AD7988-1

Manufacturer Part NumberAD7988-1
Description16-Bit, 100ksps, Ultra Low Power 16-Bit SAR ADC
ManufacturerAnalog Devices
AD7988-1 datasheet
 


Specifications of AD7988-1

Resolution (bits)16bit# Chan1
Sample Rate100kSPSInterfaceSer,SPI
Analog Input TypeDiff-UniAin Range(Vref) p-p,5V p-p,Uni (Vref),Uni 5.0V
Pkg TypeSOP  
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Data Sheet
FEATURES
Low power dissipation
AD7988-5: 3.5 mW @ 500 kSPS
AD7988-1: 700 μW @ 100 kSPS
16-bit resolution with no missing codes
Throughput: 100 kSPS/500 kSPS options
INL: ±0.6 LSB typical, ±1.25 LSB maximum
SINAD: 91.5 dB @ 10 kHz
THD: −114 dB @ 10 kHz
Pseudo differential analog input range
0 V to V
with V
from 2.5 V to 5.5 V
REF
REF
Any input range and easy to drive with the
No pipeline delay
Single-supply 2.5 V operation with 1.8 V/2.5 V/3 V/5 V
logic interface
SPI-/QSPI-/MICROWIRE™-/DSP-compatible serial interface
Daisy-chain multiple ADCs
10-lead MSOP and 10-lead, 3 mm × 3 mm LFCSP (QFN),
same space as SOT-23
Wide operating temperature range: −40°C to +125°C
APPLICATIONS
Battery-powered equipment
Low power data acquisition systems
Portable medical instruments
ATE equipment
Data acquisitions
Communications
0V TO V
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
rights of third parties that may result from its use. Specifications subject to change without notice. No
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.
PulSAR ADCs in MSOP/LFCSP (QFN)
GENERAL DESCRIPTION
The
AD7988-1/AD7988-5
analog-to-digital converters (ADC) that operate from a single
power supply, VDD. The
and the
AD7988-5
power, 16-bit sampling ADCs with a versatile serial interface
port. On the CNV rising edge, they sample an analog input,
IN+, between 0 V to V
The reference voltage, REF, is applied externally and can be set
independent of the supply voltage, VDD.
The SPI-compatible serial interface also features the ability to
ADA4841-1
daisy-chain several ADCs on a single 3-wire bus using the SDI
input. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic using
the separate supply, VIO.
The
AD7988-1/AD7988-5
MSOP or a 10-lead LFCSP (QFN) with operation specified
from −40°C to +125°C.
Table 1. MSOP, LFCSP (QFN) 14-/16-/18-Bit PulSAR® ADCs
Bits
100 kSPS
1
18
1
16
AD7684
3
16
AD7680
AD7683
AD7988-1
3
14
AD7940
1
True differential.
2
Pin-for-pin compatible.
3
Pseudo differential.
TYPICAL APPLICATION DIAGRAM
2.5V TO 5V
2.5V
VIO
1.8V TO 5.5V
REF
VDD
REF
SDI
IN+
AD7988-1/
SCK
3- OR 4-WIRE INTERFACE
AD7988-5
IN–
(SPI, DAISY CHAIN, CS)
SDO
GND
CNV
Figure 1.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
16-Bit Lower Power
AD7988-1/AD7988-5
are 16-bit, successive approximation,
AD7988-1
offers a 100 kSPS throughput,
offers a 500 kSPS throughput. They are low
with respect to a ground sense, IN−.
REF
generics are housed in a 10-lead
250
400 kSPS to
≥1000
kSPS
500 kSPS
kSPS
2
2
2
AD7691
AD7690
AD7982
2
AD7984
2
2
AD7687
AD7688
2
AD7693
2
2
2
AD7685
AD7686
AD7980
2
AD7694
AD7988-5
2
2
2
AD7942
AD7946
www.analog.com
©2012 Analog Devices, Inc. All rights reserved.
ADC Driver
ADA4941-1
ADA4841-1
ADA4941-1
ADA4841-1
ADA4841-1
ADA4841-1
ADA4841-1
ADA4841-1

AD7988-1 Summary of contents

  • Page 1

    ... Data Sheet FEATURES Low power dissipation AD7988-5: 3 500 kSPS AD7988-1: 700 μW @ 100 kSPS 16-bit resolution with no missing codes Throughput: 100 kSPS/500 kSPS options INL: ±0.6 LSB typical, ±1.25 LSB maximum SINAD: 91 kHz THD: −114 kHz Pseudo differential analog input range ...

  • Page 2

    ... AD7988-1/AD7988-5 TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 General Description ......................................................................... 1 Typical Application Diagram .......................................................... 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Timing Specifications .................................................................. 5 Absolute Maximum Ratings ............................................................ 7 ESD Caution .................................................................................. 7 Pin Configurations and Function Descriptions ........................... 8 Terminology ...................................................................................... 9 Typical Performance Characteristics ........................................... 10 Theory of Operation ...................................................................... 14 Circuit Information .................................................................... 14 Converter Operation .................................................................. 14 Typical Connection Diagram.................................................... 15 REVISION HISTORY 2/12— ...

  • Page 3

    ... REF kHz 2 REF kHz kHz kHz REF kHz 2 REF Rev Page AD7988-1/AD7988-5 Min Typ Max Unit 16 Bits REF −0 0.1 V REF −0.1 +0 See the Analog Inputs section ...

  • Page 4

    ... SOURCE POWER SUPPLIES VDD VIO Specified performance VIO Range Standby Current VDD and VIO = 2.5 V, 25° AD7988-1 Power Dissipation 10 kSPS throughput 100 kSPS throughput AD7988-5 Power Dissipation 500 kSPS throughput Energy per Conversion TEMPERATURE RANGE Specified Performance MIN With all digital inputs forced to VIO or GND as required ...

  • Page 5

    ... SCK t SCK t SCKL t SCKH t HSDO t DSDO DIS t SSDICNV t HSDICNV t HSDICNV t SSCKCNV t HSCKCNV t SSDISCK t HSDISCK Rev Page AD7988-1/AD7988-5 Min Typ Max Unit 100 kHz 9.5 μs 500 ns 10 μs 500 kHz 1.6 μs 400 ns 2 μs 500 ns 10 ...

  • Page 6

    ... AD7988-1/AD7988-5 500µ SDO C L 20pF 500µ Figure 2. Load Circuit for Digital Interface Timing Y% VIO 1 X% VIO t DELAY FOR VIO ≤ 3.0V AND Y = 10; FOR VIO > 3. 70, AND MINIMUM V AND MAXIMUM V USED. SEE DIGITAL INPUTS ...

  • Page 7

    ... V or ±130 mA REF other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ESD CAUTION Rev Page AD7988-1/AD7988-5 ...

  • Page 8

    ... AI = analog input digital input digital output, and P = power. VIO SDI SCK SDO CNV range is from 2 5 referred to the GND pin. The GND pin REF . REF Rev Page Data Sheet REF 1 10 VIO AD7988-1/ VDD 2 9 SDI AD7988-5 IN SCK TOP VIEW IN– SDO ...

  • Page 9

    ... CNV input and when the input signal is held for a conversion. Transient Response Transient response is the time required for the ADC to accurately acquire its input after a full-scale step function is applied. N /Peak-to-Peak Noise) Rev Page AD7988-1/AD7988 /RMS Input Noise) 2 ...

  • Page 10

    ... SNR = 86.7dB THD = –110.4dB –40 SFDR = 103.9dB SINAD = 86.6dB –60 –80 –100 –120 –140 –160 –180 FREQUENCY (kHz) Figure 9. AD7988-1 FFT Plot 2.5 V REF 1.25 POSITIVE INL: +0.40 LSB NEGATIVE INL: –0.35 LSB 1.00 0.75 0.50 0. 16384 32768 49152 CODE Figure 10. Integral Nonlinearity vs. Code ...

  • Page 11

    ... V Figure 17. Histogram Input at the Code Center, V REF Rev Page AD7988-1/AD7988-5 50970 45198 18848 12424 1217 2290 7FFA 7FFB 7FFC 7FFD 7FFE 7FFF 8000 8001 8002 8003 8004 8005 8006 CODE IN HEX 2 ...

  • Page 12

    ... TEMPERATURE (°C) Figure 21. SNR vs. Temperature I VDD I REF I VIO 0 2.425 2.475 2.525 2.575 VDD VOLTAGE (V) Figure 22. Operating Currents vs. Supply (AD7988-5) I VDD I REF I VIO 0 2.375 2.425 2.475 2.525 2.575 VDD VOLTAGE (V) Figure 23. Operating Currents vs. Supply (AD7988-1) 105 125 2.625 2.625 ...

  • Page 13

    ... Rev Page AD7988-1/AD7988-5 0.14 I VDD 0.12 0.10 008 0.06 I REF 0.04 I VIO 0.02 0 –55 –35 – TEMPERATURE (°C) Figure 27. Operating Currents vs. Temperature (AD7988- VDD VIO –55 –35 – TEMPERATURE (°C) Figure 28. Power-Down Currents vs. Temperature 85 105 ...

  • Page 14

    ... AD7988-1/AD7988-5 devices are fast, low power, single- supply, precise 16-bit ADCs that use a successive approximation architecture. The AD7988-1 is capable of converting 100,000 samples per second (100 kSPS), whereas the AD7988-5 throughput of 500 kSPS, and they power down between conversions. When operating at 10 kSPS, for example, the ADC consumes 70 µ ...

  • Page 15

    ... REF 2 10µF 20Ω REF VDD IN+ 2.7nF AD7988-1/ AD7988-5 4 IN– GND Figure 31. Typical Application Diagram with Multiple Supplies Rev Page AD7988-1/AD7988-5 Analog Input Digital Output Code (Hex) REF 4.999924 V FFFF 1 2.500076 V 8001 2.5 V 8000 2.499924 V 7FFF 76.3 µV 0001 ...

  • Page 16

    ... AD7988-1/AD7988-5 ANALOG INPUTS Figure 32 shows an equivalent circuit of the input structure of the AD7988-x. The two diodes, D1 and D2, provide ESD protection for the analog inputs, IN+ and IN−. Care must be taken to ensure that the analog input signal never exceeds the supply rails by more than 0 ...

  • Page 17

    ... SDI and CNV are connected together, the chain mode is selected. The user must time out the maximum conversion time prior to readback. 100 1k Rev Page AD7988-1/AD7988-5 powers down automatically at the end of each AD7988-x has a reduced number of pins, it offers ...

  • Page 18

    ... After the 16th SCK falling edge or when CNV goes high, whichever is earlier, SDO returns to high impedance. enters the CONVERT DIGITAL HOST CNV VIO AD7988-1/ SDI SDO DATA IN AD7988-5 SCK CLK Figure 34. 3-Wire CS Mode Connection Diagram ...

  • Page 19

    ... SCKL HSDO SCKH t DSDO D15 D14 D13 D1 D0 Figure 37. 4-Wire CS Mode Serial Interface Timing Rev Page AD7988-1/AD7988-5 AD7988-x CS2 CS1 CONVERT DIGITAL HOST SDO DATA IN CLK D15 D14 D1 enters the AD7988-x t DIS ...

  • Page 20

    ... SCK falling edge allows a faster reading rate and, consequently, more AD7988-x has an acceptable hold time. The maximum conversion rate may be reduced due to the total readback time. CNV AD7988-1/ SDO SDI AD7988-5 B SCK Figure 38. Chain Mode Connection Diagram ...

  • Page 21

    ... AD7988-x AD7988-x is Figure 43. Example Layout of the Rev Page AD7988-1/AD7988-5 AD7988-x voltage reference input, REF, has a dynamic input and connected using short and wide traces to AD7988-x (EVAL-AD7988- AD7988-1/ AD7988-5 Figure 42. Example Layout of the AD7988-x (Top Layer) AD7988-x (Bottom Layer) devices. ...

  • Page 22

    ... AD7988-1/AD7988-5 OUTLINE DIMENSIONS IDENTIFIER PIN 1 INDEX AREA 0.80 0.75 0.70 SEATING PLANE 3.10 3.00 2. 5.15 3.10 4.90 3.00 4.65 1 2.90 5 PIN 1 0.50 BSC 0.95 15° MAX 0.85 1.10 MAX 0.75 0.15 0.23 6° 0.30 0.05 0.13 0° 0.15 COPLANARITY 0.10 COMPLIANT TO JEDEC STANDARDS MO-187-BA Figure 44.10-Lead Mini Small Outline Package [MSOP] (RM-10) Dimensions shown in millimeters 3.10 3.00 SQ 2.90 6 0.50 0.40 0.30 5 TOP VIEW BOTTOM VIEW 0.05 MAX 0.02 NOM ...

  • Page 23

    ... QFN (LFCSP_WD) −40°C to +125°C Reel, 1,500 10-Lead QFN (LFCSP_WD) Evaluation Board with AD7988-5 Populated; Use for Evaluation of Both AD7988-1 and AD7988-5. System Demonstration Board, Used as a Controller Board for Data Transfer via USB Interface to PC. EVAL-SDZ-CB1Z for evaluation/demonstration purposes. ...

  • Page 24

    ... AD7988-1/AD7988-5 NOTES ©2012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D10231-0-2/12(A) Rev Page Data Sheet ...