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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LE33CD

Name: LE33CD
Brand: STMicroelectronics
SKU: LE33CD
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LE33CD

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: LE33CD.pdf

Description:: IC REG LINEAR 3.3V 100MA 8SO

Quantity:: RFQ Add To RFQ list

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Inventory:3,377

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Product details

Overview

LE33CD from STMicroelectronics is a 3.3 V fixed-output, very low dropout (0.2 V typ. at 100 mA) linear voltage regulator in SO-8 package with TTL-compatible inhibit control (pin 5), delivering up to 100 mA output current, ±2 % output voltage accuracy at 25 °C, and operating across –40 to 125 °C for automotive and industrial power rail regulation.

For engineers reviewing the LE33CD datasheet, LE33CD pinout, LE33CD application, or LE33CD equivalent, this device is selected for battery-powered microcontroller core supplies, low-noise sensor biasing, and always-on subsystems requiring ultra-low quiescent current (50 µA in OFF mode) and minimal dropout under load.

Technical Context

The LE33CD integrates an internal current-limit and thermal shutdown circuit, enabling robust operation without external protection components. Its inhibit function accepts TTL-level logic (V_IL ≤ 0.8 V, V_IH ≥ 2 V) to fully disable the regulator, reducing total system standby power.

Stability is achieved with only 2.2 µF output capacitance (ESR 0.1–10 Ω), eliminating need for large electrolytic capacitors. Supply voltage rejection reaches 80 dB at 120 Hz, supporting clean regulation from noisy DC-DC pre-regulators or unfiltered battery inputs.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	3.3 V ±2 % at 25 °C - ensures compatibility with 3.3 V logic families and MCU I/O rails without margin risk.
Dropout Voltage	0.2 V typical at 100 mA - enables regulation from 3.5 V input (e.g., single Li-ion cell post-boost) with full load.
Quiescent Current	0.5 mA typical in ON mode, 50 µA in OFF mode - extends battery life in sleep-state IoT nodes.
Output Current	100 mA continuous - sufficient for ARM Cortex-M0+ MCUs, CAN transceivers, and analog front-ends.
Supply Rejection	80 dB at 120 Hz - suppresses ripple from switching converters feeding the input rail.
Operating Temp	–40 to 125 °C junction - qualified for under-hood automotive and industrial motor-control environments.
Stability Cap	2.2 µF ceramic output capacitor - reduces PCB area and cost vs. legacy LDOs requiring ≥10 µF.

Pinout & Package

LE33CD is housed in an SO-8 package with internally connected pins 2, 3, 6, and 7 tied to the die attach flag for enhanced thermal dissipation (R_thJA = 55 °C/W). The package footprint matches standard SO-8 but delivers lower thermal resistance when mounted on copper heatsinking areas.

Pin/Terminal	Circuit Role	Design Meaning
1	V_OUT	Regulated 3.3 V output - connects directly to load; requires 2.2 µF ceramic bypass capacitor.
2 & 3 & 6 & 7	Ground / Thermal Flag	Internally bonded to die attach pad - must be soldered to ≥1 cm² copper pour for thermal performance.
4	V_IN	Input supply (up to 18 V) - feeds internal pass transistor; requires local 0.1 µF decoupling.
5	Inhibit (INH)	TTL-compatible shutdown control - <0.8 V disables regulator (50 µA I_Q); >2 V enables operation.
8	GND	Signal ground reference - separate from thermal flag pins but electrically common in PCB layout.

Key Features

Feature	Design Value
Very low dropout	0.2 V typical at 100 mA - supports operation down to 3.5 V input while maintaining 3.3 V output.
Inhibit control	TTL-compatible pin (pin 5) enabling system-level power gating without external MOSFETs.
Low-noise regulation	50 µV RMS output noise (10 Hz–100 kHz) - suitable for precision ADC references and RF bias rails.
Thermal robustness	Internal thermal shutdown + current limit - eliminates need for external foldback or overtemp circuitry.
Minimal BOM	Only two external capacitors required (0.1 µF input, 2.2 µF output) - reduces component count and board space.

Applications

Automotive Body Control Module

Industrial Sensor Node

Use Scenario: Powering CAN transceiver and microcontroller in door module with 12 V battery input.

IC Role / Device Role / Timing Role: Local 3.3 V LDO supplying MCU core and CAN PHY, controlled via inhibit during sleep.

Use Value: 50 µA OFF-mode current extends vehicle parasitic draw below 100 µA threshold for battery preservation.

Use Scenario: Regulating power for MEMS accelerometer and 16-bit sigma-delta ADC in predictive maintenance sensor.

IC Role / Device Role / Timing Role: Low-noise 3.3 V supply for analog signal chain, rejecting switching noise from shared DC-DC converter.

Use Value: 50 µV output noise prevents degradation of 100+ dB SNR in high-resolution measurement systems.

Portable Medical Monitor

Smart Energy Meter

Use Scenario: Providing stable 3.3 V rail to ECG front-end and Bluetooth LE SoC in handheld vital sign recorder.

IC Role / Device Role / Timing Role: Battery-sourced LDO with shutdown control synchronized to measurement duty cycle.

Use Value: 0.2 V dropout allows direct regulation from partially discharged Li-ion (3.5 V), maximizing usable battery capacity.

Use Scenario: Powering metrology ASIC and real-time clock in DIN-rail energy meter with wide ambient temperature range.

IC Role / Device Role / Timing Role: High-temp-rated LDO delivering 3.3 V to time-critical RTC and isolation interface.

Use Value: Guaranteed operation to 125 °C junction enables placement near power electronics without derating.

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LDL1133PU33R	0.35 V dropout at 150 mA, 30 µA quiescent current in OFF mode, DFN-8 package (2 × 2 mm).	Higher current capability but smaller footprint; lacks SO-8 thermal flag for high-power dissipation.	Select for space-constrained designs needing lower I_Q, but verify thermal margin without SO-8 copper heatsink.
TLV73333PDBVR	0.22 V dropout at 300 mA, 35 µA I_Q (OFF), SOT-23-5 package, no enable pin inversion.	Higher output current and smaller size, but no integrated thermal flag and limited 85 °C max ambient rating.	Prefer for consumer-grade portable devices where 125 °C operation and SO-8 thermal performance are not required.

Compared with LDL1133PU33R and TLV73333PDBVR, LE33CD offers superior thermal management via SO-8 flag pins and guaranteed 125 °C operation-critical for automotive and industrial deployments where sustained load and ambient heat coexist.

Availability

LE33CD is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor nodes, portable medical monitors, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LE33CD 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 automotive ICs with broad industrial and automotive qualification coverage.

The LE series was designed specifically for low-power, high-reliability embedded systems requiring precise, stable voltage regulation with minimal board area and thermal overhead in harsh environments.

FAQ

What is the minimum input voltage required for LE33CD to maintain regulation at full 100 mA load?

The minimum input voltage is 3.5 V, calculated as V_OUT + V_DROP = 3.3 V + 0.2 V (typical dropout). At worst-case 0.5 V dropout (over temperature), input must be ≥3.8 V to sustain 100 mA. Input voltage must not exceed 18 V per absolute maximum ratings.

Can the inhibit pin be left floating, and what is the recommended practice?

No-leaving the inhibit pin floating risks unintended shutdown due to noise coupling. The datasheet explicitly recommends grounding the pin when inhibit functionality is unused. A pull-down resistor to GND (≤10 kΩ) ensures reliable ON-state operation in noisy environments.

Is LE33CD pin-compatible with older L78L33ACZ devices?

No-LE33CD uses an SO-8 package with inhibit control on pin 5, whereas L78L33ACZ is a TO-92 3-pin device without shutdown capability. While both provide 3.3 V output, they differ in package, pin count, thermal design, and functional features; direct replacement requires PCB redesign.

What is the maximum allowable output capacitance, and does ESR affect stability?

The datasheet specifies CO = 2.2 µF typical, with acceptable range 2–10 µF and ESR between 0.1–10 Ω. Exceeding 10 µF may cause phase margin degradation and instability; low-ESR ceramic capacitors within this range ensure guaranteed stability without additional compensation components.

LE33CD Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 18V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.5V @ 100mA

Current - Output:: 100mA

Current - Quiescent (Iq):: 1 mA

Current - Supply (Max):: 3 mA

PSRR:: 80dB ~ 60dB (120Hz ~ 10kHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

LE33CD FAQ

1.How can I place an order for LE33CD through Aetrix?

Please submit a Request for Quotation (RFQ) for LE33CD 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 LE33CD reliable?

The price and inventory of LE33CD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE33CD is usually 5 days.

3.What payment methods are accepted for LE33CD?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE33CD transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LE33CD?

LE33CD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LE33CD 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 LE33CD?

For technical support, including LE33CD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE33CD requirements.

6.How does Aetrix verify that LE33CD is sourced from the original manufacturer or authorized distributors?

All LE33CD 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 LE33CD meets industry standards.

7.What is the process for return or replacement of LE33CD?

All LE33CD units undergo pre-shipment inspection (PSI). If there is an issue with LE33CD, 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 LE33CD part is unused and in its original packaging.

Return procedure for LE33CD:

1.Submit a request within 90 days.

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

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