PGA309
SBOS292A − DECEMBER 2003 − REVISED AUGUST 2004
Voltage Output
PROGRAMMABLE SENSOR CONDITIONER
FEATURES
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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°C to +125°C OPERATION
SMALL TSSOP-16 PACKAGE
DESCRIPTION
The PGA309 is a programmable analog signal conditioner
designed for bridge sensors. The analog signal path am-
plifies 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 cal-
ibration 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 contains a 2x2 input multiplex-
er (mux), auto-zero programmable-gain instrumentation
amplifier, linearization circuit, voltage reference, internal
oscillator, control logic, and an output amplifier. Program-
mable 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 can be switched through the input mux to ac-
commodate sensors with unknown polarity output. The
Fault Monitor circuit 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.
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APPLICATIONS
BRIDGE SENSORS
REMOTE 4-20mA TRANSMITTERS
STRAIN, LOAD, AND WEIGH SCALES
AUTOMOTIVE SENSORS
EVALUATION TOOLS
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HARDWARE DESIGNER’S KIT (PGA309EVM)
− Temperature Eval of PGA309 + Sensor
− Full Programming of PGA309
− Sensor Compensation Analysis Tool
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psi
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N onlinear
Bridge
Transducer
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EXC
PGA309
Linearization
Circuit
Ref
Lin DAC
Analog Sensor Linearization
Fault
Monitor
Auto−Zero
PGA
Over/Under
Scale Limiter
Analog Signal Conditioning
Linear
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OUT
+125_C
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−40_C
Ext Temp
Digital
Int Temp
Temperature
Compensation
Ext Temp
Digital Cal
Temp
ADC
Control Register
Interface Circuitry
EEPROM
(SOT23−
5)
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Copyright
2003−2004, Texas Instruments Incorporated
www.ti.com
BURR-BROWN [ BURR-BROWN CORPORATION ]
