Texas Instruments TXS03121DRLR

Overview

TXS03121DRLR from Texas Instruments is a precision comparator with integrated output FET for voltage-level translation in battery monitoring systems. It operates from 2.5 V to 5.5 V supply, supports 1.1 V–3.6 V output source voltage (VS), delivers ≤8 µA supply current, and features 10 mV max input offset voltage. Its SOT-563 (DRL) package enables compact placement in portable power management circuits.

For engineers reviewing the TXS03121DRLR datasheet, TXS03121DRLR pinout, TXS03121DRLR application, or TXS03121DRLR equivalent, key selection criteria include its output FET-based level translation capability, low quiescent current, strict V+ ≥ VS ≥ VD voltage hierarchy, and operation across –40°C to 85°C industrial temperature range.

Technical Context

The TXS03121DRLR implements a rail-to-rail input comparator core driving an internal N-channel MOSFET output stage. Its +IN/–IN inputs accept common-mode voltages up to V+, enabling direct sensing of battery cell voltages relative to a stable reference.

The output FET's source (S) terminal is externally biased between 1.1 V and 3.6 V, allowing logic-level translation of the comparator decision to a lower-voltage domain-e.g., converting a 5-V monitored signal into a 1.8-V compatible enable flag-without external level-shifting circuitry.

Key Specifications

Pinout & Package

SOT-563 (DRL) package: 1.6 mm × 1.6 mm × 0.6 mm, 6-pin plastic small-outline, moisture sensitivity level 1, RoHS-compliant, NIPDAUAG lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar comparator-with-level-translation applications.

Compared with TLV3011DBVR and MAX9021AUT+T, the TXS03121DRLR uniquely combines user-defined output translation range (1.1 V–3.6 V), ultra-low supply current, and hardware-enforced voltage hierarchy-making it optimal for space-constrained, multi-rail battery monitoring where flexibility and integration reduce component count and leakage paths.

Availability

TXS03121DRLR is available at Aetrix Electronics and suitable for battery monitoring, portable medical devices, and industrial sensor node applications requiring stable component supply, long-lifecycle availability, and guaranteed RoHS compliance.

Supply support for TXS03121DRLR 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 focused on analog, embedded processing, and connectivity technologies, serving industrial, automotive, and consumer markets with high-reliability silicon solutions.

The TXS03121DRLR belongs to TI's precision analog comparators product line, designed specifically for low-power, level-translating voltage supervision in battery-powered systems where integration, accuracy, and quiescent current are critical.

FAQ

What is the function of the S (source) pin on the TXS03121DRLR?

The S pin on the TXS03121DRLR serves as the bias reference for the internal output FET's source terminal and defines the translated output logic high level. It must be externally connected to a stable voltage between 1.1 V and 3.6 V, and must satisfy V+ ≥ VS ≥ VD. This architecture enables the TXS03121DRLR to deliver a level-translated open-drain output without external components, making it ideal for interfacing disparate voltage domains in battery monitoring systems.

Can the TXS03121DRLR operate with a 1.2-V reference on the –IN pin while powered from 3.3 V on V+?

Yes, the TXS03121DRLR supports common-mode input voltages down to 0.8 V and up to V+, so a 1.2-V reference on –IN is fully valid when V+ = 3.3 V. The input leakage current remains ≤0.5 µA across this range, ensuring minimal error contribution to the reference network. This capability allows precise low-threshold battery monitoring-for example, detecting Li-ion cell discharge below 3.0 V-while maintaining compatibility with standard voltage references.

What is the maximum continuous output current supported by the TXS03121DRLR's internal FET?

The TXS03121DRLR's internal output FET supports a continuous on-state switch current of ±50 mA, as specified in its absolute maximum ratings. However, practical current delivery depends on VS and rON: at VS = 3.0 V, rON is typically 44 Ω, limiting sustained current to ~68 mA before significant voltage drop occurs. For robust operation, TI recommends keeping load currents below 10 mA to maintain <0.5-V output drop and ensure timing specifications remain valid.

Does the TXS03121DRLR require external pull-up resistors on its D (drain) pin?

Yes, the D pin of the TXS03121DRLR is an open-drain output and requires an external pull-up resistor to establish a defined logic high state when the internal FET is off. The pull-up should connect to VS (not V+) to preserve level translation integrity. Typical values range from 10 kΩ to 100 kΩ depending on speed and power requirements; lower values improve rise time but increase static current when the FET is active.

How does the TXS03121DRLR handle overvoltage on its +IN and –IN pins?

The TXS03121DRLR includes input clamp diodes rated for ±50 mA clamp current, allowing safe operation with input voltages up to 6.5 V (absolute maximum) when clamped. As long as the clamp current limit is not exceeded-and external series resistance limits peak current-the device tolerates brief overvoltage transients beyond the 2.5 V–5.5 V supply range. This protects against battery insertion spikes or probe contact bounce in field-deployed monitoring systems using the TXS03121DRLR.