The TPSM82901SISR is a fully integrated synchronous buck converter module from Texas Instruments that packs a complete power conversion solution into a miniature 11-pin MicroSiP package measuring just 3.0 mm × 2.8 mm × 1.6 mm. By integrating the inductor, high-side and low-side MOSFETs, and control circuitry into a single module, this device eliminates the most challenging aspects of switching regulator design while delivering up to 1 A of continuous output current from an input voltage range of 3 V to 17 V. For engineers working on space-constrained designs in industrial, automotive, and portable electronics, the TPSM82901SISR offers a compelling combination of high efficiency, ultra-low quiescent current, and exceptional design flexibility.

Integrated Power Stage with MicroSiP Packaging

The defining characteristic of the TPSM82901SISR is its MicroSiP (Micro System-in-Package) construction, which incorporates a 1-µH shielded inductor alongside the switching regulator IC. This integration addresses several critical design challenges simultaneously. Traditional discrete buck converter designs require careful inductor selection, loop compensation, and layout optimization to achieve stable operation—tasks that consume significant engineering time and PCB area. The TPSM82901SISR eliminates these concerns by providing a pre-characterized, pre-compensated solution that requires only input and output capacitors to complete the design.

The 11-pin package features an optimized pinout that supports single-layer PCB routing, further simplifying layout for cost-sensitive applications. Despite its diminutive size, the module includes a thermal pad for effective heat dissipation, allowing operation over the full industrial temperature range of –40°C to 125°C.

Ultra-Low Quiescent Current and High Efficiency

For battery-powered and always-on applications, quiescent current directly impacts standby power consumption. The TPSM82901SISR achieves a typical quiescent current of just 4 µA in power save mode, extending battery life in systems that must maintain regulation during extended idle periods. This low IQ is complemented by an Automatic Efficiency Enhancement (AEE) feature that optimizes efficiency across the full input voltage, output voltage, and load current range by adjusting internal operating parameters dynamically.

The module's DCS-Control topology provides fast transient response while maintaining high output voltage accuracy of ±0.9% across temperature. The integrated MOSFETs exhibit low on-resistance—62 mΩ for the high-side device and 22 mΩ for the low-side device—minimizing conduction losses even at full load.

Flexible Configuration via MODE/S-CONF Pin

A single MODE/S-CONF pin provides access to multiple configuration options, allowing designers to tailor the module's behavior without external components. This pin can set the switching frequency to either 2.5 MHz or 1.0 MHz, select between forced PWM and auto PFM/PWM power save modes, enable or disable output discharge, and choose between internal and external feedback divider configurations. The ability to change these settings through pin strapping rather than fixed hardware means a single module can serve multiple design variants, reducing inventory complexity.

The TPSM82901SISR provides two distinct methods for setting the output voltage, each suited to different application requirements.

External Feedback Divider (VFB)

For maximum flexibility, the output voltage can be programmed using an external resistor divider connected to the FB pin. This approach supports any output voltage from 0.6 V to 5.5 V, limited only by the availability of appropriate resistor values. The external divider method is preferred when the design requires a non-standard output voltage or when the feedback network must be adjusted during prototyping.

Internal VSET Divider

When board space is at a premium and fixed output voltages are acceptable, the internal VSET divider offers 16 pre-programmed voltage options ranging from 0.4 V to 5.5 V. This eliminates two external resistors and their associated routing, saving approximately 4 mm² of PCB area per design. The VSET configuration is selected through the MODE/S-CONF pin during power-up, with the specific voltage determined by the pin strapping pattern.

Texas Instruments provides comprehensive development tools for the TPSM82901SISR. The WEBENCH Power Designer allows engineers to enter input voltage, output voltage, and load current requirements and receive a complete design including component selection, efficiency analysis, and thermal simulation. For rapid prototyping, the TPSM82901EVM evaluation module provides a fully assembled and tested platform that can be configured for various operating modes through jumper settings.

The device is also supported by the TPSM8290x application note, which details output voltage configuration at 1 MHz in auto PFM/PWM mode and provides design examples for common input and output combinations. This documentation is particularly valuable for engineers transitioning from 2.5 MHz to 1 MHz operation to improve light-load efficiency.

Industrial Sensor and Field Transmitter Power

Industrial field transmitters operating from 12-V or 24-V rails require a compact, efficient power solution that can withstand harsh environmental conditions. The TPSM82901SISR's wide input voltage range accommodates the significant voltage transients present on industrial power buses, while its 125°C maximum operating temperature ensures reliable operation in sealed enclosures. The 4-µA quiescent current is particularly valuable for loop-powered transmitters where the total available current is limited to 4 mA.

Portable Medical and Test Equipment

Battery-powered medical devices and handheld test instruments demand both high efficiency for extended runtime and low noise for sensitive analog measurements. The TPSM82901SISR's forced PWM mode provides constant-frequency operation that simplifies noise filtering, while the auto PFM/PWM mode maximizes battery life during idle periods. The integrated inductor's shielded construction minimizes radiated emissions that could couple into adjacent analog circuitry.

Distributed Power Architectures

In systems employing distributed power architectures, point-of-load regulators must be compact enough to place close to their loads while providing sufficient current for local processing or analog functions. The TPSM82901SISR's 3.0 × 2.8 mm footprint enables placement adjacent to FPGAs, DSPs, or sensor signal chains, minimizing distribution losses and improving transient response. The 100% duty cycle mode ensures regulation is maintained even when the input voltage approaches the output voltage, a common condition in battery-powered systems as the battery discharges.

When evaluating the TPSM82901SISR against alternative solutions, several factors merit consideration. Compared to discrete buck converters, the module eliminates inductor selection, loop compensation, and bootstrap capacitor design, reducing design time and board space at the cost of a slightly higher unit price. Compared to linear regulators, the switching topology provides dramatically higher efficiency at moderate to heavy loads, though careful attention to output ripple and EMI is required for noise-sensitive applications.

The TPSM82901SISR represents the 1-A member of the TPSM8290x family, which also includes 2-A and 3-A variants sharing the same package and pinout. This family compatibility allows designers to scale output current capability without PCB redesign, accommodating higher-power loads in future product revisions. For applications requiring higher current, the TPSM82902 or TPSM82903 provide drop-in replacements with appropriate thermal management.

The TPSM82901SISR demonstrates how integration can solve fundamental power design challenges. By combining the inductor, MOSFETs, and control loop into a single MicroSiP module, Texas Instruments has created a solution that reduces design complexity, shrinks PCB area, and accelerates time-to-market without compromising on efficiency or flexibility. Its 4-µA quiescent current, wide 3-V to 17-V input range, and ±0.9% output accuracy address the demanding requirements of industrial, medical, and portable applications. For engineers facing the perennial challenge of fitting more functionality into less space, the TPSM82901SISR offers a proven, well-supported path to a complete 1-A power supply in a remarkably small footprint.