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STMicroelectronics L6983C33QTR
- Part No.:
- L6983C33QTR
- Manufacturer:
- STMicroelectronics
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
L6983C33QTR.pdf
- Description:
- IC REG BUCK 3.3V 3A 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:410
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Product details
Overview
L6983C33QTR from STMicroelectronics is a synchronous step-down DC-DC converter delivering up to 3 A output current with fixed 3.3 V output, 3.5–38 V input range, 17 μA quiescent current, and QFN16 (3×3 mm) package. It supports industrial 24 V bus systems, battery-powered sensors, and always-on nodes requiring stable low-noise or high-efficiency regulation.
For engineers reviewing the L6983C33QTR datasheet, L6983C33QTR pinout, L6983C33QTR application, or L6983C33QTR equivalent, key selection criteria include light-load efficiency mode (LCM/LNM), programmable 200 kHz–2.3 MHz switching frequency, internal soft-start, Power Good signaling, and VINLDO filtering for noise-sensitive 24 V industrial power rails.
Technical Context
The L6983C33QTR implements peak current mode control with integrated slope compensation and a transconductance error amplifier featuring internal compensation. Its dual-mode operation-Low Consumption Mode (LCM) for >90% light-load efficiency and Low Noise Mode (LNM) for constant-frequency PWM-enables precise trade-offs between quiescent current (1.6 μA typ. in LNM at light load) and output ripple.
It integrates high-side (RDSON = 0.13 Ω) and low-side (RDSON = 0.085 Ω) MOSFETs, supports external clock synchronization (LNM only), optional spread spectrum (±5% dithering), and includes pulse-by-pulse overcurrent protection, thermal shutdown (165 °C), and overvoltage protection (120% VOUT trip).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 38 V - supports wide industrial 12–36 V DC buses and 24 V battery systems without pre-regulation. |
| Output Voltage | Fixed 3.3 V ±1.5% - internally trimmed feedback reference enables accurate regulation without external resistors. |
| Max Output Current | 3 A DC - sufficient for powering microcontrollers, FPGAs, and sensor signal chains in decentralized nodes. |
| Quiescent Current | 17 μA (typ.) - enables multi-year battery life in always-on sensor applications with minimal standby drain. |
| Switching Frequency | 200 kHz to 2.3 MHz (programmable) - allows EMI optimization and compact magnetics selection across diverse PCB layouts. |
| Protection Features | OVP (120% VOUT), thermal shutdown (165 °C), pulse-by-pulse current limit (4.1–4.6 A peak), UVLO - ensures robust operation under fault conditions. |
| Package | QFN16 (3 × 3 mm, 0.5 mm pitch, exposed pad) - provides low thermal resistance (Rth_JA = 30 °C/W) and space-efficient layout for dense industrial modules. |
Pinout & Package
Package: QFN16 (3 mm × 3 mm, 0.5 mm pitch, exposed thermal pad). Exposed pad must be soldered to AGND/PGND plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 12 VIN | Primary input supply rail | Accepts 3.5–38 V; pins 1/2/12 are paralleled for low-impedance high-current path and reduced trace inductance. |
| 3, 10 AGND | Analog ground reference | Separate from PGND; connects to VCC bypass cap and FB network to minimize noise coupling into error amplifier. |
| 4 EN/CLKIN | Enable input / external sync clock (LNM) | Pull ≥1.2 V to enable; in LNM versions, accepts 200–2200 kHz external clock for EMI reduction and system timing alignment. |
| 5 PGOOD | Open-drain power-good indicator | Sinks current when VOUT deviates >10% from nominal; used for sequencing, fault reporting, or MCU reset assertion. |
| 6 VBIAS | Bias supply input | Connects to regulated VOUT or external 3–VIN source to reduce IQ from VIN by ~50% in light-load conditions. |
| 7 FB/VOUT | Feedback sense / fixed-output tap | In fixed 3.3 V version, functions as internal VOUT monitor; no external divider required - simplifies BOM and layout. |
| 8 FSW | Frequency programming node | Resistor-to-VCC sets switching frequency; tie to VCC to enable ±5% spread spectrum for improved EMC compliance. |
| 9 VCC | Internal LDO output | 3.3 V ±10% regulated supply for analog circuitry; requires ≥1 µF ceramic capacitor to AGND for stability. |
| 11 BOOT | High-side gate driver bootstrap | Connects 100 nF capacitor to SW; refreshes gate charge during low-side conduction - enables efficient NMOS high-side drive. |
| 13, 16 PGND | Power ground return | High-current return path for SW node and internal FETs; must be low-inductance copper pour tied to exposed pad. |
| 14, 15 SW | Switching node | Drives external inductor; carries full AC current; requires tight loop area with PGND and input/output caps to minimize EMI. |
| Exposed PAD | Thermal & electrical ground | Mandatory connection to both AGND and PGND planes; critical for thermal performance (30 °C/W) and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Compensation Network | Eliminates external Type-II/III compensation components - reduces design cycle time and board area for 3 A buck converters. |
| Two Light-Load Modes (LCM/LNM) | LCM achieves <10 μA effective IQ at 1 mA load; LNM maintains constant fSW and <10 mVpp ripple - selectable per part number, not runtime configurable. |
| Programmable Spread Spectrum | ±5% frequency dithering via FSW pin resistor - lowers peak EMI by >10 dB without altering filter design or layout. |
| Integrated Power Good (PGOOD) | Open-drain output with 90% VOUT threshold and 3% hysteresis - enables reliable power sequencing in multi-rail industrial systems. |
| VINLDO Filtering Support | Dedicated VINLDO pin (Pin 2) with RC filter option - isolates sensitive analog circuitry from noisy input bus transients in 24 V industrial environments. |
Applications
| Industrial 24 V Bus Power | Always-On Sensor Nodes |
|---|---|
|
Use Scenario: Powering PLC I/O modules, fieldbus gateways, and motor drives from unregulated 24 V DC distribution rails. IC Role / Device Role / Timing Role: Primary point-of-load regulator converting 24 V bus to clean 3.3 V for microcontrollers, CAN transceivers, and ADCs. Use Value: Wide 3.5–38 V input handles brownouts and load-dump transients; 3 A capability supports multiple peripherals on single rail. |
Use Scenario: Battery-powered environmental sensors (temperature, humidity, gas) deployed in remote infrastructure with 10+ year lifetime targets. IC Role / Device Role / Timing Role: Always-on voltage regulator maintaining 3.3 V for ultra-low-power MCU sleep states and periodic wake-up bursts. Use Value: 17 μA quiescent current and LCM mode extend LiSOCl₂ battery life beyond 12 years at 10 μA average system load. |
| Decentralized Intelligent Nodes | Low-Noise Industrial Imaging |
|
Use Scenario: Edge AI inference nodes in factory automation using small-form-factor SoMs with local processing and wireless backhaul. IC Role / Device Role / Timing Role: Secondary regulator supplying 3.3 V to FPGA configuration memory, DDR I/O, and RF front-end bias rails. Use Value: Internal soft-start prevents inrush-induced voltage droop on shared 24 V bus; PGOOD enables coordinated boot sequencing. |
Use Scenario: High-resolution industrial cameras and X-ray detectors where switching noise corrupts analog image signals or ADC references. IC Role / Device Role / Timing Role: Low-noise 3.3 V supply for CMOS image sensor bias, analog front-end, and precision clock buffers. Use Value: LNM mode delivers constant 2.2 MHz switching and <5 mVpp ripple with MLCC output cap - meets CISPR-22 Class B conducted EMI limits. |
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 |
|---|---|---|---|
| LM61480RQR | 42 V max input, 8 A output, 15 μA IQ, but requires external compensation and has no VINLDO pin. | Higher current capacity suits larger SoCs; lacks dedicated noise-isolation input filtering for harsh 24 V industrial environments. | Select when >3 A load or higher VIN margin needed; accept added design complexity and larger solution size. |
| TPS6286413ARQYR | 36 V max input, 4 A output, 2.5 μA IQ, integrated spread spectrum, but only supports adjustable output (no fixed 3.3 V variant). | Superior light-load IQ for battery longevity; requires external resistor divider for 3.3 V - adds BOM cost and potential tolerance drift. | Select for lowest possible standby current in battery-critical designs; verify FB divider accuracy and temperature drift impact on 3.3 V regulation. |
Compared with LM61480RQR and TPS6286413ARQYR, the L6983C33QTR uniquely combines fixed 3.3 V output, VINLDO filtering, internal compensation, and dual LCM/LNM modes - making it optimal for space-constrained, noise-sensitive, or long-life industrial 24 V systems where design simplicity and reliability are prioritized over raw current headroom or sub-microamp IQ.
Availability
L6983C33QTR is available at Aetrix Electronics and suitable for industrial 24 V bus power systems, always-on sensor nodes, decentralized intelligent edge devices, and low-noise imaging subsystems requiring stable component supply across extended product lifecycles.
Supply support for L6983C33QTR 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 belongs to ST's high-voltage industrial DC-DC converter portfolio, engineered specifically for robust, low-component-count power conversion in 12–36 V industrial equipment with stringent EMI, efficiency, and reliability requirements.
FAQ
What is the difference between LCM and LNM modes in the L6983C33QTR?
LCM (Low Consumption Mode) skips pulses at light loads to minimize quiescent current - achieving ~17 μA IQ and enabling multi-year battery life. LNM (Low Noise Mode) forces continuous PWM operation at fixed frequency - reducing output voltage ripple and EMI peaks for noise-sensitive analog circuits. The mode is fixed per part number; L6983C33QTR is an LCM variant.
Can the L6983C33QTR be synchronized to an external clock?
No - only LNM-version L6983 parts (e.g., L6983N33QTR) support external clock synchronization via the EN/CLKIN pin. The L6983C33QTR is an LCM variant and does not implement clock sync functionality; its switching frequency is set solely by the FSW resistor and cannot be externally locked.
What is the purpose of the VINLDO pin (Pin 2) and how should it be used?
Pin 2 (VINLDO) supplies the internal LDO that powers analog circuitry. It can be connected directly to VIN or filtered via an RC network (e.g., 0.1 kΩ + 1 µF) to suppress high-frequency noise from the main input rail. This isolation improves PSRR and reduces switching noise coupling into the error amplifier - critical in 24 V industrial settings with heavy motor or relay loads.
Does the L6983C33QTR require external compensation components?
No - the L6983C33QTR features a fully integrated internal compensation network optimized for stability with standard ceramic output capacitors. No external Type-II or Type-III compensation network is needed, reducing bill-of-materials count, PCB area, and design validation effort while maintaining phase margin >45° across all operating conditions.
L6983C33QTR 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):
- 3.3V
- 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)
L6983C33QTR FAQ
1.How can I place an order for L6983C33QTR through Aetrix?
Please submit a Request for Quotation (RFQ) for L6983C33QTR 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 L6983C33QTR reliable?
The price and inventory of L6983C33QTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6983C33QTR is usually 5 days.
3.What payment methods are accepted for L6983C33QTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6983C33QTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L6983C33QTR?
L6983C33QTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L6983C33QTR 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 L6983C33QTR?
For technical support, including L6983C33QTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6983C33QTR requirements.
6.How does Aetrix verify that L6983C33QTR is sourced from the original manufacturer or authorized distributors?
All L6983C33QTR 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 L6983C33QTR meets industry standards.
7.What is the process for return or replacement of L6983C33QTR?
All L6983C33QTR units undergo pre-shipment inspection (PSI). If there is an issue with L6983C33QTR, 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 L6983C33QTR part is unused and in its original packaging.
Return procedure for L6983C33QTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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