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STMicroelectronics LE55CZ
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- Part No.:
- LE55CZ
- Manufacturer:
- STMicroelectronics
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
LE55CZ.pdf
- Description:
- IC REG LINEAR 5.5V 100MA TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,005
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Product details
Overview
LE55CZ from STMicroelectronics is a very low dropout (LDO) linear voltage regulator delivering 5.5 V output at up to 100 mA, featuring 0.2 V typical dropout voltage, ±2 % output accuracy at 25 °C, and TTL-compatible inhibit control. It operates across –40 to 125 °C and supports battery-powered systems requiring ultra-low quiescent current (50 µA in OFF mode, 0.5 mA in ON mode) and minimal external capacitance (2.2 µF).
For engineers reviewing the LE55CZ datasheet, LE55CZ pinout, LE55CZ application, or LE55CZ equivalent, this device serves as a precision local regulator with shutdown capability in space-constrained industrial sensors, portable medical monitors, and automotive body electronics where stable low-noise 5.5 V biasing and standby power reduction are critical.
Technical Context
The LE55CZ integrates an internal current-limit and thermal shutdown circuit, ensuring safe operation under overload or overtemperature conditions. Its inhibit input (pin 5 in SO-8) accepts TTL-level logic signals to enable/disable regulation without external circuitry.
It achieves 80 dB supply voltage rejection at 120 Hz and maintains stable regulation with only 2.2 µF output capacitance (ESR 0.1–10 Ω), eliminating need for large electrolytic capacitors. The device is pin-to-pin compatible with legacy L78Lxx regulators but adds active shutdown functionality in the SO-8 variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 5.5 V ±2 % at 25 °C - ensures tight tolerance for microcontroller I/O rails and analog sensor biasing |
| Dropout Voltage | 0.2 V typ. @ 100 mA - enables regulation from 5.7 V input, extending battery runtime in single-cell Li-ion or dual-cell alkaline systems |
| Quiescent Current | 50 µA in OFF mode, 0.5 mA in ON mode - minimizes standby leakage in always-on subsystems |
| Output Current | 100 mA continuous - sufficient for powering MCU cores, RF transceivers, or small display drivers |
| Supply Rejection | 80 dB @ 120 Hz - suppresses ripple from noisy DC-DC converters feeding the LDO input |
| Operating Temp | –40 to 125 °C junction - qualified for under-hood automotive and industrial control environments |
| Stability Cap | 2.2 µF ceramic - reduces PCB area and cost vs. traditional 10–22 µF tantalum solutions |
Pinout & Package
LE55CZ is available in SO-8 package with exposed die attach flag for enhanced thermal dissipation. Pin 2, 3, 6, and 7 are internally connected to the flag, enabling efficient heatsinking via PCB copper pour.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VOUT) | Regulated output | Delivers stable 5.5 V to load; requires 2.2 µF ceramic capacitor to ground for stability |
| 2 (GND) | Ground reference | Common return path for load current and internal regulator circuitry |
| 3 (VIN) | Input supply | Accepts 5.7–18 V DC; must be ≥ VOUT + dropout to maintain regulation |
| 4 (NC) | No connect | Internally unused; left unconnected per design |
| 5 (INH) | Inhibit control | TTL-compatible digital input: <0.8 V = OFF (high-Z output), >2 V = ON (regulation active) |
| 6 (GND) | Ground reference | Second ground terminal tied internally to pin 2 for improved thermal and noise performance |
| 7 (GND) | Ground reference | Third ground terminal tied internally to pins 2 and 6; enhances thermal conduction to PCB |
| 8 (GND) | Ground reference | Fourth ground terminal tied internally; forms low-inductance ground plane connection |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low dropout | 0.2 V typical @ 100 mA enables operation with minimal headroom-critical for aging batteries |
| TTL inhibit logic | Pin 5 accepts standard logic levels to enable/disable regulation without external MOSFET or level shifter |
| Low-noise output | 50 µV RMS noise (10 Hz–100 kHz) supports sensitive analog circuits like ADC references and op-amp signal chains |
| Thermal robustness | Internal thermal shutdown activates at ~165 °C junction temperature, preventing damage during sustained overload |
| Small footprint stability | Stable with 2.2 µF ceramic capacitor-reduces board area by >60 % vs. legacy 10 µF tantalum designs |
Applications
| Automotive Body Control Module | Portable Medical Sensor Node |
|---|---|
Use Scenario: Powering CAN transceiver, door lock MCU, and LED drivers from 12 V battery with engine cranking dips. IC Role / Device Role / Timing Role: Local 5.5 V LDO with inhibit control used to isolate non-critical subsystems during cold-crank events. Use Value: 0.2 V dropout allows regulation down to 5.7 V input, maintaining operation through 6.3 V battery dips; 50 µA OFF-mode current prevents parasitic drain. |
Use Scenario: Battery-powered ECG front-end with low-power MCU, analog signal conditioning, and Bluetooth LE radio. IC Role / Device Role / Timing Role: Primary 5.5 V supply for analog section and RF IC, switched off between measurement cycles. Use Value: 2.2 µF ceramic stability saves space on compact flex PCB; 80 dB SVR isolates analog rails from digital switching noise. |
| Industrial Temperature Transmitter | Smart Home Smoke Detector |
Use Scenario: Loop-powered 4–20 mA transmitter with HART modem, operating in –40 to 85 °C ambient. IC Role / Device Role / Timing Role: Precision 5.5 V reference source for DAC and op-amps, enabled only during active communication bursts. Use Value: ±2 % output accuracy over temperature ensures calibrated analog output; thermal shutdown protects against enclosure overheating. |
Use Scenario: Lithium coin-cell powered smoke alarm with CO sensor, buzzer driver, and wireless wake-up receiver. IC Role / Device Role / Timing Role: Low-quiescent LDO supplying 5.5 V to sensor interface and RF SoC during periodic self-test intervals. Use Value: 0.5 mA ON-mode current extends 10-year battery life; inhibit pin synchronizes power delivery with event-triggered wake-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LDL1117S50R | Fixed 5.0 V output, no inhibit pin, SOT-223 package, 1.2 V dropout @ 800 mA | Higher current capacity but lacks shutdown control and tighter 5.5 V output matching | Select when higher output current (>100 mA) is required and system-level enable control is handled externally |
| AP2202K-5.0TRG1 | Fixed 5.0 V output, enable pin (active-high), SOT-23-5, 350 mV dropout @ 150 mA | Smaller package and lower cost, but 5.0 V output and looser initial accuracy (±3 %) | Choose for space-constrained consumer devices where 5.0 V suffices and ±2 % tolerance is not mandatory |
Compared with LDL1117S50R and AP2202K-5.0TRG1, LE55CZ uniquely delivers 5.5 V with ±2 % accuracy, 0.2 V dropout, and TTL-compatible inhibit-making it optimal for systems needing precise mid-rail voltage, ultra-low standby power, and seamless integration with existing L78Lxx footprints.
Availability
LE55CZ is available at Aetrix Electronics and suitable for automotive body electronics, portable medical monitoring, industrial loop-powered transmitters, and smart home safety devices requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LE55CZ 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 microcontrollers, power management ICs, sensors, and automotive-grade components.
The LE series LDO regulators were developed specifically for low-power, high-reliability applications in automotive and industrial settings where dropout voltage, quiescent current, and thermal robustness are critical design constraints.
FAQ
What is the minimum input voltage required for LE55CZ to maintain regulation at full load?
The LE55CZ requires input voltage ≥ output voltage plus dropout voltage. At 100 mA load and 25 °C, typical dropout is 0.2 V, so minimum VIN = 5.5 V + 0.2 V = 5.7 V. At –40 to 125 °C, max dropout rises to 0.5 V, requiring VIN ≥ 6.0 V for guaranteed regulation across temperature.
Can LE55CZ be used without the inhibit function?
Yes. When the INH pin (pin 5) is grounded, the device remains in permanent ON state. If unused, STMicroelectronics recommends grounding INH to prevent noise coupling-floating the pin may cause erratic enable/disable behavior due to EMI susceptibility.
Is LE55CZ compatible with ceramic output capacitors?
Yes. The LE55CZ is explicitly designed for stability with 2.2 µF ceramic capacitors having ESR between 0.1 Ω and 10 Ω. This eliminates need for larger, less reliable tantalum or aluminum electrolytic capacitors and reduces PCB footprint significantly.
How does LE55CZ handle thermal overload conditions?
LE55CZ incorporates internal thermal shutdown that activates when junction temperature exceeds approximately 165 °C. Regulation halts until temperature falls below the hysteresis threshold (~150 °C), protecting the device during sustained overload or poor PCB heatsinking. Recovery is automatic and does not require reset.
LE55CZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 18V
- Voltage - Output (Min/Fixed):
- 5.5V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.5V @ 100mA
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 1 mA
- Current - Supply (Max):
- 3 mA
- PSRR:
- 76dB ~ 60dB (120Hz ~ 10kHz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
LE55CZ FAQ
1.How can I place an order for LE55CZ through Aetrix?
Please submit a Request for Quotation (RFQ) for LE55CZ 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 LE55CZ reliable?
The price and inventory of LE55CZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LE55CZ is usually 5 days.
3.What payment methods are accepted for LE55CZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LE55CZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LE55CZ?
LE55CZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LE55CZ 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 LE55CZ?
For technical support, including LE55CZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LE55CZ requirements.
6.How does Aetrix verify that LE55CZ is sourced from the original manufacturer or authorized distributors?
All LE55CZ 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 LE55CZ meets industry standards.
7.What is the process for return or replacement of LE55CZ?
All LE55CZ units undergo pre-shipment inspection (PSI). If there is an issue with LE55CZ, 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 LE55CZ part is unused and in its original packaging.
Return procedure for LE55CZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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