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

STMicroelectronics L6986F

Name: L6986F
Brand: STMicroelectronics
SKU: L6986F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6986F

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: L6986F.pdf

Description:: IC REG BUCK ADJ 2A 16HTSSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6986F from STMicroelectronics is a 38 V, 1.5 A synchronous step-down switching regulator with peak current mode control, 30 µA quiescent current in low-consumption mode (LCM), adjustable 250 kHz–2 MHz switching frequency, and embedded output voltage supervisor with open-drain RST. It delivers regulated DC power for industrial PLCs and decentralized intelligent nodes operating from 12 V/24 V buses.

For engineers reviewing the L6986F datasheet, L6986F pinout, L6986F application, or L6986F equivalent, key selection criteria include light-load efficiency (30 µA IQ), dual-mode operation (LCM/LNM), adjustable soft-start, overvoltage protection, and HTSSOP16 thermal performance (R_thJA = 40 °C/W).

Technical Context

The L6986F implements peak current mode architecture with pulse-by-pulse high-side/low-side current sensing for constant-current protection and foldback under heavy short-circuit. Its P-channel high-side MOSFET enables 100% duty cycle operation and low dropout behavior.

Two configurable operating modes are supported: Low Noise Mode (LNM) enforces fixed-frequency PWM to minimize output ripple across load range; Low Consumption Mode (LCM) enables frequency reduction at light load to achieve 30 µA quiescent current while maintaining regulated output.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4 V to 38 V - supports direct connection to 5 V, 12 V, and 24 V industrial bus systems without pre-regulation.
Output Current	1.5 A DC - sufficient for powering microcontrollers, FPGAs, and sensor signal chains in programmable logic controllers.
Quiescent Current (LCM)	30 µA at light load (V_OUT = 3.3 V) - extends battery life or reduces standby power in always-on industrial nodes.
Switching Frequency	Adjustable 250 kHz–2 MHz via FSW pinstrapping - enables optimization of size (high f_SW) vs. EMI/noise (low f_SW).
R_DS(on) HS / LS	180 mΩ / 150 mΩ - minimizes conduction losses and improves full-load efficiency in compact layouts.
Output Voltage Range	0.85 V to V_IN - supports core logic rails (0.85 V–3.3 V) and intermediate bus conversion (e.g., 12 V → 5 V).
Supervisor Threshold Accuracy	±1.1% on 0.85 V reference - ensures precise reset assertion for µC/FPGA power sequencing during startup.
Thermal Shutdown	165 °C with 30 °C hysteresis - protects against sustained overload or poor PCB heatsinking in enclosed enclosures.

Pinout & Package

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

Pin/Terminal	Circuit Role	Design Meaning
RST	Open-collector reset output	Asserts low when V_OUT falls below programmed threshold; supports power-good signaling and multi-rail sequencing via external capacitor delay.
VCC	Analog supply rail	Internal LDO output (3.3 V typ.) requiring ≥470 nF ceramic decoupling; powers error amplifier, reference, and control logic.
SS/INH	Soft-start/inhibit multiplexed pin	Charged by internal 4 µA current source for controlled ramp-up; pulled low to disable regulator with fast turn-off.
SYNCH/ISKP	Mode-select and sync input	Selects skip level in LCM or master/slave sync in LNM; accepts external clock up to 2.2 MHz for EMI reduction.
FSW	Frequency selection pin	Resistor-strapped to VCC or GND sets f_SW from 250 kHz to 2 MHz before soft-start; no dynamic reconfiguration.
MLF	Mode and reset threshold select	Configures LNM/LCM and selects RST trip point (80–96% of V_OUT) via resistor divider.
COMP	Error amplifier output	Connects external RC compensation network to stabilize loop response; ±12 µA drive capability supports Type II/III compensation.
DELAY	RST assertion timing capacitor	External capacitor sets delay (1–100 ms typical) between V_OUT regulation and RST release; floating = immediate RST deassertion.
FB	Feedback node	Inverting input of transconductance error amplifier; senses V_OUT via resistive divider referenced to 0.85 V internal bandgap.
SGND	Signal ground reference	Reference for analog circuitry (error amp, reference, comparators); must be star-connected to avoid noise coupling.
PGND	Power ground return	High-current return path for LX switching node and internal MOSFETs; tied to exposed pad for thermal conduction.
LX	Switching node	Drives external inductor; dual-pin layout (pins 13 & 14) reduces trace inductance and improves EMI performance.
VIN	Main power input	Accepts 4–38 V DC; requires bulk and high-frequency input capacitors near PGND to suppress switching noise.
VBIAS	Switchover auxiliary supply	Connects to regulated V_OUT (3–5.5 V) to reduce VIN quiescent current; disabled if left floating or grounded.

Key Features

Feature	Design Value
Low-Noise Mode (LNM)	Fixed-frequency PWM operation minimizes output voltage ripple across full load range - meets strict noise specs for ADCs, sensors, and RF subsystems.
Low-Consumption Mode (LCM)	30 µA quiescent current at light load with controlled ripple - extends runtime in battery-backed or energy-harvested industrial nodes.
Embedded Output Supervisor	Programmable RST threshold (80–96% of V_OUT) with adjustable delay - replaces discrete reset ICs and simplifies µC/FPGA power sequencing.
Synchronous Rectification	Integrated 180 mΩ HS / 150 mΩ LS MOSFETs eliminate external diode losses - achieves >90% efficiency at medium-to-heavy loads.
Peak Current Mode Control	Pulse-by-pulse current limiting with foldback under short-circuit - protects external inductor and capacitors without external sense resistors.
Switchover Supply Architecture	VBIAS pin allows internal regulator to draw bias current from V_OUT instead of VIN - reduces system-level standby power by up to 70%.

Applications

Programmable Logic Controllers (PLCs)

Decentralized Intelligent Nodes

Use Scenario: Powering CPU, I/O interface, and communication modules in DIN-rail mounted PLCs with 24 V DC input.

IC Role / Device Role / Timing Role: Primary DC-DC converter delivering stable 3.3 V/5 V rails; RST output sequences FPGA configuration after 12 V bus stabilization.

Use Value: 30 µA LCM IQ reduces heat buildup in sealed enclosures; HTSSOP16 package fits dense backplane layouts.

Use Scenario: Local power management for field-mounted sensor hubs communicating via CAN or RS-485.

IC Role / Device Role / Timing Role: Regulates 5 V for MCU and 3.3 V for analog front-end; LNM mode suppresses switching noise interfering with precision sensor readings.

Use Value: Adjustable f_SW allows EMI filtering at 1 MHz to avoid CAN bus interference bands; embedded supervisor eliminates external reset components.

Industrial Sensors & Transmitters

Low-Noise Analog Signal Chains

Use Scenario: Powering 4–20 mA loop-powered temperature/pressure transmitters with wide input voltage tolerance.

IC Role / Device Role / Timing Role: Step-down regulator accepting 12–36 V input; switchover to VBIAS reduces total loop current consumption.

Use Value: 4 V minimum VIN enables operation during brownout conditions; 100% duty cycle maintains output during low-VIN transients.

Use Scenario: Supplying ultra-low-noise 1.8 V/2.5 V rails for high-resolution ADCs, DACs, and op-amp signal conditioning stages.

IC Role / Device Role / Timing Role: Secondary regulator fed from main 5 V rail; LNM mode ensures fixed-frequency operation with minimal output ripple.

Use Value: 0.85 V reference accuracy ±1.1% guarantees precise reset timing; COMP pin enables custom loop compensation for stability with low-ESR ceramics.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM5164QPWPRQ1	4.5–65 V input, 1 A output, 14 µA IQ, integrated MOSFETs but no embedded supervisor or RST output.	Lacks programmable reset and voltage sequencing - requires external supervisor IC for µC/FPGA reset.	Preferred for automotive 12 V/24 V systems needing higher VIN tolerance and AEC-Q100 qualification.
TPS54202DRCT	4.5–28 V input, 2 A output, 26 µA IQ, no LNM/LCM mode selection, no RST output, no VBIAS switchover.	No low-noise fixed-frequency mode - unsuitable for noise-sensitive analog signal chains.	Better for cost-sensitive, non-critical industrial supplies where sequencing and ultra-low noise are not required.

Compared with LM5164QPWPRQ1 and TPS54202DRCT, the L6986F uniquely integrates voltage supervision, dual-mode operation (LCM/LNM), and VBIAS switchover - making it optimal for space-constrained, low-noise, and sequenced-power industrial applications where component count and standby power are critical.

Availability

L6986F is available at Aetrix Electronics and suitable for programmable logic controllers (PLCs), decentralized intelligent nodes, industrial sensors, and low-noise analog signal chains requiring stable component supply, long-term lifecycle support, and consistent parametric performance.

Supply support for L6986F 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, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The L6986F belongs to ST's high-efficiency, wide-input-voltage synchronous buck regulator product line, engineered specifically for rugged industrial power conversion where reliability, low standby power, and integrated supervision are mandatory.

FAQ

What is the purpose of the VBIAS pin on the L6986F?

The VBIAS pin enables switchover operation: when connected to a regulated output voltage between 3 V and 5.5 V, the internal regulator draws bias current from VBIAS instead of VIN, reducing total quiescent current by up to 70%. This is especially valuable in battery-backed or energy-constrained systems. If unused, VBIAS must be connected to GND.

How does the L6986F implement output voltage sequencing?

Sequencing is achieved using the RST open-drain output and DELAY pin. An external capacitor on DELAY sets the time delay between V_OUT reaching regulation and RST deassertion. This delayed RST signal can enable downstream regulators or release microcontroller reset, enabling controlled power-up order across multiple rails without additional ICs.

Can the L6986F operate with 100% duty cycle, and why is that important?

Yes - the integrated P-channel high-side MOSFET enables true 100% duty cycle operation. This allows the output voltage to track closely to VIN during low-input-voltage conditions (e.g., 5.2 V input → 5.0 V output), preventing dropout in brownout scenarios common in 12 V/24 V industrial buses with cable drop or transient sags.

What distinguishes Low Noise Mode (LNM) from Low Consumption Mode (LCM)?

LNM forces fixed-frequency PWM across all loads to minimize output voltage ripple - ideal for noise-sensitive analog circuits. LCM reduces switching frequency at light load to cut switching losses, achieving 30 µA IQ - optimal for standby/always-on operation. Mode selection is set at startup via MLF pinstrapping and cannot be changed dynamically.

L6986F Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

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

L6986F FAQ

1.How can I place an order for L6986F through Aetrix?

Please submit a Request for Quotation (RFQ) for L6986F 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 L6986F reliable?

The price and inventory of L6986F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6986F is usually 5 days.

3.What payment methods are accepted for L6986F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6986F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6986F?

L6986F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6986F 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 L6986F?

For technical support, including L6986F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6986F requirements.

6.How does Aetrix verify that L6986F is sourced from the original manufacturer or authorized distributors?

All L6986F 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 L6986F meets industry standards.

7.What is the process for return or replacement of L6986F?

All L6986F units undergo pre-shipment inspection (PSI). If there is an issue with L6986F, 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 L6986F part is unused and in its original packaging.

Return procedure for L6986F:

1.Submit a request within 90 days.

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

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