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

STMicroelectronics LDK120C28R

Name: LDK120C28R
Brand: STMicroelectronics
SKU: LDK120C28R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LDK120C28R

Manufacturer:: STMicroelectronics

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

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

Datasheet:: LDK120C28R.pdf

Description:: IC REG LIN 2.8V 200MA SOT323-5

Quantity:: RFQ Add To RFQ list

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Inventory:3,090

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Product details

Overview

LDK120C28R from STMicroelectronics is a 200 mA, 2.8 V fixed-output low-dropout (LDO) regulator with 100 mV typical dropout at 100 mA, 100 µA max quiescent current, ±2.0% output voltage tolerance at 25 °C, and operation from 1.9 V to 5.5 V input. It delivers ultra-low noise (51 µV_RMS, 10 Hz–100 kHz with 10 nF bypass) and logic-controlled shutdown (<1 µA OFF-mode current), targeting power rails in portable battery-powered systems.

For engineers reviewing the LDK120C28R datasheet, LDK120C28R pinout, LDK120C28R application, or LDK120C28R equivalent, key selection criteria include dropout performance under 200 mA load, ceramic-capacitor stability (1 µF C_OUT), thermal shutdown threshold (160 °C), enable logic thresholds (0.4 V low / 1.2 V high), and SOT323-5L package suitability for space-constrained PCB layouts.

Technical Context

The LDK120C28R employs a PMOS pass transistor architecture enabling ultra-low dropout and near-zero gate-drive current, eliminating external compensation requirements. Its internal bandgap reference and error amplifier deliver tight DC accuracy (±2.0% at 25 °C) and stable line/load regulation (0.05 %/V and 0.006 %/mA).

Noise suppression is achieved via an integrated bypass pin (BYP) supporting optional 10 nF capacitor-reducing output noise to 51 µV_RMS-and high PSRR (55 dB from 120 Hz to 10 kHz). Thermal and short-circuit protection operate independently, with 20 °C hysteresis on thermal shutdown.

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	Fixed 2.8 V ±2.0% at 25 °C - ensures stable core/peripheral rail without external resistors.
Max output current	200 mA guaranteed - supports moderate-power RF modules, sensors, and MCU I/O domains.
Dropout voltage	100 mV typ. at 100 mA - enables operation down to 2.9 V input for 2.8 V output, extending battery runtime.
Quiescent current	60 µA typ. (100 µA max) - minimizes standby drain in always-on subsystems like RTC or wake-up circuitry.
Output noise	51 µV_RMS (10 Hz–100 kHz, with 10 nF BYP cap) - meets stringent analog/RF supply requirements (e.g., ADC references, VCOs).
Enable logic	Active-high EN pin; <0.4 V = shutdown (<1 µA), >1.2 V = active - compatible with 1.8 V/3.3 V GPIO without level-shifting.
Operating temp	-40 °C to +125 °C junction - qualified for automotive cabin and industrial edge node environments.

Pinout & Package

LDK120C28R is packaged in SOT323-5L: 1.8 mm × 2.0 mm × 0.9 mm body, 0.65 mm pitch, 5-terminal surface-mount device with exposed pad not connected internally. Pin 5 is OUT; Pin 2 is GND; Pin 3 is EN; Pin 4 is BYP (bypass capacitor connection for noise reduction); Pin 1 is IN.

Pin/Terminal	Circuit Role	Design Meaning
1 (IN)	Input voltage supply	Accepts 1.9–5.5 V DC; requires 1 µF ceramic input capacitor (CI) close to pin for stability.
2 (GND)	Power ground reference	Common return path for IN, OUT, EN, and BYP; must be low-impedance plane for noise control.
3 (EN)	Enable logic input	Active-high control: drives high (>1.2 V) to enable regulator; pulls low (<0.4 V) for <1 µA shutdown.
4 (BYP)	Bypass capacitor terminal	Optional 10 nF capacitor reduces output noise to 51 µV_RMS; left floating if unused.
5 (OUT)	Regulated output voltage	Delivers 2.8 V ±2.0%; stabilized by 1 µF ceramic output capacitor (COUT) with ESR <1 Ω.

Key Features

Feature	Design Value
Ceramic capacitor compatibility	Stable with 1 µF COUT (ESR <1 Ω) - eliminates need for tantalum or aluminum electrolytic, reducing board area and cost.
Ultra-low noise with BYP pin	51 µV_RMS (10 Hz–100 kHz) when 10 nF cap applied to BYP - enables clean supply for precision analog/RF ICs.
Logic-controlled shutdown	<1 µA total current in OFF mode - critical for long-life battery applications such as IoT sensors and wearables.
Thermal and short-circuit protection	160 °C shutdown with 20 °C hysteresis + 400 mA constant-current limit - prevents damage during overload or ambient overheating.
Wide input voltage range	1.9 V to 5.5 V operation - supports single-cell Li-ion (2.7–4.2 V), LiFePO₄ (2.0–3.6 V), and 3.3 V/5 V system rails.

Applications

Mobile Phone Baseband Power

Digital Still Camera Sensor Rail

Use Scenario: Powering CMOS image sensor analog front-end and ISP core logic in compact camera modules.

IC Role / Device Role / Timing Role: Primary 2.8 V LDO delivering low-noise, tightly regulated voltage to image sensor pixel array and ADC stage.

Use Value: 51 µV_RMS noise and ±2.0% tolerance prevent fixed-pattern noise and color channel drift in raw image data.

Use Scenario: Supplying 2.8 V to RF transceiver ICs (e.g., Bluetooth LE, Zigbee) in handheld devices.

IC Role / Device Role / Timing Role: Clean, fast-transient LDO for RF VDD, decoupled from noisy digital domains via EN-controlled sequencing.

Use Value: 100 mV dropout and 1 µA shutdown enable direct Li-ion battery connection and zero-quiescent sleep modes.

Portable Medical Pulse Oximeter

Industrial Handheld Scanner

Use Scenario: Providing stable 2.8 V bias to photodiode amplifier and analog signal chain in battery-operated oximeters.

IC Role / Device Role / Timing Role: Low-drift, low-noise LDO ensuring consistent LED drive current and ADC reference integrity across temperature.

Use Value: -40 °C to +125 °C operation and 0.006 %/mA load regulation maintain measurement accuracy during rapid finger insertion/removal.

Use Scenario: Powering barcode laser driver and microcontroller I/O bank in ruggedized handheld scanners.

IC Role / Device Role / Timing Role: Robust 200 mA LDO with thermal shutdown protecting against sustained button-press or motor stall conditions.

Use Value: 400 mA short-circuit limit and 160 °C thermal cutoff prevent field failures during accidental probe shorting or drop-induced stress.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6219B282MR-G	200 mA, 2.8 V fixed, 65 µA IQ, 150 mV dropout @ 100 mA, SOT23-5	Higher dropout limits usable input range; no BYP pin → 120 µV_RMS noise	Select when board space allows SOT23-5 and noise <100 µV_RMS is acceptable.
Richtek RT9013-28GB	300 mA, 2.8 V fixed, 25 µA IQ, 250 mV dropout @ 100 mA, SOT23-5	Lower IQ saves standby power but higher dropout reduces battery utilization efficiency	Select for ultra-low-IQ priority in always-on monitoring nodes where 200 mA peak load is rare.

Compared with XC6219B282MR-G and RT9013-28GB, LDK120C28R uniquely balances ultra-low noise (51 µV_RMS), minimal dropout (100 mV), and robust thermal protection - making it optimal for noise-sensitive, battery-limited applications requiring full 200 mA capability across temperature.

Availability

LDK120C28R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, portable medical devices, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LDK120C28R 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The LDK120 series belongs to ST's high-performance analog LDO portfolio, engineered specifically for ultra-low-noise, low-quiescent-current power management in space- and energy-constrained portable electronics.

FAQ

What is the minimum input voltage required for LDK120C28R to maintain regulation at 200 mA load?

The minimum input voltage is calculated as V_OUT + V_DROP = 2.8 V + 300 mV = 3.1 V, based on the maximum dropout voltage of 300 mV specified at 200 mA and 40–125 °C. Below this, output voltage drops linearly with input; regulation is maintained only above 3.1 V under worst-case thermal and load conditions.

Can LDK120C28R operate with a 1 µF ceramic output capacitor without external compensation?

Yes. The LDK120C28R is internally compensated and explicitly characterized for stability with 1 µF X5R/X7R ceramic capacitors (ESR <1 Ω) on the output. No external compensation network is required, simplifying layout and reducing BOM count versus older LDO architectures.

Is the BYP pin mandatory for achieving 51 µV_RMS output noise?

Yes. The 51 µV_RMS noise specification applies only when a 10 nF ceramic capacitor is placed between the BYP pin and GND. Without it, noise rises to 148 µV_RMS (per Table 4), as the internal noise-reduction path remains inactive. The BYP pin must be left floating-not grounded-if unused.

Does LDK120C28R support reverse current blocking during shutdown?

No. The LDK120C28R does not integrate reverse current blocking; its PMOS pass element allows reverse current flow from OUT to IN when V_OUT > V_IN and EN = low. External reverse-blocking diodes or MOSFETs are required in systems where backfeed from downstream circuits must be prevented.

LDK120C28R 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):: 2.8V

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

LDK120C28R FAQ

1.How can I place an order for LDK120C28R through Aetrix?

Please submit a Request for Quotation (RFQ) for LDK120C28R 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 LDK120C28R reliable?

The price and inventory of LDK120C28R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDK120C28R is usually 5 days.

3.What payment methods are accepted for LDK120C28R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDK120C28R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LDK120C28R?

LDK120C28R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LDK120C28R 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 LDK120C28R?

For technical support, including LDK120C28R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDK120C28R requirements.

6.How does Aetrix verify that LDK120C28R is sourced from the original manufacturer or authorized distributors?

All LDK120C28R 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 LDK120C28R meets industry standards.

7.What is the process for return or replacement of LDK120C28R?

All LDK120C28R units undergo pre-shipment inspection (PSI). If there is an issue with LDK120C28R, 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 LDK120C28R part is unused and in its original packaging.

Return procedure for LDK120C28R:

1.Submit a request within 90 days.

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

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