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STMicroelectronics LE33ABD
- Part No.:
- LE33ABD
- Manufacturer:
- STMicroelectronics
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LE33ABD.pdf
- Description:
- IC REG LINEAR 3.3V 100MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,016
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Product details
Overview
LE33ABD from STMicroelectronics is a very low dropout (LDO) linear voltage regulator delivering 3.3 V ±1% output at up to 100 mA, with 0.2 V typical dropout at full load and 50 µA quiescent current in OFF mode. It features TTL-compatible inhibit control (pin 5), internal current/thermal limiting, and stable operation with only 2.2 µF output capacitance - optimized for battery-powered microcontroller subsystems requiring precise, low-noise 3.3 V rail.
For engineers reviewing the LE33ABD datasheet, LE33ABD pinout, LE33ABD application, or LE33ABD equivalent, this device is selected for ultra-low-power embedded systems where standby current, thermal efficiency in SO-8 packages, and supply rejection above 80 dB at 120 Hz are critical design constraints.
Technical Context
The LE33ABD integrates an enable-controlled pass transistor with precision bandgap reference and error amplifier, supporting ON/OFF logic control via dedicated INH pin. Its SO-8 package uses internally commingled pins 2, 3, 6, and 7 tied to the die attach flag for enhanced thermal dissipation (RthJA = 55 °C/W).
It operates across –40 °C to +125 °C junction temperature, maintains 3.3 V regulation within ±1% at 25 °C, and achieves 80 dB supply voltage rejection at 120 Hz - enabling clean power delivery in noise-sensitive analog and mixed-signal circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V ±1% at 25 °C - ensures compatibility with 3.3 V logic families (e.g., ARM Cortex-M I/O, SPI peripherals) |
| Dropout Voltage | 0.2 V typ. @ 100 mA - enables regulation from 3.5 V input, extending battery runtime in single-cell Li-ion or 2xAA systems |
| Quiescent Current | 50 µA in OFF mode, 0.5 mA in ON mode - minimizes standby leakage in always-on sensor nodes |
| Supply Voltage Rejection | 80 dB @ 120 Hz - suppresses ripple from switching DC/DC converters feeding the LDO input |
| Output Capacitance | 2.2 µF minimum (ESR 0.1–10 Ω) - allows use of low-profile ceramic capacitors, reducing PCB area and cost |
| Operating Temperature | –40 °C to +125 °C - supports under-hood automotive modules and industrial edge controllers |
| Thermal Resistance | RthJA = 55 °C/W (SO-8) - permits 500 mW dissipation with 25 °C ambient and adequate copper pour |
Pinout & Package
LE33ABD is supplied in an SO-8 package with exposed die attach flag (pins 2, 3, 6, 7 internally connected) for improved thermal performance. Pin numbering follows standard SO-8 top view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VOUT | Regulated 3.3 V output - connects directly to load IC VCC with local 2.2 µF bypass |
| 2 | GND | Power ground - tied internally to die flag; requires low-impedance PCB plane |
| 3 | VIN | Input supply (up to 18 V) - must be filtered prior to entry to limit high-frequency noise |
| 4 | GND | Second ground terminal - improves PSRR by separating input/output return paths |
| 5 | INH (Inhibit) | TTL-compatible shutdown control - <0.8 V disables regulator (50 µA IQ); >2 V enables |
| 6 | GND | Third ground terminal - enhances thermal conduction and reduces ground bounce |
| 7 | GND | Fourth ground terminal - part of integrated thermal flag; soldered to large copper area |
| 8 | VIN | Secondary input connection - paralleled with pin 3 to reduce trace resistance and improve current sharing |
Key Features
| Feature | Design Value |
|---|---|
| Very low dropout | 0.2 V typical at 100 mA - enables operation with minimal headroom, e.g., 3.5 V input → 3.3 V output |
| Inhibit logic control | TTL-compatible pin (pin 5) with 0.8 V/2 V thresholds - allows direct MCU GPIO control without level-shifting |
| Stability with small capacitor | Only 2.2 µF ceramic output cap required - eliminates need for larger, costly tantalum or electrolytic caps |
| High PSRR | 80 dB @ 120 Hz - rejects ripple from upstream buck converters, preserving ADC reference stability |
| Wide temperature range | –40 °C to +125 °C operation - qualified for automotive body control modules and industrial PLC I/O |
Applications
| Industrial Sensor Node | Automotive Body Control Unit |
|---|---|
|
Use Scenario: Low-power wireless temperature/humidity node powered by coin cell or energy harvester. IC Role / Device Role / Timing Role: Primary 3.3 V LDO supplying MCU, RF transceiver, and analog sensor interface. Use Value: 50 µA OFF-mode current extends shelf life; 0.2 V dropout maximizes usable battery voltage down to 3.5 V. |
Use Scenario: Door module controlling window lift, mirror fold, and interior lighting. IC Role / Device Role / Timing Role: Local 3.3 V regulator for CAN transceiver and microcontroller I/O rails. Use Value: 80 dB PSRR prevents CAN bus errors caused by alternator ripple; –40 °C to +125 °C rating ensures under-dash reliability. |
| Portable Medical Monitor | Edge AI Inference Module |
|
Use Scenario: Battery-operated ECG front-end with analog signal chain and BLE connectivity. IC Role / Device Role / Timing Role: Clean 3.3 V supply for precision op-amps, ADC, and BLE SoC core logic. Use Value: 50 µV RMS output noise preserves signal integrity; 2.2 µF ceramic cap reduces board space vs. legacy designs. |
Use Scenario: Compact vision processing unit using ultra-low-power microcontroller and neural network accelerator. IC Role / Device Role / Timing Role: Secondary LDO providing regulated 3.3 V to memory interface and peripheral I/O. Use Value: Inhibit pin enables synchronized power gating during inference idle cycles, cutting system-wide standby power by >40%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LD33CV | Fixed 3.3 V, ±2% accuracy, no inhibit pin, TO-220/TO-92 only, RthJA = 70 °C/W | Lacks logic control; suited for non-standby fixed-rail applications with higher thermal margin | Select when inhibit function is unnecessary and SO-8 thermal performance is not required. |
| STLQ015M33R | 3.3 V, ±2%, 150 mA, 38 µA IQ, no inhibit, SOT-23-5 package, RthJA = 210 °C/W | Lower quiescent current but lower current capability and inferior thermal performance than SO-8 LE33ABD | Select for space-constrained, ultra-low-IQ applications where 100 mA load and thermal dissipation are not limiting. |
Compared with LD33CV and STLQ015M33R, LE33ABD uniquely balances 100 mA output, 50 µA OFF-mode current, TTL inhibit control, and SO-8 thermal efficiency - making it optimal for thermally demanding, logic-gated embedded subsystems.
Availability
LE33ABD is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control units, portable medical monitors, and edge AI inference modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LE33ABD 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-grade analog ICs.
The LE series LDO regulators were designed specifically for ultra-low-power, high-PSRR applications in battery-operated and thermally constrained systems - emphasizing dropout voltage, quiescent current, and logic-controlled enable functionality.
FAQ
What is the maximum input voltage for LE33ABD?
The absolute maximum DC input voltage is 20 V, but the recommended operating input voltage is up to 18 V. At 100 mA load and 125 °C junction temperature, the dropout voltage rises to 0.5 V - so minimum valid input is 3.8 V for guaranteed 3.3 V output under worst-case conditions.
Can LE33ABD be used without connecting the INH pin?
Yes - if the INH pin is left floating, the device remains enabled (ON state). However, STMicroelectronics recommends grounding the INH pin when not in use to prevent noise-induced false shutdown, as stated in the datasheet's note on page 7.
Is the 2.2 µF output capacitor mandatory, and what ESR range is acceptable?
Yes - stability is guaranteed only with 2.2 µF output capacitance having ESR between 0.1 Ω and 10 Ω. Ceramic capacitors meeting this spec (e.g., X5R/X7R 0805) are preferred; tantalum or aluminum electrolytics require careful ESR verification per Table 11.
How does the SO-8 thermal design differ from standard SO-8 packages?
LE33ABD's SO-8 uses a modified frame where pins 2, 3, 6, and 7 are internally bonded to the die attach flag - lowering thermal resistance to 55 °C/W (vs. ~100+ °C/W for standard SO-8) when soldered to ≥1 cm² copper pour, enabling higher continuous power dissipation.
LE33ABD 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
LE33ABD FAQ
1.How can I place an order for LE33ABD through Aetrix?
Please submit a Request for Quotation (RFQ) for LE33ABD 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 LE33ABD reliable?
The price and inventory of LE33ABD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE33ABD is usually 5 days.
3.What payment methods are accepted for LE33ABD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE33ABD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LE33ABD?
LE33ABD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LE33ABD 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 LE33ABD?
For technical support, including LE33ABD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE33ABD requirements.
6.How does Aetrix verify that LE33ABD is sourced from the original manufacturer or authorized distributors?
All LE33ABD 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 LE33ABD meets industry standards.
7.What is the process for return or replacement of LE33ABD?
All LE33ABD units undergo pre-shipment inspection (PSI). If there is an issue with LE33ABD, 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 LE33ABD part is unused and in its original packaging.
Return procedure for LE33ABD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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