3 MSPS, 14-Bit SAR ADC AD7484 FEATURES FUNCTIONAL BLOCK DIAGRAM AV C DV V DD AGND BIAS DD DRIVE DGND Fast throughput rate: 3 MSPS Wide input bandwidth: 40 MHz No pipeline delays with SAR ADC 2.5V BUF REFOUT Excellent dc accuracy performance REFERENCE 2 parallel interface modes REFSEL REFIN Low power: 90 mW (full power) and 2.5 mW (nap mode) Standby mode: 2 A maximum 14-BIT ALGORITHMIC Single 5 V supply operation VIN SAR T/H Internal 2.5 V reference Full-scale overrange mode (using 15th bit) AD7484 System offset removal via user access offset register D14 MODE1 D13 Nominal 0 V to 2.5 V input with shifted range capability MODE2 D12 CLIP CONTROL Pin compatible upgrade of 12-bit AD7482 D11 LOGIC AND I/O NAP D10 REGISTERS STBY D9 RESET D8 CONVST D7 Figure 1. GENERAL DESCRIPTION alive for a quick power-up while consuming 2.5 mW, and a The AD7484 is a 14-bit, high speed, low power, successive standby mode that reduces power consumption to a mere 10 W. approximation ADC. The part features a parallel interface with throughput rates up to 3 MSPS. The part contains a low noise, The AD7484 features an on-board 2.5 V reference but can also wide bandwidth track-and-hold that can handle input frequencies accommodate an externally provided 2.5 V reference source. in excess of 40 MHz. The nominal analog input range is 0 V to 2.5 V, but an offset shift capability allows this nominal range to be offset by 200 mV. The conversion process is a proprietary algorithmic successive This allows the user considerable flexibility in setting the bottom approximation technique that results in no pipeline delays. The end reference point of the signal range, a useful feature when input signal is sampled, and a conversion is initiated on the falling using single-supply op amps. CONVST edge of the signal. The conversion process is controlled by an internally trimmed oscillator. Interfacing is via standard The AD7484 also provides an 8% overrange capability via a parallel signal lines, making the part directly compatible with 15th bit. Therefore, if the analog input range strays outside the microcontrollers and DSPs. nominal range by up to 8%, the user can still accurately resolve the signal by using the 15th bit. The AD7484 provides excellent ac and dc performance specifica- tions. Factory trimming ensures high dc accuracy, resulting in The AD7484 is powered by a 4.75 V to 5.25 V supply. The part very low INL, offset, and gain errors. also provides a V pin that allows the user to set the voltage DRIVE levels for the digital interface lines. The range for this V pin DRIVE The part uses advanced design techniques to achieve very low is 2.7 V to 5.25 V. The part is housed in a 48-lead LQFP package power dissipation at high throughput rates. Power consumption and is specified over a 40C to +85C temperature range. in the normal mode of operation is 90 mW. There are two power saving modes: a nap mode, which keeps the reference circuitry Rev. C 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 20022009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. CS RD WRITE BUSY D0 D1 D2 D3 D4 D5 D6 02642-001AD7484 TABLE OF CONTENTS Features .............................................................................................. 1 Circuit Description......................................................................... 12 Functional Block Diagram .............................................................. 1 Converter Operation .................................................................. 12 General Description ......................................................................... 1 Analog Input ............................................................................... 12 Revision History ............................................................................... 2 ADC Transfer Function ............................................................. 13 Specifications ..................................................................................... 3 Power Saving ............................................................................... 13 Timing Characteristics ................................................................ 5 Offset/Overrange ........................................................................ 14 Absolute Maximum Ratings ............................................................ 6 Parallel Interface ......................................................................... 15 ESD Caution .................................................................................. 6 Board Layout and Grounding ................................................... 17 Pin Configuration and Function Descriptions ............................. 7 Outline Dimensions ....................................................................... 19 Typical Performance Characteristics ............................................. 9 Ordering Guide .......................................................................... 19 Terminology .................................................................................... 11 REVISION HISTORY 12/09Rev. B to Rev. C 2/04Rev. 0 to Rev. A Changes to Table 1, Power Requirements Section ....................... 4 Updated Format .................................................................. Universal Changes to Ordering Guide .......................................................... 19 Changes to Timing Characteristics Section .................................. 5 Changes to Pin Function Descriptions Section ............................. 8 8/08Rev. A. to Rev. B Changes to Figure 9 ........................................................................ 11 Changes to Table 1 ............................................................................ 3 Changes to the Converter Operation Section............................. 13 Changes to Table 3 ............................................................................ 6 Changes to the Offset/Overrange Section ................................... 15 Changes to Typical Performance Characteristics Section ........... 9 8/02Revision 0: Initial Version Changes to Figure 9 ........................................................................ 10 Changes to Circuit Description Section ...................................... 11 Changes to Terminology Section.................................................. 11 Changes to Analog Input Section ................................................. 12 Changes to Offset/Overrange Section ......................................... 14 Changes to Table 5, Table 6, Table 7, and Table 8 ....................... 15 Changes to Parallel Interface Section ........................................... 15 Changes to Table 9 .......................................................................... 16 Changes to Board Layout and Grounding Section .................... 17 Changes to Ordering Guide .......................................................... 19 Rev. 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