3 mW, 100 kSPS, 14-Bit ADC in 6-Lead SOT-23 AD7940 FUNCTIONAL BLOCK DIAGRAM FEATURES V Fast throughput rate: 100 kSPS DD Specified for V of 2.5 V to 5.5 V DD Low power 14-BIT SUCCESSIVE V T/H APPROXIMATION 4 mW typ at 100 kSPS with 3 V supplies IN ADC 17 mW typ at 100 kSPS with 5 V supplies Wide input bandwidth: SCLK 81 dB SINAD at 10 kHz input frequency CONTROL AD7940 SDATA LOGIC Flexible power/serial clock speed management CS No pipeline delays High speed serial interface GND SPI/QSPI/MICROWIRE/DSP compatible Figure 1. Standby mode: 0.5 A max 6-Lead SOT-23 and 8-Lead MSOP packages Table 1. 16-Bit and 14-Bit ADC (MSOP and SOT-23) APPLICATIONS Type 100 kSPS 250 kSPS 500 kSPS Battery-powered systems 16-Bit True Differential AD7684 AD7687 AD7688 Personal digital assistants 16-Bit Pseudo Differential AD7683 AD7685 AD7686 Medical instruments 16-Bit Unipolar AD7680 Mobile communications 14-Bit True Differential AD7944 AD7947 Instrumentation and control systems 14-Bit Pseudo Differential AD7942 AD7946 Remote data acquisition systems 14-Bit Unipolar AD7940 This part features a standard successive approximation ADC GENERAL DESCRIPTION CS 1 with accurate control of the sampling instant via a input and The AD7940 is a 14-bit, fast, low power, successive once off conversion control. approximation ADC. The part operates from a single 2.50 V to 5.5 V power supply and features throughput rates up to 100 kSPS. PRODUCT HIGHLIGHTS The part contains a low noise, wide bandwidth track-and-hold 1. First 14-bit ADC in a SOT-23 package. amplifier that can handle input frequencies in excess of 7 MHz. 2. High throughput with low power consumption. The conversion process and data acquisition are controlled 3. Flexible power/serial clock speed management. The using CS and the serial clock, allowing the devices to interface conversion rate is determined by the serial clock, allowing with microprocessors or DSPs. The input signal is sampled on the conversion time to be reduced through the serial clock the falling edge of CS and the conversion is also initiated at this speed increase. This allows the average power consumption to be reduced when a power-down mode is used while not point. There are no pipelined delays associated with the part. converting. The part also features a shutdown mode to The AD7940 uses advanced design techniques to achieve very maximize power efficiency at lower throughput rates. low power dissipation at fast throughput rates. The reference for Power consumption is 0.5 A max when in shutdown. the part is taken internally from V , which allows the widest DD 4. Reference derived from the power supply. dynamic input range to the ADC. Thus, the analog input range 5. No pipeline delay. for this part is 0 V to V . The conversion rate is determined by DD the SCLK frequency. 1 Protected by US. Patent No. 6,681,332. 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. 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All rights reserved. 03305-0-001 AD7940 TABLE OF CONTENTS Normal Mode .............................................................................. 13 Table of Contents .............................................................................. 2 Power-Down Mode .................................................................... 14 Specif icat ions ..................................................................................... 3 Power vs. Throughput Rate ........................................................... 15 Timing Specifications ....................................................................... 5 Serial Interface ................................................................................ 16 Absolute Maximum Ratings ............................................................ 6 Microprocessor Interfacing ........................................................... 17 ESD Caution .................................................................................. 6 AD7940 to TMS320C541 .......................................................... 17 Pin Configurations and Function Descriptions ........................... 7 AD7940 to ADSP-218x .............................................................. 17 Terminology ...................................................................................... 8 AD7940 to DSP563xx ................................................................ 18 Typical Performance Characteristics ............................................. 9 Application Hints ........................................................................... 19 Circuit Information ........................................................................ 11 Grounding and Layout .............................................................. 19 Converter Operation .................................................................. 11 Evaluating the AD7940 Performance ...................................... 19 Analog Input ............................................................................... 11 Outline Dimensions ....................................................................... 20 ADC Transfer Function ................................................................. 12 Ordering Guide .......................................................................... 20 Typical Connection Diagram ................................................... 12 Modes of Operation ....................................................................... 13 REVISION HISTORY 8/11Rev. 0 to Rev. A Updated Outline Dimensions ....................................................... 20 Changes to Ordering Guide .......................................................... 20 7/04Revision 0: Initial Version