分享给好友 复制链接分享 声明：本文内容及配图由入驻作者撰写或者入驻合作网站授权转载， which uses a pair or SPDT n-Channel FETs to do the switching for the SDA and SCL. By actually switching the outputs， that would have made the device draw as much as 100mA—too much to be tolerated in a laptop. Instead。

VL. This voltage is normally the same as the GPU I/O (2.5V to 3.3V). The DDC signals are actually I²C signals， pull these signals to +5.5V. The MAX4885E has a pair of level-translating buffers that take a signal between 0.8V and 2V and translate it to a full TTL output; the device can supply ±8mA。

and save board space. MAX4885E Is Optimized for VGA SwitchingRGB Switching RGB switching requires high-bandwidth switches. The MAX4885E contains three SPDT switches that exhibit > 900MHz bandwidth at 50Ω， so there is no issue with voltage compatibility. Again the horizontal and vertical outputs have ±15kV (HBM) ESD protection，B 16-TSSOP 35   2 74LVC1G125 H，文章观点仅代表作者本人， Reference Design for Switching VGA Signals in a Laptop Abstract: This application shows how the MAX4885E low-capacitance VGA switch can be used to perform the switching function in a laptop computer. The MAX4885E draws nearly zero current， until one digital standard fully replaces the ubiquitous blue VGA connector on the laptop. Maxim introduced the MAX4885E low-capacitance VGA switch to perform that switching function. The MAX4885E draws nearly zero current， 举报投诉 ，im官网， the vast majority of projectors still only support VGA. The requirement to support VGA through the docking station and the VGA port will likely continue for many years，V SC70 8   4 2N7002 DDC SOT23 24   7 NUP2301 ESD SC88 28 Total Savings 14       95 The assortment of standard and inexpensive devices shows that the MAX4885E replaces 14 standard parts that require 95mm². There may be ways to reduce the parts count perhaps to 10 parts and 50mm² using more specific and integrated devices， FETs，不代表电子发烧友网立场，如有内容侵权或者其他违规问题， and only one control bit is required to select the dock vs. an internal connector. The circuit only draws a few µA at idle and a few mA to supply the horizontal and vertical buffers. Figure 1. Application circuit for a VGA connection between a laptop and docking station features the MAX4885A VGA switch. The connector pin assignment for the docking station is determined by the designer. This design is just an illustration of one configuration. DVI is a trademark of Digital Display Working Group (DDWG). HDMI is a trademark of HDMI Licensing。

and > 600MHz at the more common 75Ω used for video. The QSXGA format (2560 x 2048) requires ~500MHz of bandwidth so that the third harmonic is passed and the quality of the waveform is preserved. Some designers use the older "bus switches" with 12pF of capacitance which compares to the 6pF for the MAX4885E. Those older bus switches， the FET protects the GPU from signals that exceed the VL.¹ By using two SPDT n-Channel FETs， fits into a 4mm x 4mm package， the device’s LC filter draws no current and accomplishes the same task. The MAX4885E draws High Integration Reduces Component Count Table 1 shows how the MAX4885E replaces as many as 14 standard devices. Remember that the MAX4885E fits in a 16mm² package. Table 1. Components Eliminated with the MAX4885E   Quantity Component Function Package Size (mm²)   1 74FST3257 R， but the resulting component costs would undoubtedly be higher. The MAX4885E is priced to sell below the sum of the costs of these many components. The MAX4885 thus saves board space and placement cost. It improves reliability and the high-frequency analog performance of RGB switches. Applications Circuit