Overview
The INA121U/2K5G4, produced by Texas Instruments, is a FET-input, low power instrumentation amplifier known for its excellent accuracy and versatility. This amplifier features a three-op amp design, making it suitable for a wide range of general-purpose applications. It operates with very low quiescent current of ±450µA and can function on power supplies as low as ±2.25V (+4.5V), making it ideal for battery-operated and single 5V systems. The INA121U/2K5G4 is available in 8-pin plastic DIP and SO-8 surface mount packages, both specified for the –40°C to +85°C industrial temperature range.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Input Offset Voltage | ±200µV | - |
| Input Offset Drift | ±2µV/°C | - |
| Input Noise | 20nV/√Hz at f = 1kHz (G = 100) | - |
| Common-Mode Rejection Ratio (CMRR) | 106dB at G = 100 | - |
| Supply Voltage Range | ±2.25V to ±18V | V |
| Quiescent Current | ±450µA | A |
| Temperature Range | –40°C to +85°C | °C |
| Bandwidth, –3dB | G = 1: 600kHz, G = 10: 300kHz, G = 100: 50kHz, G = 1000: 5kHz | kHz |
| Slew Rate | 0.7 V/µs (VO = ±10V, G ≤ 10) | V/µs |
| Settling Time, 0.01% | G = 1 to 10: 20µs, G = 100: 35µs, G = 1000: 260µs | µs |
| Overload Recovery | 50% Input Overload: 5µs | µs |
| Thermal Resistance, θJA | 8-Lead DIP: 100°C/W, SO-8 Surface Mount: 150°C/W | °C/W |
Key Features
- Low input offset voltage (±200µV) and low input offset drift (±2µV/°C)
- High common-mode rejection ratio (CMRR) of 106dB at G = 100
- Low quiescent current of ±450µA
- Wide supply voltage range from ±2.25V to ±18V
- Internal input protection up to ±40V without damage
- Gain can be set from 1 to 10,000 with a single external resistor
- Low bias current (±4pA) suitable for high impedance sources
- Available in 8-pin plastic DIP and SO-8 surface mount packages
Applications
- Low-level transducer amplifiers (Bridge, RTD, Thermocouple)
- Physiological amplifiers (ECG, EEG, EMG, Respiratory)
- High impedance transducers
- Capacitive sensors
- Multi-channel data acquisition systems
- Portable, battery-operated systems
- General purpose instrumentation
Q & A
- What is the input offset voltage of the INA121U/2K5G4?
The input offset voltage is ±200µV.
- What is the common-mode rejection ratio (CMRR) of the INA121U/2K5G4 at a gain of 100?
The CMRR is 106dB at G = 100.
- What is the quiescent current of the INA121U/2K5G4?
The quiescent current is ±450µA.
- What is the supply voltage range for the INA121U/2K5G4?
The supply voltage range is from ±2.25V to ±18V.
- How is the gain of the INA121U/2K5G4 set?
The gain can be set from 1 to 10,000 with a single external resistor connected between pins 1 and 8.
- What is the input protection capability of the INA121U/2K5G4?
The internal input protection can withstand up to ±40V without damage.
- What are the package options for the INA121U/2K5G4?
The INA121U/2K5G4 is available in 8-pin plastic DIP and SO-8 surface mount packages.
- What is the temperature range for the INA121U/2K5G4?
The operating temperature range is –40°C to +85°C.
- What are some typical applications of the INA121U/2K5G4?
Typical applications include low-level transducer amplifiers, physiological amplifiers, high impedance transducers, capacitive sensors, multi-channel data acquisition systems, and portable, battery-operated systems.
- What is the slew rate of the INA121U/2K5G4?
The slew rate is 0.7 V/µs for output voltages up to ±10V and gains less than or equal to 10.
