AD7685CRM Analog Devices Inc, AD7685CRM Datasheet

IC ADC 16BIT PSEUDO-DIFF 10-MSOP

AD7685CRM

Manufacturer Part Number
AD7685CRM
Description
IC ADC 16BIT PSEUDO-DIFF 10-MSOP
Manufacturer
Analog Devices Inc
Series
PulSAR®r
Datasheet

Specifications of AD7685CRM

Design Resources
Parametric Measurement Unit and Supporting Components for PAD Appls Using AD5522 and AD7685 (CN0104) Integrated Device Power Supply for PAD with Output Voltage Range 0 V to 25 V (CN0130)
Number Of Bits
16
Sampling Rate (per Second)
250k
Data Interface
DSP, MICROWIRE™, QSPI™, Serial, SPI™
Number Of Converters
1
Power Dissipation (max)
15mW
Voltage Supply Source
Single Supply
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
10-TFSOP (0.118", 3.00mm Width)
For Use With
EVAL-AD7685CBZ - BOARD EVAL FOR AD7685
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD7685CRMZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD7685CRMZ-RL7
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD7685CRMZRL7
Manufacturer:
ADI/亚德诺
Quantity:
20 000
FEATURES
16-bit resolution with no missing codes
Throughput: 250 kSPS
INL: ±0.6 LSB typical, ±2 LSB maximum (±0.003% of FSR)
SINAD: 93.5 dB @ 20 kHz
THD: −110 dB @ 20 kHz
Pseudo differential analog input range
No pipeline delay
Single-supply operation 2.3 V to 5.5 V with
Serial interface SPI®-/QSPI™-/MICROWIRE™-/DSP-compatible
Daisy-chain multiple ADCs, BUSY indicator
Power dissipation
Standby current: 1 nA
10-lead package: MSOP (MSOP-8 size) and
Pin-for-pin-compatible with 10-lead MSOP/QFN PulSAR® ADCs
APPLICATIONS
Battery-powered equipment
Data acquisition
Instrumentation
Process controls
Rev. B
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.
0 V to V
1.8 V to 5 V logic interface
1.4 μW @ 2.5 V/100 SPS
1.35 mW @ 2.5 V/100 kSPS, 4 mW @ 5 V/100 kSPS
3 mm × 3 mm QFN (LFCSP) (SOT-23 size)
Medical instruments
Mobile communications
Personal digital assistants (PDAs)
–0.5
–1.0
–1.5
–2.0
2.0
1.5
1.0
0.5
0
0
REF
with V
Figure 1. Integral Nonlinearity vs. Code.
16384
REF
up to VDD
CODE
32768
POSITIVE INL = +0.33LSB
NEGATIVE INL = –0.50LSB
49152
65536
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
Table 1. MSOP, QFN (LFCSP)/SOT-23
14-/16-/18-Bit PulSAR ADC
Type
18-Bit True
16-Bit True
16-Bit Pseudo
14-Bit Pseudo
GENERAL DESCRIPTION
The AD7685 is a 16-bit, charge redistribution successive
approximation, analog-to-digital converter (ADC) that operates
from a single power supply, VDD, between 2.3 V to 5.5 V. It
contains a low power, high speed, 16-bit sampling ADC with no
missing codes, an internal conversion clock, and a versatile serial
interface port. The part also contains a low noise, wide bandwidth,
short aperture delay, track-and-hold circuit. On the CNV rising
edge, it samples an analog input IN+ between 0 V to REF with
respect to a ground sense IN−. The reference voltage, REF, is
applied externally and can be set up to the supply voltage.
Power dissipation scales linearly with throughput.
The SPI-compatible serial interface also features the ability,
using the SDI input, to daisy chain several ADCs on a single
3-wire bus or provides an optional BUSY indicator. It is
compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic using the
separate supply VIO.
The AD7685 is housed in a 10-lead MSOP or a 10-lead QFN
(LFCSP) with operation specified from −40°C to +85°C.
0 TO VREF
Differential
Differential
Differential
Differential
16-Bit, 250 kSPS PulSAR
0.5V TO VDD
100
kSPS
AD7684
AD7680
AD7683
AD7940
APPLICATION DIAGRAM
IN+
IN–
©2004–2007 Analog Devices, Inc. All rights reserved.
AD7685
GND
REF
250
kSPS
AD7691
AD7687
AD7685
AD7694
AD7942
VDD
ADC in MSOP/QFN
2.5V TO 5V
Figure 2.
SDO
SCK
CNV
VIO
SDI
400 kSPS
to
500 kSPS
AD7690
AD7982
AD7688
AD7693
AD7686
AD7946
1.8V TO VDD
3- OR 4-WIRE INTERFACE
(SPI, DAISY CHAIN, CS)
1000
kSPS
AD7982
AD7980
AD7685
www.analog.com
ADC
Driver
ADA4941
ADA4841
ADA4941
ADA4841
ADA4841
ADA4841

Related parts for AD7685CRM

AD7685CRM Summary of contents

Page 1

FEATURES 16-bit resolution with no missing codes Throughput: 250 kSPS INL: ±0.6 LSB typical, ±2 LSB maximum (±0.003% of FSR) SINAD: 93 kHz THD: −110 kHz Pseudo differential analog input range ...

Page 2

AD7685 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 Application Diagram........................................................................ 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Timing Specifications....................................................................... 5 Absolute Maximum Ratings............................................................ 7 ESD Caution.................................................................................. 7 Pin Configuration and Function Descriptions............................. 8 Terminology ...................................................................................... ...

Page 3

SPECIFICATIONS VDD = 2 5.5 V, VIO = 2 VDD, V Table 2. Parameter Conditions RESOLUTION ANALOG INPUT Voltage Range IN+ − IN− Absolute Input Voltage IN+ IN− Analog Input CMRR f = 250 kHz IN ...

Page 4

AD7685 VDD = 2 5.5 V, VIO = 2 VDD, V Table 3. Parameter Conditions REFERENCE Voltage Range Load Current 250 kSPS, REF = 5 V SAMPLING DYNAMICS −3 dB Input Bandwidth Aperture Delay VDD = ...

Page 5

TIMING SPECIFICATIONS −40°C to +85°C, VIO = 2 5 VDD + 0.3 V, whichever is the lowest, unless otherwise stated. 1 Table 4. VDD = 4 5.5 V Parameter Conversion Time: CNV Rising Edge ...

Page 6

AD7685 −40°C to +85°C, VIO = 2 4 VDD + 0.3 V, whichever is the lowest, unless otherwise stated. 1 Table 5. VDD = 2.3V to 4.5 V Parameter Conversion Time: CNV Rising Edge to Data ...

Page 7

ABSOLUTE MAXIMUM RATINGS Table 6. Parameter Rating Analog Inputs 1 1 IN+ , IN− , REF GND − 0 VDD + 0 ±130 mA Supply Voltages VDD, VIO to GND −0 VDD ...

Page 8

AD7685 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS REF 1 10 VDD 2 9 AD7685 IN TOP VIEW (Not to Scale) IN– GND 5 6 Figure 5. 10-Lead MSOP Pin Configuration Table 7. Pin Function Descriptions 1 Pin ...

Page 9

TERMINOLOGY Integral Nonlinearity Error (INL) INL refers to the deviation of each individual code from a line drawn from negative full scale through positive full scale. The point used as negative full scale occurs ½ LSB before the first code ...

Page 10

AD7685 TYPICAL PERFORMANCE CHARACTERISTICS 2.0 POSITIVE INL = +0.33LSB NEGATIVE INL = –0.50LSB 1.5 1.0 0.5 0 –0.5 –1.0 –1.5 –2.0 0 16384 32768 CODE Figure 7. Integral Nonlinearity vs. Code 250000 204292 200000 150000 100000 50000 29041 27755 0 ...

Page 11

REFERENCE VOLTAGE (V) Figure 13. SNR, SINAD, and ENOB vs. Reference Voltage 100 5V, –10dB REF 5V, –1dB REF ...

Page 12

AD7685 95 94 SNR 93 92 THD 91 90 –10 –8 –6 –4 INPUT LEVEL (dB) Figure 19. SNR and THD vs. Input Level 1000 750 VDD 500 250 VIO 0 2.3 2.7 3.1 3.5 3.9 4.3 SUPPLY (V) Figure ...

Page 13

THEORY OF OPERATION IN+ REF GND IN– CIRCUIT INFORMATION The AD7685 is a fast, low power, single-supply, precise 16-bit ADC using a successive approximation architecture. The AD7685 is capable of converting 250,000 samples per second (250 kSPS) and powers down ...

Page 14

AD7685 Transfer Functions The ideal transfer characteristic for the AD7685 is shown in Figure 26 and Table 8. 111...111 111...110 111...101 000...010 000...001 000...000 –FS – LSB –FS + 0.5 LSB ANALOG INPUT Figure 26. ADC Ideal Transfer ...

Page 15

ANALOG INPUTS Figure 28 shows an equivalent circuit of the input structure of the AD7685. 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 ...

Page 16

AD7685 DRIVER AMPLIFIER CHOICE Although the AD7685 is easy to drive, the driver amplifier needs to meet the following requirements: • The noise generated by the driver amplifier needs to be kept as low as possible to preserve the SNR ...

Page 17

The AD7685 powers down automatically at the end of each conversion phase and, therefore, the power scales linearly with the sampling rate, as shown in Figure 32. This makes the part ideal for low sampling rate (even a few Hz) ...

Page 18

AD7685 CS MODE 3-WIRE, NO BUSY INDICATOR This mode is usually used when a single AD7685 is connected to an SPI-compatible digital host. The connection diagram is shown in Figure 34, and the corresponding timing is given in Figure 35. ...

Page 19

CS MODE 3-WIRE WITH BUSY INDICATOR This mode is usually used when a single AD7685 is connected to an SPI-compatible digital host having an interrupt input. The connection diagram is shown in Figure 36, and the corresponding timing is given ...

Page 20

AD7685 CS MODE 4-WIRE, NO BUSY INDICATOR This mode is usually used when multiple AD7685s are connected to an SPI-compatible digital host. A connection diagram example using two AD7685s is shown in Figure 38, and the corresponding timing is given ...

Page 21

CS MODE 4-WIRE WITH BUSY INDICATOR This mode is usually used when a single AD7685 is connected to an SPI-compatible digital host, which has an interrupt input, and it is desired to keep CNV, which is used to sample the ...

Page 22

AD7685 CHAIN MODE, NO BUSY INDICATOR This mode can be used to daisy-chain multiple AD7685s on a 3-wire serial interface. This feature is useful for reducing component count and wiring connections, for example, in isolated multiconverter applications or for systems ...

Page 23

CHAIN MODE WITH BUSY INDICATOR This mode can also be used to daisy chain multiple AD7685s on a 3-wire serial interface while providing a BUSY indicator. This feature is useful for reducing component count and wiring connections, for example, in ...

Page 24

AD7685 APPLICATION HINTS LAYOUT The printed circuit board (PCB) that houses the AD7685 should be designed so that the analog and digital sections are separated and confined to certain areas of the board. The pinout of the AD7685 with all ...

Page 25

TRUE 16-BIT ISOLATED APPLICATION EXAMPLE In applications where high accuracy and isolation are required, for example, power monitoring, motor control, and some medical equipment, the circuit given in Figure 48, using the AD7685 and the ADuM1402C digital isolator, provides a ...

Page 26

AD7685 OUTLINE DIMENSIONS INDEX ARE A 1.50 BSC SQ 0.80 0.75 0.70 SEATING PLANE 3.10 3.00 2. 5.15 3.10 4.90 3.00 4.65 2. PIN 1 0.50 BSC 0.95 0.85 1.10 MAX 0.75 0.15 0.33 SEATING 0.23 ...

Page 27

... AD7685CCPZRL ±2 LSB max 1 AD7685CCPZRL7 ±2 LSB max AD7685CRM ±2 LSB max AD7685CRMRL7 ±2 LSB max 1 AD7685CRMZ ±2 LSB max 1 AD7685CRMZRL7 ±2 LSB max EVAL-AD7685CB EVAL-AD7685CBZ 3 EVAL-CONTROL BRD2 3 EVAL-CONTROL BRD3 RoHS Compliant Part. 2 This board can be used as a standalone evaluation board or in conjunction with the EVAL-CONTROL BRDx for evaluation/demonstration purposes. ...

Page 28

AD7685 NOTES ©2004–2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D02968-0-3/07(B) Rev Page ...

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