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

STMicroelectronics LDK715M42R

Name: LDK715M42R
Brand: STMicroelectronics
SKU: LDK715M42R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LDK715M42R

Manufacturer:: STMicroelectronics

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

Package:: SC-74A, SOT-753

Datasheet:: LDK715M42R.pdf

Description:: IC REG LINEAR 4.2V 85MA SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:1,987

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Product details

Overview

LDK715M42R from STMicroelectronics is a high-input-voltage, ultra-low-quiescent-current LDO linear regulator delivering 4.2 V at up to 85 mA output current, with 500 mV typical dropout at full load, 5 µA typical quiescent current, and stable operation from 4.3 V to 24 V input - deployed in battery-powered industrial sensors and mobile phone power rails.

For engineers reviewing the LDK715M42R datasheet, LDK715M42R pinout, LDK715M42R application, or LDK715M42R equivalent, key selection criteria include input voltage range compatibility (4.3–24 V), ceramic capacitor support (0.47–10 µF), thermal performance (R_thJA = 195 °C/W for SOT23-5L), and guaranteed 85 mA output under -40 °C to 125 °C junction temperature.

Technical Context

The LDK715M42R implements a bandgap reference-based control loop with internal current limiting and thermal shutdown. Its architecture supports stable regulation across wide input ranges without external compensation, enabled by low-output-impedance design and optimized phase margin with ceramic capacitors as low as 0.47 µF.

It features an enable-controlled startup sequence (0.7 ms turn-on time), 38 dB supply voltage rejection at 1 kHz, and 57 dB at 100 kHz. Fault protection includes short-circuit current limit (~120 mA) and thermal foldback, ensuring safe operation during overloads and ambient extremes.

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	Fixed 4.2 V ±2% over -40 °C to 125 °C; enables direct charging interface or MCU core rail in portable systems.
Input voltage range	4.3 V to 24 V DC; supports wide-range industrial supplies and automotive battery transients without pre-regulation.
Max output current	85 mA guaranteed; sufficient for low-power microcontrollers, RF modules, and sensor signal chains.
Dropout voltage	500 mV typ. at 85 mA; allows regulation from 4.7 V input to 4.2 V output - critical for single-cell LiFePO₄ or dual-cell alkaline systems.
Quiescent current	5 µA typ. at full load; extends battery life in always-on monitoring nodes where standby current dominates energy budget.
Output noise	210 µV_RMS (200 Hz–100 kHz); meets noise-sensitive analog front-end requirements without additional filtering.
Capacitor compatibility	Stable with 0.47–10 µF ceramic output capacitors; eliminates need for tantalum or electrolytic, reducing BOM cost and footprint.

Pinout & Package

LDK715M42R is packaged in SOT23-5L - a 5-pin surface-mount package with exposed pad for thermal enhancement. Pin 1 is NC, Pin 2 is GND, Pin 3 is NC, Pin 4 is IN, Pin 5 is OUT.

Pin/Terminal	Circuit Role	Design Meaning
IN (Pin 4)	Regulator input	Accepts 4.3–24 V DC; requires ≥0.1 µF bypass capacitor close to pin for transient immunity.
GND (Pin 2)	Power ground reference	Common return path for input/output currents; must be low-impedance connection to minimize noise coupling.
OUT (Pin 5)	Regulated output	Delivers stable 4.2 V; connects directly to load with 0.47–10 µF ceramic capacitor to GND for loop stability.
NC (Pins 1 & 3)	No internal connection	Must remain unconnected; floating or tied to GND per layout best practice - no electrical function.

Key Features

Feature	Design Value
Ultra-low quiescent current	5 µA at full 85 mA load - enables >10-year battery life in 10 µA average-current IoT endpoints.
Wide input voltage range	4.3–24 V operation - eliminates need for upstream buck converter in industrial 12/24 V systems.
Ceramic capacitor stability	Validated with 0.47 µF minimum C_OUT - reduces board area and improves reliability vs. electrolytic alternatives.
Integrated fault protection	Short-circuit current limit (~120 mA) and thermal shutdown - prevents damage during wiring faults or PCB shorts.
High PSRR at RF frequencies	57 dB rejection at 100 kHz - suppresses switching noise from adjacent DC-DC converters in mixed-signal designs.

Applications

Industrial Sensor Node

Portable Medical Monitor

Use Scenario: Battery-powered temperature/humidity sensor transmitting via BLE every 5 minutes.

IC Role / Device Role / Timing Role: Primary 4.2 V power rail for MCU, BLE SoC, and analog sensor interface.

Use Value: 5 µA quiescent current minimizes self-discharge; 85 mA headroom supports brief 40 mA BLE transmit bursts.

Use Scenario: Handheld pulse oximeter using coin-cell battery and low-noise analog front-end.

IC Role / Device Role / Timing Role: Clean 4.2 V supply for ADC reference and op-amp signal conditioning.

Use Value: 210 µV_RMS output noise avoids SNR degradation; ceramic capacitor compatibility reduces size and aging drift.

Smart Meter Auxiliary Rail

Automotive Telematics Tracker

Use Scenario: Secondary 4.2 V rail powering real-time clock, secure element, and backup SRAM in utility meter.

IC Role / Device Role / Timing Role: Always-on LDO maintaining timekeeping and security functions during main power loss.

Use Value: -40 °C to 125 °C operating range ensures functionality in outdoor meter enclosures; 24 V max input tolerates surge events.

Use Scenario: GPS/GSM tracker mounted in vehicle cabin with 12 V battery input subject to load-dump transients.

IC Role / Device Role / Timing Role: Pre-regulator feeding 3.3 V buck converter for baseband processor and GNSS receiver.

Use Value: 4.3–24 V input range accepts cold-crank (6.5 V) to load-dump (24 V); thermal shutdown protects during enclosure overheating.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6219B422MR-G	4.2 V output, 100 mA rating, 300 mV dropout, but 15 µA IQ - 3× higher than LDK715M42R.	Lacks extended 24 V input capability (max VIN = 6 V); unsuitable for industrial 24 V bus or automotive use.	Select only when lower dropout is prioritized over input range and quiescent current.
Diodes Inc. AP7361-C42W5-7	4.2 V output, 300 mA rating, 400 mV dropout, 25 µA IQ, supports 5.5 V max input.	Not rated beyond 5.5 V input - incompatible with 12/24 V systems; requires upstream buck stage.	Choose only for low-dropout, high-current needs in 3.3–5 V domains where IQ is secondary.

Compared with XC6219B422MR-G and AP7361-C42W5-7, the LDK715M42R uniquely combines 24 V input tolerance, 5 µA IQ, and 4.2 V precision in one SOT23-5L package - making it irreplaceable for long-life, wide-input industrial and automotive auxiliary rails.

Availability

LDK715M42R is available at Aetrix Electronics and suitable for industrial sensor nodes, portable medical monitors, smart meter auxiliary rails, and automotive telematics trackers requiring stable component supply across extended temperature and input voltage ranges.

Supply support for LDK715M42R 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 LDK715 series belongs to ST's high-voltage, ultra-low-I_Q LDO portfolio - engineered specifically for battery longevity and robustness in harsh, wide-input industrial and portable applications.

FAQ

What is the minimum output capacitor required for stability?

The LDK715M42R is stable with ceramic output capacitors as low as 0.47 µF and up to 10 µF, per ST's validated stability region (Figure 7 in DocID026678 Rev 3). ESR is not critical due to internal compensation, and no series resistor is needed - simplifying layout and reducing bill-of-materials count.

Does LDK715M42R include an enable pin?

No, the LDK715M42R does not feature an enable (EN) pin. It operates continuously when input voltage exceeds 4.3 V. For controlled startup, external circuitry such as a MOSFET high-side switch or microcontroller-driven power sequencer must be used - consistent with its role as a simple, always-on auxiliary regulator.

Can LDK715M42R be used with aluminum polymer capacitors?

Yes - while optimized for ceramic capacitors (0.47–10 µF), the LDK715M42R remains stable with aluminum polymer capacitors meeting the same capacitance and ESR envelope specified in Figure 7. However, ceramics are preferred for lower ESL, smaller footprint, and superior lifetime reliability in extended-temperature deployments.

What is the thermal derating behavior above 25 °C ambient?

With R_thJA = 195 °C/W in SOT23-5L, power dissipation must be linearly derated above 25 °C ambient. At 85 mA and 24 V input, worst-case power dissipation is (24 V − 4.2 V) × 0.085 A ≈ 1.69 W - exceeding the 0.45 W package limit. Thus, maximum safe input voltage drops to ~9.5 V at 85 mA above 25 °C unless heatsinking or airflow is added.

LDK715M42R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: SC-74A, SOT-753

Packaging:: Tape & Reel (TR)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 24V

Voltage - Output (Min/Fixed):: 4.2V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 1V @ 85mA

Current - Output:: 85mA

Current - Quiescent (Iq):: 7 µA

Current - Supply (Max):: 8.5 µA

PSRR:: 57dB ~ 38dB (100kHz ~ 1kHz)

Control Features:: -

Protection Features:: Over Current, Over Temperature

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

LDK715M42R FAQ

1.How can I place an order for LDK715M42R through Aetrix?

Please submit a Request for Quotation (RFQ) for LDK715M42R 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 LDK715M42R reliable?

The price and inventory of LDK715M42R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LDK715M42R is usually 5 days.

3.What payment methods are accepted for LDK715M42R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LDK715M42R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LDK715M42R?

LDK715M42R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LDK715M42R 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 LDK715M42R?

For technical support, including LDK715M42R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LDK715M42R requirements.

6.How does Aetrix verify that LDK715M42R is sourced from the original manufacturer or authorized distributors?

All LDK715M42R 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 LDK715M42R meets industry standards.

7.What is the process for return or replacement of LDK715M42R?

All LDK715M42R units undergo pre-shipment inspection (PSI). If there is an issue with LDK715M42R, 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 LDK715M42R part is unused and in its original packaging.

Return procedure for LDK715M42R:

1.Submit a request within 90 days.

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

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