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STMicroelectronics L4978D — Crystals & Oscillators
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STMicroelectronics / Crystals & Oscillators

L4978D STMicroelectronics Step-Down Buck Regulator 2A

MPN L4978D
End of Life Spot Stock · 24-48h Dispatch 100% Original Sealed

STMicroelectronics L4978D, step-down buck regulator, 2A output, adjustable output, 55V max input, 100kHz–300kHz switching, -40°C to 150°C junction, 16-SOIC (0.295", 7.50mm width), tube packaging.

In Stock: 1,138 pcs
MOQ: 1 pcs
Logistics: DHL / FedEx DAP (Global Express · 3-7d) Russia & CIS DDP (Door-to-Door Cleared)
Dispatch: Shenzhen / HK
Unit Price (USD)
$4.12 / pc
Direct Purchase Ready
Volume Pricing Breaks Confirmed upon quotation
1+ pcs
$4.12
10+ pcs
$3.71
30+ pcs
$3.38
100+ pcs
$3.05
500+ pcs
$2.84
1,000+ pcs
$2.68
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$4.12 / ea

1,138 in stock — maximum per order · 3–4 days lead time

$3.71 / ea from 10 pcs
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100% Original Sealed 45x Microscope QC 30-Day Warranty · COC USD T/T & PI · DAP/DDP
[SPEC] Essential Parameters Snapshot Full Specifications (15)
Package / Case 16-SOIC (0.295", 7.50mm Width)

Full Technical Specifications

15 Parameters
L4978D specifications
Parameter / AttributeSpecification / Value
Output typeAdjustable
MountingSurface Mount
Voltage - input55V
Voltage - output50V
Voltage - output (Min (Fixed))3.3V
Output current2A
Frequency - switching100kHz ~ 300kHz
I/O channels1
Operating temperature-40°C ~ 150°C (TJ)
PackageTube
FunctionStep-Down
TopologyBuck
Case16-SOIC (0.295\", 7.50mm Width)
Output configurationPositive
Synchronous rectifierNo
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Standard factory-sealed packaging compliant with EIA-481 standards for automated high-speed SMT pick-and-place lines.

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Technical Details & Description

What this buck regulator delivers

The L4978D is a 2A step-down buck regulator from STMicroelectronics, accepting an input from 8V up to 55V and delivering an adjustable output down to 3.3V. The 2A continuous output current sets the load budget for the downstream rail; the 55V input ceiling gives headroom for 48V telecom or 24V industrial buses with margin for transients. Switching frequency spans 100kHz to 300kHz, which directly affects inductor physical size and output ripple — lower frequencies ease EMI but need larger magnetics. The part does not include synchronous rectification, so the external Schottky diode must handle the full 2A peak current.

The wide range means derating the output current above 85°C ambient per the datasheet thermal curves; the 16-SO W package relies on the copper pour area on the PCB to keep the junction within limits.

For BOM quantities, we source per RFQ — confirm the required volume and we will quote against current market pricing.

Frequently asked questions

What is the output current of L4978D?

The L4978D delivers 2A continuous output current. This is the maximum DC load the regulator can supply; the actual limit at elevated ambient temperature depends on the PCB copper area and airflow.

What is the switching frequency of L4978D?

The switching frequency is adjustable between 100kHz and 300kHz. Lower frequencies reduce switching losses but require larger inductors; higher frequencies shrink magnetics but increase EMI filtering demands.

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