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STMicroelectronics L6983NQTR
- Part No.:
- L6983NQTR
- Manufacturer:
- STMicroelectronics
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
L6983NQTR.pdf
- Description:
- IC REG BUCK ADJ 3A 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,703
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Product details
Overview
L6983NQTR from STMicroelectronics is a synchronous monolithic step-down DC-DC converter delivering up to 3 A output current with 3.5 V to 38 V input range, 0.85 V to VIN adjustable output, and 17 μA quiescent current in LCM mode. It integrates peak current mode control, internal compensation, and dual operating modes (LCM for light-load efficiency, LNM for low-noise fixed-frequency operation), targeting industrial 24 V bus systems and always-on sensor nodes.
For engineers reviewing the L6983NQTR datasheet, L6983NQTR pinout, L6983NQTR application, or L6983NQTR equivalent, key selection criteria include programmable 200 kHz–2.3 MHz switching frequency, integrated soft-start and overvoltage protection, QFN16 3×3 mm package with exposed thermal pad, and verified compatibility with low-ESR ceramic output capacitors.
Technical Context
The L6983NQTR implements peak current mode control with slope compensation to prevent subharmonic oscillation, featuring an integrated transconductance error amplifier and pulse-by-pulse high-side/low-side current sensing for constant-current protection. Its architecture supports both discontinuous conduction mode (DCM) in LCM and forced continuous conduction mode (CCM) in LNM.
Two distinct operational modes are hardware-defined: LCM enables pulse-skipping at light loads to achieve ≤3.5 μA IQ_VBIAS (typ.), while LNM enforces constant-frequency PWM with synchronization capability (200–2200 kHz external clock input on EN/CLKIN) and optional spread spectrum for EMC compliance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 38 V - supports direct connection to 24 V industrial buses and wide-range battery inputs without pre-regulation. |
| Output Current | 3 A DC - delivers full rated load continuously with thermal shutdown at 165 °C and 30 °C hysteresis. |
| Quiescent Current | 17 μA (LCM, VIN supply) - enables multi-year operation in battery-powered always-on sensors. |
| Switching Frequency | 200 kHz to 2.3 MHz (programmable via FSW resistor) - allows optimization of size (high fSW) vs. efficiency (low fSW) and EMI filtering. |
| Feedback Reference | 0.85 V ±0.5% - enables precise output regulation from 0.85 V up to VIN using external resistor divider. |
| Protection Features | Overvoltage (120% VREF trip), thermal shutdown, pulse-by-pulse current limiting (4.6 A peak), and PGOOD open-drain monitoring - ensures robust system-level fault handling. |
| Package | QFN16 3×3 mm, 0.5 mm pitch, exposed thermal pad - provides low thermal resistance (Rth_JA = 30 °C/W) and compact footprint for space-constrained PCBs. |
Pinout & Package
QFN16 (3 mm × 3 mm, 0.5 mm pitch) with exposed thermal pad connected to AGND and PGND per layout guidelines. Pin 1 marked by top-side dot; pin numbering follows standard counter-clockwise sequence from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 12 VIN | Primary input power rail | Accepts 3.5–38 V; pins 1 & 12 are parallel-connected for reduced trace inductance and improved current sharing. |
| 3, 10 AGND | Analog ground reference | Separate from PGND to minimize noise coupling into feedback and bias circuitry; must be tied to exposed pad. |
| 4 EN/CLKIN | Enable input / external sync clock | Pull ≥1.2 V to enable; in LNM versions, accepts 200–2200 kHz square wave for frequency synchronization. |
| 5 PGOOD | Open-drain power-good indicator | Sinks 4 mA when VOUT drops below 90% of target; used for sequencing or system reset assertion. |
| 6 VBIAS | Bias supply input | Connect to VOUT or external 3–VIN source to reduce VIN current draw at light load; improves LCM efficiency. |
| 7 FB/VOUT | Feedback input / fixed-output sense | In adjustable versions, connects to resistor divider; in fixed 3.3 V/5 V versions, internally tied to precision voltage divider. |
| 8 FSW | Frequency programming node | Resistor-to-VCC sets switching frequency; tie to VCC to enable ±5% spread spectrum dithering. |
| 9 VCC | Internal LDO output | 3.3 V ±10% regulated supply for analog circuitry; requires ≥1 µF ceramic bypass capacitor. |
| 11 BOOT | High-side gate driver bootstrap | Connects via 100 nF capacitor to SW; refreshes gate charge during low-side conduction for NMOS drive. |
| 13, 16 PGND | Power ground return | Low-impedance path for switch currents; must be solidly connected to exposed pad and separated from AGND traces. |
| 14, 15 SW | Switching node | Drives external inductor; high di/dt node requiring minimized loop area and tight layout to reduce EMI. |
| Exposed PAD | Thermal and electrical ground | Mandatory connection to both AGND and PGND planes; primary thermal path for junction-to-board heat transfer. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated compensation network | Eliminates need for external Type II/III compensation components, reducing BOM count and design iteration time. |
| Programmable soft-start (1.3 ms typical) | Controls inrush current during power-up and after UVLO/thermal events, preventing input rail collapse and downstream stress. |
| Two selectable light-load modes | LCM achieves ≤3.5 μA VBIAS current at light load; LNM maintains <1% output ripple with constant 200–2300 kHz switching. |
| Output voltage sequencing support | PGOOD signal and controlled enable timing allow coordination with other rails in multi-rail systems (e.g., FPGA, MCU cores). |
| Spread spectrum modulation | ±5% frequency dithering reduces peak EMI amplitude by spreading energy across bandwidth-critical for CISPR 32 Class B compliance. |
Applications
| Industrial 24 V Power Systems | Decentralized Intelligent Nodes |
|---|---|
|
Use Scenario: Power conversion in PLC I/O modules, motor drives, and fieldbus gateways operating directly from 24 V DC industrial buses. IC Role / Device Role / Timing Role: Primary buck regulator supplying 3.3 V or 5 V logic rails with high input transient tolerance (up to 42 V abs max) and robust thermal management. Use Value: Enables single-stage conversion without pre-regulator, reducing component count and board area while maintaining >92% efficiency at 2 A load. |
Use Scenario: Compact edge-node controllers in predictive maintenance sensors, wireless gateways, and IIoT endpoints deployed in harsh environments. IC Role / Device Role / Timing Role: Always-on power manager delivering stable 3.3 V to ultra-low-power MCUs and RF transceivers with <17 μA quiescent draw. Use Value: Extends battery life beyond 5 years in coin-cell–powered devices while supporting fast wake-up via EN pin threshold control. |
| Low-Noise Sensor Signal Chains | Automated Test Equipment (ATE) Supplies |
|
Use Scenario: Powering precision analog front-ends (ADCs, op-amps, MEMS sensors) in medical diagnostics and vibration monitoring equipment. IC Role / Device Role / Timing Role: Low-noise LNM-mode buck converter providing clean 5 V rail with <10 mVpp ripple (100 kHz BW) using MLCC output filter. Use Value: Eliminates need for post-regulation LDOs, cutting power loss and thermal load while meeting SNR requirements for 24-bit ADCs. |
Use Scenario: Programmable power supplies in benchtop ATE where multiple DUT voltages must be sequenced and monitored with high accuracy. IC Role / Device Role / Timing Role: Adjustable-output buck stage (0.85–VIN) with PGOOD and external sync for synchronized multi-rail startup and fault reporting. Use Value: Enables precise voltage ramping (via soft-start), real-time rail health monitoring, and deterministic timing across 16+ channel test systems. |
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 |
|---|---|---|---|
| LM61480RQWR | 42 V max input, 8 A output, 15 μA IQ, but requires external compensation and has no LNM mode. | Higher current capacity suits motor drivers; lacks built-in spread spectrum and fixed-frequency low-noise operation. | Select when >3 A output or higher VIN margin is required, and layout allows external compensation network. |
| TPS6286418RTER | 36 V input, 4 A output, 2.5 μA IQ, integrated PMBus interface, but only fixed 1.8 V output. | Targeted at compute applications needing telemetry; not adjustable and lacks EN/CLKIN sync capability. | Choose for digital power monitoring in server or telecom systems where 1.8 V rail and telemetry outweigh flexibility needs. |
Compared with LM61480RQWR and TPS6286418RTER, the L6983NQTR uniquely balances ultra-low IQ, dual-mode light-load optimization, and full adjustability in a compact QFN16 package-making it optimal for space- and power-constrained industrial edge nodes where both efficiency and noise performance are non-negotiable.
Availability
L6983NQTR is available at Aetrix Electronics and suitable for industrial 24 V bus systems, decentralized intelligent nodes, and low-noise sensor signal chains requiring stable component supply across long product lifecycles.
Supply support for L6983NQTR 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 ICs, sensors, and analog products for industrial, automotive, and consumer markets.
The L6983 series belongs to ST's high-voltage synchronous buck regulator product line, engineered specifically for robust, low-quiescent-power DC-DC conversion in industrial automation and IoT edge devices operating from unregulated 12–36 V sources.
FAQ
What is the difference between LCM and LNM modes in the L6983NQTR?
LCM (Low Consumption Mode) uses pulse-skipping at light loads to minimize quiescent current-achieving as low as 17 μA from VIN-ideal for battery-powered always-on applications. LNM (Low Noise Mode) enforces constant-frequency PWM operation, eliminating frequency variation and minimizing output voltage ripple, making it suitable for noise-sensitive analog circuits like precision ADCs and RF receivers. The mode is determined by part number suffix and cannot be changed in-circuit.
Can the L6983NQTR synchronize to an external clock, and what are the requirements?
Only LNM-version devices (e.g., L6983NQTR is LNM) support external clock synchronization via the EN/CLKIN pin. The input clock must be a square wave with frequency between 200 kHz and 2200 kHz, amplitude ≥2.3 V, and pulse ON/OFF times ≥60 ns (at 2.3 V threshold) or ≥20 ns (above 2.5 V). Synchronization overrides internal oscillator and locks switching frequency precisely to the external source, improving system-level EMI predictability.
How does the VBIAS pin improve efficiency, and how should it be connected?
VBIAS supplies part of the internal analog circuitry, reducing current drawn from VIN-especially critical in LCM mode. When connected to the regulated output (e.g., 5 V), total VIN current drops per Equation (4) in the datasheet. If unused, VBIAS must be tied to AGND. For best light-load efficiency, connect VBIAS to VOUT via short trace; avoid floating or resistive connections that degrade regulation accuracy or increase leakage.
What layout practices are essential for stable operation and low EMI?
Minimize SW and PGND loop area using solid copper polygons; place input capacitor (≥10 µF ceramic) within 3 mm of VIN/PGND pins; connect exposed thermal pad to both AGND and PGND with ≥6 thermal vias; separate AGND and PGND planes except at the pad; route FB trace away from noisy nodes and guard it with AGND; use 100 nF ceramic for CBOOT placed adjacent to BOOT/SW pins. These practices ensure stability with low-ESR capacitors and meet CISPR 32 radiated emissions limits.
L6983NQTR 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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 38V
- Voltage - Output (Min/Fixed):
- 0.85V
- Voltage - Output (Max):
- 38V
- 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)
L6983NQTR FAQ
1.How can I place an order for L6983NQTR through Aetrix?
Please submit a Request for Quotation (RFQ) for L6983NQTR 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 L6983NQTR reliable?
The price and inventory of L6983NQTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6983NQTR is usually 5 days.
3.What payment methods are accepted for L6983NQTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6983NQTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L6983NQTR?
L6983NQTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L6983NQTR 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 L6983NQTR?
For technical support, including L6983NQTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6983NQTR requirements.
6.How does Aetrix verify that L6983NQTR is sourced from the original manufacturer or authorized distributors?
All L6983NQTR 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 L6983NQTR meets industry standards.
7.What is the process for return or replacement of L6983NQTR?
All L6983NQTR units undergo pre-shipment inspection (PSI). If there is an issue with L6983NQTR, 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 L6983NQTR part is unused and in its original packaging.
Return procedure for L6983NQTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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