14-Bit 333 kSPS a Serial A/D Converter AD7851 FUNCTIONAL BLOCK DIAGRAM FEATURES Single 5 V Supply AV AGND AGND DD 333 kSPS Throughput Rate/ 2 LSB DNLA Grade 285 kSPS Throughput Rate/ 1 LSB DNLK Grade AIN (+) DV DD T/H A and K Grades Guaranteed to 125 C/238 kSPS AIN () AD7851 DGND Throughput Rate 4.096V Pseudo-Differential Input with Two Input Ranges REFERENCE System and Self-Calibration with Autocalibration on REF / Power-Up IN BUF COMP REF OUT Read/Write Capability of Calibration Data AMODE Low Power: 60 mW Typ Power-Down Mode: 5 W Typ Power Consumption Flexible Serial Interface: 8051/SPI /QSPI/ P Compatible CLKIN C CHARGE REF1 REDISTRIBUTION 24-Lead PDIP, SOIC, and SSOP Packages CONVST DAC SAR + ADC CONTROL C BUSY REF2 APPLICATIONS SLEEP Digital Signal Processing CALIBRATION CAL MEMORY Speech Recognition and Synthesis AND CONTROLLER Spectrum Analysis DSP Servo Control Instrumentation and Control Systems SERIAL INTERFACE/CONTROL REGISTER High Speed Modems Automotive SM1 SM2 SYNC DIN DOUT SCLK POLARITY GENERAL DESCRIPTION PRODUCT HIGHLIGHTS The AD7851 is a high speed, 14-bit ADC that operates from a 1. Single 5 V supply. single 5 V power supply. The ADC powers up with a set of default 2. Operates with reference voltages from 4 V to V . DD conditions at which time it can be operated as a read-only ADC. 3. Analog input ranges from 0 V to V . DD The ADC contains self-calibration and system calibration options 4. System and self-calibration including power-down mode. to ensure accurate operation over time and temperature and has a 5. Versatile serial I/O port. number of power-down options for low power applications. The AD7851 is capable of a 333 kHz throughput rate. The input track-and-hold acquires a signal in 0.33 s and features a pseudo-differential sampling scheme. The AD7851 has the added advantage of two input voltage ranges (0 V to V and REF V /2 to +V /2 centered about V /2). Input signal REF REF REF range is to V and the part is capable of converting full DD power signals to 20 MHz. CMOS construction ensures low power dissipation (60 mW typ) with power-down mode (5 W typ). The part is available in a 24-lead, 0.3 inch-wide PDIP, a 24-lead SOIC, and a 24-lead SSOP package. REV. B 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 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: 781/326-8703 2004 Analog Devices, Inc. All rights reserved.AD7851 TABLE OF CONTENTS FEATURES . 1 CALIBRATION SECTION 21 GENERAL DESCRIPTION . 1 Calibration Overview 21 PRODUCT HIGHLIGHTS . 1 Automatic Calibration on Power-On 21 SPECIFICATIONS . 3 Self-Calibration Description . 21 TIMING SPECIFICATIONS . 5 Self-Calibration Timing 22 TYPICAL TIMING DIAGRAMS 6 System Calibration Description 22 ABSOLUTE MAXIMUM RATINGS . 7 System Gain and Offset Interaction . 23 ORDERING GUIDE 7 System Calibration Timing . 23 PINOUTS . 7 SERIAL INTERFACE SUMMARY 24 TERMINOLOGY . 8 Resetting the Serial Interface 24 PIN FUNCTION DESCRIPTIONS 9 DETAILED TIMING 25 AD7851 ON-CHIP REGISTERS 10 Mode 1 (2-Wire 8051 Interface) . 25 Addressing the On-Chip Registers 10 Mode 2 (3-Wire SPI/QSPI Interface Mode) . 26 Writing/Reading 10 Mode 3 (QSPI Interface Mode) 26 CONTROL REGISTER . 11 Mode 4 and 5 (Self-Clocking Modes) . 27 STATUS REGISTER . 12 CONFIGURING THE AD7851 . 28 CALIBRATION REGISTERS 13 AD7851 as a Read-Only ADC . 28 Addressing the Calibration Registers 13 Writing to the AD7851 29 Writing to/Reading from the Calibration Registers 13 Interface Modes 2 and 3 Configuration 29 Adjusting the Offset Calibration Register . 14 Interface Mode 1 Configuration 30 Adjusting the Gain Calibration Registers . 14 Interface Modes 4 and 5 Configuration 30 CIRCUIT INFORMATION 15 MICROPROCESSOR INTERFACING . 31 CONVERTER DETAILS 15 AD7851 to 8XC51/PIC17C42 Interface . 31 TYPICAL CONNECTION DIAGRAM 15 AD7851 to 68HC11/16/L11/PIC16C42 Interface 31 ANALOG INPUT 16 AD7851 to ADSP-21xx Interface 32 Acquisition Time . 16 AD7851 to DSP56000/1/2/L002 Interface . 32 DC/AC Applications 16 AD7851 to TMS320C20/25/5x/LC5x Interface . 32 Input Ranges 17 APPLICATIONS HINTS 33 Transfer Functions 17 Grounding and Layout . 33 REFERENCE SECTION 18 Evaluating the AD7851 Performance 33 AD7851 PERFORMANCE CURVES 18 OUTLINE DIMENSIONS . 34 POWER-DOWN OPTIONS 19 REVISION HISTORY 35 POWER-UP TIMES 20 Using an External Reference 20 Using the Internal (On-Chip) Reference . 20 POWER VS. THROUGHPUT RATE 20 REV. B 2