SBAS680 July   2015 ADS8684A , ADS8688A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements: Serial Interface
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Analog Inputs
      2. 8.3.2  Analog Input Impedance
      3. 8.3.3  Input Overvoltage Protection Circuit
      4. 8.3.4  Programmable Gain Amplifier (PGA)
      5. 8.3.5  Second-Order, Low-Pass Filter (LPF)
      6. 8.3.6  ADC Driver
      7. 8.3.7  Multiplexer (MUX)
      8. 8.3.8  Reference
        1. 8.3.8.1 Internal Reference
        2. 8.3.8.2 External Reference
      9. 8.3.9  Auxiliary Channel
        1. 8.3.9.1 Input Driver for the AUX Channel
      10. 8.3.10 ADC Transfer Function
      11. 8.3.11 Alarm Feature
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Interface
        1. 8.4.1.1 Digital Pin Description
          1. 8.4.1.1.1 CS (Input)
          2. 8.4.1.1.2 SCLK (Input)
          3. 8.4.1.1.3 SDI (Input)
          4. 8.4.1.1.4 SDO (Output)
          5. 8.4.1.1.5 DAISY (Input)
          6. 8.4.1.1.6 RST/PD (Input)
        2. 8.4.1.2 Data Acquisition Example
        3. 8.4.1.3 Host-to-Device Connection Topologies
          1. 8.4.1.3.1 Daisy-Chain Topology
          2. 8.4.1.3.2 Star Topology
      2. 8.4.2 Device Modes
        1. 8.4.2.1 Continued Operation in the Selected Mode (NO_OP)
        2. 8.4.2.2 Frame Abort Condition (FRAME_ABORT)
        3. 8.4.2.3 STANDBY Mode (STDBY)
        4. 8.4.2.4 Power-Down Mode (PWR_DN)
        5. 8.4.2.5 Auto Channel Enable with Reset (AUTO_RST)
        6. 8.4.2.6 Manual Channel n Select (MAN_Ch_n)
        7. 8.4.2.7 Channel Sequencing Modes
        8. 8.4.2.8 Reset Program Registers (RST)
    5. 8.5 Register Maps
      1. 8.5.1 Command Register Description
      2. 8.5.2 Program Register Description
        1. 8.5.2.1 Program Register Read/Write Operation
        2. 8.5.2.2 Program Register Map
        3. 8.5.2.3 Program Register Descriptions
          1. 8.5.2.3.1 Auto-Scan Sequencing Control Registers
            1. 8.5.2.3.1.1 Auto-Scan Sequence Enable Register (address = 01h)
            2. 8.5.2.3.1.2 Channel Power Down Register (address = 02h)
          2. 8.5.2.3.2 Device Features Selection Control Register (address = 03h)
          3. 8.5.2.3.3 Range Select Registers (addresses 05h-0Ch)
          4. 8.5.2.3.4 Alarm Flag Registers (Read-Only)
            1. 8.5.2.3.4.1 ALARM Overview Tripped-Flag Register (address = 10h)
            2. 8.5.2.3.4.2 Alarm Flag Registers: Tripped and Active (address = 11h to 14h)
          5. 8.5.2.3.5 Alarm Threshold Setting Registers
          6. 8.5.2.3.6 Command Read-Back Register (address = 3Fh)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Phase-Compensated, 8-Channel, Multiplexed Data Acquisition System for Power Automation
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
      2. 9.2.2 16-Bit, 8-Channel, Integrated Analog Input Module for Programmable Logic Controllers (PLCs)
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
  10. 10Power-Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
AIN_nP, AIN_nGND to GND(2) –20 20 V
AIN_nP, AIN_nGND to GND(3) –11 11 V
AUX_GND to GND –0.3 0.3 V
AUX_IN to GND –0.3 AVDD + 0.3 V
AVDD to GND or DVDD to GND –0.3 7 V
REFCAP to REFGND or REFIO to REFGND –0.3 5.7 V
GND to REFGND –0.3 0.3 V
Digital input pins to GND –0.3 DVDD + 0.3 V
Digital output pins to GND –0.3 DVDD + 0.3 V
Operating temperature, TA –40 125 °C
Storage temperature, Tstg –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) AVDD = 5 V or offers a low impedance of < 30 kΩ.
(3) AVDD = floating with an impedance > 30 kΩ.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) Analog input pins (AIN_nP; AIN_nGND) ±4000 V
All other pins ±2000
Charged device model (CDM), per JEDEC specification JESD22-C101(2) ±500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
AVDD Analog supply voltage 4.75 5 5.25 V
DVDD Digital supply voltage 1.65 3.3 AVDD V

7.4 Thermal Information

THERMAL METRIC(1) ADS8684A, ADS8688A UNIT
DBT (TSSOP)
38 PINS
RθJA Junction-to-ambient thermal resistance 68.8 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 19.9 °C/W
RθJB Junction-to-board thermal resistance 30.4 °C/W
ψJT Junction-to-top characterization parameter 1.3 °C/W
ψJB Junction-to-board characterization parameter 29.8 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance NA °C/W
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

7.5 Electrical Characteristics

Minimum and maximum specifications are at TA = –40°C to 125°C. Typical specifications are at TA = 25°C.
AVDD = 5 V, DVDD = 3 V, VREF = 4.096 V (internal), and fSAMPLE = 500 kSPS, unless otherwise noted.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT TEST LEVEL(1)
ANALOG INPUTS
Full-scale input span(2)
(AIN_nP to AIN_nGND)		 Input range = ±2.5 × VREF –2.5 × VREF 2.5 × VREF V A
Input range = ±1.25 × VREF –1.25 × VREF 1.25 × VREF A
Input range = ±0.625 × VREF –0.625 × VREF 0.625 × VREF A
Input range = ±0.3125 × VREF –0.3125 × VREF 0.3125 × VREF A
Input range = ±0.15625 × VREF –0.15625 × VREF 0.15625 × VREF A
Input range = 2.5 × VREF 0 2.5 × VREF A
Input range = 1.25 × VREF 0 1.25 × VREF A
Input range = 0.625 × VREF 0 0.625 × VREF A
Input range = 0.3125 × VREF 0 0.3125 × VREF A
AIN_nP Operating input range,
positive input		 Input range = ±2.5 × VREF –2.5 × VREF 2.5 × VREF V A
Input range = ±1.25 × VREF –1.25 × VREF 1.25 × VREF A
Input range = ±0.625 × VREF –0.625 × VREF 0.625 × VREF A
Input range = ±0.3125 × VREF –0.3125 × VREF 0.3125 × VREF A
Input range = ±0.15625 × VREF –0.15625 × VREF 0.15625 × VREF A
Input range = 2.5 × VREF 0 2.5 × VREF A
Input range = 1.25 × VREF 0 1.25 × VREF A
Input range = 0.625 × VREF 0 0.625 × VREF A
Input range = 0.3125 × VREF 0 0.3125 × VREF A
AIN_nGND Operating input range,
negative input		 All input ranges –0.1 0 0.1 V B
zi Input impedance At TA = 25°C,
all input ranges		 0.85 1 1.15 MΩ B
Input impedance drift All input ranges 7 25 ppm/°C B
IIkg(in) Input leakage current With voltage at AIN_nP pin = VIN,
input range = ±2.5 × VREF		 VIN – 2.25
————
RIN 		µA A
With voltage at AIN_nP pin = VIN,
input range = ±1.25 × VREF		 VIN – 2.00
————
RIN 		A
With voltage at AIN_nP pin = VIN,
input ranges = ±0.625 × VREF; ±0.3125 × VREF; ±0.15625 × VREF		 VIN – 1.60
————
RIN 		A
With voltage at AIN_nP pin = VIN,
input range = 2.5 × VREF		 VIN – 2.50
————
RIN 		A
With voltage at AIN_nP pin = VIN,
input range = 1.25 × VREF; 0.625 × VREF; 0.3125 × VREF		 VIN – 2.50
————
RIN 		A
INPUT OVERVOLTAGE PROTECTION
VOVP Overvoltage protection voltage AVDD = 5 V or offers low impedance < 30 kΩ, all input ranges –20 20 V B
AVDD = floating with impedance
> 30 kΩ, all input ranges		 –11 11 B
SYSTEM PERFORMANCE
Resolution 16 Bits A
NMC No missing codes 16 Bits A
DNL Differential nonlinearity –0.99 ±0.5 1.5 LSB(3) A
INL Integral nonlinearity(6) –2 ±0.75 2 LSB A
EG Gain error At TA = 25°C, all input ranges ±0.02 ±0.05 %FSR(4) A
Gain error matching
(channel-to-channel)		 At TA = 25°C, all input ranges ±0.02 ±0.05 %FSR A
Gain error temperature drift All input ranges 1 4 ppm/°C B
EO Offset error At TA = 25°C,
input range = ±2.5 × VREF(10)		 ±0.5 ±1 mV A
At TA = 25°C,
input range = ±1.25 × VREF		 ±0.5 ±1 A
At TA = 25°C,
input range = ±0.625 × VREF		 ±0.5 ±1.5 A
At TA = 25°C,
input range = ±0.3125 × VREF		 ±0.5 ±1.5 A
At TA = 25°C,
input range = ±0.15625 × VREF		 ±0.5 ±1.5 A
At TA = 25°C,
all unipolar input ranges		 ±0.5 ±2 A
Offset error matching
(channel-to-channel)		 At TA = 25°C,
input range = ±2.5 × VREF(10)		 ±0.5 ±1 mV A
At TA = 25°C,
input range = ±1.25 × VREF		 ±0.5 ±1 A
At TA = 25°C,
input range = ±0.625 × VREF		 ±0.5 ±1.5 A
At TA = 25°C,
input range = ±0.3125 × VREF		 ±0.5 ±1.5 A
At TA = 25°C,
input range = ±0.15625 × VREF		 ±0.5 ±1.5 A
At TA = 25°C,
all unipolar input ranges		 ±0.5 ±2 A
Offset error temperature drift Input range = ±2.5 × VREF 1 3 ppm/°C B
Input range = ±1.25 × VREF 1 3 B
Input range = ±0.625 × VREF 1 3 B
Input range = ±0.3125 × VREF 2 6 B
Input range = ±0.15625 × VREF 4 12 B
Input range = 0 to 2.5 × VREF 1 3 B
Input range = 0 to 1.25 × VREF 1 3 B
Input range = 0 to 0.625 × VREF 2 6 B
Input range = 0 to 0.3125 × VREF 4 12 B
SAMPLING DYNAMICS
tCONV Conversion time 850 ns A
tACQ Acquisition time 1150 ns A
fS Maximum throughput rate
without latency		 500 kSPS A
DYNAMIC CHARACTERISTICS
SNR Signal-to-noise ratio
(VIN – 0.5 dBFS at 1 kHz)		 Input range = ±2.5 × VREF 90 92 dB A
Input range = ±1.25 × VREF 89 91 A
Input range = ±0.625 × VREF 87.5 89 A
Input range = ±0.3125 × VREF 81.5 83 A
Input range = ±0.15625 × VREF 75.5 77 A
Input range = 2.5 × VREF 88.5 90.5 A
Input range = 1.25 × VREF 87.5 89 A
Input range = 0.625 × VREF 81.5 83 A
Input range = 0.3125 × VREF 75.5 77 A
THD Total harmonic distortion(5)
(VIN – 0.5 dBFS at 1 kHz)		 Input ranges = ±2.5 × VREF, ±1.25 × VREF, ±0.625 × VREF, 2.5 × VREF, 1.25 × VREF -102 dB B
Input ranges = ±0.3125 × VREF, ±0.15625 × VREF, 0.625 × VREF, 0.3125 × VREF -100
SINAD Signal-to-noise ratio
(VIN – 0.5 dBFS at 1 kHz)		 Input range = ±2.5 × VREF 89 91.5 dB A
Input range = ±1.25 × VREF 88.5 91 A
Input range = ±0.625 × VREF 87 89 A
Input range = ±0.3125 × VREF 81 83 A
Input range = ±0.15625 × VREF 75 77 A
Input range = 2.5 × VREF 87.5 90.5 A
Input range = 1.25 × VREF 87 89 A
Input range = 0.625 × VREF 81 83 A
Input range = 0.3125 × VREF 75 77 A
SFDR Spurious-free dynamic range
(VIN – 0.5 dBFS at 1 kHz)		 Input ranges = ±2.5 × VREF, ±1.25 × VREF, ±0.625 × VREF, 2.5 × VREF, 1.25 × VREF 103 dB B
Input ranges = ±0.3125 × VREF, ±0.15625 × VREF, 0.625 × VREF, 0.3125 × VREF 101
Crosstalk isolation(7) Aggressor channel input overdriven to 2 × maximum input voltage 110 dB B
Crosstalk memory(8) Aggressor channel input overdriven to 2 × maximum input voltage 90 dB B
BW(–3 dB) Small-signal bandwidth, –3 dB At TA = 25°C, all input ranges 15 kHz B
BW(–0.1 dB) Small-signal bandwidth, –0.1 dB At TA = 25°C, all input ranges 2.5 kHz B
AUXILIARY CHANNEL
Resolution 16 Bits A
V(AUX_IN) AUX_IN voltage range (AUX_IN – AUX_GND) 0 VREF V A
Operating input range AUX_IN 0 VREF V A
AUX_GND 0 V A
Ci Input capacitance During sampling 75 pF C
During conversion 5 pF C
IIkg(in) Input leakage current 100 nA A
DNL Differential nonlinearity –0.99 ±0.6 1.5 LSB A
INL Integral nonlinearity –4 ±1.5 4 LSB A
EG(AUX) Gain error At TA = 25°C ±0.02 ±0.2 %FSR A
EO(AUX) Offset error At TA = 25°C –5 5 mV A
SNR Signal-to-noise ratio V(AUX_IN) = –0.5 dBFS at 1 kHz 87 89 dB A
THD Total harmonic distortion(5) V(AUX_IN) = –0.5 dBFS at 1 kHz –102 dB B
SINAD Signal-to-noise + distortion V(AUX_IN) = –0.5 dBFS at 1 kHz 86 88.5 dB A
SFDR Spurious-free dynamic range V(AUX_IN) = –0.5 dBFS at 1 kHz 103 dB B
INTERNAL REFERENCE OUTPUT
V(REFIO_INT)(9) Voltage on REFIO pin
(configured as output)		 At TA = 25°C 4.095 4.096 4.097 V A
Internal reference temperature drift 6 10 ppm/°C B
C(OUT_REFIO) Decoupling capacitor on REFIO 10 22 µF B
V(REFCAP) Reference voltage to ADC
(on REFCAP pin)		 At TA = 25°C 4.095 4.096 4.097 V A
Reference buffer output impedance 0.5 1 Ω B
Reference buffer temperature drift 0.6 1.5 ppm/°C B
C(OUT_REFCAP) Decoupling capacitor on REFCAP 10 22 μF B
Turn-on time C(OUT_REFCAP) = 22 µF,
C(OUT_REFIO) = 22 µF		 15 ms B
EXTERNAL REFERENCE INPUT
VREFIO_EXT External reference voltage on REFIO (configured as input) 4.046 4.096 4.146 V C
POWER-SUPPLY REQUIREMENTS
AVDD Analog power-supply voltage Analog supply 4.75 5 5.25 V B
DVDD Digital power-supply voltage Digital supply range 1.65 3.3 AVDD V B
Digital supply range for specified performance 2.7 3.3 5.25 B
IAVDD_DYN Analog supply current Dynamic, AVDD For the ADS8688; AVDD = 5 V, fS = maximum and internal reference 13 16 mA A
For the ADS8684; AVDD = 5 V, fS = maximum and internal reference 8.5 11.5 A
IAVDD_STC Static For the ADS8688; AVDD = 5 V, device not converting and internal reference 10 12 mA A
For the ADS8684; AVDD = 5 V, device not converting and internal reference 5.5 8.5 A
ISTDBY Standby At AVDD = 5 V, device in STDBY mode and internal reference 3 4.5 mA A
IPWR_DN Power-down At AVDD = 5 V, device in PWR_DN 3 20 μA B
IDVDD_DYN Digital supply current At DVDD = 3.3 V, output = 0000h 0.5 mA A
DIGITAL INPUTS (CMOS)
VIH Digital input logic levels
DVDD > 2.1 V		 0.7 × DVDD DVDD + 0.3 V A
VIL –0.3 0.3 × DVDD A
VIH Digital input logic levels
DVDD ≤ 2.1 V		 0.8 × DVDD DVDD + 0.3 V A
VIL –0.3 0.2 × DVDD A
Input leakage current 100 nA A
Input pin capacitance 5 pF C
DIGITAL OUTPUTS (CMOS)
VOH Digital output logic levels IO = 500-μA source 0.8 × DVDD DVDD V A
VOL IO = 500-μA sink 0 0.2 × DVDD A
Floating state leakage current Only for SDO 1 µA A
Internal pin capacitance 5 pF C
TEMPERATURE RANGE
TA Operating free-air temperature –40 125 °C B
(1) Test Levels: (A) Tested at final test. Over temperature limits are set by characterization and simulation. (B) Limits set by characterization and simulation, across temperature range. (C) Typical value only for information, provided by design simulation.
(2) Ideal input span, does not include gain or offset error.
(3) LSB = least significant bit.
(4) FSR = full-scale range.
(5) Calculated on the first nine harmonics of the input frequency.
(6) This parameter is the endpoint INL, not best-fit INL.
(7) Isolation crosstalk is measured by applying a full-scale sinusoidal signal up to 10 kHz to a channel, not selected in the multiplexing sequence, and measuring its effect on the output of any selected channel.
(8) Memory crosstalk is measured by applying a full-scale sinusoidal signal up to 10 kHz to a channel that is selected in the multiplexing sequence, and measuring its effect on the output of the next selected channel for all combinations of input channels.
(9) Does not include the variation in voltage resulting from solder-shift and long-term effects.
(10) Does not include the shift in offset over time.

7.6 Timing Requirements: Serial Interface

Minimum and maximum specifications are at TA = –40°C to 125°C. Typical specifications are at TA = 25°C.
AVDD = 5 V, DVDD = 3 V, VREF = 4.096 V (internal), SDO load = 20 pF, and fSAMPLE = 500 kSPS, unless otherwise noted.
MIN TYP MAX UNIT
TIMING SPECIFICATIONS
fS Sampling frequency (fCLK = max) 500 kSPS
tS ADC cycle time period (fCLK = max) 2 µs
fSCLK Serial clock frequency (fS = max) 17 MHz
tSCLK Serial clock time period (fS = max) 59 ns
tCONV Conversion time 850 ns
tDZ_CSDO Delay time: CS falling to data enable 10 ns
tD_CKCS Delay time: last SCLK falling to CS rising 10 ns
tDZ_CSDO Delay time: CS rising to SDO going to 3-state 10 ns
TIMING REQUIREMENTS
tACQ Acquisition time 1150 ns
tPH_CK Clock high time 0.4 0.6 tSCLK
tPL_CK Clock low time 0.4 0.6 tSCLK
tPH_CS CS high time 30 ns
tSU_CSCK Setup time: CS falling to SCLK falling 30 ns
tHT_CKDO Hold time: SCLK falling to (previous) data valid on SDO 10 ns
tSU_DOCK Setup time: SDO data valid to SCLK falling 25 ns
tSU_DICK Setup time: SDI data valid to SCLK falling 5 ns
tHT_CKDI Hold time: SCLK falling to (previous) data valid on SDI 5 ns
tSU_DSYCK Setup time: DAISY data valid to SCLK falling 5 ns
tHT_CKDSY Hold time: SCLK falling to (previous) data valid on DAISY 5 ns
ADS8684A ADS8688A tim_interface_sbas582.gifFigure 1. Serial Interface Timing Diagram

7.7 Typical Characteristics

At TA = 25°C, AVDD = 5 V, DVDD = 3 V, internal reference VREF = 4.096 V, and fSAMPLE = 500 kSPS, unless otherwise noted.
ADS8684A ADS8688A C001_SBAS680.png
Figure 2. Input I-V Characteristic
ADS8684A ADS8688A C005_SBAS680.png
Figure 4. Input Impedance Variation vs Temperature
ADS8684A ADS8688A C007_SBAS680.png
Mean = 32768.67, sigma = 0.58, input = 0 V,
range = ±2.5 × VREF
Figure 6. DC Histogram for Mid-Scale Inputs (±2.5 × VREF)
ADS8684A ADS8688A C009_SBAS680.png
Mean = 32768.8, sigma = 0.76, input = 0 V,
range = ±0.625 × VREF
Figure 8. DC Histogram for Mid-Scale Inputs (±0.625 × VREF)
ADS8684A ADS8688A C011_SBAS680.png
Mean = 32768.2, sigma = 0.75, input = 0.625 × VREF,
range = 1.25 × VREF
Figure 10. DC Histogram for Mid-Scale Inputs
(1.25 × VREF)
ADS8684A ADS8688A C013_SBAS680.png
Mean = 32768.5, sigma = 2.68, input = 0 V,
range = ±0.15625 × VREF
Figure 12. DC Histogram for Mid-Scale Inputs
(±0.15625 x VREF)
ADS8684A ADS8688A C015_SBAS680.png
Mean = 32768.5, sigma = 2.68, input = 0.15625 × VREF,
range = 0.3125 × VREF
Figure 14. DC Histogram for Mid-Scale Inputs
(0.3125 x VREF)
ADS8684A ADS8688A C017_SBAS680.png
All input ranges
Figure 16. DNL vs Temperature
ADS8684A ADS8688A C019_SBAS680.png
Range = ±1.25 × VREF
Figure 18. Typical INL for All Codes
ADS8684A ADS8688A C021_SBAS680.png
Range = 2.5 × VREF
Figure 20. Typical INL for All Codes
ADS8684A ADS8688A C023_SBAS680.png
Range = ±0.3125 × VREF
Figure 22. Typical INL for All Codes
ADS8684A ADS8688A C025_SBAS680.png
Range = 0.625 × VREF
Figure 24. Typical INL for All Codes
ADS8684A ADS8688A C027_SBAS680.png
Range = ±2.5 × VREF
Figure 26. INL vs Temperature (±2.5 × VREF)
ADS8684A ADS8688A C029_SBAS680.png
Range = ±0.625 × VREF
Figure 28. INL vs Temperature (±0.625 × VREF)
ADS8684A ADS8688A C031_SBAS680.png
Range = 1.25 × VREF
Figure 30. INL vs Temperature (1.25 × VREF)
ADS8684A ADS8688A C033_SBAS680.png
Range = ±0.15625 × VREF
Figure 32. INL vs Temperature (±0.15625 × VREF)
ADS8684A ADS8688A C035_SBAS680.png
Range = 0.3125 × VREF
Figure 34. INL vs Temperature (0.3125 × VREF)
ADS8684A ADS8688A C037_SBAS680.png
Range = ±2.5 × VREF
Figure 36. Typical Histogram for Offset Drift
ADS8684A ADS8688A C039_SBAS680.png
Figure 38. Gain Error vs Temperature Across Input Ranges
ADS8684A ADS8688A C041_SBAS680.png
Range = ±2.5 × VREF
Figure 40. Gain Error vs Temperature Across Channels
ADS8684A ADS8688A C043_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 92.3 dB,
SINAD = 91.9 dB, THD = 101 dB, SFDR = 104 dB
Figure 42. Typical FFT Plot (±2.5 × VREF)
ADS8684A ADS8688A C045_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 89.6 dB,
SINAD = 89.5 dB, THD = 106 dB, SFDR = 107 dB
Figure 44. Typical FFT Plot (±0.625 × VREF)
ADS8684A ADS8688A C047_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 89.6 dB,
SINAD = 89.5 dB, THD = –106 dB, SFDR = 107 dB
Figure 46. Typical FFT Plot (1.25 × VREF)
ADS8684A ADS8688A C049_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 77.6 dB,
SINAD = 77.6 dB, THD = –106 dB, SFDR = 107 dB
Figure 48. Typical FFT Plot (±0.15625 × VREF)
ADS8684A ADS8688A C051_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 77.55 dB,
SINAD = 77.5 dB, THD = –100 dB, SFDR = 107 dB
Figure 50. Typical FFT Plot (0.3125 × VREF)
ADS8684A ADS8688A C053_SBAS680.png
fIN = 1 kHz
Figure 52. SNR vs Temperature
ADS8684A ADS8688A C055_SBAS680.png
fIN = 1 kHz
Figure 54. SINAD vs Temperature
ADS8684A ADS8688A C057_SBAS680.png
fIN = 1 kHz
Figure 56. THD vs Temperature
ADS8684A ADS8688A C059_SBAS680.png
Figure 58. Isolation Crosstalk vs Frequency
ADS8684A ADS8688A C061_SBAS680.png
Input = 2 × maximum input voltage
Figure 60. Isolation Crosstalk vs Frequency for
Overrange Inputs
ADS8684A ADS8688A C075_SBAS680.png
Figure 62. AVDD Current vs Temperature for the ADS8688A
(During Sampling)
ADS8684A ADS8688A C083_SBAS680.png
Figure 64. AVDD Current vs Temperature for the ADS8684A
(During Sampling)
ADS8684A ADS8688A C077_SBAS680.png
Figure 66. AVDD Current vs Temperature
(Power Down)
ADS8684A ADS8688A C002_SBAS680.png
Input range = ±2.5 × VREF
Figure 3. Input Current vs Temperature
ADS8684A ADS8688A C006_SBAS680.png
Number of samples = 1160
Figure 5. Typical Distribution of Input Impedance
ADS8684A ADS8688A C008_SBAS680.png
Mean = 32768.60, sigma = 0.63, input = 0 V,
range = ±1.25 × VREF
Figure 7. DC Histogram for Mid-Scale Inputs (±1.25 × VREF)
ADS8684A ADS8688A C010_SBAS680.png
Mean = 32767.75, sigma = 0.65, input = 1.25 × VREF,
range = 2.5 × VREF
Figure 9. DC Histogram for Mid-Scale Inputs (2.5 × VREF)
ADS8684A ADS8688A C012_SBAS680.png
Mean = 32768.5, sigma = 1.30, input = 0 V,
range = ±0.3125 × VREF
Figure 11. DC Histogram for Mid-Scale Inputs
(±0.3125 x VREF)
ADS8684A ADS8688A C014_SBAS680.png
Mean = 32768.5, sigma = 1.30, input = 0.3125 × VREF,
range = 0.625 × VREF
Figure 13. DC Histogram for Mid-Scale Inputs
(0.625 x VREF)
ADS8684A ADS8688A C016_SBAS680.png
All input ranges
Figure 15. Typical DNL for All Codes
ADS8684A ADS8688A C018_SBAS680.png
Range = ±2.5 × VREF
Figure 17. Typical INL for All Codes
ADS8684A ADS8688A C020_SBAS680.png
Range = ±0.625 × VREF
Figure 19. Typical INL for All Codes
ADS8684A ADS8688A C022_SBAS680.png
Range = 1.25 × VREF
Figure 21. Typical INL for All Codes
ADS8684A ADS8688A C024_SBAS680.png
Range = ±0.15625 × VREF
Figure 23. Typical INL for All Codes
ADS8684A ADS8688A C026_SBAS680.png
Range = 0.3125 × VREF
Figure 25. Typical INL for All Codes
ADS8684A ADS8688A C028_SBAS680.png
Range = ±1.25 × VREF
Figure 27. INL vs Temperature (±1.25 × VREF)
ADS8684A ADS8688A C030_SBAS680.png
Range = 2.5 × VREF
Figure 29. INL vs Temperature (2.5 × VREF)
ADS8684A ADS8688A C032_SBAS680.png
Range = ±0.3125 × VREF
Figure 31. INL vs Temperature (±0.3125 × VREF)
ADS8684A ADS8688A C034_SBAS680.png
Range = 0.625 × VREF
Figure 33. INL vs Temperature (0.625 × VREF)
ADS8684A ADS8688A C036_SBAS680.png
Figure 35. Offset Error vs
Temperature Across Input Ranges
ADS8684A ADS8688A C038_SBAS680.png
Range = ±2.5 × VREF
Figure 37. Offset Error vs Temperature Across Channels
ADS8684A ADS8688A C040_SBAS680.png
Range = ±2.5 × VREF
Figure 39. Typical Histogram for Gain Error Drift
ADS8684A ADS8688A C042_SBAS680.png
Figure 41. Gain Error vs External Resistance (REXT)
ADS8684A ADS8688A C044_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 91.4 dB,
SINAD = 91.2 dB, THD = 105 dB, SFDR = 107 dB
Figure 43. Typical FFT Plot (±1.25 × VREF)
ADS8684A ADS8688A C046_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 90.93 dB,
SINAD = 90.48 dB, THD = 100 dB, SFDR = 102 dB
Figure 45. Typical FFT Plot (2.5 × VREF)
ADS8684A ADS8688A C048_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 83.55 dB,
SINAD = 83.5 dB, THD = –104 dB, SFDR = 107 dB
Figure 47. Typical FFT Plot (±0.3125 × VREF)
ADS8684A ADS8688A C050_SBAS680.png
Number of points = 64k, fIN = 1 kHz, SNR = 83.55 dB,
SINAD = 83.5 dB, THD = –103 dB, SFDR = 107 dB
Figure 49. Typical FFT Plot (0.625 × VREF)
ADS8684A ADS8688A C052_SBAS680.png
Figure 51. SNR vs Input Frequency
ADS8684A ADS8688A C054_SBAS680.png
Figure 53. SINAD vs Input Frequency
ADS8684A ADS8688A C056_SBAS680.png
Figure 55. THD vs Input Frequency
ADS8684A ADS8688A C058_SBAS680.png
Figure 57. Memory Crosstalk vs Frequency
ADS8684A ADS8688A C060_SBAS680.png
Input = 2 × maximum input voltage
Figure 59. Memory Crosstalk vs Frequency for
Overrange Inputs
ADS8684A ADS8688A C074_SBAS680.png
Figure 61. AVDD Current vs Temperature for the ADS8688A
(fS = 500 kSPS)
ADS8684A ADS8688A C082_SBAS680.png
Figure 63. AVDD Current vs Temperature for the ADS8684A
(fS = 500 kSPS)
ADS8684A ADS8688A C076_SBAS680.png
Figure 65. AVDD Current vs Temperature
(STANDBY)