2.7 V to 5.5 V, 5 s, 8-Bit a ADC in 8-Lead microSOIC/DIP AD7823 FEATURES FUNCTIONAL BLOCK DIAGRAM 8-Bit ADC with 4 s Conversion Time V V Small Footprint 8-Lead microSOIC Package DD AGND REF Specified Over a 40 C to +125 C Temperature Range Inherent Track-and-Hold Functionality AD7823 CHARGE D OUT SERIAL REDISTRIBUTION PORT Operating Supply Range: 2.7 V to 5.5 V DAC SCLK Specifications at 2.7 V to 5.5 V and 5 V 10% CLOCK Microcontroller Compatible Serial Interface OSC Optional Automatic Power-Down V IN+ Low Power Operation: CONTROL COMP 570 W at 10 kSPS Throughput Rate V IN LOGIC V /3 DD 2.9 mW at 50 kSPS Throughput Rate Analog Input Range: 0 V to V REF Reference Input Range: 0 V to V DD CONVST Drop In Upgrade to 10 Bits Available (AD7810) APPLICATIONS Low Power, Hand-Held Portable Applications Requiring Analog-to-Digital Conversion with 8-Bit Accuracy, e.g., Battery-Powered Test Equipment Battery-Powered Communications Systems PRODUCT HIGHLIGHTS GENERAL DESCRIPTION 1. Complete, 8-Bit ADC in 8-Lead Package The AD7823 is a high speed, low power, 8-bit A/D converter The AD7823 is an 8-bit 4 s typ ADC with inherent track- that operates from a single 2.7 V to 5.5 V supply. The part con- and-hold functionality and a high speed serial interfaceall tains a 4 s typ successive approximation A/D converter, inherent in an 8-lead microSOIC package. V may be connected to track-and-hold functionality (with a pseudo differential input) REF V to eliminate the need for an external reference. The result and a high speed serial interface that interfaces to most microcon- DD is a high speed, low power, space saving ADC solution. trollers. The AD7823 is fully specified over a temperature range of 40C to +125C. 2. Low Power, Single Supply Operation The AD7823 operates from a single 2.7 V to 5.5 V supply and By using a technique that samples the state of the CONVST typically consumes only 9 mW of power. The power dissipa- (convert start) signal at the end of a conversion, the AD7823 tion can be significantly reduced at lower throughput rates by may be used in an automatic power-down mode. When used in using the automatic power-down mode, e.g., at a throughput this mode, the AD7823 powers down automatically at the end rate of 10 kSPS the power consumption is only 570 W. of a conversion and wakes up at the start of a new conversion. This feature significantly reduces the power consumption of the 3. Automatic Power-Down part at lower throughput rates. The AD7823 can also operate in The automatic power-down mode, whereby the AD7823 a high speed mode where the part is not powered down between powers down at the end of a conversion and wakes up conversions. In this high speed mode of operation, the conver- before the next conversion, means the AD7823 is ideal for sion time of the AD7823 is 4 s typ. The maximum throughput battery powered applications. See Power vs. Throughput rate is dependent on the speed of the serial interface of the Rate section. microcontroller. 4. Serial Interface The part is available in a small, 8-lead 0.3 wide, plastic dual-in- An easy to use, fast serial interface allows connection to most line package (mini-DIP) in an 8-lead, small outline IC (SOIC) popular microprocessors with no external circuitry. and in an 8-lead microSOIC package. REV. C Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. use, nor for any infringements of patents or other rights of third parties Tel: 781/329-4700 World Wide Web Site: AD7823SPECIFICATIONS (GND = 0 V, V = V . All specifications 40 C to +125 C unless otherwise noted.) REF DD Parameter Y Version Unit Test Conditions/Comments DYNAMIC PERFORMANCE f = 30 kHz, f = 133 kHz IN SAMPLE 1, 2 Signal to (Noise + Distortion) Ratio 48 dB min 1 Total Harmonic Distortion 70 dB typ 1 Peak Harmonic or Spurious Noise 70 dB typ 2 Intermodulation Distortion fa = 48 kHz, fb = 48.5 kHz 2nd Order Terms 77 dB typ 3rd Order Terms 77 dB typ DC ACCURACY Resolution 8 Bits 1 Relative Accuracy 0.5 LSB max 1 Differential Nonlinearity (DNL) 0.5 LSB max 1 Gain Error 1LSB max 1 Offset Error 1LSB max 1 Total Unadjusted Error 1LSB max Minimum Resolution for Which No Missing Codes Are Guaranteed 8 Bits ANALOG INPUT Input Voltage Range 0 V min V V max REF 2 1 A max Input Leakage Current 2 Input Capacitance 15 pF max 2 REFERENCE INPUTS V Input Voltage Range 1.2 V min REF V V max DD Input Leakage Current 1 A max Input Capacitance 20 pF max 2 LOGIC INPUTS V , Input High Voltage 2.0 V min INH V , Input Low Voltage 0.4 V max INL Input Current, I 1 A max Typically 10 nA, V = 0 V to V IN IN DD Input Capacitance, C 8 pF max IN LOGIC OUTPUTS Output High Voltage, V 2.4 V min I = 200 A OH SOURCE Output Low Voltage, V 0.4 V max I = 200 A OL SINK High Impedance Leakage Current 1 A max High Impedance Capacitance 15 pF max CONVERSION RATE Conversion Time 4 s typ 1 Track/Hold Acquisition Time 100 ns max See DC Acquisition Section POWER SUPPLY V 2.75.5 Volts For Specified Performance DD I 3.5 mA max Sampling at 133 kSPS and Logic DD Inputs V or 0 V. V = 5 V DD DD Power Dissipation 17.5 mW max Nominal Supplies Power-Down Mode I 1 A max DD Power Dissipation 5 W max Nominal Supplies Automatic Power Down V = 3 V DD 1 kSPS Throughput 54 W max 10 kSPS Throughput 540 W max 50 kSPS Throughput 2.7 mW max NOTES 1 See Terminology. 2 Sample tested during initial release and after any redesign or process change that may affect this parameter. Specifications subject to change without notice. REV. C 2