where the best
solution is a lookup table for each cable type. Table 1 shows the
best values for a typical Cat 5 cable.
+1V
FIGURE 11. POWER SUPPLY SEQUENCING
-3V
t > 0ms
V+
V-
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相关代理商/技术参数 |
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| ISL59911IRZ-EVALZ | 功能描述:EVALUATION BOARD FOR ISL59911 RoHS:是 类别:编程器，开发系统 >> 评估演示板和套件 系列:- 标准包装:1 系列:PCI Express® (PCIe) 主要目的:接口，收发器，PCI Express 嵌入式:- 已用 IC / 零件:DS80PCI800 主要属性:- 次要属性:- 已供物品:板 |
| ISL59911IRZ-T7 | 功能描述:视频 IC ISL9519C EVALRD 1 50LD BATRY CHRGR RoHS:否 制造商:Fairchild Semiconductor 工作电源电压:5 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:TSSOP-28 封装:Reel |
| ISL59913 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Triple Differential Receiver/Equalizer |
| ISL59913IRZ | 功能描述:视频 IC ISL95210 5V/10AUCK FET INDSTRL TEMP RNG RoHS:否 制造商:Fairchild Semiconductor 工作电源电压:5 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:TSSOP-28 封装:Reel |
| ISL59913IRZ-EVALZ | 功能描述:EVAL BOARD FOR ISL59913IRZ RoHS:是 类别:编程器，开发系统 >> 评估演示板和套件 系列:* 标准包装:1 系列:PCI Express® (PCIe) 主要目的:接口，收发器，PCI Express 嵌入式:- 已用 IC / 零件:DS80PCI800 主要属性:- 次要属性:- 已供物品:板 |
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