Texas Instruments LP5907MFX-1.5/NOPB

LP5907MFX-1.5/NOPB Product Summary

The LP5907MFX-1.5/NOPB from Texas Instruments is a high-performance, ultra-low-noise, low-quiescent-current low dropout (LDO) regulator in a compact SOT-23-5 package. It delivers a fixed 1.5V output at up to 250mA load, optimized for both noise-sensitive analog and RF circuit applications. With a focus on small footprint and minimal external components, the LP5907MFX-1.5/NOPB is suitable for a wide range of portable and space-constrained designs. It is especially well-matched to supply rails for systems such as smartphones, tablets, digital still cameras, communications equipment, and factory automation.

Main Attributes and Performance Metrics of the LP5907MFX-1.5/NOPB

The LP5907MFX-1.5/NOPB’s architecture addresses the core requirements of modern, sensitive analog and RF designs. It supports an input voltage range of 2.2V to 5.5V, making it compatible with typical Li-ion batteries and low-voltage rails. The output is factory-set at 1.5V and is tightly regulated with a typical tolerance of ±2%, ensuring high supply voltage accuracy for demanding loads.

A standout aspect is its ultra-low output voltage noise, measuring less than 6.5μVRMS, and excellent Power Supply Rejection Ratio (PSRR) of 82dB at 1kHz. These metrics make it a prime choice for noise-sensitive analog, sensor, and wireless/RF domains. The device also features a remarkable low quiescent current (I_Q) of 12μA (enabled), supporting extended battery life in portable applications.

Key circuit protection features include thermal-overload and short-circuit protection. The device operates reliably across a junction temperature range of –40°C to +125°C, further increasing its utility in industrial and extended-temperature designs.

Electrical Characteristics of the LP5907MFX-1.5/NOPB

For robust power supply planning, the LP5907MFX-1.5/NOPB specifies:

Maximum output current: 250mA

Dropout voltage: 120mV (typical) at 250mA load

Input and output capacitance: Stable with 1μF (ceramic) each

Output voltage accuracy: ±2%

Enable threshold: Defined to ensure precise turn-on/off control

No-load regulation: Maintaining stability even with zero external load

ESD rating: Robust for standard manufacturing conditions (per JEDEC JEP155 and JEP157)

Internal discharge feature: 230Ω (typical) resistor ensures fast output discharge when disabled

Engineers should note that the LP5907MFX-1.5/NOPB maintains regulation without external load, and is designed to start regulating once VIN exceeds the higher value of 2.2V or (VOUT + VDO).

Pinout Diagram and Functional Details of the LP5907MFX-1.5/NOPB

Housed in the industry-standard 5-pin SOT-23 package, the LP5907MFX-1.5/NOPB offers straightforward implementation. The primary pins are:

IN: Input voltage

GND: Ground connection

EN: Enable input (logic-level enable/disable control, internally pulled down with 1MΩ resistor)

OUT: Output voltage

NC (if present): No connection

The enable (EN) function allows for flexible power sequencing or shutdown control. When disabled, an internal pulldown ensures output discharge, preventing residual voltage at the output and supporting safe, predictable system states.

The reference voltage generation is followed by a low-pass RC filter (~0.1Hz –3dB frequency point) for minimal output noise. The device requires at least a 1μF capacitor at the output, which can be placed up to 10cm away—ideal for distributed or remote power architectures.

Recommended External Circuitry and PCB Design Guidelines for the LP5907MFX-1.5/NOPB

Correct external capacitor selection and layout are central to achieving the LP5907MFX-1.5/NOPB’s specified noise performance and stability. Both input and output capacitors must be at least 1μF ceramic (X7R type recommended for stability over temperature). The input capacitor should be placed within 1cm of the IC, and the grounding for both should be via short, wide traces directly to the device’s ground pin.

A unique advantage of the LP5907MFX-1.5/NOPB is tolerant output capacitor placement—up to 10cm away—allowing designers flexibility in modular or physically distributed systems. For best dynamic performance, avoid narrow traces and minimize parasitic inductance and resistance in all critical paths.

The device remains stable with no external load, and its enable pin can be directly tied to the input when shutdown is not required.

Usage Recommendations for the LP5907MFX-1.5/NOPB

The LP5907MFX-1.5/NOPB excels as a supply for analog, RF, or sensor rails in portable and industrial systems. Example applications include noise-sensitive VCOs, PLL supplies, ADC/DAC references, and blocks within wireless modules. Its high PSRR extends its suitability to post-switcher filtering, cleaning up rails from noisy DC/DC sources.

Designers should carefully manage power dissipation, especially under continuous high current or elevated ambient conditions. Use the following thermal calculations for robust designs:

Maximum allowable dissipation: PDmax = (TJmax – TA) / θJA

Device power dissipation: PD = (VIN – VOUT) × IOUT

Mitigate thermal stress by optimizing input voltage (keeping it close to VOUT plus dropout) and, where necessary, derating maximum ambient temperature.

System-level considerations include ensuring a well-regulated, low-noise input supply and adopting best PCB layout practices to maximize transient, noise, and PSRR performance.

Packaging and Environmental Information for the LP5907MFX-1.5/NOPB

The SOT-23-5 package offers a combination of compact footprint (1.45mm max height) and ease of automated assembly that suits modern high-density boards. The device is RoHS and REACH compliant, with an MSL (Moisture Sensitivity Level) rating of 1 (unlimited), facilitating straightforward handling in standard assembly environments.

Texas Instruments provides detailed guidance for mounting and layout for all supported package variants, including DSBGA and X2SON, in addition to SOT-23-5, covering thermal pad requirements, solder stencil recommendations, and optimal land patterns.

Possible Alternative or Substitute Parts for the LP5907MFX-1.5/NOPB

For engineers seeking second-source options, pin-compatibility, or migration paths, several alternatives can be evaluated. Within Texas Instruments’ own portfolio, the TPS7A20 is recommended as an updated LDO with similar functional characteristics but improved parameters in certain operating regions.

For automotive-grade environments, the LP5907-Q1 variant offers qualified performance according to AEC-Q100. Other competing models might include LDOs of similar voltage, current rating, PSRR, and noise attributes from major analog IC vendors, but system validation is advised due to differences in enable logic, transient response, and output noise.

Conclusion

The Texas Instruments LP5907MFX-1.5/NOPB delivers a compelling blend of low-noise operation, high PSRR, low dropout, and energy-efficient performance in a widely adopted footprint. Its robust protection features, wide operating temperature range, and straightforward integration make it a top-tier LDO regulator for noise-critical applications in consumer, industrial, and communications designs. By following best design practice and considering both system-level needs and potential alternatives, engineers can confidently deploy the LP5907MFX-1.5/NOPB in new power rail implementation or system upgrades requiring superior analog/RF power quality.