Crosspoint switches operate above 500 MHz

6th September 2006

Analog Devices

ES Admin

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The AD8117 and AD8118 are said to achieve a bandwidth of more than 500 MHz-65 percent higher than the nearest competitive 32 × 32 arrays-making them the industry's first single-chip 32 × 32 analog crosspoint switches to achieve the highspeeds required to route Quantum Extended Graphics Array (QXGA) video signals without degrading image quality. QXGA is a high-resolution display standard (2048 × 1536 pixels) that enables very fine detail video images in LCD monitors. Without these two new devices, professional video engineers had to use at least eight analog crosspoint switches to achieve a comparable level of video switching performance at QXGA bandwidths.

The combination of bandwidth and array size of the AD8117 andAD8118 are achieved through the use of the industry's first fully-differential analog crosspoint core architecture. This design offers
customers greater flexibility by enabling any combination of differential or single-ended inputs and outputs. Superior image fidelity is accomplished with bandwidth of 500 MHz, slew rate of 1800 volts per microsecond, gain flatness of 0.1 dB out to 100 MHz, and crosstalk of -40 dB at 500 MHz.

The AD8117 and AD8118 consume only 2.5 mW per point-50 percent less power per point than competitive QXGA-capable analog crosspoint solutions. The low power consumption cuts system cost by reducing power supply requirements-the devices operate with a single +5 V supply or dual ±2.5 V
supplies-eliminating the need for external heat sinks. In addition, the switches consume 200 mA of standby current and 500 mA of quiescent current.

The analog crosspoint switches can be easily programmed and reprogrammed. Channel switching is performed via a double-buffered, serial digital control-which can accommodate daisy chaining of several devices-or through a parallel control that allows updating of individual outputs without
reprogramming the entire array. The AD8117 and AD8118 are differentiated by output gain-one for the AD8117 and two for the AD8118-making them easier to
use in back-terminated load applications.