INA2128 Dual Low-Power Instrumentation Amplifier

INA2128 Dual Low-Power Instrumentation Amplifier is a high-precision, low-power integrated circuit that contains two independent instrumentation amplifiers in a single package. Consequently, this dual configuration allows engineers to save significant board space while maintaining exceptional signal integrity for multi-channel data acquisition systems. Each amplifier features a classic three-op-amp architecture, which provides high common-mode rejection and excellent input impedance. Furthermore, a single external resistor sets the gain for each amplifier independently, offering flexible scaling from 1 to 10,000. Therefore, the INA2128 serves as an ideal solution for bridge amplifiers, medical instrumentation, and industrial process control where precision and power efficiency are paramount.

Key Features:

• Dual Channel Architecture: This IC houses two independent precision instrumentation amplifiers, significantly reducing component count and PCB footprint.
• Wide Gain Range: You can easily set the gain from 1 to 10,000 using only one external resistor per channel.
• Low Power Consumption: The device operates with a very low quiescent current of only 1.2 mA (total for both amplifiers), making it suitable for battery-operated devices.
• Excellent Precision: It features low offset voltage (50 μV max) and low drift (0.5 μV/°C max), ensuring high accuracy over time and temperature.
• High Common-Mode Rejection: The amplifier delivers a minimum CMRR of 120 dB at high gains, which effectively eliminates noise in differential signal paths.

Technical Specifications:

• Supply Voltage Range: ±2.25 V to ±18 V
• Input Offset Voltage: ±50 μV (Maximum)
• Gain Equation: G = 1 + (50 kΩ / R_G)
• Bandwidth: 1.3 MHz (at G=1)
• Slew Rate: 0.3 V/μs
• Input Bias Current: 2 nA (Maximum)
• Quiescent Current: 600 μA per amplifier

Mechanical Specifications:

• Package Type: DIP-16 (Dual In-line Package) or SO-16 (Surface Mount)
• Case Material: Molded Plastic
• Lead Finish: Tin/Lead or Matte Tin (Lead-Free versions available)
• Thermal Resistance: ≈ 80 °C/W (DIP package)

Dimensions:

• Body Length (DIP-16): ≈ 19.30 mm
• Body Width (DIP-16): ≈ 6.35 mm
• Lead Pitch: 2.54 mm (0.1 inch)
• Overall Height: ≈ 5.08 mm (including leads)

Pinout and Wiring:

• Pins 1 & 16 (R_G1): Connect the external resistor for Amplifier 1 gain setting.
• Pin 2 (Vin1-): Negative differential input for Amplifier 1.
• Pin 3 (Vin1+): Positive differential input for Amplifier 1.
• Pin 4 (Ref1): Reference terminal for Amplifier 1; however, it must connect to a low-impedance point.
• Pin 5 (V-): Negative power supply connection.
• Pin 6 (Ref2): Reference terminal for Amplifier 2.
• Pin 7 (Vin2+): Positive differential input for Amplifier 2.
• Pin 8 (Vin2-): Negative differential input for Amplifier 2.
• Pins 9 & 10 (R_G2): Connect the external resistor for Amplifier 2 gain setting.
• Pin 11 (Vout2): Output of Amplifier 2.
• Pin 12 (V+): Positive power supply connection.
• Pin 13 (Vout1): Output of Amplifier 1.

Datasheet Reference:

• Download INA2128 Datasheet

Commonly Used in:

• Medical Monitoring: Used extensively in ECG and EEG equipment for multi-lead signal amplification.
• Multi-Channel Sensor Interfaces: Provides high-accuracy amplification for multiple pressure or strain sensors simultaneously.
• Industrial PLC Modules: Standardizes low-level analog signals for 4-20mA or 0-10V control loops.

Applications:

• Bridge Amplifiers: Ideal for weighing scales and load cell transmitters requiring high precision.
• Thermocouple Amplification: Measures tiny voltage differences while rejecting large common-mode noise.
• Differential Voltage Measurement: Safely monitors signals in environments with significant ground potential differences.

Equivalent Models:

• AD620 (Analog Devices): A single-channel equivalent; however, two units are required to match the INA2128’s density.
• INA128: The single-amplifier version of this IC, sharing the same precision and architecture.
• INA2129: A similar dual-channel variant optimized for slightly different gain ranges or bandwidth needs.

Package Includes:

• 1 x INA2128 Dual Low-Power Instrumentation Amplifier IC