Complete 12-Bit, 25 MSPSMonolithic A/D ConverterAD9225FEATURESFUNCTIONAL BLOCK DIAGRAMMonolithic 12-Bit, 25 MSPS ADC Low Power Dissipation: 280 mWCLKAVDDDRVDDSingle 5 V SupplySHANo Missing Codes GuaranteedVINAMDAC1MDAC2MDAC3VINBGAIN = 16GAIN = 4GAIN = 4Differential Nonlinearity Error:0.4 LSB533Complete On-Chip Sample-and-Hold Amplifier andADCADCADCADCCAPTVoltage Reference5334CAPBDIGITAL CORRECTION LOGICSignal-to-Noise and Distortion Ratio: 71 dB12Spurious-Free Dynamic Range: –85 dBVREFOUTPUT BUFFERSOTROut-of-Range IndicatorSENSEBIT 1Straight Binary Output Data(MSB)1VMODESELECTBIT 12AD922528-Lead SOIC(LSB)28-Lead SSOPREFCOMAVSSDRVSSCMLCompatible with 3 V LogicGENERAL DESCRIPTION A single clock input is used to control all internal conversion The AD9225 is a monolithic, single-supply, 12-bit, 25 MSPS cycles. The digital output data is presented in straight binary analog-to-digital converter with an on-chip, high performance output format. An out-of-range signal indicates an overflow sample-and-hold amplifier and voltage reference. The AD9225 condition that can be used with the most significant bit to deter- uses a multistage differential pipelined architecture with output mine low or high overflow. error correction logic to provide 12-bit accuracy at 25 MSPS data rates, and guarantees no missing codes over the full operat- PRODUCT HIGHLIGHTS ing temperature range. The AD9225 is fabricated on a very cost effective CMOS pro- cess. High speed precision analog circuits are combined with The AD9225 combines a low cost, high speed CMOS process high density logic circuits. and a novel architecture to achieve the resolution and speed of existing bipolar implementations at a fraction of the power The AD9225 offers a complete, single-chip sampling, 12-bit, consumption and cost. 25 MSPS analog-to-digital conversion function in 28-lead SOIC and SSOP packages. The input of the AD9225 allows for easy interfacing to both imaging and communications systems. With the device’s truly Low Power —The AD9225 at 280 mW consumes a fraction of differential input structure, the user can select a variety of input the power presently available in monolithic solutions. ranges and offsets, including single-ended applications. The On-Board Sample-and-Hold Amplifier (SHA) —The versa- dynamic performance is excellent. tile SHA input can be configured for either single-ended or The sample-and-hold amplifier (SHA) is well suited for both differential inputs. multiplexed systems that switch full-scale voltage levels in succes- Out-of-Range (OTR) —The OTR output bit indicates when sive channels and sampling single-channel inputs at frequencies the input signal is beyond the AD9225’s input range. up to and well beyond the Nyquist rate. Single Supply —The AD9225 uses a single 5 V power supply, The AD9225’s wideband input, combined with the power and simplifying system power supply design. It also features a sepa- cost savings over previously available monolithics, suits applica- rate digital driven supply line to accommodate 3 V and 5 V logic tions in communications, imaging, and medical ultrasound. families. The AD9225 has an on-board programmable reference. An Pin Compatibility —The AD9225 is pin compatible with the external reference can also be chosen to suit the dc accuracy AD9220, AD9221, AD9223, and AD9224 ADCs. and temperature drift requirements of an application. Rev. C Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. under any patent or patent rights of Analog Devices. Trademarks and Tel: 781/329-4700 www.analog.com registered trademarks are the property of their respective owners. Fax: 781/461-3113
