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Analog Sensor Linearization
Digital
Temperature
Compensation
Analog Signal Conditioning
PGA309
Digital Cal
VEXC
0
50
psi
P
Ext Temp
Ext Temp
Nonlinear
Bridge
Transducer
Linearization
Circuit
Auto- Zero
PGA
Fault
Monitor
Int Temp
Control Register
Interface Circuitry
EEPROM
(SOT23-5)
Ref
T
+125 C°
- °40 C
Over/Under
Scale Limiter
Lin DAC
Temp
ADC
Linear
V
OUT
V
S
PGA309
www.ti.com
SBOS292C –DECEMBER 2003–REVISED JANUARY 2011
Voltage Output
Programmable Sensor Conditioner
Check for Samples: PGA309
1
FEATURES
DESCRIPTION
2
• Complete Bridge Sensor Conditioner
The PGA309 is a programmable analog signal
conditioner designed for bridge sensors. The analog
• Voltage Output: Ratiometric or Absolute
signal path amplifies the sensor signal and provides
• Digital Cal: No Potentiometers/Sensor Trims
digital calibration for zero, span, zero drift, span drift,
• Sensor Error Compensation
and sensor linearization errors with applied stress
– Span, Offset, and Temperature Drifts (pressure, strain, etc.). The calibration is done via a
One-Wire digital serial interface or through a
• Low Error, Time-Stable
Two-Wire industry-standard connection. The
• Sensor Linearization Circuitry
calibration parameters are stored in external
• Temperature Sense: Internal or External
nonvolatile memory (typically SOT23-5) to eliminate
manual trimming and achieve long-term stability.
• Calibration Lookup Table Logic
– Uses External EEPROM (SOT23-5) The all-analog signal path contains a 2x2 input
multiplexer (mux), auto-zero programmable-gain
• Over/Under-Scale Limiting
instrumentation amplifier, linearization circuit, voltage
• Sensor Fault Detection
reference, internal oscillator, control logic, and an
• +2.7V TO +5.5V Operation
output amplifier. Programmable level shifting
compensates for sensor dc offsets.
• –40°C to +125°C Operation
• Small TSSOP-16 Package 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 +
APPLICATIONS
Output Amplifier can be adjusted from 2.7V/V to
• Bridge Sensors
1152V/V. The polarity of the inputs can be switched
• Remote 4-20mA Transmitters
through the input mux to accommodate sensors with
• Strain, Load, and Weigh Scales
unknown polarity output. The Fault Monitor circuit
detects and signals sensor burnout, overload, and
• Automotive Sensors
system fault conditions.
EVALUATION TOOLS
For detailed application information, see the PGA309
• Hardware Designer’s Kit (PGA309EVM)
User's Guide (SBOU024) available for download at
www.ti.com.
– Temperature Eval of PGA309 + Sensor
– Full Programming of PGA309
– Sensor Compensation Analysis Tool
1
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.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2003–2011, Texas Instruments Incorporated
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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