3 V/5 V, 2 MSPS, 8-Bit, 8-Channel ADC AD7829-1 FEATURES FUNCTIONAL BLOCK DIAGRAM V 8-bit half-flash ADC with 420 ns conversion time DD CONVST EOC A0 A1 A2 Eight single-ended analog input channels Available with input offset adjust CONTROL COMP LOGIC 2.5V On-chip track-and-hold REF SNR performance given for input frequencies V IN1 up to10 MHz BUF V V REF IN/OUT IN2 On-chip reference (2.5 V) V IN3 8-BIT INPUT V Automatic power-down at the end of conversion IN4 HALF T/H MUX V FLASH IN5 Wide operating supply range ADC DB7 V PARALLEL IN6 PORT DB0 V 3 V 10% and 5 V 10% IN7 V IN8 Input ranges 0 V to 2 V p-p, V = 3 V 10% DD V MID AGND DGND CS RD 0 V to 2.5 V p-p, VDD = 5 V 10% Figure 1. EOC Flexible parallel interface with pulse to allow stand-alone operation APPLICATIONS Data acquisition systems, DSP front ends Disk drives Mobile communication systems, subsampling applications GENERAL DESCRIPTION The AD7829-1 is a high speed 8-channel, microprocessor- The AD7829-1 is available in a 28-lead, wide body, small outline compatible, 8-bit analog-to-digital converter with a maximum IC (SOIC W) and a 28-lead thin shrink small outline package throughput of 2 MSPS. The AD7829-1 contains an on-chip (TSSOP). reference of 2.5 V (2% tolerance) a track-and-hold amplifier PRODUCT HIGHLIGHTS a 420 ns, 8-bit half-flash ADC and a high speed parallel 1. Fast Conversion Time. The AD7829-1 has a conversion interface. The converter can operate from a single 3 V 10% time of 420 ns. Faster conversion times maximize the DSP and 5 V 10% supply. processing time in a real-time system. The AD7829-1 combines the convert start and power-down 2. Analog Input Span Adjustment. The V pin allows the MID functions at one pin, that is, the CONVST pin. This allows a user to offset the input span. This feature can reduce the unique automatic power-down at the end of a conversion to be requirements of single-supply op amps and take into CONVST implemented. The logic level on the pin is sampled account any system offsets. EOC after the end of a conversion when an (end of conversion) 3. FPBW (Full Power Bandwidth) of Track-and-Hold. The signal goes high, and if it is logic low at that point, the ADC is track-and-hold amplifier has excellent high frequency powered down. The parallel interface is designed to allow easy performance. The AD7829-1 is capable of converting full- interfacing to microprocessors and DSPs. Using only address scale input signals up to a frequency of 10 MHz, making decoding logic, the parts are easily mapped into the microprocessor the parts ideally suited to subsampling applications. address space. 4. Channel Selection. Channel selection is made without the EOC The pulse allows the ADCs to be used in a stand-alone necessity of writing to the part. manner (see the Parallel Interface section). Rev. 0 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 06179-001AD7829-1 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Connection Diagram ................................................... 10 Applications....................................................................................... 1 ADC Transfer Function............................................................. 11 General Description ......................................................................... 1 Analog Input ............................................................................... 11 Functional Block Diagram .............................................................. 1 Power-Up Times......................................................................... 14 Product Highlights ........................................................................... 1 Power vs. Throughput................................................................ 14 Revision History ............................................................................... 2 Operating Modes........................................................................ 15 Specifications..................................................................................... 3 Parallel Interface......................................................................... 17 Timing Characteristics ................................................................ 5 Microprocessor Interfacing........................................................... 18 Timing Diagram ........................................................................... 5 AD7829-1 to 8051 ...................................................................... 18 Absolute Maximum Ratings............................................................ 6 AD7829-1 to PIC16C6x/PIC16C7x......................................... 18 ESD Caution.................................................................................. 6 AD7829-1 to ADSP-21xx .......................................................... 18 Pin Configuration and Function Descriptions............................. 7 Interfacing Multiplexer Address Inputs .................................. 18 Terminology ...................................................................................... 8 Outline Dimensions....................................................................... 20 Circuit Information........................................................................ 10 Ordering Guide .......................................................................... 20 Circuit Description..................................................................... 10 REVISION HISTORY 7/06Revision 0: Initial Version Rev. 0 Page 2 of 20