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STMicroelectronics L78L33ACZ-AP
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- Part No.:
- L78L33ACZ-AP
- Manufacturer:
- STMicroelectronics
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
L78L33ACZ-AP.pdf
- Description:
- IC REG LINEAR 3.3V 100MA TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,767
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Product details
Overview
L78L33ACZ-AP from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 3.3 V output at up to 100 mA, with ±4% output tolerance (A-grade), thermal overload and short-circuit protection, and no external components required. It serves as a local on-card regulator for noise-sensitive digital logic rails in microcontroller-based industrial control modules.
For engineers reviewing the L78L33ACZ-AP datasheet, L78L33ACZ-AP pinout, L78L33ACZ-AP application, or L78L33ACZ-AP equivalent, key selection criteria include dropout voltage (2 V), quiescent current (6 mA at 25 °C), supply voltage rejection (41–49 dB at 120 Hz), and TO-92 package thermal resistance (RthJA = 200 °C/W).
Technical Context
The L78L33ACZ-AP implements a monolithic silicon voltage regulator with internal current limiting, thermal shutdown, and safe-area protection-enabling robust operation without external compensation. Its architecture delivers stable 3.3 V output across input voltages from 5.3 V to 20 V and load currents from 1 mA to 100 mA.
It operates over an ambient temperature range of 0 to 125 °C (L78LxxAC grade), features 40 µV RMS output noise (10 Hz–100 kHz), and maintains line regulation within 100 mV and load regulation within 30 mV under specified conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3 V ±4% (±0.132 V) at 25 °C; ensures compatibility with 3.3 V logic families (e.g., ARM Cortex-M I/O, SPI peripherals) |
| Max Output Current | 100 mA continuous; sufficient for powering low-power MCUs, sensors, and interface ICs without heatsinking |
| Dropout Voltage | 2 V typical at 40 mA; requires minimum 5.3 V input for stable 3.3 V output under full load |
| Quiescent Current | 6 mA at 25 °C; enables predictable power budgeting in always-on monitoring circuits |
| Supply Rejection | 41–49 dB at 120 Hz; suppresses ripple from unregulated wall adapters or switching pre-regulators |
| Output Noise | 40 µV RMS (10 Hz–100 kHz); supports noise-sensitive analog sections like ADC reference buffers |
| Thermal Protection | Internal junction thermal shutdown at ~150 °C; prevents failure during sustained overload or poor PCB copper layout |
Pinout & Package
Package: TO-92 (3-pin plastic transistor outline), lead-free and RoHS-compliant per ECOPACK2 specification. Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output - verified per DS0424 Rev 30 Figure 2 (top view).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Input) | Voltage input terminal | Accepts 5.3–20 V DC; must be decoupled with ≥0.33 µF ceramic capacitor close to pin |
| Pin 2 (Ground) | Common reference node | Low-impedance return path for load current and regulator bias; connects directly to PCB ground plane |
| Pin 3 (Output) | Regulated 3.3 V source | Delivers up to 100 mA; requires ≥0.1 µF ceramic output capacitor for stability and transient response |
Key Features
| Feature | Design Value |
|---|---|
| No external components needed | Self-contained regulation eliminates BOM cost and layout complexity for point-of-load applications |
| Internal current limiting | Prevents destructive overcurrent during short-circuit events without external foldback circuitry |
| Thermal shutdown protection | Automatically disables output above safe junction temperature, enabling safe recovery after fault clearance |
| Low output noise (40 µV) | Reduces jitter in clock distribution and improves SNR in mixed-signal sensor interfaces |
| Fixed ±4% output tolerance | Meets tight voltage margin requirements for 3.3 V FPGA I/O banks and USB PHY power domains |
Applications
| Industrial Sensor Node | USB-C Peripherals |
|---|---|
|
Use Scenario: Powering a battery-backed environmental sensor module with MCU, I²C temperature/humidity sensor, and BLE radio. IC Role / Device Role / Timing Role: Local 3.3 V regulator supplying core logic and analog front-end; replaces discrete Zener/resistor solution. Use Value: Eliminates 20–30 mV output drift seen with Zener diodes under varying load, improving ADC reference accuracy by >0.5 LSB. |
Use Scenario: Providing clean 3.3 V to USB-C controller (e.g., TUSB320) and Type-C port configuration channel (CC) logic. IC Role / Device Role / Timing Role: Dedicated low-noise supply for USB PD communication circuitry requiring stable VDD. Use Value: 40 µV noise floor prevents false CC line state detection during hot-plug events, ensuring reliable enumeration. |
| Programmable Logic Controller I/O | Medical Wearable Display |
|
Use Scenario: Regulating 3.3 V for isolated digital I/O expansion cards in DIN-rail mounted PLCs. IC Role / Device Role / Timing Role: On-card regulator eliminating noise coupling from shared 24 V backplane supply. Use Value: 49 dB SVR at 120 Hz attenuates rectified AC ripple from industrial SMPS, preventing false GPIO toggling. |
Use Scenario: Supplying OLED display driver IC and touch controller in compact wearable health monitor. IC Role / Device Role / Timing Role: Low-quiescent-current (6 mA) regulator extending battery life in always-on display mode. Use Value: Enables >72-hour runtime on CR2032 coin cell when paired with duty-cycled display refresh. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM78L33ACZ/NOPB | Same 3.3 V/100 mA spec, but ±5% tolerance (vs. ±4%), higher quiescent current (5.5–8 mA), and lower SVR (38–45 dB) | Suitable for non-critical logic rails where tighter output accuracy is not required | Select if legacy TI design reuse is prioritized and ±5% tolerance is acceptable |
| MCP1700T-3302E/TT | Lower quiescent current (1.6 µA), but only 250 mA max output and 600 mV dropout; CMOS-based, not bipolar | Better for ultra-low-power battery applications, but lacks thermal/short-circuit robustness of L78L series | Choose only when micropower operation dominates over fault resilience and high-temp reliability |
Compared with LM78L33ACZ/NOPB, L78L33ACZ-AP offers tighter output tolerance and superior ripple rejection; versus MCP1700T-3302E/TT, it trades ultra-low IQ for proven ruggedness in industrial ambient conditions up to 125 °C.
Availability
L78L33ACZ-AP is available at Aetrix Electronics and suitable for industrial automation controllers, medical wearable electronics, and USB-C peripheral designs requiring stable component supply with long-term manufacturability.
Supply support for L78L33ACZ-AP 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.
The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-sensitive, reliability-critical applications where simplicity, fault tolerance, and wide operating temperature range outweigh ultra-low IQ or ultra-low dropout requirements.
FAQ
What is the minimum input voltage required for stable 3.3 V output at 100 mA?
The L78L33ACZ-AP requires a minimum input voltage of 5.3 V to maintain regulated 3.3 V output at full 100 mA load, based on its 2 V dropout voltage specification and worst-case line/load regulation limits. Below this, output voltage collapses nonlinearly.
Can L78L33ACZ-AP be used in parallel to increase output current?
No-parallel operation is not recommended. The L78L33ACZ-AP lacks current-sharing capability; mismatched output voltages between units will cause one device to dominate conduction, leading to thermal imbalance and premature failure.
Is a heat sink required for continuous 100 mA operation in TO-92 package?
At 100 mA with 12 V input, power dissipation is ~870 mW. With RthJA = 200 °C/W, junction temperature rise exceeds 170 °C-well above the 125 °C maximum. A minimal copper pour (≥6 cm²) is mandatory; discrete heat sinking is strongly advised for sustained full-load operation.
Does L78L33ACZ-AP support reverse-polarity input protection?
No. The device has no internal reverse-voltage protection. Applying negative input voltage relative to ground may damage the IC. An external series diode (e.g., 1N4001) is required if reverse polarity exposure is possible in the system.
L78L33ACZ-AP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 5.5 mA
- Current - Supply (Max):
- 6 mA
- PSRR:
- 49dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
L78L33ACZ-AP FAQ
1.How can I place an order for L78L33ACZ-AP through Aetrix?
Please submit a Request for Quotation (RFQ) for L78L33ACZ-AP 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 L78L33ACZ-AP reliable?
The price and inventory of L78L33ACZ-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78L33ACZ-AP is usually 5 days.
3.What payment methods are accepted for L78L33ACZ-AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78L33ACZ-AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L78L33ACZ-AP?
L78L33ACZ-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L78L33ACZ-AP 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 L78L33ACZ-AP?
For technical support, including L78L33ACZ-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78L33ACZ-AP requirements.
6.How does Aetrix verify that L78L33ACZ-AP is sourced from the original manufacturer or authorized distributors?
All L78L33ACZ-AP 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 L78L33ACZ-AP meets industry standards.
7.What is the process for return or replacement of L78L33ACZ-AP?
All L78L33ACZ-AP units undergo pre-shipment inspection (PSI). If there is an issue with L78L33ACZ-AP, 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 L78L33ACZ-AP part is unused and in its original packaging.
Return procedure for L78L33ACZ-AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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