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

6.2.8 Register 7: Output Enable Counter Control Register (Read/Write, Address Pointer = 00111)

Bit # D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
Bit Name RFB RFB RFB RFB DLY3 DLY2 DLY1 DLY0 OEN7 OEN6 OEN5 OEN4 OEN3 OEN2 OEN1 OEN0
POR Value 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Bit Descriptions:

RFB: Reserved Factory Bit: Set to zero for proper operation

DLY[3:0]: Temp ADC Delay

Temp ADC begins conversion after DLY[3:0] x 10ms after valid WRITE to this register. Initial count, DLY[3:0] is decremented every 10ms to zero count and then Temp ADC is enabled. This allows for linearization and excitation analog circuitry to settle before applying temperature compensation.

OEN[7:0]: Output Enable Counter for One-Wire Interface/VOUT Multiplexed Mode.

VOUT is enabled after a valid WRITE to this register. Any non-zero value = VOUT Enable initial count, decremented every 10ms to zero count, and then VOUTis disabled. After VOUT is disabled, a one-second internal timer is set. If serial communication takes place from an outside controller on either the One-Wire interface (PRG pin) or Two-Wire interface, then VOUT will remain disabled as long as the PGA309 is addressed at least once per second.

Table 6-18 Temp ADC—Delay After VOUT Enable
DLY3
[11]		 DLY2
[10]		 DLY1
[9]		 DLY0
[8]		 Decimal Equivalent
(Initial Counter Value)		 Temp ADC Delay(1)
(ms)
0 0 0 0 0 0
0 0 0 1 1 14
0 0 1 0 2 28
0 0 1 1 3 42
0 1 0 0 4 56
0 1 0 1 5 70
0 1 1 0 6 84
0 1 1 1 7 98
1 0 0 0 8 112
1 0 0 1 9 126
1 0 1 0 10 140
1 0 1 1 11 154
1 1 0 0 12 168
1 1 0 1 13 182
1 1 1 0 14 196
1 1 1 1 15 210
(1) Temp ADC Delay = Initial Counter Value x 14ms
Table 6-19 Output Enable Counter for One-Wire Interface/VOUT Multiplexed Mode
Digital Input
OEN7……OEN0 [7……0]
(Binary)		 Decimal Equivalent
(Initial Counter Value)		 VOUT Enable Timeout(1)(ms)
0000 0000 0 0 (VOUT disabled)
0010 0000 32 448
0100 0000 64 896
0110 0000 96 1344
1000 0000 128 1792
1010 0000 160 2240
1100 0000 192 2688
1110 0000 224 3136
1111 1111 255 3570
(1) VOUT Enable Timeout = Initial Counter Value x 14ms