2.7 V to 5.5 V, 12-Bit, 8 s ADC in 8-Lead SOIC/PDIP AD7896 FEATURES FUNCTIONAL BLOCK DIAGRAM 100 kHz Throughput Rate Fast 12-Bit Sampling ADC with 8 s Conversion Time V DD 8-Lead PDIP and SOIC Single 2.7 V to 5.5 V Supply Operation AD7896 High Speed, Easy-to-Use Serial Interface TRACK-AND-HOLD On-Chip Track-and-Hold Amplifier V IN Analog Input Range Is 0 V to Supply 12-BIT High Input Impedance ADC Low Power: 9 mW Typ OUTPUT CONVST REGISTER CLOCK AGND DGND BUSY SCLK SDATA GENERAL DESCRIPTION PRODUCT HIGHLIGHTS The AD7896 is a fast, 12-bit ADC that operates from a single 1. Complete, 12-bit ADC in an 8-Lead Package. 2.7 V to 5.5 V supply and is housed in small 8-lead PDIP and The AD7896 contains an 8 s ADC, a track-and-hold ampli- 8-lead SOIC packages. The part contains an 8 s successive fier, control logic, and a high speed serial interface, all in an approximation ADC, an on-chip track-and-hold amplifier, an 8-lead PDIP. The V input is used as the reference for the DD on-chip clock, and a high speed serial interface. part, so no external reference is needed. This offers consider- able space saving over alternative solutions. Output data from the AD7896 is provided via a high speed, serial interface port. This 2-wire serial interface has a serial 2. Low Power, Single-Supply Operation. clock input and a serial data output with the external serial The AD7896 operates from a single 2.7 V to 5.5 V supply clock accessing the serial data from the part. and consumes only 9 mW typical. The automatic power- down mode, where the part goes into power down once In addition to the traditional dc accuracy specifications, such as conversion is complete and wakes up before the next con- linearity, full-scale, and offset errors, the AD7896 is also speci- version cycle, makes the AD7896 ideal for battery-powered fied for dynamic performance parameters, including harmonic or portable applications. distortion and signal-to-noise ratio. 3. High Speed Serial Interface. The part accepts an analog input range of 0 V to V and operates DD The part provides high speed serial data and serial clock lines from a single 2.7 V to 5.5 V supply, consuming only 9 mW allowing for an easy, 2-wire serial interface arrangement. typical. The V input is also used as the reference for the part DD so that no external reference is required. The AD7896 features a high sampling rate mode and, for low power applications, a proprietary automatic power-down mode where the part automatically goes into power-down once conver- sion is complete and wakes up before the next conversion cycle. The part is available in a small, 8-lead, 0.3 wide, plastic or hermetic dual-in-line package (PDIP) and in an 8-lead, small outline IC (SOIC). Rev. D 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. may result from its use. No license is granted by implication or otherwise Tel: 781/329-4700 www.analog.com under any patent or patent rights of Analog Devices. Trademarks and Fax: 781/461-3113 19942011 Analog Device, Inc. All rights reserved. registered trademarks are the property of their respective companies.(V = 2.7 V to 5.5 V, AGND = DGND = 0 V. All specifications T to T , DD MIN MAX AD7896SPECIFICATIONS unless otherwise noted.) Test Conditions/ 1 Parameter A Version B Version J Version S Version Unit Comments 2 DYNAMIC PERFORMANCE 3 Signal-to-(Noise + Distortion) Ratio 25C7070 70 typ 70 dB min f = 10 kHz Sine Wave, IN f = 100 kHz SAMPLE T to T 70 dB min MIN MAX 3 Total Harmonic Distortion (THD) 77 77 80 typ 77 dB max f = 10 kHz Sine Wave, IN f = 100 kHz SAMPLE 3 Peak Harmonic or Spurious Noise 80 80 80 typ dB max f = 10 kHz Sine Wave, IN f = 100 kHz SAMPLE 3 Intermodulation Distortion (IMD) fa = 9 kHz, fb = 9.5 kHz, f = 100 kHz SAMPLE Second Order Terms 77 77 80 typ 77 dB max Third Order Terms 80 80 80 typ 80 dB max DC ACCURACY Resolution 12 12 12 12 Bits Minimum Resolution for Which No Missing Codes Are Guaranteed 12 12 12 12 Bits 3 Relative Accuracy 1 1/2 1 1LSB max 3 Differential Nonlinearity 1 1 1 1LSB max 3 Positive Full-Scale Error 3 1.5 3 3LSB max Unipolar Offset Error 4 4 5 4LSB max V = 5 V 10% DD 4 3 5 4LSB max V = 2.7 V to 3.6 V DD ANALOG INPUT Input Voltage Range 0 to +V 0to+V 0to+V 0 to +V V DD DD DD DD Input Current 2 2 2 5 A max LOGIC INPUTS Input High Voltage, V 2.0 2.0 2.0 2.0 V min V = 2.7 V to 3.6 V INH DD 2.4 2.4 2.4 2.4 V = 5 V 10% DD Input Low Voltage, V 0.8 0.8 0.8 0.8 V max INL Input Current, I 10 10 10 10 A max V = 0 V to V IN IN DD 4 Input Capacitance, C 10 10 10 10 pF max IN LOGIC OUTPUTS Output High Voltage, V 2.4 2.4 2.4 2.4 V min I = 400 A OH SOURCE Output Low Voltage, V 0.4 0.4 0.4 0.4 V max I = 1.6 mA OL SINK Output Coding Straight (Natural) Binary CONVERSION RATE Conversion Time Mode 1 Operation 8 8 8 8.5 s max 5 Mode 2 Operation 14 14 14 14.5 s max 3 Track-and-Hold Acquisition Time 1.5 1.5 1.5 1.5 s max 2 Rev. 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