PGA309_11 Datasheet, PDF (1/24 Pages) Texas Instruments – Voltage Output Programmable Sensor Conditioner

PGA309
www.ti.com
SBOS292C – DECEMBER 2003 – REVISED JANUARY 2011
Voltage Output
Programmable Sensor Conditioner
Check for Samples: PGA309
FEATURES
1
•2 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
APPLICATIONS
• Bridge Sensors
• Remote 4-20mA Transmitters
• Strain, Load, and Weigh Scales
• Automotive Sensors
EVALUATION TOOLS
• Hardware Designer’s Kit (PGA309EVM)
– Temperature Eval of PGA309 + Sensor
– Full Programming of PGA309
– Sensor Compensation Analysis Tool
DESCRIPTION
The 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 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
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 can be switched
through the input mux to accommodate 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.
V_S
P
psi
0 50
+125°C
T
-40°C
Nonlinear
Bridge
Transducer
PGA309
VEXC
Linearization
Circuit
Analog Sensor Linearization
Ref
Lin DAC
Ext Temp
Fault
Monitor
Auto- Zero
PGA
Over/Under
Scale Limiter
Analog Signal Conditioning
Digital
Temperature
Int Temp
Compensation
Ext Temp
Temp
ADC
Control Register
Interface Circuitry
Linear
V_OUT
Digital Cal
EEPROM
(SOT23-5)
1
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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