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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LDLN025PU29R

Name: LDLN025PU29R
Brand: STMicroelectronics
SKU: LDLN025PU29R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LDLN025PU29R

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 4-XDFN Exposed Pad

Datasheet:: LDLN025PU29R.pdf

Description:: IC REG LINEAR 2.9V 250MA 4DFN

Quantity:: RFQ Add To RFQ list

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Product details

Overview

LDLN025PU29R from STMicroelectronics is a 250 mA ultra-low-noise low-dropout (LDO) voltage regulator with 2.9 V fixed output, operating from 1.5 V to 5.5 V input. It delivers 6.5 µV_RMS output noise, 80 dB PSRR at 100 Hz, and 250 mV dropout at full load in DFN4-1x1 package-designed for powering noise-sensitive RF modules and image sensors in mobile devices.

For engineers reviewing the LDLN025PU29R datasheet, LDLN025PU29R pinout, LDLN025PU29R application, or LDLN025PU29R equivalent, this LDO offers verified performance in battery-powered instrumentation, VCO biasing, ADC reference supplies, and high-PSRR post-regulation where quiescent current below 12 µA and output discharge capability are critical selection criteria.

Technical Context

The LDLN025PU29R uses a bandgap-referenced error amplifier and PMOS pass transistor to maintain tight output regulation across line, load, and temperature (±2% accuracy). Its controlled quiescent current architecture sustains sub-25 µA I_Q even in dropout, extending runtime in deep-sleep states.

Internal soft-start limits inrush current; logic-controlled EN pin enables shutdown with <1 µA total current; output discharge path (230 Ω) actively pulls VOUT to GND when disabled. Thermal and short-circuit protections operate autonomously without external components.

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	Fixed 2.9 V ±2% over -40 °C to +125 °C, 1 mA–250 mA load, and 1.5 V–5.5 V input
Dropout voltage	250 mV at 250 mA (DFN4-1x1), enabling operation down to VIN = 3.15 V while sustaining regulated 2.9 V
Output noise	6.5 µV_RMS (10 Hz–100 kHz, 250 mA load), suitable for VCOs and high-resolution ADCs
PSRR	80 dB @ 100 Hz, 60 dB @ 100 kHz-rejects switching noise from upstream DC/DC converters
Quiescent current	12 µA at no-load; remains ≤425 µA at 250 mA and full temperature range
Enable threshold	V_IH = 1.2 V, V_IL = 0.4 V-compatible with 1.8 V and 3.3 V logic systems
Thermal protection	Activates at 160 °C junction temperature with 20 °C hysteresis for reliable fault recovery

Pinout & Package

LDLN025PU29R is packaged in DFN4-1x1 (1.0 mm × 1.0 mm × 0.38 mm), featuring an exposed thermal pad that must be soldered to PCB GND for optimal thermal performance (R_thJA = 220 °C/W).

Pin/Terminal	Circuit Role	Design Meaning
VIN	Input supply connection	Accepts 1.5–5.5 V; requires ≥0.7 µF ceramic input capacitor close to pin
VOUT	Regulated output	Delivers stable 2.9 V; supports 0.7–10 µF ceramic output capacitor with ESR 5–500 mΩ
GND	Power ground reference	Common return for VIN, VOUT, EN, and exposed pad; must be low-impedance plane
EN	Logic-enable control input	Pulled down internally (1 MΩ); drives high (>1.2 V) to enable, low (<0.4 V) to shut down
NC	No-connect terminal	Not internally connected; may be tied to GND for mechanical stability or left floating

Key Features

Feature	Design Value
Ultra-low noise regulation	6.5 µV_RMS output noise enables clean power for RF synthesizers and precision analog front-ends
Controlled dropout I_Q	Quiescent current stays ≤425 µA at 250 mA load and full temperature range-no efficiency collapse in dropout
Output discharge	230 Ω internal FET discharges VOUT to GND within microseconds after EN deactivation-prevents floating bias
Stability with ceramics	Guaranteed stable with 0.7–10 µF X7R/X5R ceramic capacitors-eliminates need for tantalum or electrolytic
Logic-compatible enable	V_IH/V_IL thresholds support direct interfacing with 1.8 V, 2.5 V, and 3.3 V microcontrollers

Applications

Smartphone RF Front-End

High-Speed Image Sensor Bias

Use Scenario: Powering VCO and PLL circuitry in LTE/Wi-Fi transceivers where supply ripple induces phase noise.

IC Role / Device Role / Timing Role: Ultra-low-noise post-regulator supplying clean 2.9 V bias to VCO core and fractional-N synthesizer.

Use Value: 6.5 µV_RMS noise and 80 dB PSRR at 100 Hz reduce integrated phase jitter by >30% versus standard LDOs.

Use Scenario: Providing analog supply to CMOS image sensor pixel arrays during high-frame-rate capture.

IC Role / Device Role / Timing Role: Low-noise, fast-transient LDO delivering stable 2.9 V to sensor analog rail with <40 mV load-step deviation.

Use Value: 10 µs load transient response and 250 mV dropout allow operation from shared 3.3 V DC/DC rail without headroom penalty.

Portable Instrumentation ADC Reference

IoT Wireless Node Subsystem

Use Scenario: Supplying reference voltage circuitry for 16-bit SAR ADCs in handheld multimeters and data loggers.

IC Role / Device Role / Timing Role: Precision LDO generating quiet 2.9 V reference rail decoupled from noisy digital subsystems.

Use Value: ±2% output accuracy over temperature and 0.007 %/mA load regulation ensure <0.5 LSB gain error across operating range.

Use Scenario: Powering BLE/Wi-Fi SoC RF and sensor interface blocks in battery-operated edge nodes.

IC Role / Device Role / Timing Role: Enable-controlled LDO providing 2.9 V to RF section only during active transmit/receive bursts.

Use Value: 12 µA no-load I_Q and <1 µA shutdown current extend 10-year coin-cell lifetime in periodic wake-up applications.

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-noise LDO applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6210B292MR-G	2.9 V fixed, 200 mA, 12 µV_RMS noise, no output discharge, SOT-25 package	Lacks output discharge and thermal shutdown; lower PSRR (70 dB @ 100 Hz)	Choose if board space allows SOT-25 and discharge function is unnecessary
Analog Devices ADM7172ACPZ-2.9-R7	2.9 V fixed, 2 A, 3.2 µV_RMS, 120 dB PSRR @ 100 Hz, 10-lead LFCSP	Higher cost, larger footprint, over-specified current capacity for 250 mA use cases	Choose only if >1 A output or sub-4 µV_RMS noise is required; not drop-in compatible

Compared with XC6210B292MR-G, LDLN025PU29R adds output discharge and superior thermal protection; versus ADM7172ACPZ-2.9-R7, it delivers optimized size, cost, and quiescent current for portable 250 mA loads without over-engineering.

Availability

LDLN025PU29R is available at Aetrix Electronics and suitable for smartphone RF modules, image sensor bias rails, portable instrumentation ADC references, and IoT wireless node subsystems requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LDLN025PU29R 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in power management, analog, MEMS, and microcontrollers for automotive, industrial, and consumer markets.

The LDLN025 series belongs to ST's ultra-low-noise LDO product line, engineered specifically for noise-critical analog and RF subsystems in battery-constrained portable electronics where PSRR, dropout, and standby current are co-optimized.

FAQ

What is the minimum input voltage required for LDLN025PU29R to maintain regulation at 250 mA?

The minimum input voltage is calculated as V_OUT + V_DROP = 2.9 V + 0.25 V = 3.15 V under worst-case conditions (DFN4-1x1 package, -40 °C to +125 °C). At room temperature, typical dropout is 120 mV, allowing regulation down to 3.02 V. Input must remain ≥1.5 V per absolute rating, but regulation ceases below 3.15 V at full load.

Can LDLN025PU29R be used with a 1 µF ceramic output capacitor?

Yes-1 µF X7R/X5R ceramic is explicitly validated in the datasheet (Table 5) and falls within the stable region shown in Figure 19. The device requires no ESR tuning and remains stable with ESR as low as 5 mΩ. A 1 µF capacitor meets both minimum (0.7 µF) and recommended (1 µF) values for optimal transient response and noise filtering.

Does the NC pin on LDLN025PU29R require PCB connection?

No-the NC pin is not internally connected and has no electrical function. Per Table 1 and Figure 2, it may be left unconnected or tied to GND for mechanical reinforcement or thermal relief; neither choice affects regulation, noise, or enable behavior. Do not route signals or supply lines to this pin.

How does the output discharge feature operate during shutdown?

When EN is pulled low (<0.4 V), an internal 230 Ω NMOS switch connects VOUT to GND, discharging external output capacitance. This occurs within microseconds (Figure 29), preventing residual voltage from interfering with downstream logic sequencing or causing latch-up in powered-down sections of the system.

LDLN025PU29R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 4-XDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 2.9V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.25V @ 250mA

Current - Output:: 250mA

Current - Quiescent (Iq):: 25 µA

Current - Supply (Max):: 425 µA

PSRR:: 80dB ~ 60dB (100Hz ~ 100KHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature, Short Circuit, Soft Start

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 4-DFN (1x1)

LDLN025PU29R FAQ

1.How can I place an order for LDLN025PU29R through Aetrix?

Please submit a Request for Quotation (RFQ) for LDLN025PU29R on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LDLN025PU29R reliable?

The price and inventory of LDLN025PU29R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDLN025PU29R is usually 5 days.

3.What payment methods are accepted for LDLN025PU29R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDLN025PU29R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LDLN025PU29R?

LDLN025PU29R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LDLN025PU29R order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LDLN025PU29R?

For technical support, including LDLN025PU29R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDLN025PU29R requirements.

6.How does Aetrix verify that LDLN025PU29R is sourced from the original manufacturer or authorized distributors?

All LDLN025PU29R products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LDLN025PU29R meets industry standards.

7.What is the process for return or replacement of LDLN025PU29R?

All LDLN025PU29R units undergo pre-shipment inspection (PSI). If there is an issue with LDLN025PU29R, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LDLN025PU29R part is unused and in its original packaging.

Return procedure for LDLN025PU29R:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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