Texas Instruments INA281A5IDBVR

Overview

INA281A5IDBVR from Texas Instruments is a high-precision, unidirectional current-sense amplifier with 500 V/V fixed gain, −4 V to +110 V common-mode input range, 1.3 MHz bandwidth, ±0.5% max gain error, and ±15 µV max input offset voltage (−40 °C to +125 °C). It enables accurate low-side and high-side shunt-based current monitoring in telecom power supplies and 48-V server rails.

For engineers reviewing the INA281A5IDBVR datasheet, INA281A5IDBVR pinout, INA281A5IDBVR application, or INA281A5IDBVR equivalent, this device delivers verified high-speed overcurrent detection (<2 µs response on 75-A/2-mΩ shunt), rail-to-rail output swing capability, and stable operation across −40 °C to +125 °C - critical for industrial PSU and RRU protection circuits.

Technical Context

The INA281A5IDBVR uses a transconductance architecture with current-feedback amplifier topology, enabling 20 µA typical input bias current at 110 V common-mode voltage and supporting both low- and high-side sensing without supply-voltage dependency on V_CM. Its zero-drift input stage ensures ±0.1 µV/°C offset drift and maintains <0.01% nonlinearity error.

It operates from a single 2.7 V to 20 V supply, draws 1.5 mA quiescent current, and delivers 2.5 V/µs slew rate with 900 kHz small-signal bandwidth (at V_SENSE = 8 mV). The device is unidirectional only and requires ≥16 µV differential input to remain in linear output region (GND + 20 mV zero-current output).

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package, 2.90 mm × 1.60 mm body size, surface-mount, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA281A5IDBVR, INA240A5IDR trades bandwidth and V_CM headroom for cost, while MAX40056ASA+T offers similar speed but lacks −4 V capability and has 10× higher offset - making INA281A5IDBVR optimal for wide-rail, precision, high-speed telecom current sensing.

Availability

INA281A5IDBVR is available at Aetrix Electronics and suitable for 48-V rack server power monitoring, macro remote radio unit (RRU) protection, and telecom equipment power supply applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for INA281A5IDBVR 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 company specializing in analog and embedded processing technologies, with leadership in precision signal chain and power management ICs.

The INA281 family is designed for high-accuracy, high-bandwidth current sensing in telecom infrastructure, server PSUs, and industrial power systems - emphasizing wide V_CM, low drift, and fast fault response.

FAQ

What is the maximum common-mode voltage the INA281A5IDBVR can withstand during normal operation?

The INA281A5IDBVR operates reliably with a common-mode input voltage range of −4 V to +110 V under recommended conditions. This allows it to sense current on high-side 48-V rails or below-ground recirculating paths in half-bridge motor drives. Its survival rating extends to −20 V to +120 V, but continuous operation outside −4 V to +110 V is not specified. The INA281A5IDBVR achieves this without requiring the supply voltage (Vs) to track V_CM, unlike many competing amplifiers.

Does the INA281A5IDBVR support bidirectional current sensing?

No, the INA281A5IDBVR is strictly unidirectional. It measures current flowing from power source to load only - not reverse or regenerative current. Its functional block diagram and electrical specifications confirm single-quadrant operation. For bidirectional applications, TI recommends the INA229 or INA240 families. The INA281A5IDBVR's negative V_CM capability (down to −4 V) supports recirculating current *measurement* in half-bridge topologies, but only when the current direction remains consistent with its input polarity convention.

What is the minimum differential input voltage required for linear operation of the INA281A5IDBVR?

The INA281A5IDBVR requires a minimum differential input voltage of ≥16 µV to maintain linear output behavior, derived from its maximum zero-current output voltage of GND + 20 mV and 500 V/V gain (20 mV ÷ 500 = 40 µV theoretical; derated to 16 µV per design margin). Below this, output compression occurs. This enables accurate sensing down to ~16 mA on a 1-mΩ shunt. The INA281A5IDBVR's ±15 µV max offset ensures usable dynamic range even at microamp-level differentials when paired with appropriate filtering.

Can the INA281A5IDBVR drive a 10-kΩ load across its full temperature range?

Yes, the INA281A5IDBVR is fully specified to drive a 10-kΩ load from −40 °C to +125 °C, with guaranteed output swing of GND + 5 mV to Vs − 150 mV under those conditions. Its output stage is optimized for low-impedance buffering into ADC inputs or comparator thresholds. Driving capacitive loads >500 pF may cause instability; a series resistor (≤10 Ω) is recommended if routing to long traces or high-C nodes. The INA281A5IDBVR's 2.5 V/µs slew rate ensures clean settling into such loads.

How does the INA281A5IDBVR's 500 V/V gain affect its usable V_SENSE range?

With 500 V/V gain, the INA281A5IDBVR scales input differential voltage by 500×, limiting its maximum usable V_SENSE to 8 mV (for 4-V output with 5-V supply) to avoid clipping. This makes it ideal for ultra-low-loss shunts (e.g., 1–2 mΩ) in high-current applications like 100-A server rails. At 8 mV V_SENSE, bandwidth remains 900 kHz - higher than lower-gain variants at same V_SENSE. The INA281A5IDBVR's ±15 µV offset contributes just 0.003% error at 8-mV full scale, preserving resolution.