SBOU024C august   2004  – july 2023 PGA309

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Related Documentation from Texas Instruments
    3.     If You Need Assistance
    4.     Information About Cautions and Warnings
    5.     FCC Warning
    6.     Trademarks
  3. 1Introduction
    1. 1.1  PGA309 Functional Description
    2. 1.2  Sensor Error Adjustment Range
    3. 1.3  Gain Scaling
    4. 1.4  Offset Adjustment
    5. 1.5  Voltage Reference
    6. 1.6  Sensor Excitation and Linearization
    7. 1.7  ADC for Temperature Sensing
    8. 1.8  External EEPROM and Temperature Coefficients
    9. 1.9  Fault Monitor
    10. 1.10 Over-Scale and Under-Scale Limits
    11. 1.11 Power-Up and Normal Operation
    12. 1.12 Digital Interface
    13. 1.13 Pin Configuration
  4. 2Detailed Description
    1. 2.1  Gain Scaling
      1. 2.1.1 PGA309 Transfer Function
      2. 2.1.2 Solving For Gain Settings
    2. 2.2  Offset Scaling
    3. 2.3  Zero DAC and Gain DAC Architecture
    4. 2.4  Output Amplifier
    5. 2.5  Reference Voltage
    6. 2.6  Linearization Function
      1. 2.6.1 System Definitions
      2. 2.6.2 Key Linearization Design Equations
        1. 2.6.2.1 Lin DAC Counts Conversion
      3. 2.6.3 Key Ideal Design Equations
        1. 2.6.3.1 Linearization Design
        2.       37
    7. 2.7  Temperature Measurement
      1. 2.7.1 Temp ADC Start-Convert Control
      2. 2.7.2 External Temperature Sensing with an Excitation Series Resistor
    8. 2.8  Fault Monitor
    9. 2.9  Over-Scale and Under-Scale
      1. 2.9.1 Over-Scale and Under-Scale Calculation
      2.      44
    10. 2.10 Noise and Coarse Offset Adjust
    11. 2.11 General AC Considerations
  5. 3Operating Modes
    1. 3.1 Power-On Sequence and Normal Stand-Alone Operation
    2. 3.2 EEPROM Content and Temperature Lookup Table Calculation
      1. 3.2.1 Temperature Lookup Table Calculation
        1. 3.2.1.1 Temperature Lookup Table Calculation
        2.       52
        3.       53
    3. 3.3 Checksum Error Event
    4. 3.4 Test Pin
    5. 3.5 Power-On Initial Register States
      1. 3.5.1 PGA309 Power-Up State
  6. 4Digital Interface
    1. 4.1  Description
    2. 4.2  Two-Wire Interface
      1. 4.2.1 Device Addressing
      2. 4.2.2 Two-Wire Access to PGA309
    3. 4.3  One-Wire Interface
    4. 4.4  One-Wire Interface Timeout
    5. 4.5  One-Wire Interface Timing Considerations
    6. 4.6  Two-Wire Access to External EEPROM
    7. 4.7  One-Wire Interface Initiated Two-Wire EEPROM Transactions
    8. 4.8  PGA309 Stand-Alone Mode and Two-Wire Transactions
    9. 4.9  PGA309 Two-Wire Bus Master Operation and Bus Sharing Considerations
    10. 4.10 One-Wire Operation with PRG Connected to VOUT
    11. 4.11 Four-Wire Modules and One-Wire Interface (PRG)
  7. 5Application Background
    1. 5.1 Bridge Sensors
    2. 5.2 System Scaling Options for Bridge Sensors
      1. 5.2.1 Absolute Scale
      2. 5.2.2 Ratiometric Scale
    3. 5.3 Trimming Real World Bridge Sensors for Linearity
    4. 5.4 PGA309 Calibration Procedure
  8. 6Register Descriptions
    1. 6.1 Internal Register Overview
    2. 6.2 Internal Register Map
      1. 6.2.1 Register 0: Temp ADC Output Register (Read Only, Address Pointer = 00000)
      2. 6.2.2 Register 1: Fine Offset Adjust (Zero DAC) Register (Read/Write, Address Pointer = 00001)
      3. 6.2.3 Register 2: Fine Gain Adjust (Gain DAC) Register (Read/Write, Address Pointer = 00010)
      4. 6.2.4 Register 3: Reference Control and Linearization Register (Read/Write, Address Pointer = 00011)
      5. 6.2.5 Register 4: PGA Coarse Offset Adjust and Gain Select/Output Amplifier Gain Select Register (Read/Write, Address Pointer = 00100)
      6. 6.2.6 Register 5: PGA Configuration and Over/Under-Scale Limit Register (Read/Write, Address Pointer = 00101)
      7. 6.2.7 Register 6: Temp ADC Control Register (Read/Write, Address Pointer = 00110)
      8. 6.2.8 Register 7: Output Enable Counter Control Register (Read/Write, Address Pointer = 00111)
      9. 6.2.9 Register 8: Alarm Status Register (Read Only, Address Pointer = 01000)
  9.   A External EEPROM Example
    1.     A.1 PGA309 External EEPROM Example
      1.      A.1.1 Gain and Offset Scaling for External EEPROM
      2.      94
  10.   B Detailed Block Diagram
    1.     B.1 Detailed Block Diagram
  11.   C Glossary
  12.   Revision History

6.2.1 Register 0: Temp ADC Output Register (Read Only, Address Pointer = 00000)

Bit #D15D14D13D12D11D10D9D8D7D6D5D4D3D2D1D0
Bit NameAD15AD14AD13AD12AD11AD10AD9AD8AD7AD6AD5AD4AD3AD2AD1AD0
POR Value0000000000000000

Bit Descriptions:

AD[15:0] Temp ADC Output

Internal Temperature Mode: 12-bit + sign extended, right justified, Twos Complement data format
External Temperature Mode: 15-bit + sign extended, right-justified, Twos Complement data format

GUID-CA2E19EE-3ED6-42EB-9B6B-B40FB79CF577-low.gifFigure 6-1 Internal Temperature Mode; Register 6[9] = ‘1’
Table 6-2 Internal Temperature Mode−Data Format (12-Bit Resolution). TEN = 1; R1, R0 = ‘11’(1)
Temperature (°C)Digital Output AD15............AD0 (Binary)Digital Output (Hex)
1500000 1001 0110 0000960
1280000 1000 0000 0000800
127.93750000 0111 1111 111107FF
1000000 0110 0100 0000640
800000 0101 0000 0000500
750000 0100 1011 000004B0
500000 0011 0010 0000320
250000 0001 1001 0000190
0.250000 0000 0000 01004
00000 0000 0000 00000
−0.251111 1111 1111 1100FFFC
−251111 1110 0111 0000FE70
−551111 1100 1001 0000FC90
(1) The resolution for the Temp ADC in Internal Temperature Mode is 0.0625°C/count.
For positive temperatures (for example, +50°C):
(50°C)/(0.0625°C/count) = 800 → 320h → 0011 0010 0000
50°C will be read by the Temp ADC as 0000 0011 0010 0000 → 0320h
For negative temperatures (for example, −25°C):
(|[−25]|)/(0.0625°C/count) = 400 → 190h → 0001 1001 0000
Convert to Twos Complement notation.
−25°C will be read by the Temp ADC as 1111 1110 0111 0000 → FE70h
GUID-50236E23-7EFB-417F-9056-B9A396B42824-low.gifFigure 6-2 External Signal Mode; Register 6 = ‘0000 0100 0011 0000’
Table 6-3 External Signal Mode—Data Format Example (Register 6 = ‘0000 0100 0011 0011’), 15-Bit + Sign Resolution. REN = 1, RS = 1
TEMPIN
(V)		Temp ADC Input
(V)		Temp ADC Input
(Ratio to Full Scale)(1)		Digital Output
AD15............AD0
(Binary)		Digital Output
(Hex)
0.00012.49992371+0.999969 VREFT0111 1111 1111 11117FFF
+0.625+1.875+0.75 VREFT0110 0000 0000 00006000
+1.25+1.25+0.5 VREFT0100 0000 0000 00004000
+1.925+0.575+0.23 VREFT0001 1101 0111 00011D71
+2.4999+0.00007629+(1/32768) VREFT0000 0000 0000 00010001
+2.50+0 VREFT0000 0000 0000 00000000
+2.50007629−0.00007629−(1/32768) VREFT1111 1111 1111 1111FFFF
+3.075−0.575−0.23 VREFT1110 0010 1000 1111E28F
+3.75−1.25−0.5 VREFT1100 0000 0000 0000C000
+4.375−1.875−0.75 VREFT1010 0000 0000 0000A000
+5−2.5−1 VREFT1000 0000 0000 00008000
(1) VREFT can be VSA, VEXC, or VREF.