Texas Instruments INA296B3IDDFR

Overview

INA296B3IDDFR from Texas Instruments is a bidirectional, ultra-precise current sense amplifier optimized for 48V high-voltage DC/DC converters and battery management systems. It operates over −5V to 110V common-mode voltage, delivers 50V/V fixed gain, 1.1MHz bandwidth, 8V/µs slew rate, and ±150µV max input offset voltage. Its SOT-23-8 package supports space-constrained high-side sensing in telecom and server power rails.

For engineers reviewing the INA296B3IDDFR datasheet, INA296B3IDDFR pinout, INA296B3IDDFR application, or INA296B3IDDFR equivalent, this page provides verified specifications, validated pin functions, confirmed use cases in 48V BMS and RRU, and two technically documented alternative parts with explicit functional and application-level differences.

Technical Context

The INA296B3IDDFR employs a zero-drift, high-common-mode topology enabling precise bidirectional current measurement independent of supply voltage (2.7V–20V). Its input bias current remains constant at 35µA (typ) across −20V to 120V survival range, eliminating CMV-dependent leakage errors in high-side shunt configurations.

It achieves 1% settling in 1µs with 1.1MHz small-signal bandwidth and 120dB min CMRR (INA296B grade), supporting fast overcurrent detection in transient-sensitive applications like macro remote radio units and rack-server PSU protection circuits.

Key Specifications

Pinout & Package

INA296B3IDDFR uses an 8-pin SOT-23 (DDF) package measuring 2.9mm × 2.8mm, optimized for high-density PCB layouts in telecom and server power modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA240A3IDR and MAX40056ATA+T, the INA296B3IDDFR uniquely combines 110V upper common-mode limit, 1.1MHz bandwidth, and bidirectional operation in SOT-23 - making it the only option for compact, high-speed 48V telecom power monitoring where negative voltage headroom and fast transient response are mandatory.

Availability

INA296B3IDDFR is available at Aetrix Electronics and suitable for 48V battery management systems, macro remote radio units, and 48V rack server power supplies requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for INA296B3IDDFR 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 delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The INA296x product line was designed specifically for high-accuracy, high-speed bidirectional current sensing in next-generation 48V power architectures - targeting telecom infrastructure, datacenter PSUs, and electric vehicle auxiliary systems.

FAQ

What is the maximum common-mode voltage the INA296B3IDDFR can withstand during normal operation?

The INA296B3IDDFR operates continuously over a common-mode input range of −5V to 110V. This allows direct high-side sensing on 48V buses without attenuation or level-shifting. Its survival rating extends to −20V to 120V, ensuring robustness against transient overvoltage events in real-world 48V systems. The INA296B3IDDFR maintains specified performance across this full operational range.

How does the INA296B3IDDFR achieve bidirectional current measurement?

The INA296B3IDDFR achieves bidirectional measurement by using its dual reference inputs (REF1 and REF2) to set the zero-current output voltage at their midpoint. When REF1 = VS and REF2 = GND, the output centers at VS/2 - positive current raises output above VS/2, negative current lowers it below. This architecture enables precise regenerative current detection in 48V BMS without external op-amps. The INA296B3IDDFR's internal design guarantees monotonic response across the full bidirectional range.

What is the purpose of the NC pin (Pin 4) on the INA296B3IDDFR DDF package?

Pin 4 on the INA296B3IDDFR is designated NC (No Connect) but must be externally tied to GND per the official datasheet. This connection stabilizes internal substrate bias and reduces susceptibility to EMI in high-noise 48V power environments. Leaving Pin 4 floating may cause output instability or increased offset drift, particularly during fast CMV transients. The INA296B3IDDFR's reliability in telecom RRU applications depends on correct NC pin grounding.

Can the INA296B3IDDFR be used with a 3.3V supply voltage?

Yes, the INA296B3IDDFR operates with supply voltages from 2.7V to 20V, including 3.3V. At VS = 3.3V, its output swings from ≥20mV above GND to ≤70mV below VS (i.e., up to 3.23V), maintaining full 50V/V gain functionality. This enables integration into 3.3V microcontroller-based monitoring systems while still sensing 48V bus currents - a key advantage over rail-to-rail output amplifiers limited by supply constraints. The INA296B3IDDFR's supply independence from VCM makes this possible.

What is the typical input bias current of the INA296B3IDDFR, and why is it important?

The INA296B3IDDFR has a typical input bias current of 35µA per input pin, and critically, this value remains constant across its entire −20V to 120V common-mode range. Unlike conventional current sense amplifiers, its bias current does not scale with VCM - eliminating gain error drift caused by shunt resistor self-heating or bus voltage fluctuations. This stability ensures consistent accuracy in 48V BMS and RRU applications where VCM varies dynamically. The INA296B3IDDFR's constant bias current is a defining specification for high-precision designs.