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I want to use AD506 as a multiplexer in a high frequency design (50MHz).

It receives 1.2 Vpp sine wave signal from AD9850 and sends the signal for amplification.

According to page 2 of its datasheet, its transition time is 200ns. When I convert it to frequency I assume it should support up to 5MHz.

But it works just fine up to 50MHz ! I want to know if I have a mistake in my calculation or the device really supports higher frequencies or its working in such high frequency may lead to damage or something?

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Page 8 defines tTRANSITION as "Delay time between the 50% and 90% points of the digital inputs and switch “ON” condition when switching from one address state to another". In order words, this parameter only affects switching between channels, not the analog signal on either one.

The bandwidth of the analog signal is affected by RON and the input capacitance of the next stage, both of which limit the slew rate of the signal.

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  • \$\begingroup\$ Thanks! you mean this device has not a specific bandwidth? For my design, I have no capacitive load in next stage. as Ron=500Ω and we assume 1pF stray capacitance for the PCB, I should expect around 300 MHz of the bandwidth. Is that correct? \$\endgroup\$
    – Aug
    Commented Oct 19, 2013 at 14:18
  • \$\begingroup\$ TI literature number SNOA852 has the specific calculations for bandwidth. \$\endgroup\$
    – Ignacio Vazquez-Abrams
    Commented Oct 19, 2013 at 14:34

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