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

STMicroelectronics LDK120C29R

Name: LDK120C29R
Brand: STMicroelectronics
SKU: LDK120C29R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LDK120C29R

Manufacturer:: STMicroelectronics

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

Package:: 5-TSSOP, SC-70-5, SOT-353

Datasheet:: LDK120C29R.pdf

Description:: IC REG LINEAR 2.9V200MA SOT323-5

Quantity:: RFQ Add To RFQ list

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Inventory:2,950

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Product details

Overview

LDK120C29R from STMicroelectronics is a 200 mA, 2.9 V fixed-output low-dropout (LDO) regulator in SOT323-5L package, featuring 100 mV typical dropout at 100 mA, ±2.0% output voltage tolerance at 25 °C, and 100 µA max quiescent current - optimized for battery-powered mobile phones and digital still cameras requiring ultra-low noise and logic-controlled shutdown.

For engineers reviewing the LDK120C29R datasheet, LDK120C29R pinout, LDK120C29R application, or LDK120C29R equivalent, this page delivers verified electrical specs, thermal performance data, ceramic-capacitor stability guidance, and real-world use cases for low-power portable systems with tight noise and standby-current constraints.

Technical Context

The LDK120C29R employs a PMOS pass transistor architecture enabling ultra-low dropout (100 mV typ. at 100 mA) and sub-1 µA shutdown current. Its internal bandgap reference and error amplifier deliver ±2.0% initial accuracy over temperature and load, with integrated thermal shutdown (160 °C) and short-circuit current limiting (400 mA).

Noise performance is enhanced via optional 10 nF bypass capacitor on the BYP pin, reducing output noise to 51 µV_RMS (10 Hz–100 kHz); without bypass, noise rises to 148 µV_RMS. Supply voltage rejection remains ≥55 dB from 120 Hz to 10 kHz under 100 mV ripple.

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	Fixed 2.9 V ±2.0% at 25 °C - ensures stable core/peripheral rail for 3.0 V nominal logic with margin for voltage drop.
Max output current	200 mA guaranteed - supports moderate-power RF modules or image sensors in compact handheld devices.
Dropout voltage	100 mV typ. at 100 mA - enables operation down to 3.0 V input for 2.9 V output, extending battery runtime in single-cell Li-ion systems.
Quiescent current	60 µA typ. (100 µA max) - minimizes no-load drain in always-on subsystems like RTC or sensor hubs.
Output noise	51 µV_RMS (10 Hz–100 kHz, with 10 nF BYP cap) - meets stringent analog/RF supply requirements for camera ISPs or audio codecs.
Enable threshold	V_IL ≤ 0.4 V, V_IH ≥ 1.2 V - compatible with 1.8 V/3.3 V GPIOs for precise power sequencing control.
Operating temp	−40 °C to +125 °C junction - qualified for automotive infotainment displays and industrial handheld terminals.

Pinout & Package

LDK120C29R is packaged in SOT323-5L (1.8 × 2.0 mm, 0.95 mm pitch), a space-constrained 5-pin surface-mount package suitable for high-density portable PCBs. Pin functions are validated per STMicroelectronics DS9378 Rev 9, Figure 2 and Table 1.

Pin/Terminal	Circuit Role	Design Meaning
1 (IN)	Input voltage supply	Accepts 1.9–5.5 V DC; requires 1 µF ceramic input capacitor for stability and transient response.
2 (GND)	Power ground reference	Common return path for IN, OUT, EN, and BYP; must be low-impedance connection to minimize noise coupling.
3 (EN)	Logic enable input	Active-high control: <0.4 V = shutdown (<1 µA I_Q), >1.2 V = regulation; supports direct MCU GPIO drive.
4 (BYP)	Bypass capacitor terminal	Optional 10 nF capacitor reduces output noise by ~65%; floating if unused - no routing or stubs permitted.
5 (OUT)	Regulated output	Delivers 2.9 V ±2.0% to load; stabilized with 1–22 µF ceramic output capacitor (ESR <1 Ω @ 100 kHz).

Key Features

Feature	Design Value
Ultra-low noise regulation	51 µV_RMS output noise with BYP cap - enables clean power for CMOS image sensors and precision ADCs.
Sub-µA shutdown mode	<1 µA total current consumption when EN = GND - preserves battery life during extended sleep states.
Ceramic capacitor compatibility	Stable with 1 µF C_OUT (min), eliminating need for costly tantalum or electrolytic capacitors.
Integrated protection	Thermal shutdown (160 °C) and constant-current short-circuit limit (400 mA) - prevents damage during fault conditions.
Wide input range	1.9–5.5 V operation - supports single-cell Li-ion (2.7–4.2 V), Li-polymer, and 3.3 V/5 V system rails.

Applications

Mobile Phone Power Rail

Digital Still Camera Sensor Supply

Use Scenario: Providing regulated 2.9 V to baseband processor I/O or display interface in slim smartphone designs.

IC Role / Device Role / Timing Role: Primary LDO for noise-sensitive digital subsystems requiring fast load transient response and low standby leakage.

Use Value: 100 µA max quiescent current extends standby time; 100 mV dropout enables full utilization of declining Li-ion cell voltage.

Use Scenario: Powering CMOS image sensor analog front-end and ISP core in compact digital cameras.

IC Role / Device Role / Timing Role: Low-noise post-regulator downstream of buck converter, decoupling switching noise from sensitive analog circuitry.

Use Value: 51 µV_RMS noise with BYP cap suppresses image fixed-pattern noise; −40 °C to +125 °C rating supports outdoor operation.

Personal Digital Assistant (PDA) Core Logic

Cordless Phone Baseband IC

Use Scenario: Delivering stable 2.9 V to ARM-based application processor and memory interface in legacy PDA platforms.

IC Role / Device Role / Timing Role: Fixed-output LDO with enable control for selective subsystem power gating during UI idle periods.

Use Value: Logic-compatible EN pin simplifies integration with existing power management firmware; ±2.0% accuracy maintains timing margin for DDR I/O.

Use Scenario: Supplying 2.9 V to DECT or Bluetooth baseband IC in cordless phone handsets with limited PCB area.

IC Role / Device Role / Timing Role: Compact, thermally robust LDO replacing larger regulators to meet strict thermal dissipation limits in plastic enclosures.

Use Value: SOT323-5L footprint saves >30% board space vs. SO-8; 237 °C/W R_thJA allows 200 mA continuous output without heatsink.

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6219B292MR-G	200 mA, 2.9 V fixed, 150 mV dropout (typ. at 100 mA), 12 µA I_Q, SOT23-5	Lower quiescent current but higher dropout - better for ultra-low-I_Q always-on nodes, worse for low-V_IN battery end-of-life.	Select for longest battery shelf life; verify thermal margin at 200 mA in SOT23-5 due to higher R_thJA.
ROHM BD3985FVM-2.9TR	300 mA, 2.9 V fixed, 120 mV dropout (typ. at 150 mA), 60 µA I_Q, VSON-6	Higher current rating and slightly larger package - suited for future-proofing or higher transient loads.	Choose when system may require >200 mA headroom; VSON-6 offers better thermal performance than SOT323-5L.

Compared with XC6219B292MR-G, LDK120C29R provides lower dropout for deeper battery discharge support; versus BD3985FVM-2.9TR, it offers smaller footprint and identical I_Q, making it optimal for space-constrained 200 mA applications.

Availability

LDK120C29R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, PDAs, and cordless phones requiring stable component supply across extended product lifecycles and seasonal demand spikes.

Supply support for LDK120C29R 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, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The LDK120 series targets ultra-low-power portable electronics, delivering high PSRR, low noise, and minimal quiescent current in miniature packages - specifically engineered for battery longevity and signal integrity in space-constrained devices.

FAQ

What is the minimum input voltage required for LDK120C29R to maintain regulation at 200 mA load?

The minimum input voltage is calculated as V_OUT + V_DROP = 2.9 V + 300 mV (max dropout at 200 mA, 40–125 °C) = 3.2 V. Below this, output voltage drops linearly with input; operation below 1.9 V violates absolute maximum rating and risks malfunction.

Can LDK120C29R be used with a 10 µF ceramic output capacitor?

Yes - the device is stable with 1–22 µF ceramic capacitors (ESR <1 Ω at 100 kHz). A 10 µF X5R/X7R MLCC meets both capacitance and ESR requirements and improves load transient response versus the 1 µF minimum, with no risk of oscillation.

Is the BYP pin mandatory for LDK120C29R operation?

No - the BYP pin is optional. When unused, it must be left floating with no PCB trace or pad connection. Adding a 10 nF capacitor reduces output noise from 148 µV_RMS to 51 µV_RMS; omitting it increases noise but does not affect regulation or stability.

Does LDK120C29R support reverse current blocking during shutdown?

No - the LDK120C29R lacks reverse current blocking. When EN = low and V_OUT > V_IN, current can flow from OUT to IN through the internal pass device body diode. External reverse-blocking MOSFET or diode is required in systems where backfeed must be prevented.

LDK120C29R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 5-TSSOP, SC-70-5, SOT-353

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):: 0.3V @ 200mA

Current - Output:: 200mA

Current - Quiescent (Iq):: 60 µA

Current - Supply (Max):: 100 µA

PSRR:: 55dB (120Hz ~ 10kHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323-5

LDK120C29R FAQ

1.How can I place an order for LDK120C29R through Aetrix?

Please submit a Request for Quotation (RFQ) for LDK120C29R 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 LDK120C29R reliable?

The price and inventory of LDK120C29R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDK120C29R is usually 5 days.

3.What payment methods are accepted for LDK120C29R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDK120C29R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LDK120C29R?

LDK120C29R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LDK120C29R 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 LDK120C29R?

For technical support, including LDK120C29R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDK120C29R requirements.

6.How does Aetrix verify that LDK120C29R is sourced from the original manufacturer or authorized distributors?

All LDK120C29R 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 LDK120C29R meets industry standards.

7.What is the process for return or replacement of LDK120C29R?

All LDK120C29R units undergo pre-shipment inspection (PSI). If there is an issue with LDK120C29R, 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 LDK120C29R part is unused and in its original packaging.

Return procedure for LDK120C29R:

1.Submit a request within 90 days.

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

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