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

STMicroelectronics L6986TR

Name: L6986TR
Brand: STMicroelectronics
SKU: L6986TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6986TR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 16-PowerTSSOP (0.173", 4.40mm Width)

Datasheet:: L6986TR.pdf

Description:: IC REG BUCK ADJ 2A 16HTSSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6986TR from STMicroelectronics is a 38 V, 2 A synchronous step-down switching regulator featuring peak current mode control, adjustable 250 kHz–2 MHz switching frequency, 30 μA quiescent current in low-consumption mode (LCM), and embedded output voltage supervisor with open-drain RST. It delivers regulated DC power for industrial PLCs and decentralized sensor nodes operating from 12 V/24 V buses.

For engineers reviewing the L6986TR datasheet, L6986TR pinout, L6986TR application, or L6986TR equivalent, key selection criteria include its dual-mode operation (LCM/LNM), 0.85 V to VIN adjustable output, 100% duty cycle capability via P-channel high-side MOSFET, thermal shutdown at 165 °C, and HTSSOP16 package with exposed pad for thermal management.

Technical Context

The L6986TR implements peak current mode architecture with pulse-by-pulse current sensing on both high-side (R_DS(on) = 180 mΩ) and low-side (R_DS(on) = 150 mΩ) MOSFETs, enabling precise constant-current protection and foldback during short-circuit events. Its internal transconductance error amplifier (G_m = 85–210 μS) drives the PWM comparator with 100 dB gain and ±12 μA output current capability.

Two configurable operating modes are supported: Low Noise Mode (LNM) enforces fixed-frequency PWM across full load range for EMI-sensitive applications, while Low Consumption Mode (LCM) enables discontinuous conduction mode at light loads to achieve 30 μA I_Q. The switchover feature allows VBIAS connection to reduce VIN-referred quiescent current when output voltage is ≥3 V.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4 V to 38 V - supports direct connection to 12 V and 24 V industrial buses without pre-regulation.
Output Current	2 A DC - sufficient for powering microcontrollers, FPGAs, and analog sensor front-ends in compact designs.
Quiescent Current (LCM)	30 μA at light load - extends battery life in always-on industrial monitoring systems.
Switching Frequency	250 kHz to 2 MHz - adjustable via FSW pinstrapping to optimize efficiency vs. EMI vs. component size.
Output Voltage Range	0.85 V to VIN - enables generation of core logic voltages (e.g., 1.2 V, 1.8 V, 3.3 V) and bias rails from wide-input sources.
R_DS(on) HS / LS	180 mΩ / 150 mΩ - minimizes conduction losses and thermal rise at full load in HTSSOP16 package.
Thermal Shutdown	165 °C with 30 °C hysteresis - protects IC and external components during overload or poor heatsinking conditions.

Pinout & Package

Package: HTSSOP16 (exposed pad), R_thJA = 40 °C/W, R_thJC = 5 °C/W. Exposed pad must be connected to SGND/PGND for thermal and electrical integrity.

Pin/Terminal	Circuit Role	Design Meaning
RST	Open-collector reset output	Asserts low when VOUT falls below programmable threshold; supports power-good signaling and sequencing with external delay capacitor.
VCC	Analog supply rail	Supplies internal reference and analog circuitry; requires ≥470 nF ceramic capacitor to GND for stability.
SS/INH	Soft-start/inhibit control	Charged by 1–4 μA internal current source; clamping to GND disables regulator and reduces shutdown current to 8 μA.
SYNCH	Master/slave synchronization input	Accepts external clock (266.5 kHz min) in LNM; floating in LCM; supports up to 6 slave devices.
FSW	Frequency selection	Resistor divider to VCC/GND sets fSW before soft-start; avoids dynamic reconfiguration during operation.
MLF	Mode and reset threshold select	Configures LNM/LCM and RST trip point (80–96% of VOUT); strapping active only pre-soft-start.
COMP	Error amplifier output	Connects to external RC compensation network to stabilize loop response across load/line variations.
DELAY	RST assertion timing	External capacitor sets delay time (μs to ms) before RST releases after VOUT recovery.
FB	Voltage feedback input	Monitors output via resistive divider; internal reference = 0.85 V ±1.1%, enabling accurate regulation.
SGND / PGND	Signal / power ground	Separate ground pins minimize noise coupling between analog control and high-current switching paths.
LX	Switching node	Connects to external inductor; dual LX pins (13 & 14) reduce parasitic inductance and improve EMI performance.
VIN	Main power input	Accepts 4–38 V DC; includes UVLO (2.5–3.5 V hysteresis) to prevent erratic startup at marginal input.
VBIAS	Switchover supply input	Optional connection to regulated output (3–5.5 V) to reduce VIN-referred I_Q by sourcing internal bias current.

Key Features

Feature	Design Value
100% duty cycle operation	Enabled by integrated P-channel high-side MOSFET - maintains regulation down to VOUT ≈ VIN − dropout, critical for battery-backed systems.
Embedded output voltage supervisor	Programmable RST threshold (via MLF) and adjustable delay (via DELAY capacitor) - eliminates need for external reset IC in µC/FPGA power-up sequencing.
Synchronous rectification	Integrated N-channel low-side MOSFET replaces Schottky diode - improves full-load efficiency by ~5–8% and reduces thermal footprint.
Adjustable soft-start time	Externally set via SS/INH capacitor - controls inrush current to limit stress on input capacitors and upstream converters.
Overvoltage protection (OVP)	Triggers at 115–125% of VREF - actively discharges output capacitor to protect downstream loads during regulation failure.

Applications

Industrial PLC Power Supply

Decentralized Sensor Node

Use Scenario: Providing stable 3.3 V/2 A power to modular I/O modules in factory automation cabinets with 24 V DC bus.

IC Role / Device Role / Timing Role: Primary buck regulator delivering isolated, sequenced, and supervised DC power to ARM Cortex-M7 microcontrollers and isolated CAN transceivers.

Use Value: LCM mode reduces standby power to <100 μW, extending system uptime during idle cycles without compromising transient response.

Use Scenario: Powering low-noise analog signal chains (e.g., 24-bit ADCs, precision op-amps) in wireless vibration sensors mounted on rotating machinery.

IC Role / Device Role / Timing Role: Fixed-frequency LNM regulator minimizing switching noise injection into sensitive analog measurement paths.

Use Value: Constant 1.5 MHz fSW ensures switching harmonics fall outside 10 kHz–100 kHz sensor bandwidth, preserving SNR >105 dB.

Programmable Logic Controller (PLC) CPU Board

Smart Actuator Control Module

Use Scenario: Generating 1.2 V core voltage for Xilinx Spartan FPGA and 5 V auxiliary rail for interface ICs on a DIN-rail mountable PLC backplane.

IC Role / Device Role / Timing Role: Dual-output capable buck controller (with external LDO post-regulation) providing tightly tracked, sequenced power domains with RST-driven FPGA configuration lockout.

Use Value: Adjustable soft-start and output sequencing ensure FPGA config memory initializes only after stable 1.2 V and 5 V rails are established, preventing configuration errors.

Use Scenario: Supplying 24 V-to-5 V conversion for motor driver gate drivers and position feedback circuits in servo valve controllers operating in harsh electromagnetic environments.

IC Role / Device Role / Timing Role: High-efficiency synchronous buck converter with thermal shutdown and overcurrent foldback protecting against shorted solenoid coils.

Use Value: Integrated current limiting (2.1–2.6 A peak) and thermal shutdown (165 °C) enable robust operation without external protection circuitry, reducing BOM count.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous step-down regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM5164QPWPRQ1	4.5–65 V input, 1 A output, 14 μA I_Q, no integrated LDO or RST supervisor	Lacks embedded voltage supervisor and sequencing support; requires external reset IC for FPGA/µC use cases	Select when ultra-wide VIN and automotive AEC-Q100 qualification are required, but system-level supervision is handled externally.
TPS54202DRCT	4.5–28 V input, 2 A output, 45 μA I_Q, no LNM/LCM mode selection, no VBIAS switchover	Fixed PWM-only operation; higher light-load I_Q limits battery runtime in always-on nodes	Select for cost-sensitive industrial applications where 28 V max input suffices and lowest possible BOM count outweighs light-load efficiency.

Compared with LM5164QPWPRQ1 and TPS54202DRCT, the L6986TR uniquely integrates output voltage supervision with programmable RST timing, dual LNM/LCM modes for EMI vs. efficiency trade-offs, and VBIAS switchover-making it optimal for space-constrained, multi-rail industrial controllers requiring autonomous power sequencing and ultra-low standby consumption.

Availability

L6986TR is available at Aetrix Electronics and suitable for industrial PLCs, decentralized sensor nodes, smart actuator modules, and programmable logic controller CPU boards requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for L6986TR 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, specializing in power management, microcontrollers, and analog/mixed-signal ICs for industrial, automotive, and consumer markets.

The L6986TR belongs to ST's high-voltage synchronous buck regulator product line, designed specifically for rugged 12 V/24 V industrial power systems demanding low quiescent current, integrated supervision, and flexible mode selection in compact packages.

FAQ

What is the minimum recommended input voltage for reliable operation?

The L6986TR has a guaranteed operational input range starting at 4 V, with VCC UVLO rising threshold at 2.7–3.5 V. Below 4 V, output regulation cannot be maintained due to insufficient headroom for the P-channel high-side MOSFET. For 5 V bus applications, ensure input remains ≥4.2 V under worst-case load and cable drop to avoid brownout.

How does the switchover feature affect total system quiescent current?

When VBIAS is connected to a ≥3 V regulated output (e.g., 3.3 V rail), the internal regulator draws bias current from VBIAS instead of VIN, reducing VIN-referred I_Q from 70 μA (LCM, VBIAS = GND) to 45 μA (LCM, VBIAS = 3.3 V). This directly lowers total system standby power in multi-rail designs.

Can the RST pin drive a microcontroller reset directly without external pull-up?

No - RST is an open-collector output requiring an external pull-up resistor (typically 10 kΩ to VCC or VOUT). The internal structure sinks up to 4 mA when asserted low. Direct connection to µC reset inputs without pull-up will leave the reset line floating and cause undefined behavior during startup or fault conditions.

What is the maximum allowable inductor DCR for stable current limit operation?

Peak current limit accuracy depends on sensing voltage across high-side MOSFET R_DS(on). Inductor DCR contributes series resistance that distorts sensed current waveform. ST recommends DCR ≤ 20 mΩ for 2 A designs to maintain ±10% current limit tolerance; higher DCR requires compensation via external sense resistor or reduced ILIM setting.

L6986TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-PowerTSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 4V

Voltage - Input (Max):: 38V

Voltage - Output (Min/Fixed):: 0.85V

Voltage - Output (Max):: 38V

Current - Output:: 2A

Frequency - Switching:: 250kHz ~ 2MHz

Synchronous Rectifier:: Yes

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-HTSSOP

L6986TR FAQ

1.How can I place an order for L6986TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L6986TR 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 L6986TR reliable?

The price and inventory of L6986TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6986TR is usually 5 days.

3.What payment methods are accepted for L6986TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6986TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6986TR?

L6986TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6986TR 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 L6986TR?

For technical support, including L6986TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6986TR requirements.

6.How does Aetrix verify that L6986TR is sourced from the original manufacturer or authorized distributors?

All L6986TR 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 L6986TR meets industry standards.

7.What is the process for return or replacement of L6986TR?

All L6986TR units undergo pre-shipment inspection (PSI). If there is an issue with L6986TR, 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 L6986TR part is unused and in its original packaging.

Return procedure for L6986TR:

1.Submit a request within 90 days.

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

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