SBAS453G July   2009  – August 2016 ADS1146 , ADS1147 , ADS1148

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
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Noise Performance
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagrams
    3. 9.3 Feature Description
      1. 9.3.1  ADC Input and Multiplexer
      2. 9.3.2  Low-Noise PGA
        1. 9.3.2.1 PGA Common-Mode Voltage Requirements
        2. 9.3.2.2 PGA Common-Mode Voltage Calculation Example
        3. 9.3.2.3 Analog Input Impedance
      3. 9.3.3  Clock Source
      4. 9.3.4  Modulator
      5. 9.3.5  Digital Filter
      6. 9.3.6  Voltage Reference Input
      7. 9.3.7  Internal Voltage Reference
      8. 9.3.8  Excitation Current Sources
      9. 9.3.9  Sensor Detection
      10. 9.3.10 Bias Voltage Generation
      11. 9.3.11 General-Purpose Digital I/O
      12. 9.3.12 System Monitor
        1. 9.3.12.1 Power-Supply Monitor
        2. 9.3.12.2 External Voltage Reference Monitor
        3. 9.3.12.3 Ambient Temperature Monitor
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power Up
      2. 9.4.2 Reset
      3. 9.4.3 Power-Down Mode
      4. 9.4.4 Conversion Control
        1. 9.4.4.1 Settling Time for Channel Multiplexing
        2. 9.4.4.2 Channel Cycling and Overload Recovery
        3. 9.4.4.3 Single-Cycle Settling
        4. 9.4.4.4 Digital Filter Reset Operation
      5. 9.4.5 Calibration
        1. 9.4.5.1 Offset Calibration Register: OFC[2:0]
        2. 9.4.5.2 Full-Scale Calibration Register: FSC[2:0]
        3. 9.4.5.3 Calibration Commands
          1. 9.4.5.3.1 System Offset and Self Offset Calibration
          2. 9.4.5.3.2 System Gain Calibration
        4. 9.4.5.4 Calibration Timing
    5. 9.5 Programming
      1. 9.5.1 Digital Interface
        1. 9.5.1.1 Chip Select (CS)
        2. 9.5.1.2 Serial Clock (SCLK)
        3. 9.5.1.3 Data Input (DIN)
        4. 9.5.1.4 Data Ready (DRDY)
        5. 9.5.1.5 Data Output and Data Ready (DOUT/DRDY)
        6. 9.5.1.6 SPI Reset
        7. 9.5.1.7 SPI Communication During Power-Down Mode
      2. 9.5.2 Data Format
      3. 9.5.3 Commands
        1. 9.5.3.1  WAKEUP (0000 000x)
        2. 9.5.3.2  SLEEP (0000 001x)
        3. 9.5.3.3  SYNC (0000 010x)
        4. 9.5.3.4  RESET (0000 011x)
        5. 9.5.3.5  RDATA (0001 001x)
        6. 9.5.3.6  RDATAC (0001 010x)
        7. 9.5.3.7  SDATAC (0001 011x)
        8. 9.5.3.8  RREG (0010 rrrr, 0000 nnnn)
        9. 9.5.3.9  WREG (0100 rrrr, 0000 nnnn)
        10. 9.5.3.10 SYSOCAL (0110 0000)
        11. 9.5.3.11 SYSGCAL (0110 0001)
        12. 9.5.3.12 SELFOCAL (0110 0010)
        13. 9.5.3.13 NOP (1111 1111)
        14. 9.5.3.14 Restricted Command (1111 0001)
    6. 9.6 Register Maps
      1. 9.6.1 ADS1146 Register Map
      2. 9.6.2 ADS1146 Detailed Register Definitions
        1. 9.6.2.1 BCS—Burn-out Current Source Register (offset = 00h) [reset = 01h]
        2. 9.6.2.2 VBIAS—Bias Voltage Register (offset = 01h) [reset = 00h]
        3. 9.6.2.3 MUX—Multiplexer Control Register (offset = 02h) [reset = x0h]
        4. 9.6.2.4 SYS0—System Control Register 0 (offset = 03h) [reset = 00h]
        5. 9.6.2.5 OFC—Offset Calibration Coefficient Registers (offset = 04h, 05h, 06h) [reset = 00h, 00h, 00h]
        6. 9.6.2.6 FSC—Full-Scale Calibration Coefficient Registers (offset = 07h, 08h, 09h) [reset = 00h, 00h, 40h]
        7. 9.6.2.7 ID—ID Register (offset = 0Ah) [reset = x0h]
      3. 9.6.3 ADS1147 and ADS1148 Register Map
      4. 9.6.4 ADS1147 and ADS1148 Detailed Register Definitions
        1. 9.6.4.1  MUX0—Multiplexer Control Register 0 (offset = 00h) [reset = 01h]
        2. 9.6.4.2  VBIAS—Bias Voltage Register (offset = 01h) [reset = 00h]
        3. 9.6.4.3  MUX1—Multiplexer Control Register 1 (offset = 02h) [reset = x0h]
        4. 9.6.4.4  SYS0—System Control Register 0 (offset = 03h) [reset = 00h]
        5. 9.6.4.5  OFC—Offset Calibration Coefficient Register (offset = 04h, 05h, 06h) [reset = 00h, 00h, 00h]
        6. 9.6.4.6  FSC—Full-Scale Calibration Coefficient Register (offset = 07h, 08h, 09h) [reset = 00h, 00h, 40h]
        7. 9.6.4.7  IDAC0—IDAC Control Register 0 (offset = 0Ah) [reset = x0h]
        8. 9.6.4.8  IDAC1—IDAC Control Register 1 (offset = 0Bh) [reset = FFh]
        9. 9.6.4.9  GPIOCFG—GPIO Configuration Register (offset = 0Ch) [reset = 00h]
        10. 9.6.4.10 GPIODIR—GPIO Direction Register (offset = 0Dh) [reset = 00h]
        11. 9.6.4.11 GPIODAT—GPIO Data Register (offset = 0Eh) [reset = 00h]
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Serial Interface Connections
      2. 10.1.2 Analog Input Filtering
      3. 10.1.3 External Reference and Ratiometric Measurements
      4. 10.1.4 Establishing a Proper Common-Mode Input Voltage
      5. 10.1.5 Isolated (or Floating) Sensor Inputs
      6. 10.1.6 Unused Inputs and Outputs
      7. 10.1.7 Pseudo Code Example
      8. 10.1.8 Channel Multiplexing Example
      9. 10.1.9 Power-Down Mode Example
    2. 10.2 Typical Applications
      1. 10.2.1 Ratiometric 3-Wire RTD Measurement System
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Topology
          2. 10.2.1.2.2 RTD Selection
          3. 10.2.1.2.3 Excitation Current
          4. 10.2.1.2.4 Reference Resistor, RREF
          5. 10.2.1.2.5 PGA Setting
          6. 10.2.1.2.6 Common-Mode Input Range
          7. 10.2.1.2.7 Input and Reference Low-Pass Filters
          8. 10.2.1.2.8 Register Settings
        3. 10.2.1.3 Application Curves
      2. 10.2.2 K-Type Thermocouple Measurement (-200°C to 1250°C) With Cold-Junction Compensation
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
          1. 10.2.2.2.1 Biasing Resistors
          2. 10.2.2.2.2 Input Filtering
          3. 10.2.2.2.3 PGA Setting
          4. 10.2.2.2.4 Cold-Junction Measurement
          5. 10.2.2.2.5 Calculated Resolution
          6. 10.2.2.2.6 Register Settings
    3. 10.3 Do's and Don'ts
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Sequencing
    2. 11.2 Power Supply Decoupling
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

See(1)
MIN MAX UNIT
Power-supply voltage AVDD to AVSS –0.3 5.5 V
AVSS to DGND –2.8 0.3
DVDD to DGND –0.3 5.5
Analog input voltage AINx, REFPx, REFNx, VREFOUT, VREFCOM, IEXC1, IEXC2 AVSS – 0.3 AVDD + 0.3 V
Digital input voltage SCLK, DIN, DOUT/DRDY, DRDY, CS, START, RESET, CLK DGND – 0.3 DVDD + 0.3 V
Input current Continuous, any pin except power supply pins –10 10 mA
Momentary, any pin except power supply pins –100 100
Temperature Junction, TJ 150 °C
Storage, Tstg –60 150
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which 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.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±750
(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 ambient temperature range (unless otherwise noted)
MIN NOM MAX UNIT
POWER SUPPLY
Analog power supply AVDD to AVSS 2.7 5.25 V
AVSS to DGND –2.65 0.1
AVDD to DGND 2.25 5.25
Digital power supply DVDD to DGND 2.7 5.25 V
ANALOG INPUTS(2)
VIN Differential input voltage V(AINP) – V(AINN)(1) –VREF / Gain VREF / Gain V
VCM Common-mode input voltage (V(AINP) + V(AINN)) / 2 See Equation 3
VOLTAGE REFERENCE INPUTS(3)
VREF Differential reference input voltage V(REFPx) – V(REFNx) 0.5 (AVDD – AVSS) – 1 V
V(REFNx) Absolute negative reference voltage AVSS – 0.1 V(REFPx) – 0.5 V
V(REFPx) Absolute positive reference voltage V(REFNx) + 0.5 AVDD + 0.1 V
EXTERNAL CLOCK INPUT(4)
fCLK External clock frequency 1 4.5 MHz
External clock duty cycle 25% 75%
GENERAL-PURPOSE INPUTS AND OUTPUTS (GPIO)
GPIO input voltage AVSS AVDD V
DIGITAL INPUTS
Digital input voltage DGND DVDD V
TEMPERATURE RANGE
TA Operating ambient temperature –40 125 °C
Specified ambient temperature –40 105 °C
(1) For VREF > 2.7 V, the differential input voltage must not exceed 2.7 V / Gain.
(2) AINP and AINN denote the positive and negative inputs of the PGA.
(3) REFPx and REFNx denote the differential reference input pair (ADS1146, ADS1147), or one of the two available differential reference input pairs (ADS1148).
(4) External clock only required if the internal oscillator is not used.

7.4 Thermal Information

THERMAL METRIC(1) ADS1146 ADS1147 ADS1148 UNIT
PW (TSSOP) PW (TSSOP) PW (TSSOP) RHB (VQFN)
16 PINS 20 PINS 28 PINS 32 PINS
RθJA Junction-to-ambient thermal resistance 95.2 87.4 74.2 32.5 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 28.9 21.7 20.2 23.9 °C/W
RθJB Junction-to-board thermal resistance 41 39.6 31.8 6.6 °C/W
ψJT Junction-to-top characterization parameter 1.5 0.8 0.8 0.3 °C/W
ψJB Junction-to-board characterization parameter 40.4 38.9 31.3 6.6 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance — — — 1.6 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

7.5 Electrical Characteristics

Minimum and maximum specifications apply from TA = –40°C to +105°C. Typical specifications are at TA = 25°C.
All specifications are at AVDD = 5 V, DVDD = 3.3 V, AVSS = 0 V, VREF = 2.048 V, and fCLK = 4.096 MHz (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ANALOG INPUTS
Differential input current 100 pA
Absolute input current See Table 4
PGA
PGA gain settings 1, 2, 4, 8, 16, 32, 64, 128 V/V
SYSTEM PERFORMANCE
Resolution No missing codes 16 Bits
DR Data rate 5, 10, 20, 40, 80, 160, 320, 640, 1000, 2000 SPS
ADC conversion time Single-cycle settling See Table 10
INL Integral nonlinearity Differential input, end point fit,
Gain = 1, VCM = 2.5 V		 –1 0.5 1 LSB
Offset error After calibration –1 1 LSB
Offset drift Gain = 1 100 nV/°C
Gain = 128 15 nV/°C
Gain error Excluding VREF errors –0.5% 0.5%
Gain drift Gain = 1, excludes VREF drift 1 ppm°C
Gain = 128, excludes VREF drift –3.5 ppm/°C
Noise See Table 1 and Table 2
NMRR Normal mode rejection See Table 6
CMRR Common-mode rejection At DC, Gain = 1 90 dB
At DC, Gain = 32 100
PSRR Power supply rejection AVDD, DVDD at DC 100 dB
VOLTAGE REFERENCE INPUTS
Reference input current 30 nA
INTERNAL VOLTAGE REFERENCE
VREF Internal reference voltage 2.038 2.048 2.058 V
Reference drift(1) TA = –40°C to +105°C 20 50 ppm/°C
Output current(2) –10 10 mA
Load regulation 50 µV/mA
Start-up time See Table 7
INTERNAL OSCILLATOR
Internal oscillator frequency 3.89 4.096 4.3 MHz
EXCITATION CURRENT SOURCES (IDACs)
Output current settings 50, 100, 250, 500, 750, 1000, 1500 µA
Compliance voltage All currents See Figure 9 and Figure 10
Absolute error All currents, each IDAC –6% ±1% 6%
Absolute mismatch All currents, between IDACs ±0.2%
Temperature drift Each IDAC 200 ppm/°C
Temperature drift matching Between IDACs 10 ppm/°C
BURN-OUT CURRENT SOURCES
Burn-out current source settings 0.5, 2, 10 µA
BIAS VOLTAGE
Bias voltage (AVDD + AVSS) / 2 V
Bias voltage output impedance 400 Ω
TEMPERATURE SENSOR
Output voltage TA = 25°C 118 mV
Temperature coefficient 405 µV/°C
GENERAL-PURPOSE INPUTS AND OUTPUTS (GPIO)
VIL Low-level input voltage AVSS 0.3 × AVDD V
VIH High-level input voltage 0.7 × AVDD AVDD V
VOL Low-level output voltage IOL = 1 mA AVSS 0.2 × AVDD V
VOH High-level output voltage IOH = 1 mA 0.8 × AVDD V
DIGITAL INPUTS AND OUTPUTS (OTHER THAN GPIO)
VIL Low-level input voltage DGND 0.3 × DVDD V
VIH High-level input voltage 0.7 × DVDD DVDD V
VOL Low-level output voltage IOL = 1 mA DGND 0.2 × DVDD V
VOH High-level output voltage IOH = 1 mA 0.8 × DVDD V
Input leakage DGND < VIN < DVDD –10 10 µA
POWER SUPPLY
IAVDD Analog supply current Power-down mode 0.1 µA
Converting, AVDD = 3.3 V,
DR = 20 SPS, external reference		 212
Converting, AVDD = 5 V,
DR = 20 SPS, external reference		 225
Additional current with internal reference enabled 180
IDVDD Digital supply current Power-down mode 0.2 µA
Normal operation, DVDD = 3.3 V,
DR = 20 SPS, internal oscillator		 210
Normal operation, DVDD = 5 V,
DR = 20 SPS, internal oscillator		 230
PD Power dissipation AVDD = DVDD = 3.3 V,
DR = 20 SPS, internal oscillator, external reference		 1.4 mW
AVDD = DVDD = 5 V,
DR = 20 SPS, internal oscillator, external reference		 2.3
(1) Specified by the combination of design and final production test.
(2) Do not exceed this loading on the internal voltage reference.

7.6 Timing Requirements

At TA = –40°C to +105°C and DVDD = 2.7 V to 5.5 V (unless otherwise noted)
PARAMETER MIN NOM MAX UNIT
SERIAL INTERFACE (SEE Figure 1 AND Figure 2)
tCSSC Delay time, first SCLK rising edge after CS falling edge 10 ns
tSCCS Delay time, CS rising edge after final SCLK falling edge 7 tCLK(1)
tCSPW Pulse duration, CS high 5 tCLK
tSCLK SCLK period 488 ns
64 Conversions
tSPWH Pulse duration, SCLK high 0.25 0.75 tSCLK
tSPWL Pulse duration, SCLK low 0.25 0.75 tSCLK
tDIST Setup time, DIN valid before SCLK falling edge 5 ns
tDIHD Hold time, DIN valid after SCLK falling edge 5 ns
tSTD Setup time, SCLK low before DRDY rising edge 5 tCLK
tDTS Delay time, SCLK rising edge after DRDY falling edge 1 tCLK
MINIMUM START TIME PULSE DURATION (SEE Figure 3)
tSTART Pulse duration, START high 3 tCLK
RESET PULSE DURATION, SERIAL INTERFACE COMMUNICATION AFTER RESET (SEE Figure 4)
tRESET Pulse duration, RESET low 4 tCLK
tRHSC Delay time, SCLK rising edge (start of serial interface communication) after RESET rising edge 0.6(2) ms
(1) tCLK = 1 / fCLK. The default clock frequency fCLK = 4.096 MHz.
(2) Applicable only when fCLK = 4.096 MHz, scales proportionally with fCLK frequency.

7.7 Switching Characteristics

At TA = –40°C to +105°C and DVDD = 2.7 V to 5.5 V (unless otherwise noted; see Figure 1 and Figure 2)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
tDOPD Propagation delay time,
SCLK rising edge to valid new DOUT		 DVDD ≤ 3.6 V 50 ns
DVDD > 3.6 V 180
tDOHD DOUT hold time 0 ns
tCSDO Propagation delay time,
CS rising edge to DOUT high impedance		 10 ns
tPWH Pulse duration, DRDY high 3 tCLK
ADS1146 ADS1147 ADS1148 timing_ser_int_sbas426.gif Figure 1. Serial Interface Timing, DRDY MODE Bit = 0
ADS1146 ADS1147 ADS1148 timing_rdatac_sbas426.gif
1. This timing diagram is applicable only when the CS pin is low. SCLK does not need to be low during tSTD when CS is high.
2. SCLK must only be sent in multiples of eight during partial retrieval of output data.
Figure 2. Serial Interface Timing to Allow Conversion Result Loading
ADS1146 ADS1147 ADS1148 timing_start_bas426.gif Figure 3. Minimum Start Pulse Duration
ADS1146 ADS1147 ADS1148 timing_reset_bas426.gif Figure 4. Reset Pulse Duration and Serial Interface Communication After Reset

7.8 Typical Characteristics

TA = 25°C, AVDD = 5 V, AVSS = 0 V, and VREF = 2.5 V (unless otherwise noted)
ADS1146 ADS1147 ADS1148 tc_Vref_1000hrdrift_bas453.png Figure 5. Internal Reference Long-Term Drift
ADS1146 ADS1147 ADS1148 tc_idac_line_reg_bas453.gif Figure 7. IDAC Line Regulation
ADS1146 ADS1147 ADS1148 tc_idac_compliance2_bas453.png Figure 9. IDAC Voltage Compliance
ADS1146 ADS1147 ADS1148 tc_analog-data_rate_bas453.gif Figure 11. Analog Supply Current vs Data Rate
ADS1146 ADS1147 ADS1148 tc_analog-tmp_5V_bas453.gif Figure 13. Analog Supply Current vs Temperature
ADS1146 ADS1147 ADS1148 tc_ana_cur-tmp_3V_bas453.gif Figure 15. Analog Supply Current vs Temperature
ADS1146 ADS1147 ADS1148 tc_data_rate-tmp_bas453.gif Figure 6. Data Rate Error vs Temperature
ADS1146 ADS1147 ADS1148 tc_idac_drift_bas453.gif Figure 8. IDAC Drift
ADS1146 ADS1147 ADS1148 tc_idac_compliance1_bas453.png Figure 10. IDAC Voltage Compliance
ADS1146 ADS1147 ADS1148 tc_digital-data_rate_bas453.gif Figure 12. Digital Supply Current vs Data Rate
ADS1146 ADS1147 ADS1148 tc_digital-tmp_bas453.gif Figure 14. Digital Supply Current vs Temperature
ADS1146 ADS1147 ADS1148 tc_digi_cur-tmp_3V_bas453.gif Figure 16. Digital Supply Current vs Temperature