250 kSPS, 10-/12-Bit ADCs in 6-Lead SC70 AD7910/AD7920 FEATURES FUNCTIONAL BLOCK DIAGRAM Throughput rate: 250 kSPS V DD Specified for VDD of 2.35 V to 5.25 V Low power 3.6 mW typ at 250 kSPS with 3 V supplies 10-/12-BIT SUCCESSIVE V IN T/H 12.5 mW typ at 250 kSPS with 5 V supplies APPROXIMATION ADC Wide input bandwidth 71 dB SNR at 100 kHz input frequency Flexible power/serial clock speed management SCLK No pipeline delays SDATA CONTROL LOGIC High speed serial interface CS SPI-/QSPI-/MICROWIRE-/DSP-compatible Standby mode: 1 A max AD7910/AD7920 6-lead SC70 package 8-lead MSOP package GND Figure 1. APPLICATIONS Battery-powered systems Personal digital assistants Medical instruments Mobile communications Instrumentation and control systems Data acquisition systems High speed modems Optical sensors GENERAL DESCRIPTION PRODUCT HIGHLIGHTS 1 The AD7910/AD7920 are, respectively, 10-bit and 12-bit, high 1. 10-/12-bit ADCs in SC70 and MSOP packages. speed, low power, successive approximation ADCs. The parts 2. Low power consumption. operate from a single 2.35 V to 5.25 V power supply and feature throughput rates up to 250 kSPS. The parts contain a low noise, 3. Flexible power/serial clock speed management. The wide bandwidth track-and-hold amplifier that can handle input conversion rate is determined by the serial clock, allowing frequencies in excess of 13 MHz. the conversion time to be reduced through the serial clock speed increase. This allows the average power consumption The conversion process and data acquisition are controlled to be reduced when power-down mode is used while not using CS and the serial clock, allowing the devices to interface converting. The part also features a power-down mode to with microprocessors or DSPs. The input signal is sampled on maximize power efficiency at lower throughput rates. the falling edge of CS and the conversion is initiated at this Current consumption is 1 A maximum and 50 nA typically point. There are no pipeline delays associated with the part. when in power-down mode. The AD7910/AD7920 use advanced design techniques to 4. Reference derived from the power supply. achieve very low power dissipation at high throughput rates. 5. No pipeline delay. The parts feature a standard successive The reference for the part is taken internally from V . This DD approximation ADC with accurate control of the sampling allows the widest dynamic input range to the ADC. Thus, the CS instant via a input and once-off conversion control. analog input range for the part is 0 to V . The conversion rate DD is determined by the SCLK. 1 Protected by U.S. Patent No. 6,681,332. 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 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 02976-001AD7910/AD7920 TABLE OF CONTENTS Features .............................................................................................. 1 ADC Transfer Function............................................................. 14 Applications....................................................................................... 1 Typical Connection Diagram ................................................... 14 Functional Block Diagram .............................................................. 1 Analog Input ............................................................................... 15 General Description ......................................................................... 1 Digital Inputs .............................................................................. 15 Product Highlights ........................................................................... 1 Modes of Operation ....................................................................... 16 Specifications..................................................................................... 3 Normal Mode.............................................................................. 16 AD7910.......................................................................................... 3 Power-Down Mode.................................................................... 16 AD7920.......................................................................................... 4 Power-Up Time .......................................................................... 16 Timing Specifications .................................................................. 6 Power vs. Throughput Rate........................................................... 18 Timing Examples.............................................................................. 7 Serial Interface ................................................................................ 19 Timing Example 1 ........................................................................ 7 Microprocessor Interfacing........................................................... 20 Timing Example 2 ........................................................................ 7 AD7910/AD7920 to TMS320C541 Interface ......................... 20 Absolute Maximum Ratings............................................................ 8 AD7910/AD7920 to ADSP-218x.............................................. 20 ESD Caution.................................................................................. 8 AD7910/AD7920 to DSP563xx Interface ............................... 21 Pin Configurations and Function Descriptions ........................... 9 Application Hints ........................................................................... 22 Typical Performance Characteristics ........................................... 10 Grounding and Layout .............................................................. 22 Terminology .................................................................................... 12 Evaluating Performance ............................................................ 22 Circuit Information........................................................................ 13 Outline Dimensions ....................................................................... 23 Converter Operation...................................................................... 14 Ordering Guide .......................................................................... 24 REVISION HISTORY 8/03Rev. 0 to Rev. A 9/05Rev. B to Rev. C Changes to Ordering Guide.............................................................6 Updated Formatting ..........................................................Universal Changes to Evaluating the AD7910/AD7920 Performance Updated Outline Dimensions....................................................... 23 Section.............................................................................................. 18 Changes to Ordering Guide.......................................................... 24 Updated Outline Dimensions ...................................................... 19 3/04Rev. A to Rev. B Added U.S. Patent Number ............................................................ 1 Changes to Note 5 ............................................................................ 2 Changes to Note 6 of AD7920 Specifications............................... 4 Changes to Note 1 of Timing Specifications ................................ 4 Changes to Absolute Maximum Ratings ...................................... 6 Changes to Ordering Guide............................................................ 6 Rev. C Page 2 of 24