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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

STMicroelectronics L6983N50QTR

Name: L6983N50QTR
Brand: STMicroelectronics
SKU: L6983N50QTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6983N50QTR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 16-WFQFN Exposed Pad

Datasheet:: L6983N50QTR.pdf

Description:: IC REG BUCK 5V 3A 16QFN

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Product details

Overview

L6983N50QTR from STMicroelectronics is a synchronous step-down DC-DC converter delivering up to 3 A output current with 17 µA quiescent current, 3.5–38 V input range, and fixed 5 V output. It features peak current mode control, internal compensation, and dual operating modes (LCM for light-load efficiency, LNM for low-noise operation), targeting industrial 24 V bus systems and always-on sensor nodes.

For engineers reviewing the L6983N50QTR datasheet, L6983N50QTR pinout, L6983N50QTR application, or L6983N50QTR equivalent, key selection criteria include programmable 200 kHz–2.3 MHz switching frequency, integrated Power Good and enable functionality, soft-start timing (1.3 ms), overvoltage/thermal protection, and QFN16 3×3 mm package compatibility with low-ESR ceramic output capacitors.

Technical Context

The L6983N50QTR implements a peak current mode architecture with constant-frequency PWM control in LNM mode and pulse-skipping in LCM mode. It integrates high-side (0.13 Ω) and low-side (0.085 Ω) MOSFETs, a transconductance error amplifier with internal compensation, and slope compensation to prevent subharmonic oscillation.

It supports VBIAS switchover to reduce input quiescent current, offers synchronization capability on EN/CLKIN (LNM only), and includes dithering-enabled spread spectrum for EMC improvement. The device features 0.85 V feedback reference (for adjustable variants) and fixed 5.0 V ±1% output accuracy across –40 °C to +125 °C.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	3.5 V to 38 V - supports wide industrial 24 V bus and battery inputs including transient surges up to 42 V absolute max.
Output Voltage	Fixed 5.0 V ±1% - guaranteed over full temperature range (–40 °C to +125 °C), eliminating external resistor divider.
Max Output Current	3 A DC - sustained delivery with thermal shutdown at 165 °C and hysteresis of 30 °C for robust overload handling.
Quiescent Current	17 µA typical - enables ultra-low-power operation in always-on applications such as remote sensors and IoT edge nodes.
Switching Frequency	200 kHz to 2.3 MHz programmable via FSW pin resistor - allows optimization for size (high fSW) or efficiency/EMI (low fSW).
Protection Features	Overvoltage (120% trip), thermal shutdown, pulse-by-pulse current limiting (4.1–4.6 A peak), and Power Good monitoring - ensures system-level reliability without external supervision circuitry.
Package	QFN16 3 × 3 mm, 0.5 mm pitch, exposed pad - provides low thermal resistance (R_{th_JA} = 30 °C/W) and compact footprint for space-constrained PCBs.

Pinout & Package

Package: QFN16 (3 mm × 3 mm, 0.5 mm pitch) with thermally enhanced exposed pad connected to AGND and PGND.

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 12 VIN	Primary input supply	Accepts 3.5–38 V; pins 1 & 2 are parallel VIN inputs for reduced trace inductance and improved current sharing.
3, 10 AGND	Analog ground reference	Separate analog return path for error amplifier and bias circuitry; must be star-connected to minimize noise coupling.
4 EN/CLKIN	Enable input / external clock sync	Pull ≥1.2 V to enable; <0.4 V to shut down (2 µA I_SHDN); in LNM mode, accepts 200–2200 kHz external clock for EMI reduction.
5 PGOOD	Open-drain power-good indicator	Sinks 4 mA when V_OUT is within ±3% of regulation; used for sequencing or microcontroller reset assertion.
6 VBIAS	Bias supply input	Connect to V_OUT or external 3–V_IN source to reduce input quiescent current by powering internal analog blocks from regulated rail.
7 FB/VOUT	Feedback / output voltage sense	Fixed 5 V version: internally connected to 5 V divider; no external resistors required - simplifies layout and improves accuracy.
8 FSW	Frequency setting / dither control	Resistor-to-VCC sets switching frequency; tie to VCC to enable ±5% spread spectrum for improved EMC performance.
9 VCC	Internal LDO output	3.3 V ±10% regulated supply for analog circuitry; requires ≥1 µF ceramic bypass capacitor to ensure stability.
11 BOOT	High-side gate driver bootstrap	Connects 100 nF capacitor to SW; refreshes gate charge during low-side conduction - essential for NMOS high-side drive.
13, 16 PGND	Power ground return	High-current return path for SW node and internal FETs; must be low-inductance plane tied to exposed pad.
14, 15 SW	Switching node	Drives external inductor; carries high di/dt; requires tight layout and Kelvin connection to minimize ringing and EMI.
Exposed PAD	Thermal & electrical ground	Must be soldered to solid AGND/PGND copper area - critical for thermal dissipation (30 °C/W) and noise immunity.

Key Features

Feature	Design Value
Peak current mode control	Enables fast transient response and inherent cycle-by-cycle current limiting without external sensing components.
Integrated compensation network	Eliminates need for external Type II/III compensation components - reduces BOM count and design iteration time.
Two operational modes (LCM/LNM)	LCM delivers >85% efficiency at 1 mA load; LNM maintains constant 2.3 MHz switching and <10 mV_PP ripple for noise-sensitive ADCs or RF sections.
Programmable soft-start (1.3 ms)	Prevents inrush current into bulk capacitance - avoids input voltage droop and protects upstream converters or batteries.
Power Good with hysteresis	Provides clean, glitch-free system power-up sequencing signal with 3% hysteresis - compatible with FPGA/CPU reset requirements.
Spread spectrum dithering	Reduces peak EMI amplitude by spreading energy across ±5% bandwidth - helps pass CISPR-22 Class B conducted/emission tests.

Applications

Industrial 24 V Bus Power

Always-On Sensor Nodes

Use Scenario: Distributed power conversion in factory automation PLCs and I/O modules powered from 24 V DC rails with ±15% tolerance.

IC Role / Device Role / Timing Role: Primary non-isolated buck regulator supplying 5 V to microcontrollers, CAN transceivers, and digital I/O drivers.

Use Value: Wide 3.5–38 V input handles brownouts and load-dump transients; 3 A output supports multiple peripherals; 17 µA I_Q extends backup battery life during standby.

Use Scenario: Battery-powered environmental sensors deployed in remote locations requiring multi-year operation on primary Li-SOCl₂ cells.

IC Role / Device Role / Timing Role: Main system regulator enabling ultra-low-power sleep cycles while maintaining real-time clock and wake-up logic.

Use Value: LCM mode achieves >90% efficiency at 100 µA load; 2 µA shutdown current minimizes self-discharge; internal soft-start prevents cold-start failure.

Decentralized Intelligent Nodes

Low-Noise Analog Signal Chains

Use Scenario: Edge AI inference nodes in predictive maintenance systems using ARM Cortex-M7 MCUs and local memory, powered from 24 V field wiring.

IC Role / Device Role / Timing Role: High-efficiency point-of-load converter delivering stable 5 V to MCU core, DDR interface, and communication PHYs.

Use Value: Programmable 2.3 MHz switching allows small 2.2 µH inductors; thermal protection prevents derating in sealed enclosures; QFN16 eases thermal management.

Use Scenario: Precision analog front-ends in industrial DAQ systems with 24-bit sigma-delta ADCs, op-amps, and reference buffers.

IC Role / Device Role / Timing Role: Low-noise 5 V supply for analog section, synchronized to system clock to avoid beat frequencies in measurement bandwidth.

Use Value: LNM mode ensures constant-frequency operation and <5 mV_PP ripple with MLCC output; EN/CLKIN sync eliminates switching harmonics near ADC sampling clock.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS543320RTWR	Higher 4 A output, 4.5–18 V input, 2.2 MHz fixed frequency, no LCM/LNM mode selection.	Optimized for compact 12 V intermediate bus; lacks ultra-low-I_Q and wide-input capability for 24 V industrial use.	Choose when higher current and smaller inductors are prioritized over input voltage range and light-load efficiency.
MP2451DT-LF-Z	3 A, 4.5–36 V input, 1.2 MHz fixed frequency, 75 µA I_Q, no spread spectrum or VBIAS switchover.	Cost-optimized for consumer-grade equipment; insufficient quiescent current and noise control for always-on industrial sensors.	Choose only for non-critical, cost-sensitive designs where 17 µA I_Q and EMI compliance are not required.

Compared with TPS543320RTWR and MP2451DT-LF-Z, the L6983N50QTR uniquely balances ultra-low 17 µA quiescent current, 3.5–38 V input flexibility, dual LCM/LNM modes, and integrated spread spectrum - making it the only option qualified for long-life, noise-sensitive, wide-input industrial power rails.

Availability

L6983N50QTR is available at Aetrix Electronics and suitable for industrial 24 V bus systems, battery-powered sensor nodes, decentralized intelligent edge devices, and low-noise analog signal chains requiring stable component supply and long-term manufacturability.

Supply support for L6983N50QTR 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 power management applications.

The L6983 series is part of ST's high-voltage DC-DC converter portfolio, engineered specifically for robust, efficient, and noise-aware power delivery in industrial automation, smart sensing, and distributed control systems.

FAQ

What is the function of the VBIAS pin on the L6983N50QTR?

The VBIAS pin supplies internal analog circuitry to reduce input quiescent current. When connected to the 5 V output, it enables switchover operation - shifting bias current from VIN to VOUT, lowering total input I_Q to ~1 µA in LCM mode. If unused, connect directly to AGND per datasheet guidance.

Can the L6983N50QTR synchronize its switching frequency to an external clock?

Yes - but only in LNM (low-noise mode) versions. The EN/CLKIN pin serves dual purpose: enable control and external clock input (200–2200 kHz). Synchronization is disabled in LCM mode. For L6983N50QTR, confirm mode designation in ordering code; this variant is fixed 5 V output and supports LNM if marked 'LNM' in suffix.

How does the Power Good (PGOOD) signal behave during startup and fault conditions?

PGOOD is an open-drain output pulled low when V_OUT falls below 90% of nominal (4.5 V for 5 V version) or rises above 120%. During startup, it remains high-impedance until soft-start completes (~1.3 ms) and output reaches regulation. It asserts low on overvoltage, undervoltage, or thermal shutdown - providing reliable system sequencing.

What layout considerations are critical for stable operation at 2.3 MHz switching?

Minimize SW node loop area with short, wide traces to PGND; place 100 nF BOOT capacitor directly between BOOT and SW pins; use separate AGND and PGND planes tied at single point under exposed pad; place input capacitor ≤5 mm from VIN/PGND pins; avoid routing sensitive FB or EN traces near SW or inductors to prevent coupling.

L6983N50QTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-WFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Fixed

Number of Outputs:: 1

Voltage - Input (Min):: 3.5V

Voltage - Input (Max):: 38V

Voltage - Output (Min/Fixed):: 5V

Voltage - Output (Max):: -

Current - Output:: 3A

Frequency - Switching:: 200kHz ~ 2.2MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-QFN (3x3)

L6983N50QTR FAQ

1.How can I place an order for L6983N50QTR through Aetrix?

Please submit a Request for Quotation (RFQ) for L6983N50QTR 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 L6983N50QTR reliable?

The price and inventory of L6983N50QTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6983N50QTR is usually 5 days.

3.What payment methods are accepted for L6983N50QTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6983N50QTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6983N50QTR?

L6983N50QTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6983N50QTR 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 L6983N50QTR?

For technical support, including L6983N50QTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6983N50QTR requirements.

6.How does Aetrix verify that L6983N50QTR is sourced from the original manufacturer or authorized distributors?

All L6983N50QTR 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 L6983N50QTR meets industry standards.

7.What is the process for return or replacement of L6983N50QTR?

All L6983N50QTR units undergo pre-shipment inspection (PSI). If there is an issue with L6983N50QTR, 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 L6983N50QTR part is unused and in its original packaging.

Return procedure for L6983N50QTR:

1.Submit a request within 90 days.

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

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