Texas Instruments INA849DGKT

Overview

INA849DGKT from Texas Instruments is an ultra-low-noise (1 nV/√Hz), high-bandwidth instrumentation amplifier optimized for precision signal conditioning in high-resolution data acquisition systems. It delivers 28 MHz bandwidth at G = 1, 35 V/µs slew rate, and 120 dB minimum CMRR at maximum gain - enabling direct interface with 16–24-bit ADCs in ECG, flow transmitters, and battery test equipment.

For engineers reviewing the INA849DGKT datasheet, INA849DGKT pinout, INA849DGKT application, or INA849DGKT equivalent, this page provides verified technical context, validated pin functions, confirmed package mapping to VSSOP-8, real-world application constraints, and two rigorously cross-checked alternative parts - all grounded in TI's SBOS945B production datasheet.

Technical Context

The INA849DGKT employs a current-feedback input stage with super-beta NPN transistors, delivering 20 nA max input bias current and 0.4 µV/°C max offset drift. Its four-resistor difference amplifier output stage uses laser-trimmed 5-kΩ internal resistors for 92-dB CMRR at G = 1 across full common-mode range.

Gain is set by a single external resistor (RG) between pins 2 and 3 per G = 1 + 6 kΩ/RG. The device operates from ±4 V to ±18 V dual supply or 8 V to 36 V single supply, with guaranteed performance from –40°C to +125°C and 0.4 µs settling time (0.01%) at G = 1–100.

Key Specifications

Pinout & Package

INA849DGKT is packaged in an 8-pin VSSOP (DGK) with body size 3.00 mm × 3.00 mm, optimized for space-constrained PCB layouts while maintaining thermal resistance of 168.7°C/W (junction-to-ambient).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar instrumentation amplifier applications.

Compared with INA821IDGKT and INA819IDGKT, the INA849DGKT uniquely balances ultra-low 1-nV/√Hz noise with 28-MHz bandwidth and 0.4-µs settling - making it irreplaceable in high-fidelity, high-speed medical and metrology applications where both noise and transient fidelity are simultaneously constrained.

Availability

INA849DGKT is available at Aetrix Electronics and suitable for ECG monitoring systems, industrial flow transmitters, battery electrochemical testers, and LCD panel characterization requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for INA849DGKT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal chain solutions.

The INA849DGKT belongs to TI's high-accuracy instrumentation amplifier product line, engineered specifically for applications demanding simultaneous ultra-low noise, wide bandwidth, and exceptional DC precision - such as medical diagnostics, scientific instrumentation, and industrial process control.

FAQ

What is the maximum gain achievable with INA849DGKT, and how is it set?

The INA849DGKT supports gains from 1 to 10,000, set by a single external resistor (RG) connected between pins 2 and 3 per the equation G = 1 + 6 kΩ/RG. For G = 10,000, RG = 0.6 Ω - requiring careful layout to minimize parasitic resistance. At G = 1000, the device maintains 1.25 MHz bandwidth and 0.4 µs settling time, as verified in TI's SBOS945B datasheet Section 7.5. This resistor-based gain flexibility makes INA849DGKT adaptable across multiple sensor signal ranges without redesigning the amplifier stage.

Does INA849DGKT support single-supply operation, and what is the minimum supply voltage?

Yes, INA849DGKT supports true single-supply operation from 8 V to 36 V, with guaranteed specifications over the full –40°C to +125°C range. At 8 V, the input common-mode range extends from 2.5 V above ground to 2.5 V below V+, enabling use with 10 V or 12 V rails in portable test equipment. The device's rail-to-rail output swing (within 150 mV of each rail) and REF pin functionality allow seamless interfacing with single-supply ADCs - a capability confirmed in TI's Application Report SBAA344.

How does the REF pin affect common-mode rejection in INA849DGKT?

The REF pin directly impacts INA849DGKT's DC CMRR: any series impedance >0.1 Ω at this pin degrades CMRR below 100 dB, as shown in Figure 9-2 of the SBOS945B datasheet. This occurs because REF connects to an internal 5-kΩ resistor in the output-stage difference amplifier; mismatch from external resistance unbalances the ratio-matched network. For optimal performance, drive REF with a low-impedance voltage reference (e.g., REF5025) or op-amp buffer - not a resistive divider - ensuring the INA849DGKT maintains its specified 120 dB minimum CMRR at maximum gain.

What thermal considerations apply to INA849DGKT in VSSOP-8 (DGK) packaging?

INA849DGKT in DGK package has a junction-to-ambient thermal resistance (RθJA) of 168.7°C/W, significantly higher than the SOIC-8 variant (119.6°C/W). At 6.6 mA quiescent current and ±15 V supply, power dissipation reaches ~200 mW - potentially raising junction temperature by >33°C above ambient in still air. To ensure reliability at +125°C ambient, use thermal vias under the exposed pad (if present), minimize copper isolation around the package, and avoid stacking heat-generating components nearby. TI's Thermal Metrics Report SPRA953 confirms these values for the DGK variant.

Can INA849DGKT drive ADC inputs directly, and what layout practices ensure stability?

Yes, INA849DGKT is explicitly characterized to drive high-resolution ADCs directly, with 0.4 µs settling time (0.01%) and stability into 200 pF capacitive loads. To preserve this performance: place 0.1-µF ceramic bypass capacitors within 2 mm of pins 5 (–VS) and 8 (+VS); route RG traces symmetrically with minimal stub length; keep REF trace short and low-impedance; and avoid routing noisy digital lines adjacent to –IN/+IN. These practices are validated in TI's Layout Example (Section 11.2, SBOS945B) and prevent gain error, CMRR loss, or oscillation in production-grade data acquisition boards.