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STMicroelectronics E-L4971D
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- Part No.:
- E-L4971D
- Manufacturer:
- STMicroelectronics
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
E-L4971D.pdf
- Description:
- IC REG BUCK ADJ 1.5A 16SO W
- Quantity:
- Payment:
- Shipping:
Inventory:1,218
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Product details
Overview
E-L4971D from STMicroelectronics is a monolithic step-down switching regulator IC delivering up to 1.5A output current, operating from 8V to 55V input, with adjustable output voltage from 3.3V to 50V, internal 3.3V ±1% reference, and switchable frequency up to 300kHz. It integrates a power D-MOS transistor (RDS(on) = 0.25Ω typ.) and supports zero-load operation in inhibit mode for industrial power supplies and telecom DC-DC conversion.
For engineers reviewing the E-L4971D datasheet, E-L4971D pinout, E-L4971D application, or E-L4971D equivalent, key selection criteria include input voltage range (8–55V), output adjustability (3.3–50V), thermal shutdown behavior, soft-start timing control via external capacitor, and SO16W package compatibility with high-density SMD layouts.
Technical Context
The L4971 employs voltage feedforward regulation to maintain stable switching frequency across wide input voltage variations, with oscillator timing set by an external R-C network on the OSC pin. Its error amplifier features 57dB open-loop gain and 2.5mS transconductance, enabling precise loop compensation via the COMP pin.
Internal protection includes pulse-by-pulse current limiting (2.5A typ.), hiccup-mode short-circuit response, feedback disconnection detection, and thermal shutdown at 150°C. The BOOT pin drives the internal high-side DMOS gate using a bootstrap capacitor referenced to the OUT node.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8V to 55V - supports wide-range industrial and telecom inputs without pre-regulation |
| Output Current | Up to 1.5A continuous - sufficient for mid-power point-of-load conversion |
| Output Voltage Range | 3.3V to 50V adjustable - set via external resistor divider on FB pin |
| Switching Frequency | Adjustable up to 300kHz - balances efficiency vs. size of external inductor/capacitors |
| Reference Voltage | 3.3V ±1% - enables accurate low-voltage regulation (e.g., 3.3V logic rails) |
| RDS(on) | 0.25Ω typical - reduces conduction loss and improves full-load efficiency (>85% at 3.3V/1.5A) |
| Quiescent Current | 6mA typical operating, 200µA standby - minimizes no-load power draw in battery-backed systems |
Pinout & Package
Package: SO16W (wide-body SOIC-16), surface-mount, 1.27mm pitch, 10.1–10.5mm × 7.4–7.6mm body, 2.35–2.65mm height. Thermal resistance Rth(j-amb) = 110°C/W (mounted on board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 7, 8, 9, 10, 15, 16 | No Connect (NC) | Not internally bonded - must be left floating or grounded per layout guidelines |
| 3 | SS_INH | Active-low inhibit/soft-start control - capacitor to GND sets soft-start time; grounding disables device |
| 4 | OSC | Oscillator timing node - external R to VCC + C to GND sets switching frequency and enables voltage feedforward |
| 5, 6 | OUT | Power output node - connects to inductor and output filter; also serves as bootstrap return path |
| 11 | VCC | Unregulated input supply - powers internal circuitry; must be ≥8V and ≤55V |
| 12 | BOOT | Bootstrap capacitor connection - forms floating supply for internal high-side DMOS gate drive |
| 13 | COMP | Error amplifier output - external compensation network (R+C) connects here for loop stability |
| 14 | FB | Feedback input - direct connection yields 3.3V output; resistive divider scales higher voltages |
Key Features
| Feature | Design Value |
|---|---|
| Voltage Feedforward Regulation | Stabilizes switching frequency against input ripple, reducing output voltage variation under line transients |
| Pulse-by-Pulse Current Limiting | 2.5A typical limit with cycle-by-cycle monitoring - prevents MOSFET failure during overload or short-circuit |
| Hiccup-Mode Short-Circuit Protection | Auto-retry after thermal recovery - avoids latch-up while maintaining safe junction temperature |
| Soft Start with External Timing | Capacitor on SS_INH pin controls ramp rate - eliminates inrush current and output overshoot at startup |
| Inhibit Function with Zero-Current Standby | 100–300µA standby current when SS_INH < 0.9V - enables ultra-low-power sleep states |
Applications
| Industrial PLC Power Supply | Telecom Line Card DC-DC |
|---|---|
|
Use Scenario: Providing isolated 5.1V/1.5A rail from 24–48V backplane in programmable logic controller modules. IC Role / Device Role / Timing Role: Primary step-down regulator controlling power delivery to FPGA, I/O drivers, and communication interfaces. Use Value: Wide 8–55V input accommodates brownout and surge conditions; hiccup-mode protection ensures field reliability without manual reset. |
Use Scenario: Generating 12V/1.2A for Ethernet PHY and management MCU from -48V telecom supply (with polarity inversion stage). IC Role / Device Role / Timing Role: Non-isolated buck converter operating at 100kHz with feedforward for stable output under fast load steps. Use Value: 0.25Ω RDS(on) and 86% efficiency at 12V/1.5A reduce thermal load in confined card slots. |
| Automotive Body Control Module | Test Equipment Auxiliary Rail |
|
Use Scenario: Deriving 3.3V/1.0A for microcontroller and CAN transceiver from 12V battery (with cold-crank tolerance down to 6V). IC Role / Device Role / Timing Role: Main system regulator with soft start and thermal shutdown for safety-critical subsystems. Use Value: 3.3V ±1% reference and 3mV line regulation ensure ADC accuracy and digital logic integrity during engine cranking. |
Use Scenario: Supplying adjustable 15V/1A bench rail from lab power supply for prototype validation of analog front-ends. IC Role / Device Role / Timing Role: Programmable output regulator with external feedback divider and COMP-based loop tuning. Use Value: Adjustable 3.3–50V output and 300kHz max frequency enable rapid iteration across multiple DUT voltage requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down switching regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-ADJ | Fixed 150kHz frequency, 3A rating, no voltage feedforward, larger dropout (1.5V min) | Lacks hiccup-mode protection and zero-load inhibit; requires larger input capacitor for same line rejection | Prefer for cost-sensitive, lower-frequency designs where thermal margin exceeds 1.5A load |
| MP2315GJ-Z | 40V max input, 2A output, integrated MOSFETs, 500kHz switching, no BOOT pin | Higher frequency allows smaller magnetics but limited to 40V input - unsuitable for 48V telecom or industrial 55V rails | Choose when board space is constrained and input stays ≤40V; avoid for 48–55V applications |
Compared with LM2596S-ADJ and MP2315GJ-Z, E-L4971D uniquely supports 55V input, hiccup-mode fault recovery, and voltage feedforward for superior line transient immunity - critical for unregulated industrial and telecom sources.
Availability
E-L4971D is available at Aetrix Electronics and suitable for industrial PLC power supplies, telecom line card DC-DC conversion, and automotive body control modules requiring stable component supply and long-term lifecycle support.
Supply support for E-L4971D 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.
E-L4971D belongs to ST's legacy power management IC portfolio, engineered specifically for robust, high-voltage step-down conversion in harsh environments where reliability, thermal resilience, and wide-input operation are mandatory.
FAQ
What is the maximum recommended input voltage for E-L4971D?
The absolute maximum input voltage is 58V, but the recommended operating range is 8V to 55V per datasheet Table 3. Exceeding 55V risks violating the internal VCC clamp and may trigger premature thermal shutdown or degrade long-term reliability. For 48V systems with surge margins, design to stay within 55V peak including transients.
Can E-L4971D regulate output below 3.3V?
No - the internal reference is fixed at 3.3V ±1%, and the feedback architecture is designed for outputs ≥3.3V. Attempting sub-3.3V regulation via external divider violates the error amplifier's common-mode input range and results in unstable or non-regulated operation. Use a dedicated low-VREF regulator like L4970A for 1.25V outputs.
How does the BOOT pin function, and what capacitor value is required?
The BOOT pin supplies the gate drive voltage for the internal high-side DMOS transistor. A ceramic capacitor (typically 100nF) must connect between BOOT and OUT to form a charge pump. This capacitor must withstand ≥70V peak (per Table 3) and be placed close to the IC to minimize loop inductance and prevent shoot-through during switching transitions.
Is E-L4971D RoHS compliant and halogen-free?
Yes - E-L4971D is manufactured in STMicroelectronics' RoHS-compliant and halogen-free processes per specification document "E-L4971D Packaging Information" (Doc ID 12723, Rev 4). The SO16W package uses lead-free matte tin plating and meets JEDEC J-STD-020 moisture sensitivity level MSL3.
E-L4971D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 8V
- Voltage - Input (Max):
- 55V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- 50V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 100kHz ~ 300kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO W
E-L4971D FAQ
1.How can I place an order for E-L4971D through Aetrix?
Please submit a Request for Quotation (RFQ) for E-L4971D 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 E-L4971D reliable?
The price and inventory of E-L4971D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-L4971D is usually 5 days.
3.What payment methods are accepted for E-L4971D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-L4971D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for E-L4971D?
E-L4971D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your E-L4971D 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 E-L4971D?
For technical support, including E-L4971D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-L4971D requirements.
6.How does Aetrix verify that E-L4971D is sourced from the original manufacturer or authorized distributors?
All E-L4971D 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 E-L4971D meets industry standards.
7.What is the process for return or replacement of E-L4971D?
All E-L4971D units undergo pre-shipment inspection (PSI). If there is an issue with E-L4971D, 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 E-L4971D part is unused and in its original packaging.
Return procedure for E-L4971D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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