8-Channel, 1 MSPS, 10-Bit SAR ADC AD7298-1 FEATURES FUNCTIONAL BLOCK DIAGRAM V DD GND 10-bit SAR ADC 8 single-ended inputs V Channel sequencer functionality REF Fast throughput of 1 MSPS REF BUF Analog input range: 0 V to 2.5 V 10-BIT Temperature range: 40C to +125C V IN0 SUCCESSIVE T/H Specified for V of 2.8 V to 3.6 V APPROXIMATION DD ADC Logic voltage V = 1.65 V to 3.6 V DRIVE INPUT Power-down current: <10 A AD7298-1 V MUX IN7 Internal 2.5 V reference SEQUENCER Internal power-on reset SCLK DOUT High speed serial interface SPI CONTROL DIN LOGIC 20-lead LFCSP CS V DRIVE PD/RST Figure 1. GENERAL DESCRIPTION The AD7298-1 is a 10-bit, high speed, low power, 8-channel, PRODUCT HIGHLIGHTS successive approximation ADC. The part operates from a single 1. Ideally Suited to Monitoring System Variables in a Variety 3.3 V power supply and features throughput rates up to 1 MSPS. of Systems. This includes telecommunications, and process The device contains a low noise, wide bandwidth track-and-hold and industrial control. amplifier that can handle input frequencies in excess of 30 MHz. 2. High Throughput Rate of 1 MSPS with Low Power The AD7298-1 offers a programmable sequencer, which enables Consumption. the selection of a preprogrammable sequence of channels for 3. Eight Single-Ended Inputs with a Channel Sequencer. A conversion. The device has an on-chip, 2.5 V reference that can consecutive sequence of channels can be selected on which be disabled to allow the use of an external reference. the ADC cycles and converts. The device offers a 4-wire serial interface compatible with SPI and DSP interface standards. The AD7298-1 uses advanced design techniques to achieve very low power dissipation at high throughput rates. The part also offers flexible power/throughput rate management options. The part is offered in a 20-lead LFCSP package. Rev. A 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. Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 20102011 Analog Devices, Inc. All rights reserved. 09321-001AD7298-1 TABLE OF CONTENTS Features .............................................................................................. 1 Analog Input ............................................................................... 13 Functional Block Diagram .............................................................. 1 V ............................................................................................ 14 DRIVE General Description ......................................................................... 1 The Internal or External Reference .......................................... 14 Product Highlights ........................................................................... 1 Control Register .............................................................................. 15 Revision History ............................................................................... 2 Modes of Operation ....................................................................... 16 Specifications ..................................................................................... 3 Traditional Multichannel Mode of Operation ........................ 16 Timing Specifications .................................................................. 5 Repeat Operation ....................................................................... 17 Absolute Maximum Ratings ............................................................ 6 Power-Down Modes .................................................................. 18 Thermal Resistance ...................................................................... 6 Powering Up the AD7298-1 ...................................................... 19 ESD Caution .................................................................................. 6 Reset ............................................................................................. 19 Pin Configuration and Function Description .............................. 7 Serial Interface ................................................................................ 20 Typical Performance Characteristics ............................................. 9 Layout and Configuration ............................................................. 21 Terminology .................................................................................... 12 Outline Dimensions ....................................................................... 22 Circuit Information ........................................................................ 13 Ordering Guide .......................................................................... 22 Converter Operation .................................................................. 13 REVISION HISTORY 1/11Rev. 0 to Rev. A Removed Input Impedance Parameter .......................................... 3 Added Input Capacitance Parameter of 8 pF ................................ 3 Changes to Figure 10 ...................................................................... 10 Changed C1 Value to 8 pF in Analog Input Section .................. 13 Changes to Figure 22 ...................................................................... 14 10/10Revision 0: Initial Version Rev. A Page 2 of 24