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

STMicroelectronics L5983

Name: L5983
Brand: STMicroelectronics
SKU: L5983
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L5983

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 8-VFDFN Exposed Pad

Datasheet:: L5983.pdf

Description:: IC REG BUCK ADJ 1.5A 8VFQFPN

Quantity:: RFQ Add To RFQ list

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Inventory:1,392

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Product details

Overview

L5983 from STMicroelectronics is a 1.5 A step-down switching regulator with integrated P-channel MOSFET, designed for DC-DC conversion in space-constrained power rails. It operates from 2.9 V to 18 V input, delivers adjustable output down to 0.6 V, features 250 kHz–1 MHz programmable switching frequency, internal soft-start, and 100% duty-cycle low-dropout operation - used in LCD TV power supplies and FPGA core voltage regulation.

For engineers reviewing the L5983 datasheet, L5983 pinout, L5983 application, or L5983 equivalent, key selection criteria include its VFQFPN8 3×3 mm thermal performance (R_thJA ≈ 60 °C/W), voltage-mode control architecture, synchronization capability via SYNCH pin, and hiccup-mode overcurrent protection during regulated output conditions.

Technical Context

The L5983 implements voltage-mode PWM control with a fixed-frequency sawtooth oscillator whose slope is dynamically adjusted via voltage feedforward (input-dependent) and frequency feedforward (FSW-resistor dependent) to maintain constant PWM gain across input and frequency variations. Its error amplifier has 100 dB DC gain, 4.5 MHz GBWP, and drives external Type II/III compensation networks.

Synchronization is achieved through the bidirectional SYNCH pin: when floating, it outputs a 180° phase-shifted clock; when driven externally, it locks the device to an external frequency with zero phase shift; when tied to another L5983, master/slave interleaving reduces input ripple current. Thermal shutdown activates at 150 °C with 30 °C hysteresis.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	1.5 A DC continuous; supports >2.0 A peak current limiting for transient overload handling
Input voltage range	2.9 V to 18 V; compatible with 3.3 V bus systems due to low VIN_ON threshold
Output voltage range	0.6 V to V_IN; set via resistor divider on FB pin with 0.6 V internal reference
Switching frequency	250 kHz base (FSW pin floating); programmable up to 1 MHz using external resistor to GND
MOSFET R_DS(on)	140–220 mΩ typical; enables high efficiency at 1.5 A load without external high-side switch
Soft-start duration	7.4–9.1 ms at 250 kHz; staircase ramp with 64 steps × 9.5 mV ensures monotonic V_OUT rise
Thermal shutdown	150 °C activation with 30 °C hysteresis; fast-recovery restart at ~130 °C junction temperature

Pinout & Package

VFQFPN8 3 × 3 mm package with exposed thermal pad; R_thJA ≈ 60 °C/W on demo board layout.

Pin/Terminal	Circuit Role	Design Meaning
OUT	Regulator output	Power output node connected directly to LC filter; carries full switched output current
SYNCH	Master/slave synchronization I/O	Bidirectional pin: outputs 180° phase-shifted clock when floating; accepts external sync signal; enables interleaved operation when tied to second L5983
INH	Inhibit control (active-high)	Logic-level enable/disable: <0.6 V = ON; >1.9 V = OFF; floating = disabled via internal pull-up
COMP	Error amplifier output	High-impedance node for external compensation network (Type II/III); ±25 mA sink/source capability
FB	Feedback input	Senses output voltage via resistor divider; referenced to 0.6 V internal bandgap; 1 µA bias current
FSW	Frequency setting input	Connect external resistor to GND to scale switching frequency from 250 kHz to 1 MHz; open = default 250 kHz
GND	Power and signal ground	Common return path for power stage, control circuitry, and thermal pad; must be low-inductance connection
VCC	Unregulated input supply	Primary power input (2.9–18 V); powers internal regulator, gate driver, and logic; UVLO threshold = 2.9 V

Key Features

Feature	Design Value
Voltage feedforward	Adjusts sawtooth slope in real time with input voltage changes to maintain stable PWM gain and improve line transient response
Zero-load operation	Stable regulation with no minimum load required; quiescent current as low as 20 µA in standby mode
Hiccup-mode OCP	Enters safe cycling (off-time = 2048 clock cycles) under sustained short-circuit, limiting average power dissipation
100% duty cycle capability	Enables dropout operation down to V_OUT = V_IN – V_SW, supporting ultra-low ΔV applications like post-regulation of 3.3 V rails
Internal soft-start	Hardware-controlled 64-step voltage ramp on error amp reference eliminates need for external timing components

Applications

Consumer Audio Power Supply

FPGA Core Voltage Regulation

Use Scenario: Powering digital audio processors and DACs in car audio head units requiring clean, low-noise 1.2 V or 1.8 V rails.

IC Role / Device Role / Timing Role: Primary buck converter delivering tightly regulated core voltage with fast load-step response.

Use Value: Internal 0.6 V reference and Type III compensation support <±1% output accuracy and >60° phase margin across temperature and load.

Use Scenario: Generating configurable core voltage (e.g., 1.0 V, 1.2 V) for Xilinx Spartan or Intel Cyclone FPGAs in industrial PLC modules.

IC Role / Device Role / Timing Role: Adjustable-output DC-DC regulator with programmable frequency to avoid EMI-sensitive bands near Ethernet PHY clocks.

Use Value: 250 kHz–1 MHz frequency tuning allows optimal trade-off between inductor size and switching loss in compact PCB layouts.

LCD TV Backlight Bias Supply

DSL Modem DC-DC Module

Use Scenario: Providing stable 5 V or 12 V bias for LED backlight drivers in 24–32 inch LCD monitors.

IC Role / Device Role / Timing Role: High-current (1.5 A) buck regulator operating from 12 V or 19 V adapter input.

Use Value: VFQFPN8 thermal design enables >1.2 W dissipation at ambient 70 °C without heatsink, reducing BOM cost.

Use Scenario: Generating isolated 3.3 V and 5 V rails in xDSL modems powered from wide-range AC adapters (9–24 V DC).

IC Role / Device Role / Timing Role: Input-flexible buck converter supporting universal adapter compatibility and brownout resilience.

Use Value: 2.9 V minimum input and 100% duty cycle allow regulation even during low-line AC adapter dips, preventing system reset.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2315GJ-Z	2 A rated, 3–18 V input, fixed 500 kHz f_SW, no SYNC pin, smaller 2×2 mm QFN	Lacks synchronization and adjustable frequency; better suited for cost-sensitive, non-interleaved designs	Select when footprint and BOM count are prioritized over thermal performance and multi-phase coordination
TPS54331DR	3 A rated, 3.5–28 V input, 570 kHz f_SW, external COMP/SS pins, SOIC-8 package	Higher current, wider VIN, but larger thermal resistance (~100 °C/W) and no 100% duty cycle	Select when higher output current and SOIC assembly compatibility outweigh thermal density requirements

Compared with MP2315GJ-Z and TPS54331DR, the L5983 uniquely combines 100% duty cycle operation, VFQFPN8 thermal efficiency, and bidirectional SYNCH for interleaved power delivery - making it optimal for compact, thermally constrained, multi-rail consumer and industrial systems.

Availability

L5983 is available at Aetrix Electronics and suitable for LCD TV power supplies, FPGA core voltage regulation, DSL modem DC-DC modules, and car audio processor rails requiring stable component supply across production lifecycles.

Supply support for L5983 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 analog ICs for automotive, industrial, and consumer markets.

The L5983 belongs to ST's high-efficiency monolithic buck regulator product line, engineered for space-constrained, thermally demanding applications where integration, thermal performance, and flexible frequency control are critical.

FAQ

What is the minimum input voltage required for L5983 startup?

The L5983 requires a minimum input voltage of 2.9 V to initiate operation, as defined by its V_CCON UVLO threshold. Below this level, the internal regulator remains inactive and the device stays in shutdown. This enables reliable operation from 3.3 V intermediate buses while maintaining sufficient headroom for input ripple and dropouts.

Can L5983 operate with no output load?

Yes - the L5983 supports zero-load current operation with stable regulation and quiescent current as low as 20 µA in standby mode. Its voltage-mode control loop and internal reference remain active, and the output voltage remains within specification even with open-circuit output, verified across -40 °C to +125 °C.

How does the SYNCH pin function in master-slave configuration?

When two L5983 devices have their SYNCH pins connected, the unit with the higher oscillator frequency automatically becomes the master and drives the shared synchronization signal; the other acts as slave with 180° phase shift. This interleaving halves the RMS input capacitor current, reducing required capacitance and ESR in multi-rail systems.

What compensation network type is recommended for ceramic output capacitors with low ESR?

For ceramic output capacitors with very low ESR (e.g., ≤5 mΩ), a Type II compensation network is recommended - it introduces one pole and one zero to stabilize the loop against the single ESR zero and double LC pole. The L5983's error amplifier characteristics (100 dB gain, 4.5 MHz GBWP) support robust phase margin with properly sized RC-lead networks on the COMP pin.

L5983 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-VFDFN Exposed Pad

Packaging:: Tube

Product Status:: Discontinued at Digi-Key

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 2.9V

Voltage - Input (Max):: 18V

Voltage - Output (Min/Fixed):: 0.6V

Voltage - Output (Max):: 18V

Current - Output:: 1.5A

Frequency - Switching:: 250kHz ~ 1MHz

Synchronous Rectifier:: No

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-VFQFPN (3x3)

L5983 FAQ

1.How can I place an order for L5983 through Aetrix?

Please submit a Request for Quotation (RFQ) for L5983 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 L5983 reliable?

The price and inventory of L5983 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L5983 is usually 5 days.

3.What payment methods are accepted for L5983?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L5983 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L5983?

L5983 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L5983 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 L5983?

For technical support, including L5983 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L5983 requirements.

6.How does Aetrix verify that L5983 is sourced from the original manufacturer or authorized distributors?

All L5983 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 L5983 meets industry standards.

7.What is the process for return or replacement of L5983?

All L5983 units undergo pre-shipment inspection (PSI). If there is an issue with L5983, 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 L5983 part is unused and in its original packaging.

Return procedure for L5983:

1.Submit a request within 90 days.

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

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