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

STMicroelectronics L4963W

Name: L4963W
Brand: STMicroelectronics
SKU: L4963W
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L4963W

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 18-DIP (0.300", 7.62mm)

Datasheet:: L4963W.pdf

Description:: IC REG BUCK ADJ 1.5A 18DIP

Quantity:: RFQ Add To RFQ list

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Inventory:2,658

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Product details

Overview

L4963W from STMicroelectronics is a monolithic step-down switching regulator delivering 1.5A at 5.1V with adjustable output from 5.1V to 36V, operating in discontinuous variable-frequency mode. It integrates on-chip 5.1V reference (±2%), open-collector reset and power-fail outputs for microprocessor supervision, TTL-level inhibit control, internal current limiting, and thermal shutdown. Used in industrial power supplies requiring stable mid-current DC-DC conversion with system monitoring.

For engineers reviewing the L4963W datasheet, L4963W pinout, L4963W application, or L4963W equivalent, this page provides verified technical context, confirmed pin functions, real-world application cards, validated alternatives, and supply-chain support details specific to the Powerdip12+3+3 package variant.

Technical Context

The L4963W implements a self-oscillating discontinuous conduction mode (DCM) buck topology with no external frequency compensation required. Regulation relies on two comparators comparing feedback voltage against a precise internal 5.1V reference, latched drive control, and zero-current detection via catch diode conduction end.

It features programmable oscillator frequency (via R_OSC on Pin 20), adjustable power-fail threshold (via external divider on Pin 8), user-set reset delay (via capacitor on Pin 10), and remote TTL inhibit (Pin 18). Thermal protection activates at ~150°C with 30°C hysteresis; current limit trips at 3.5–6.5A depending on junction temperature and input voltage.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Current	1.5A continuous at 5.1V; derated above 5.1V due to power dissipation limits
Output Voltage Range	5.1V to 36V adjustable via external resistor divider on Feedback pin (Pin 13)
Reference Voltage	5.1V ±2% internal reference (Pin 12); 0.4 mV/°C tempco ensures stability across 0–125°C
Input Voltage Range	9V to 46V (absolute max 47V); supports wide industrial input rails including 24V and 36V systems
Efficiency	65–75% typical at 1.5A/5.1V; optimized for minimal external component count without compensation networks
Thermal Shutdown	Triggers at 145–150°C junction temperature with 30°C hysteresis to prevent oscillation near trip point
Reset Delay Control	Programmable via capacitor on Pin 10; sets time before RESET output asserts after valid output is achieved

Pinout & Package

L4963W is supplied in a Powerdip12+3+3 (18-pin staggered dual-in-line) package with 12 main leads plus 3 auxiliary pins on each side - optimized for high-current thermal dissipation and PCB layout simplicity in industrial power modules.

Pin/Terminal	Circuit Role	Design Meaning
1, 3	Signal Supply Voltage / Unregulated Input	Pins 1 and 3 must be connected together to supply unregulated input (9–46V); powers internal logic and switch driver
2	Regulator Output	Main switched output node; connects to inductor and output filter capacitor; dropout voltage ≤2V at 3A
4–7, 13–15, 17	Ground	Common ground return path for power stage, feedback, and logic circuits; multiple pins reduce impedance
8	Power Fail Input	Monitors input rail via external voltage divider; default threshold ≈5.1V when left open
9	Power Fail Output	Open-collector signal asserted high when input voltage exceeds programmed threshold; requires pull-up
10	Reset Delay Input	Capacitor-to-ground sets delay time before RESET output becomes valid after startup or recovery
11	Reset Output	Open-collector reset signal high when output voltage is within regulation (±100–150mV of Vref)
12	Feedback Input	Closed-loop regulation node; direct connection yields 5.1V; resistor divider enables higher outputs
16	Inhibit Input	TTL-compatible active-low enable; logic low disables switching and reduces quiescent current to ~11mA
17	Oscillator Capacitor	Capacitor-to-ground sets minimum oscillator period; works with Pin 20 to define max frequency
18	Oscillator Resistor	Resistor-to-ground (e.g., 51kΩ) defines maximum switching frequency (42–83kHz)
19	Reference Voltage Output	Stable 5.1V ±2% source for external circuitry or precision divider biasing

Key Features

Feature	Design Value
No external compensation required	Discontinuous mode operation eliminates need for loop compensation components - reduces BOM and layout complexity
Integrated microprocessor supervision	Dual open-collector outputs (RESET and POWER FAIL) with programmable thresholds and delays simplify system-level power sequencing
Adjustable oscillator frequency	Max switching frequency set by single resistor (Pin 20) and capacitor (Pin 17), enabling EMI optimization per application
Robust protection suite	Combined overcurrent (3.5–6.5A), thermal (145–150°C), and undervoltage lockout (via PF input) ensure reliable field operation
Low-component-count design	Operates with only inductor, catch diode, input/output capacitors, and optional feedback divider - ideal for space-constrained industrial modules

Applications

Industrial PLC Power Supply

Telecom Line Card DC-DC

Use Scenario: Primary 5.1V or 12V local power rail generation in programmable logic controller backplanes with wide input range (24V–48V DC).

IC Role / Device Role / Timing Role: Step-down switching regulator with integrated reset and power-fail signaling to coordinate CPU boot and brownout response.

Use Value: Eliminates need for separate supervisor ICs; maintains deterministic reset timing even during input transients down to 9V.

Use Scenario: Mid-current (1–1.5A) isolated or non-isolated DC-DC stage powering DSPs, PHYs, and interface ASICs on telecom line cards.

IC Role / Device Role / Timing Role: Regulator with programmable oscillator and thermal shutdown ensures stable operation under variable load and ambient conditions.

Use Value: Adjustable output (up to 36V) supports diverse sub-rail requirements; low external part count accelerates qualification in carrier-grade designs.

Automotive Body Control Module

Test & Measurement Equipment

Use Scenario: Secondary 5.1V/12V supply in body control units powered from 12V battery with load dump immunity up to 46V.

IC Role / Device Role / Timing Role: High-input-voltage buck regulator with built-in current limiting and thermal protection for harsh automotive environments.

Use Value: Internal 47V absolute max rating and 30°C thermal hysteresis prevent nuisance shutdowns during engine cranking or hot-soak conditions.

Use Scenario: Lab-grade bench power module generating stable, adjustable DC outputs (5.1–36V) for device-under-test biasing.

IC Role / Device Role / Timing Role: Programmable regulator with precise 5.1V reference and low line/load regulation (≤50mV) for calibration-critical applications.

Use Value: On-chip reference stability (0.4 mV/°C) and <±2% accuracy enable traceable voltage sourcing without external references.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2596-5.0	Fixed 5V output only; no adjustable range, no power-fail or reset outputs; requires external compensation	Lacks microprocessor supervision features; suitable only for basic fixed-output use cases	Select when cost sensitivity outweighs system-monitoring needs and output voltage is strictly 5V
TPS5430	Higher 3A output; requires external compensation; no integrated reset/power-fail; 5.5–36V input	Targets higher-current applications but adds design complexity and external ICs for supervision	Choose when >1.5A load current is required and board space allows additional supervision circuitry

Compared with LM2596-5.0 and TPS5430, the L4963W uniquely combines adjustable output (5.1–36V), integrated reset/power-fail signaling, and no-compensation DCM operation - making it optimal for industrial and embedded systems needing both flexibility and system-level reliability in one package.

Availability

L4963W is available at Aetrix Electronics and suitable for industrial PLC power supplies, telecom line card DC-DC stages, and automotive body control modules requiring stable component supply with long lifecycle visibility.

Supply support for L4963W 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 analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

The L4963W belongs to ST's legacy power management portfolio targeting robust, low-complexity DC-DC conversion for industrial and embedded applications where reliability, integration, and wide input range are critical.

FAQ

What is the maximum input voltage the L4963W can safely handle?

The L4963W has an absolute maximum input voltage rating of 47V across Pins 1 and 3. Continuous operation is specified from 9V to 46V. Exceeding 46V risks permanent damage, especially during transient events like load dump - design margin should maintain Vi ≤ 44V under worst-case conditions.

Can the L4963W generate output voltages below 5.1V?

No - the internal 5.1V reference sets the minimum regulated output. The device is not designed for buck-boost or negative output configurations. Output voltages less than 5.1V cannot be achieved using the standard feedback configuration and violate the regulation architecture described in the datasheet.

How does the oscillator frequency adjustment work on Pins 17 and 18?

Pin 17 (C_OSC) accepts a capacitor to ground that sets the minimum oscillator period, while Pin 18 (R_OSC) accepts a resistor to ground that defines the maximum frequency. Together they constrain the variable-frequency operation between ~42kHz and 83kHz, allowing EMI tuning without altering core regulation behavior.

Is the L4963W RoHS compliant and lead-free?

Yes - the L4963W Powerdip12+3+3 package is RoHS compliant and lead-free, consistent with STMicroelectronics' 2006 transition to lead-free packaging. The device carries the "ECOPACK®" designation and meets JEDEC J-STD-020 moisture sensitivity level MSL3.

L4963W Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 18-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 9V

Voltage - Input (Max):: 46V

Voltage - Output (Min/Fixed):: 5.1V

Voltage - Output (Max):: 36V

Current - Output:: 1.5A

Frequency - Switching:: 42kHz ~ 83kHz

Synchronous Rectifier:: No

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 18-DIP

L4963W FAQ

1.How can I place an order for L4963W through Aetrix?

Please submit a Request for Quotation (RFQ) for L4963W 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 L4963W reliable?

The price and inventory of L4963W are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L4963W is usually 5 days.

3.What payment methods are accepted for L4963W?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L4963W transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L4963W?

L4963W orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L4963W 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 L4963W?

For technical support, including L4963W datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L4963W requirements.

6.How does Aetrix verify that L4963W is sourced from the original manufacturer or authorized distributors?

All L4963W 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 L4963W meets industry standards.

7.What is the process for return or replacement of L4963W?

All L4963W units undergo pre-shipment inspection (PSI). If there is an issue with L4963W, 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 L4963W part is unused and in its original packaging.

Return procedure for L4963W:

1.Submit a request within 90 days.

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

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