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STMicroelectronics L7983PUR
- Part No.:
- L7983PUR
- Manufacturer:
- STMicroelectronics
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
L7983PUR.pdf
- Description:
- IC REG BUCK ADJ 300MA 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,467
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Product details
Overview
L7983PUR from STMicroelectronics is a 3.5 V to 60 V input, synchronous step-down DC-DC regulator delivering up to 300 mA output current with adjustable output voltage (0.85 V to VIN), 10 µA quiescent current in Low Consumption Mode (LCM), and programmable switching frequency from 200 kHz to 2.2 MHz. It integrates high-side P-MOS and low-side N-MOS, internal compensation, and supports dynamic LCM/LNM mode selection for industrial bus (12 V/24 V/48 V) and battery-powered sensor nodes.
For engineers reviewing the L7983PUR datasheet, L7983PUR pinout, L7983PUR application, or L7983PUR equivalent, key selection criteria include its dual-mode operation (LCM for ultra-low IQ, LNM for constant-frequency low-noise regulation), integrated RST open-collector reset supervisor, and VIN-compatible EN/UVLO with adjustable undervoltage lockout threshold.
Technical Context
The L7983PUR employs peak current mode control with integrated slope compensation and an internal transconductance amplifier (gm), enabling stable loop response without external compensation components. Its dual-mode architecture dynamically selects between Low Consumption Mode (LCM) - where switching is pulse-skipped at light load to achieve 10 µA IQ - and Low Noise Mode (LNM) - where fixed-frequency operation ensures controlled ripple and fast transient response.
It features synchronized MOSFET gate drive with anti-shoot-through logic and adaptive deadtime, plus cycle-by-cycle overcurrent protection using both peak (IPK = 0.47 A typ.) and valley (IVY = 0.52 A typ.) current sensing. The RST pin provides active-low, hysteresis-based (2%) output voltage supervision with 2 ms release delay, supporting power-up sequencing for microcontrollers and FPGAs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 60 V - supports direct connection to 12 V, 24 V, and 48 V industrial buses without pre-regulation. |
| Output Current | 300 mA DC - sufficient for powering microcontrollers, sensors, and low-power FPGA I/O banks. |
| Quiescent Current (LCM) | 10 µA at VIN > 24 V - enables multi-year battery life in always-on IoT edge nodes. |
| Switching Frequency | 200 kHz to 2.2 MHz - selectable via external resistor on FSW pin; enables compact magnetics or EMI-sensitive placement. |
| Feedback Reference | 0.850 V ±0.6% - sets precise output voltage via external resistor divider; supports 0.85 V to VIN adjustment range. |
| Reset Threshold Accuracy | 92% of VREF ±2% - ensures reliable power-good signaling for digital loads during startup and brownout conditions. |
| Thermal Shutdown | 165 °C with 30 °C hysteresis - protects against sustained overload or poor PCB thermal design without latch-off. |
Pinout & Package
Package: HTSSOP-10 (exposed pad), 3 mm × 3 mm, pitch 0.5 mm - optimized for thermal dissipation and space-constrained industrial PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VOUT/FB | Output voltage feedback node | Connects to external resistor divider for adjustable output; internally tied to 0.85 V reference for regulation. |
| 2 VBIAS | LDO bias supply input | Accepts auxiliary rail or regulated output to improve light-load efficiency; bypass with 100 nF if used. |
| 3 VCC | Internal LDO output | Supplies analog circuitry; requires 470 nF ceramic capacitor to GND for stable reference filtering. |
| 4 FSW | Frequency programming input | Resistor-to-GND or resistor-to-VCC sets switching frequency; dithering enabled when connected to VCC. |
| 5 LNM/LCM | Mode selection / clock sync input | High = LNM (constant frequency); low = LCM (pulse-skipping); external clock input for synchronization. |
| 6 RST | Open-drain reset output | Asserts low when VOUT drops below 92% VREF; releases after 2 ms delay once valid - enables MCU/FPGA power sequencing. |
| 7 EN/UVLO | Enable / UVLO threshold input | VIN-compatible; external resistor divider sets custom turn-on voltage (e.g., 18 V for 24 V bus). |
| 8 VIN | Main power input | Accepts 3.5–60 V; feeds HS MOS source and internal LDO; absolute max 63 V. |
| 9 LX | Switching node | Connects to external inductor; carries pulsed current; must be routed with minimal loop area for EMI control. |
| 10 GND + EP | Power and signal ground | Exposed pad must be soldered to large GND copper pour for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic LCM ↔ LNM transition | Enables real-time trade-off between ultra-low IQ (10 µA) and low-noise regulation (fixed fSW) without reconfiguration. |
| Integrated RST supervisor | Provides hysteresis-controlled, delay-stabilized reset signal - eliminates need for external supervisor IC in MCU/FPGA designs. |
| Synchronous rectification | P-MOS HS + N-MOS LS reduces conduction loss vs. diode-based buck; improves efficiency across 10 mA–300 mA load range. |
| Programmable UVLO | EN/UVLO pin accepts resistor divider to set custom input turn-on voltage - ensures robust start-up on fluctuating industrial rails. |
| Internal compensation network | Removes requirement for external Type II/III compensation components - simplifies layout and reduces BOM count. |
Applications
| Industrial 24 V Bus Power | Battery-Powered Sensor Node |
|---|---|
Use Scenario: Powering PLC I/O modules and fieldbus interface circuits on 24 V factory floor distribution rails. IC Role / Device Role / Timing Role: Primary buck regulator converting 24 V bus to 3.3 V for microcontroller, CAN transceiver, and analog front-end. Use Value: Adjustable UVLO prevents erratic startup during rail sag; LCM mode extends maintenance interval by minimizing standby drain. | Use Scenario: Supplying ultra-low-power environmental sensors (temperature/humidity/CO₂) in wireless mesh networks. IC Role / Device Role / Timing Role: Main system regulator delivering 1.8 V or 3.3 V from primary Li-SOCl₂ or AA cells with multi-year shelf life. Use Value: 10 µA quiescent current in LCM enables >10-year battery life; RST pin directly resets sensor MCU on brownout. |
| Decentralized Intelligent Node | Fail-Safe System Monitoring |
Use Scenario: Powering edge AI inference accelerators and local decision logic in distributed automation controllers. IC Role / Device Role / Timing Role: Secondary regulator generating clean 1.2 V core voltage for low-power DSP or RISC-V SoC under variable load. Use Value: LNM mode ensures stable switching frequency during burst inference workloads - avoids EMI coupling into sensitive analog inputs. | Use Scenario: Providing monitored 5 V rail for safety-critical watchdog timers, relay drivers, and diagnostic LEDs in railway signaling systems. IC Role / Device Role / Timing Role: Regulator with built-in OVP, OTP, and RST supervision - acts as self-contained power health monitor. Use Value: RST assertion on 2% VOUT deviation triggers immediate fail-safe action; thermal shutdown prevents cascade failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR36503RNXR | 4.2–65 V input, 300 mA, 26 µA IQ (not mode-switchable), no RST output | Lacks integrated reset supervisor and dynamic LCM/LNM; requires external reset IC for sequencing | Select when lowest possible BOM cost is prioritized over supervision and noise control. |
| TPS63020DSJR | Buck-boost topology, 1.8–5.5 V output, 2 A capability, 30 µA IQ | Supports wide output range but higher IQ and no programmable UVLO or RST | Select only when input can drop below output (e.g., single-cell Li-ion), not for fixed 24/48 V bus use. |
Compared with LMR36503RNXR and TPS63020DSJR, the L7983PUR uniquely combines ultra-low IQ in LCM mode, integrated RST supervision, and dynamic noise/efficiency optimization - making it optimal for industrial bus and battery-powered applications requiring both longevity and reliability.
Availability
L7983PUR is available at Aetrix Electronics and suitable for industrial 24 V bus power, battery-powered sensor nodes, decentralized intelligent nodes, and fail-safe system monitoring requiring stable component supply and long-term lifecycle support.
Supply support for L7983PUR 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, specializing in power management, microcontrollers, and automotive-grade ICs with strong industrial and automotive certification heritage.
The L7983 series targets high-reliability industrial power conversion - designed specifically for decentralized nodes, fail-safe systems, and battery-backed applications demanding wide VIN, ultra-low IQ, and integrated supervision.
FAQ
What is the minimum recommended output capacitor for stable operation of L7983PUR?
A minimum 10 µF X5R/X7R ceramic capacitor with ≤5 mΩ ESR is required at the VOUT pin. ST recommends 22 µF total capacitance (e.g., one 22 µF + one 100 nF) placed within 3 mm of VOUT/FB and GND pins to ensure stability across all load and temperature conditions per DS13354 Section 7.2.
Can L7983PUR operate with an input voltage lower than 3.5 V?
No. The absolute minimum operating input voltage is 3.5 V per datasheet Section 3.3. Below this, the internal LDO cannot power control circuitry and the HS MOSFET gate drive becomes insufficient. Attempting operation below 3.5 V may cause unregulated output or intermittent shutdown.
How does the LNM/LCM pin behave during external clock synchronization?
When an external clock (180–2400 kHz) is applied to LNM/LCM, the device synchronizes switching and automatically enters LNM mode. If the clock stops for ≥14 µs, it reverts to free-running frequency set by the FSW resistor. No additional configuration is needed - clock edges directly override internal oscillator timing.
Is the RST pin compatible with 5 V logic systems?
Yes. The RST pin is open-drain with 4 mA sink capability and 0.4 V max VOL at 4 mA. It can directly drive standard 5 V TTL/CMOS inputs when pulled up to 5 V via a 10 kΩ resistor. No level-shifter is required for interfacing with 5 V microcontrollers or CPLDs.
L7983PUR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 10-WFDFN 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):
- 60V
- Voltage - Output (Min/Fixed):
- 0.85V
- Voltage - Output (Max):
- 60V
- Current - Output:
- 300mA
- Frequency - Switching:
- 200kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
L7983PUR FAQ
1.How can I place an order for L7983PUR through Aetrix?
Please submit a Request for Quotation (RFQ) for L7983PUR 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 L7983PUR reliable?
The price and inventory of L7983PUR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L7983PUR is usually 5 days.
3.What payment methods are accepted for L7983PUR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L7983PUR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L7983PUR?
L7983PUR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L7983PUR 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 L7983PUR?
For technical support, including L7983PUR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L7983PUR requirements.
6.How does Aetrix verify that L7983PUR is sourced from the original manufacturer or authorized distributors?
All L7983PUR 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 L7983PUR meets industry standards.
7.What is the process for return or replacement of L7983PUR?
All L7983PUR units undergo pre-shipment inspection (PSI). If there is an issue with L7983PUR, 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 L7983PUR part is unused and in its original packaging.
Return procedure for L7983PUR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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