AD6522NACA

The AD6522NACA is one member of the AD652 series.The AD652 Synchronous Voltage-to-Frequency Converter(SVFC) is a powerful building block for precision analog-todigital conversion, offering typical nonlinearity of 0.002% (0.005% maximum) at a 100 kHz output frequency. The inherent monotonicity of the transfer function and wide range of clock frequencies allows the conversion time and resolution to be optimized for specific applications.

Features of the AD6522NACA are:(1)full-scale frequency (up to 2 MHz) set by external system clock; (2)extremely low linearity error (0.005% max at 1 MHz FS, 0.02% max at 2 MHz FS); (3)no critical external components required; (4)accurate 5 V reference voltage; (5)low drift (25 ppm/ max); (6)dual or single supply operation; (7)voltage or current input; (8)MIL-STD-883 compliant versions availabler.The AD652 uses a variation of the popular charge-balancing technique to perform the conversion function. The AD652 uses an external clock to define the full-scale output frequency,rather than relying on the stability of an external capacitor. The result is a more stable, more linear transfer function, with significant application benefits in both single- and multichannel systems.

The absolute maximum ratings of the AD6522NACA can be summarized as:(1)total supply voltage:36V;(2)storage temperature:-65 to +150;(3)maximum input voltage:36V;(4)maximum output current:50 mA;(5)amplifier short circuit to ground:indefinite.A synchronous VFC is similar to other voltage-to-frequency converters in that an integrator is used to perform a chargebalance of the input signal with an internal reference current.However, rather than using a one-shot as the primary timing element which requires a high quality and low drift capacitor,a synchronous voltage-to-frequency converter (SVFC) uses an external clock; this allows the designer to determine the system stability and drift based upon the external clock selected. A crystal oscillator may also be used if desired.The SVFC architecture provides other system advantages besides low drift. If the output frequency is measured by counting pulses gated to a signal which is derived from the clock, the clock stability is unimportant and the device simply performs as a voltage controlled frequency divider, producing a high resolution A/D.