Texas Instruments TPS61291DRVR

Overview

TPS61291 from Texas Instruments is a low-quiescent-current boost converter with integrated bypass switch, designed for battery-powered systems requiring dual-mode operation. It delivers 3.3V/200mA output from 1.8V input in boost mode and provides direct VIN-to-VOUT conduction with only 15nA quiescent current in bypass mode, enabling ultra-low-power MCU operation (e.g., MSP430) from single Li-MnO₂ or dual alkaline cells.

For engineers reviewing the TPS61291 datasheet, TPS61291 pinout, TPS61291 application, or TPS61291 equivalent, key selection criteria include startup voltage (1.5V), pin-selectable output (2.5V/3.0V/3.3V), bypass switch R_DS(ON) (1.2Ω), thermal shutdown (140°C), and 2mm × 2mm SON-6 package compatibility with space-constrained metering and remote control designs.

Technical Context

The TPS61291 implements a hysteretic current-mode controller with synchronous rectification for high efficiency across load ranges, supporting discontinuous conduction mode at light loads to maintain 5.7μA boost-mode I_Q. Its dual-path architecture separates regulation (boost mode) and direct conduction (bypass mode), with independent control logic for EN/BYP and latched VSEL configuration.

Bypass transition is actively controlled to prevent reverse current into the battery by delaying switch activation until V_OUT ≤ V_IN; overvoltage protection (5.4V) operates independently of the feedback divider and is active only in boost mode. Undervoltage lockout (0.9V threshold) disables boost operation but leaves bypass functionality intact.

Key Specifications

Pinout & Package

TPS61291 is housed in a thermally enhanced 2mm × 2mm × 0.75mm SON-6 package with exposed thermal pad (soldered to GND). The 6-pin layout supports compact PCB design and efficient heat dissipation in battery-operated applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boost-with-bypass applications.

Compared with TPS61292DRVR and MAX17222ETA+, the TPS61291 uniquely balances ultra-low 15nA bypass current, 3-output-voltage flexibility via VSEL, and 200mA boost capability in the smallest 2mm × 2mm footprint-making it the optimal choice for space-constrained, long-life battery applications demanding configurable regulation.

Availability

TPS61291 is available at Aetrix Electronics and suitable for gas/water smart meters, remote controls, home security sensors, industrial wireless transmitters, and battery-powered IoT edge nodes requiring stable component supply across multi-year production cycles.

Supply support for TPS61291 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 power management ICs for battery-operated and industrial applications.

The TPS61291 belongs to TI's ultra-low-power boost converter product line, engineered specifically for energy-harvesting and long-life battery systems where minimizing quiescent current and enabling seamless bypass-to-boost transitions are critical design requirements.

FAQ

What is the minimum input voltage required for TPS61291 to start up?

The TPS61291 requires a minimum input voltage of 1.5V at 20mA load to initiate startup. This allows reliable operation from partially discharged alkaline or lithium-manganese dioxide batteries. Once started, the device continues operating down to 0.9V input, enabling extended battery utilization before cutoff.

How does the TPS61291 prevent reverse current flow into the battery during bypass mode transition?

The TPS61291 integrates controlled bypass transition logic that delays activation of the internal P-channel MOSFET until the output voltage (V_OUT) drops to or below the input voltage (V_IN). This prevents stored charge in the output capacitor from flowing back into the battery, protecting cell chemistry and extending service life in applications like smart meters.

Can the output voltage of the TPS61291 be changed dynamically during operation?

No. The TPS61291 reads the VSEL pin state only during startup and latches the selected output voltage (2.5V, 3.0V, or 3.3V) internally. Changing VSEL after startup has no effect on regulation. For dynamic voltage scaling, an external DAC-controlled feedback resistor network would be required-but this is not supported by the TPS61291's architecture.

What is the maximum continuous output current the TPS61291 can deliver in boost mode?

The TPS61291 guarantees a minimum output current of 200mA at 3.3V V_OUT when supplied from 1.8V V_IN. Under optimal conditions (e.g., 2.5V input, 22μF C_OUT, 3.3μH inductor), peak output current reaches approximately 300mA before current-limit protection engages, as confirmed by efficiency curves and switch current limit specification (700–1300mA).

Is the exposed thermal pad on the TPS61291 DRVR package electrically connected?

No. The exposed thermal pad on the TPS61291DRVR SON-6 package is not electrically connected to any internal circuitry (NC). However, it must be soldered to the PCB's GND plane to achieve specified thermal performance (R_θJB = 46.7°C/W) and ensure reliable operation under sustained load conditions.