Analog to Digital Converter
Fri, 09/28/2001 - 9:40am
Meeting the demand for increased channel count on ADCs for optical, wired and wireless communications and all forms of data acquisition, the AD7490 is a 12-bit, 1 MSPS, 16-channel successive-approximation (SAR) analog-to-digital converter (ADC). This converter is appropriate for multi-channel applications such as optical networking where multiple temperatures are monitored for laser frequency control and power is measured to determine gain. Also featured is a sequencer which is controlled by a shadow register that allows continuous or single conversions on selected channels. The channel selection function can be altered while the sequence is in progress. The AD7490 uses advanced design techniques to achieve very low power dissipation at high throughput rates. Three power management modes further maximize performance efficiency at lower throughput rates: full power down, auto shutdown and auto standby. Full power dissipation is just 3.6 mW and in the shutdown mode, power consumption is only 1 μA(microAmp). This ADC operates from a single 2.7 to 5.25 V supply and contains a Vdrive (interface drive voltage) function to allow the serial interface to connect directly to either 3 or 5 V processor systems independent of Vdd (power supply voltage). Additionally, the converter contains a low-noise, wide bandwidth track/hold amplifier which can handle input frequencies in excess of 1 MHz.