1FEATURES

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.