AD585SQ/883B

AD585SQ/883B FEATURES

3.0 �s Acquisition Time to �0.01% maxLow Droop Rate: 1.0 mV/ms maxSample/Hold Offset Step: 3 mV maxAperture Jitter: 0.5 nsExtended Temperature Range: –55�C to +125�C

AD585SQ/883B PRODUCT DESCRIPTION

The AD585 is a complete monolithic sample-and-hold circuitconsisting of a high performance operational amplifier in serieswith an ultralow leakage analog switch and a FET input inte-grating amplifier. An internal holding capacitor and matchedapplications resistors have been provided for high precision andapplications flexibility.The performance of the AD585 makes it ideal for high speed10- and 12-bit data acquisition systems, where fast acquisitiontime, low sample-to-hold offset, and low droop are critical. TheAD585 can acquire a signal to ±0.01% in 3 µs maximum, andthen hold that signal with a maximum sample-to-hold offset of3 mV and less than 1 mV/ms droop, using the on-chip holdcapacitor. If lower droop is required, it is possible to add alarger external hold capacitor.The high speed analog switch used in the AD585 exhibitsaperture jitter of 0.5 ns, enabling the device to sample full scale(20 V peak-to-peak) signals at frequencies up to 78 kHz with12-bit precision.The AD585 can be used with any user-defined feedback net-work to provide any desired gain in the sample mode. On-chipprecision thin-film resistors can be used to provide gains of +1,–1, or +2. Output impedance in the hold mode is sufficientlylow to maintain an accurate output signal even when driving thedynamic load presented by a successive-approximation A/Dconverter. However, the output is protected against damagefrom accidental short circuits.The control signal for the HOLD command can be either activehigh or active low. The differential HOLD signal is compatiblewith all logic families, if a suitable reference level is provided. Anon-chip TTL reference level is provided for TTL compatibility.The AD585 is available in three performance grades. The JPgrade is specified for the 0°C to +70°C commercial temperaturerange and packaged in a 20-pin PLCC. The AQ grade is speci-fied for the –25°C to +85°C industrial temperature range and ispackaged in a 14-pin cerdip. The SQ and SE grades are speci-fied for the –55°C to +125°C military temperature range andare packaged in a 14-pin cerdip and 20-pin LCC.

AD585SQ/883B APPLICATIONS