Features: `COMPLETE BRIDGE SENSOR CONDITIONER
`VOLTAGE OUTPUT: Ratiometric or Absolute
`DIGITAL CAL: No Potentiometers/Sensor Trims
`SENSOR ERROR COMPENSATION
− Span, Offset, and Temperature Drifts
`LOW ERROR, TIME-STABLE
`SENSOR LINEARIZATION CIRCUITRY
`TEMPERATURE SENSE: Internal or External
`CALIBRATION LOOKUP TABLE LOGIC
− Uses External EEPROM (SOT23-5)
`OVER/UNDER-SCALE LIMITING
`SENSOR FAULT DETECTION
`+2.7V TO +5.5V OPERATION
`−40 to +125 OPERATION
`SMALL TSSOP-16 PACKAGEApplication·BRIDGE SENSORS
·REMOTE 4-20mA TRANSMITTERS
·STRAIN, LOAD, AND WEIGH SCALES
·AUTOMOTIVE SENSORSPinout
SpecificationsSupply Voltage, VSD, VSD.......... +7.0V
Input Voltage, VIN1, VIN2(2).−0.3V to VSA +0.3V
Input Current, VFB, VOUT........ ±150mA
Input Current .............. ±10mA
Output Current Limit ............50mA
Storage Temperature Range .. −60to +150
Operating Temperature Range . −55 to +150
Junction Temperature ........ .. +150
Lead Temperature (soldering, 10s).... +300
ESD Protection (Human Body Model)... ..4kVDescriptionThe PGA309 is a programmable analog signal conditioner designed for bridge sensors. The analog signal path amplifies the sensor signal and provides digital calibration for zero, span, zero drift, span drift, and sensor linearization errors with applied stress (pressure, strain, etc.). The calibration PGA309 is done via a One-Wire digital serial interface or through a Two-Wire industry-standard connection. The calibration parameters are stored in external nonvolatile memory (typically SOT23-5) to eliminate manual trimming and achieve long-term stability.
The all-analog signal path PGA309 contains a 2x2 input multiplexer (mux), auto-zero programmable-gain instrumentation amplifier, linearization circuit, voltage reference, internal oscillator, control logic, and an output amplifier. Programmable level shifting compensates for sensor DC offsets.
The core of the PGA309 is the precision, low-drift, no 1/f noise Front-End PGA (Programmable Gain Amplifier). The overall gain of the Front-End PGA + Output Amplifier can be adjusted from 2.7V/V to 1152V/V. The polarity of the inputs PGA309 can be switched through the input mux to accommodate sensors with unknown polarity output. The Fault Monitor circuit PGA309 detects and signals sensor burnout, overload, and system fault conditions.
For detailed application information, see the PGA309 User's Guide (SBOU024), available for download at www.ti.com.
PGA309 Data Sheet
