PGA309 Datasheet, PDF (1/20 Pages) Burr-Brown (TI) – Voltage Output PROGRAMMABLE SENSOR CONDITIONER

PGA309
SBOS292A − DECEMBER 2003 − REVISED AUGUST 2004
Voltage Output
PROGRAMMABLE SENSOR CONDITIONER
FEATURES
D COMPLETE BRIDGE SENSOR CONDITIONER
D VOLTAGE OUTPUT: Ratiometric or Absolute
D DIGITAL CAL: No Potentiometers/Sensor Trims
D SENSOR ERROR COMPENSATION
− Span, Offset, and Temperature Drifts
D LOW ERROR, TIME-STABLE
D SENSOR LINEARIZATION CIRCUITRY
D TEMPERATURE SENSE: Internal or External
D CALIBRATION LOOKUP TABLE LOGIC
− Uses External EEPROM (SOT23-5)
D OVER/UNDER-SCALE LIMITING
D SENSOR FAULT DETECTION
D +2.7V TO +5.5V OPERATION
D −40°C to +125°C OPERATION
D SMALL TSSOP-16 PACKAGE
APPLICATIONS
D BRIDGE SENSORS
D REMOTE 4-20mA TRANSMITTERS
D STRAIN, LOAD, AND WEIGH SCALES
D AUTOMOTIVE SENSORS
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.
EVALUATION TOOLS
D HARDWARE DESIGNER’S KIT (PGA309EVM)
− Temperature Eval of PGA309 + Sensor
− Full Programming of PGA309
− Sensor Compensation Analysis Tool
N onlinear
Bridge
P
Transducer
psi
0 50
For detailed application information, see the PGA309
User’s Guide (SBOU024), available for download at
www.ti.com.
V_S
V_EXC
PGA309
Linearization
Circuit
Analog Sensor Linearization
Ref
Lin DAC
+125_ C
T
−40_C
Ext Temp
Fault
Monitor
Auto−Zero
PGA
Over/Under
Scale Limiter
Analog Signal Conditioning
Digital
Int Temp
Temperature
Compensation
Ext Temp
Temp
ADC
Control Register
Interface Circuitry
Linear
V_OUT
Digital Cal
EEPROM
(SOT23−5)
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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.
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