ICBOMS
STMicroelectronics L7818CV — Power Management (PMIC / Gate Driver)
Technical Documents PDF / CAD
Download Datasheet (PDF) Preview ↓
RoHS Compliant · Lead-Free EIA-481 Standard
STMicroelectronics / Power Management (PMIC / Gate Driver)

STMicroelectronics L7818CV 18V 1.5A Positive Fixed LDO

MPN L7818CV
End of Life Spot Stock · 24-48h Dispatch 100% Original Sealed

STMicroelectronics L7818CV, positive fixed linear voltage regulator, 18 V output, 1.5 A, TO-220-3, tube package, 53 dB PSRR at 120 Hz.

In Stock: 6,327 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)
$0.88 / pc
Direct Purchase Ready
Volume Pricing Breaks Confirmed upon quotation
1+ pcs
$0.88
10+ pcs
$0.79
30+ pcs
$0.72
100+ pcs
$0.65
500+ pcs
$0.61
1,000+ pcs
$0.57
Working on a production BOM or have a target unit price? Submit Target Price
Buy Now

$0.88 / ea

6,327 in stock — maximum per order · 3–4 days lead time

$0.79 / ea from 10 pcs
Upload Full BOM List
100% Original Sealed 45x Microscope QC 30-Day Warranty · COC USD T/T & PI · DAP/DDP
[SPEC] Essential Parameters Snapshot Full Specifications (14)
Package / Case TO-220-3
ALT
Facing long factory lead times or allocation on L7818CV? Verified pin-compatible alternatives available with active Shenzhen stock and 100% solder-ready footprint match.
View Pin Alternates (3)

Full Technical Specifications

14 Parameters
L7818CV specifications
Parameter / AttributeSpecification / Value
Output typeFixed
MountingThrough Hole
Voltage - input35V
Voltage dropout2V @ 1A (Typ)
Voltage - output (Min (Fixed))18V
Output current1.5A
Current - quiescent8 mA
Operating temperature0°C ~ 125°C
PSRR53dB (120Hz)
PackageTube
CaseTO-220-3
Protection featuresOver Temperature, Short Circuit
Number of regulators1
Output configurationPositive
100% Footprint Match · Solder-Ready (No PCB Redesign Needed)

Need Stock or a Drop-in Second-Source for L7818CV?

Package: TO-220 / TO-92 (78L) / DPAK · Pin-compatible replacements with immediate Shenzhen spot stock

Footprint Match 98%
Supply Chain & Allocation Reality:

The 7805 is the most-produced linear regulator in history - five volts, three pins, a heatsink tab - and its family is the most casually substituted row of parts on any bench. The middle letter is the current grade and the packages follow it: 78L05 is 100mA in TO-92, 78M05 is 500mA class, the plain 7805 is 1A in TO-220. Downward substitutions work when the load fits; upward ones need the space and the heatsink. Two traps close the story: the 79xx negative series shares the family name and nothing else, and the low-dropout parts (1117 class) have quietly replaced the 7805 in 3.3V designs where the 2V dropout of a 7805 simply cannot regulate.

Verified Pin-Compatible Replacements (3 verified alternatives)

78L05 Multiple fabs TO-92
Functional Equivalent
Availability & Target Pricing:

The 100mA Member - Big Package Not Required

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The TO-92 grade of the same regulator: 100mA output against the 1A of the TO-220 part, same 5V fixed output, same 2V-class dropout.

Same input window; dissipation is the tiny body limit - bias and standby rails only.

Compatibility & Drop-In Notes: Substitution direction rule: a higher-rated part can serve a lower-rated position when it physically fits (a 7805 standing in for a 78L05 is fine and current-rich); the reverse fits the socket but starves the load at the worst moment.
Package & Solder Footprint: TO-92 against TO-220: lead order follows the package drawing, not the family habit - verify, because the pinouts do differ between grades.
Shenzhen Warehouse Stock & MOQ: Commodity stock everywhere; the bias-rail part in every drawer.
Request Volume Quote for 78L05 Compare L7818CV vs 78L05 Spec Matrix
78M05 Multiple fabs TO-220 / DPAK (medium)
Functional Equivalent
Availability & Target Pricing:

The 500mA Middle Rung

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The medium grade: 500mA class output (some vendors rate closer to the full ampere - read the specific datasheet).

Same 5V output and dropout class; dissipation scales with the smaller die.

Compatibility & Drop-In Notes: The current grade is the specification - the family name hides it in one letter. When a regulator runs hot in a design, the first question of this family is which grade the BOM actually specified.
Package & Solder Footprint: DPAK versions put the tab on the output node in some makers - the mechanical drawing decides.
Shenzhen Warehouse Stock & MOQ: Wide stock; grade printed on the body.
Request Volume Quote for 78M05 Compare L7818CV vs 78M05 Spec Matrix
L7905 STMicroelectronics / TI TO-220
Functional Equivalent
Availability & Target Pricing:

The Negative Mirror - Different Wiring Entirely

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The negative-rail counterpart: -5V at the same 1A class - the 79xx family mirrors the 78xx ratings across the entire row.

Negative supplies only; the pin order is NOT the mirrored connector of the 7805 - the ground pin sits differently and the tab follows the input side.

Compatibility & Drop-In Notes: The classic repair error this entry exists for: a 7805 pressed into a 7905 socket (or the reverse) sometimes looks like it almost works and then shorts the rail. The 78 and the 79 are relatives in name only.
Package & Solder Footprint: TO-220 with the 79xx pin arrangement - read the drawing, never the memory.
Shenzhen Warehouse Stock & MOQ: Stocked as the pair for analog and audio repair.
Request Volume Quote for L7905 Compare L7818CV vs L7905 Spec Matrix
Buyer & Quality Checklist for Sourcing Alternatives
  • The grade letter is the current rating: 78L05 = 100mA (TO-92), 78M05 = 500mA class, 7805 = 1A (TO-220), 78S/T = 2-3A in large cans. Higher grades substitute downward; lower grades do not substitute upward.
  • Dropout is the other hidden number: the 78xx family needs 2V to 2.5V of input headroom. The 1117-class LDOs (AMS1117 and relatives) sit near 1.1V. A 7805 is not a replacement for a 1117 in any design whose input margin was computed for low dropout - the output just sags.
  • 78xx versus 79xx: positive against negative rails, and the pinouts are different in a way that punishes memory. Read the datasheet drawing of the exact part.
  • Dissipation is the real design: (Vin minus 5V) times current, in watts, given to a TO-220 or a TO-92 body. A "1A" regulator at 12V input delivering 500mA burns 3.5W and needs the heatsink the schematic never drew.
  • The output capacitor small print: the classic 78xx wants the output decoupling the old datasheets specify; in modern low-ESR cap designs, some vendors note stability margins change - check the specific datasheet note.
  • Counterfeits are as old as the part: source 78xx from documented lots, and distrust cases where a "1A" part dies at 300mA cold - the die tells the truth the marking does not.
Frequently Asked Technical Questions

Q: What is the difference between 7805, 78L05 and 78M05?

A: Current grade and package: 78L05 is 100mA in TO-92, 78M05 is 500mA class, the plain 7805 is 1A in TO-220. Same 5V output and same 2V-class dropout; the letter is the die size.

Q: Can a 7805 replace a 7905 or vice versa?

A: No - the 78xx family regulates positive rails and the 79xx negative, with different pinouts. They belong to different circuits; the family name rhymes, the wiring does not.

Q: Why does my circuit sag when I replaced a 1117 regulator with a 7805?

A: Dropout: the 1117-class LDO needs about 1.1V of headroom, the 7805 needs over 2V. In a design sized around low dropout the 7805 simply cannot regulate, and the output follows the input minus dropout.

Technical Details & Description

The L7818CV is a positive fixed linear voltage regulator from STMicroelectronics, delivering a regulated 18 V output at up to 1.5 A continuous current. It is a single-regulator device in the standard TO-220-3 through-hole package, supplied in tube packaging.

Regulation and protection

Ripple rejection is specified at 53 dB at 120 Hz, which is the standard rectified line frequency — this means the output ripple from a full-wave rectifier is attenuated by a factor of roughly 450, keeping the DC rail clean for downstream analog or digital loads. Maximum dropout voltage is 2 V at 1 A output (typical), so the input rail must stay at least 2 V above the 18 V output under full load to maintain regulation. The quiescent current is 8 mA, typical for a 1.5 A LDO of this generation. Built-in over-temperature and short-circuit protection allow the regulator to survive output faults and thermal overload without external clamping diodes. Operating temperature range is 0°C to 125°C, covering commercial and industrial ambient environments but not extended automotive or military temperature extremes.

The TO-220-3 package (supplier device package TO-220) is a through-hole, tab-mount form factor. The metal tab is internally connected to the output pin — it should be soldered to a copper plane or heatsink for thermal management at 1.5 A continuous load. The mounting hole suits a standard TO-220 heatsink clip or screw. Maximum input voltage is 35 V, so the regulator can be fed from a 24 VDC rail or a rectified 24 VAC transformer with margin for line transients.

Frequently asked questions

What is the difference between L7818CV and L7818CV-DG?

The L7818CV-DG is a functionally identical part with the same 18 V output, 1.5 A current, TO-220 package, and 53 dB PSRR. The -DG suffix typically indicates a different packing or environmental grade — both are active and pin-compatible, so the L7818CV-DG can serve as a drop-in second source for the L7818CV without board changes.

L7818CV
Verified Allocation
Quote