UM1660S Low Power DC/DC Boost Converter

Overview

The Union UM1660S is a high-efficiency, compact boost converter designed to step up input voltages as low as 0.9V to regulated output levels up to 28V. It is ideal for applications such as white LED drivers, sensor biasing, and portable electronics. In comparison, Texas Instruments’ TPS61040DBVR is a widely adopted 28V boost converter with similar application scope. However, UM1660S offers significant advantages in terms of start-up voltage, current capability, efficiency, and BOM optimization, making it highly competitive in performance-critical and cost-sensitive markets.

Start-up and Input Voltage Range

Union’s UM1660S supports a wide input voltage range from 0.9V to 10V, which allows it to operate directly from single-cell NiMH, alkaline, or Li-ion batteries. The low start-up voltage of 0.9V is particularly advantageous for battery-operated systems where maintaining functionality under depleted power conditions is crucial.

In contrast, the TPS61040 requires a minimum start-up voltage of 1.8V, which limits its usability in ultra-low-voltage designs or applications with slowly declining battery curves. Thus, UM1660S provides greater flexibility for energy-harvesting and low-voltage portable systems.

Output Current Capability and Efficiency

The UM1660S can deliver up to 28V output at 120 mA, with high conversion efficiency across a wide load range—typically up to 85–90% at moderate load conditions. Its optimized internal switch and control loop allow for high-efficiency operation with minimal external components.

The TPS61040 also supports up to 28V output, but its peak switch current is limited to 250 mA, and its load current capability is generally lower in comparison for higher output voltages. Union’s UM1660S offers better high-voltage drive strength with more output current headroom, especially important in applications such as LED backlighting or bias voltage generation.

Switching Frequency and Passive Component Size

The UM1660S operates at a switching frequency of 1.2 MHz, enabling the use of small external inductors and capacitors, which helps reduce overall BOM size and cost. This high frequency also facilitates faster transient response and tighter voltage regulation.

The TPS61040 switches at 600 kHz, requiring larger inductors and capacitors for stable operation at similar output conditions. This not only increases PCB footprint, but may also limit performance in fast-transient or space-constrained designs. Therefore, UM1660S provides better component flexibility and smaller overall solution size.

Shutdown Current and Thermal Characteristics

Union’s UM1660S features ultra-low shutdown current (<1 µA), which is essential for extending battery life in power-down modes of portable systems. It also integrates over-temperature and over-voltage protection to ensure reliable operation under extreme conditions.

While the TPS61040 also provides similar protections, its shutdown current is typically higher (~0.5–1 µA), and thermal performance may be more constrained under heavy loads due to lower switching frequency and drive capability. UM1660S offers a better power-performance balance in compact, thermally challenging environments.

Packaging and Footprint

The UM1660S is available in an SOT-23-5 package, ensuring full compatibility with standard layouts and automated assembly. This package is identical to that of the TPS61040DBVR, making UM1660S a direct pin-to-pin alternative for easy design replacement or cost-down engineering efforts.

Additionally, Union provides strong local support and flexible lead times, helping customers manage sourcing risks and production schedules more effectively.

Conclusion

Union’s UM1660S boost converter presents a robust and efficient solution that compares favorably to Texas Instruments’ TPS61040DBVR across several critical parameters:

• Lower start-up voltage (0.9V vs. 1.8V)

• Higher output current capability at high output voltages

• Smaller passive components enabled by 1.2 MHz switching

• Ultra-low shutdown current for longer battery life

• Fully pin-compatible in SOT-23-5 package

For applications requiring compact size, low input operation, and high-efficiency boost performance, the UM1660S is a superior choice, offering both performance and cost advantages in today’s competitive power management landscape.