PGA281 - Zero-Drift Programmable Gain Instrumentation Amplifier | TI
MPN: PGA281 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.5 | $8.50 |
| 10 | $7.65 | $76.50 |
| 100 | $6.8 | $680.00 |
| 500 | $6.12 | $3,060.00 |
| 1,000 | $5.5 | $5,500.00 |
PGA281 Overview
An instrumentation amplifier (INA) is a type of differential amplifier that amplifies the difference between two input signals while rejecting common-mode voltages. It is characterized by high input impedance, high common-mode rejection ratio (CMRR), and low offset voltage. The PGA281 belongs to the family of programmable gain instrumentation amplifiers (PGIAs), which allow the gain to be set digitally or via external resistors, providing flexibility in signal conditioning chains. This category sits within the broader hierarchy of analog amplifiers, which are essential building blocks in electronic systems for signal conditioning and measurement.
Key features of the PGA281 include gain programmable from G = 0.2 to 10,000 using an external resistor, fully differential outputs with integrated clamping, low offset voltage of 10 µV (typ) and 35 µV (max), low offset drift of 0.1 µV/°C (typ) and 0.3 µV/°C (max), and low input bias current of 5 pA (typ). These specifications make it ideal for high-accuracy applications where drift and noise are critical.
The PGA281 employs a zero-drift architecture that continuously corrects offset and drift, achieving near-zero temperature coefficients. The integrated clamping circuitry protects the outputs from overvoltage conditions, enhancing system robustness. The device supports a wide supply range, typically ±5V, and provides rail-to-rail output swing, maximizing dynamic range.
Typical applications include precision current sensing (10 µA to 100 mA), sensor signal conditioning for bridge sensors, thermocouple amplifiers, and data acquisition front-ends. Its low offset and drift make it suitable for medical instrumentation, industrial process control, and test and measurement equipment.
When designing with the PGA281, ensure proper decoupling of the power supply pins and consider the thermal performance of the TSSOP package. The gain-setting resistor should be a precision resistor to maintain gain accuracy. The device's signal-integrity test capability allows for system-level diagnostics, which is valuable in safety-critical applications.
Drop-in alternatives for PGA281 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PGA281AIPWRG4
✅ Drop-In📋 Reference alternative (not in catalog)
PGA280
⚡ Same Package📋 Reference alternative (not in catalog)
PGA855
⚡ Same Package📋 Reference alternative (not in catalog)
INA851
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AD8231
⚡ Same Package ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
PGA281 Maximum Ratings & Electrical Characteristics
| Gain Range | 0.2 to 10,000 (external resistor) |
| Offset Voltage | 10 µV (typ), 35 µV (max) |
| Offset Drift | 0.1 µV/°C (typ), 0.3 µV/°C (max) |
| Input Bias Current | 5 pA (typ) |
| Output Type | Fully differential with integrated clamping |
| Supply Voltage Range | ±5V (typical) |
| Package | 16-TSSOP (PW) |
| Operating Temperature Range | -40°C to +125°C |
| Number of Circuits | 1 |
| Rail-to-Rail Output | Yes |
| 1/f Noise | Nearly none (autozeroing) |
| Linearity | Excellent (per datasheet) |
| Signal-Integrity Test | Yes |
| RoHS | Compliant |
| Mounting Type | Surface Mount |
PGA281 Pin Configuration
| Pin 1 | V+ — Positive supply voltage |
| Pin 2 | IN+ — Non-inverting input |
| Pin 3 | IN- — Inverting input |
| Pin 4 | V- — Negative supply voltage |
| Pin 5 | RG — Gain setting resistor connection |
| Pin 6 | RG — Gain setting resistor connection |
| Pin 7 | OUT+ — Positive differential output |
| Pin 8 | OUT- — Negative differential output |
| Pin 9 | CLAMP+ — Positive clamp voltage input |
| Pin 10 | CLAMP- — Negative clamp voltage input |
| Pin 11 | TEST — Signal-integrity test input |
| Pin 12 | GND — Ground |
| Pin 13 | NC — No connect |
| Pin 14 | NC — No connect |
| Pin 15 | NC — No connect |
| Pin 16 | NC — No connect |
Typical Applications
PGA281 is suitable for 6 applications: Precision Current Sensing, Bridge Sensor Signal Conditioning, Thermocouple Amplifier, Data Acquisition Front-End, Medical Instrumentation, Industrial Process Control.
Precision Current Sensing
The PGA281 is ideal for precision current sensing in applications such as battery monitoring, motor control, and power management. Its low offset voltage (10 µV) and drift (0.1 µV/°C) ensure accurate measurement of small voltage drops across shunt resistors. The programmable gain (0.2 to 10,000) allows optimization for different current ranges, from microamps to amps. The differential outputs interface directly with differential ADCs, preserving signal integrity. In a typical circuit, the shunt resistor is placed in the current path, and the PGA281 amplifies the voltage drop. The integrated clamping protects the ADC from overvoltage. This makes the PGA281 suitable for high-side and low-side current sensing in industrial and automotive systems.
Recommended
Bridge Sensor Signal Conditioning
The PGA281 is well-suited for conditioning signals from bridge sensors such as strain gauges, load cells, and pressure sensors. These sensors produce small differential voltages that require high gain and low offset to be accurately digitized. The PGA281's gain range up to 10,000 allows amplifying microvolt-level signals to the full-scale range of an ADC. Its low input bias current (5 pA) minimizes loading on the bridge, preserving measurement accuracy. The zero-drift architecture ensures stable readings over temperature, which is critical for industrial weighing and pressure monitoring. The differential outputs can drive a differential ADC directly, reducing external components. The signal-integrity test capability allows system self-diagnostics, enhancing reliability in safety-critical applications.
Recommended
Thermocouple Amplifier
The PGA281 is an excellent choice for thermocouple signal conditioning due to its low offset voltage (10 µV) and drift (0.1 µV/°C), which are essential for accurate temperature measurement. Thermocouples produce small voltages (tens of microvolts per degree) that require high gain and low noise. The PGA281's programmable gain allows matching the thermocouple output to the ADC input range. Its low input bias current minimizes errors from source impedance. The differential outputs interface with differential ADCs, improving noise immunity. The zero-drift architecture ensures stable readings over temperature, which is critical for industrial process control. The signal-integrity test capability can be used to detect sensor faults, enhancing system reliability.
Recommended
Data Acquisition Front-End
The PGA281 serves as a versatile front-end for data acquisition systems, providing programmable gain and signal conditioning for various sensors. Its wide gain range (0.2 to 10,000) allows adapting to different signal amplitudes, from microvolt-level sensors to larger voltages. The low offset and drift ensure high DC accuracy, while the differential outputs reduce noise and improve common-mode rejection. The integrated clamping protects the ADC from overvoltage, enhancing system robustness. The signal-integrity test capability allows system-level diagnostics, which is valuable in test and measurement equipment. The PGA281 can be used in multi-channel systems with multiplexed inputs, providing a flexible and accurate analog front-end.
Recommended
Medical Instrumentation
The PGA281 is suitable for medical instrumentation such as ECG, EEG, and patient monitoring systems, where precision and low noise are critical. Its low offset voltage (10 µV) and drift (0.1 µV/°C) ensure accurate biopotential measurements. The high input impedance and low bias current (5 pA) minimize loading on electrodes. The programmable gain allows adjusting sensitivity for different signal amplitudes. The differential outputs interface with differential ADCs, improving noise rejection. The zero-drift architecture ensures stable performance over time and temperature, which is essential for long-term monitoring. The signal-integrity test capability can be used for lead-off detection, enhancing patient safety.
Recommended
Industrial Process Control
The PGA281 is ideal for industrial process control applications such as pressure, temperature, and flow monitoring. Its low offset and drift ensure accurate measurement over a wide temperature range. The programmable gain allows adapting to different sensor outputs, from 4-20 mA loops to small bridge signals. The differential outputs provide good noise immunity in industrial environments. The integrated clamping protects the ADC from transients. The signal-integrity test capability enables system diagnostics, improving reliability in critical processes. The PGA281 can be used in PLC analog input modules, providing a flexible and accurate signal conditioning solution.
Recommended
Recommended Products Summary
Engineering reference data for PGA281 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PGA281AIPWRG4 | PGA280 | PGA855 | INA851 | AD8231 |
|---|---|---|---|---|---|---|
| Package | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP | 16-TSSOP |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Gain Range | 0.2 to 10,000 | 0.2 to 10,000 | 0.2 to 10,000 | 0.125 to 8 | 0.1 to 1000 | 1 to 128 |
| Offset Voltage | 10 µV (typ) | 10 µV (typ) | 10 µV (typ) | 25 µV (typ) | 25 µV (typ) | 10 µV (typ) |
| Offset Drift | 0.1 µV/°C (typ) | 0.1 µV/°C (typ) | 0.1 µV/°C (typ) | 0.05 µV/°C (typ) | 0.1 µV/°C (typ) | 0.05 µV/°C (typ) |
| Input Bias Current | 5 pA (typ) | 5 pA (typ) | 5 pA (typ) | 10 pA (typ) | 10 pA (typ) | 1 nA (typ) |
| Differential Outputs | Yes | Yes | No | No | No | No |
| Integrated Clamping | Yes | Yes | No | No | No | No |
Key Differentiators
- Fully differential outputs with integrated clamping (vs PGA280)
- Wider gain range (0.2 to 10,000) (vs PGA855)
- Lower input bias current (5 pA) (vs AD8231)
Design Notes
The PGA281 operates from a typical ±5V supply. Ensure that the power supply is well-regulated and decoupled with 0.1 µF ceramic capacitors placed close to the V+ and V- pins. For noisy environments, additional bulk capacitors (10 µF) may be needed. The supply voltage must not exceed the absolute maximum ratings specified in the datasheet to prevent damage.
For optimal performance, place the gain-setting resistor (RG) close to the RG pins to minimize parasitic capacitance and inductance. Use a precision resistor with low temperature coefficient to maintain gain accuracy. Keep the input traces short and shielded to reduce noise pickup. The exposed pad (if present) should be connected to ground for thermal and electrical stability.
A common mistake is using a standard resistor for RG, which can degrade gain accuracy. Use a 0.1% tolerance resistor with a low TC. Also, ensure that the input common-mode voltage is within the specified range to avoid output saturation. The clamping pins (CLAMP+ and CLAMP-) should be connected to appropriate voltages to protect the outputs; leaving them floating may cause unpredictable behavior.
Compliance Information
RoHS compliance is indicated on TI product page. Other compliance details not specified in the provided data.
