Description

The AD7470/AD7472 are 10-bit /12-bit high speed, low power, successive-approximation ADCs. The parts operate from a single 2.7 V to 5.25 V power supply and feature throughput rates up to 1.5 MSPS for the 12-bit AD7472 and up to 1.75 MSPS for the 10-bit AD7470. The parts contain a low-noise, wide bandwidth track/hold amplifier which can handleinput frequencies in excess of 20 MHz.The conversion process and data acquisition are controlledusing standard control inputs, allowing easy interfacing tomicroprocessors or DSPs. The input signal is sampled on thefalling edge of CONVST, and conversion is also initiated atthis point. BUSY goes high at the start of conversion andgoes low 531.66 ns after falling edge of CONVST (AD7472with a clock frequency of 26 MHz) to indicate that the conversionis complete. There are no pipeline delays associatedwith the parts. The conversion result is accessed via standardCS and RD signals over a high speed parallel interface.The AD7470/AD7472 use advanced design techniques toachieve very low power dissipation at high throughput rates. With3 V supplies and 1.5 MSPS throughput rates, the AD7470typically consumes, on average, just 1.1 mA. With 5 V suppliesand 1.75 MSPS, the average current consumption is typically1.6 mA. The part also offers flexible power/throughput ratemanagement. Operating the AD7470 with 3 V supplies and500 kSPS throughput reduces the current consumption to 713 μA.At 5 V supplies and 500 kSPS, the part consumes 944 μA.It is also possible to operate the parts in an auto sleep mode,where the part wakes up to do a conversion and automaticallyenters sleep mode at the end of conversion. This method allowsvery low power dissipation numbers at lower throughput rates.In this mode, the AD7472 can be operated with 3 V supplies at100 kSPS, and consume an average current of just 124 μA. At5 V supplies and 100 kSPS, the average current consumption is171 μA.The analog input range for the part is 0 V to REF IN. The 2.5 Vreference is applied externally to the REF IN pin. The conversionrate is determined by the externally-applied clock.ol { margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:25px; padding-top:0px; padding-right:0px; padding-bottom:10px; padding-left:0px;}li { padding-top:0px; padding-right:0px; padding-bottom:5px; padding-left:0px; margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px;}Product HighlightsHigh Throughput with Low Power Consumption. TheAD7470 offers 1.75 MSPS throughput and the AD7472offers 1.5 MSPS throughput rates with 4 mW powerconsumption.Flexible Power/Throughput Rate Management. The conversionrate is determined by an externally-applied clock allowingthe power to be reduced as the conversion rate is reduced.The part also features an auto sleep mode to maximize powerefficiency at lower throughput rates.No Pipeline Delay. The part features a standard successiveapproximation ADC with accurate control of the samplinginstant via a CONVST input and once off conversion control.