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Texas Instruments LM78L12ACZ/LFT4
- Part No.:
- LM78L12ACZ/LFT4
- Manufacturer:
- Texas Instruments
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
LM78L12ACZ/LFT4.pdf
- Description:
- IC REG LINEAR 12V 100MA TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,977
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Product details
Overview
LM78L12ACZ/LFT4 from Texas Instruments is a 100mA fixed-output linear voltage regulator delivering +12V with ±5% output tolerance, input voltage support up to 30V (legacy chip), and thermal overload/current limiting protection. It uses TO-92 packaging and serves as a Zener-diode/resistor replacement in low-power local regulation for servo drives, battery chargers, and portable instrumentation.
For engineers reviewing the LM78L12ACZ/LFT4 datasheet, LM78L12ACZ/LFT4 pinout, LM78L12ACZ/LFT4 application, or LM78L12ACZ/LFT4 equivalent, key selection factors include guaranteed 12V output at 100mA, TO-92 thermal performance (0°C to 125°C junction), legacy-chip absolute max input of 35V, and no external capacitor requirement for stability.
Technical Context
The LM78L12ACZ/LFT4 implements a classic series-pass transistor architecture with internal current-limiting and thermal shutdown circuitry. Its design targets low-cost, robust local regulation where simplicity and reliability outweigh efficiency demands.
As a legacy-chip variant in the LM78Lxx family, it adheres to older electrical specifications: 11.4V–12.6V output over full temperature range, 30–100mV load regulation (1–100mA), and 140mA peak output current at 25°C. It does not support SOT-89 or DSBGA packages-only TO-92 (LP) and SOIC (D).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 12V ±5% (11.4V–12.6V over full temp range); enables stable logic/analogue supply in cost-sensitive systems |
| Max Output Current | 100mA continuous; sufficient for microcontroller peripherals, sensors, and LED biasing without heatsinking |
| Input Voltage Range | Up to 30V operating / 35V absolute max; supports unregulated 24V rail derating and transient margin |
| Junction Temp Range | 0°C to 125°C (TO-92 package); validated for industrial ambient environments without derating |
| Load Regulation | ≤100mV (1–100mA, TJ = 25°C); ensures <1% output shift across full load, critical for analog sensor references |
| Line Regulation | ≤180mV (14.5–27V input, TJ = 25°C); maintains regulation despite input ripple or battery sag |
| Quiescent Current | 3–5mA (TJ = 25°C); enables low standby power in always-on instrumentation |
Pinout & Package
LM78L12ACZ/LFT4 uses the TO-92 (LP) 3-pin through-hole package (5.20mm × 3.68mm), optimized for manual assembly and board-level heat dissipation via leadframe conduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: VOUT | Regulated output voltage node | Delivers stable +12V; requires 0.1µF ceramic capacitor near pin for transient response |
| 2: GND | Ground reference and thermal path | Serves as common return and primary heat conduction path to PCB copper; must be low-impedance |
| 3: VIN | Unregulated input supply node | Accepts 13.7–35V input; benefits from 0.33µF input capacitor to suppress source impedance-induced oscillation |
Key Features
| Feature | Design Value |
|---|---|
| No external capacitors required | Internally compensated for stability with 0.1µF COUT and 0.33µF CIN - eliminates BOM cost and layout risk |
| Thermal overload protection | Shuts down automatically above 125°C junction temperature, preventing permanent damage during sustained overload |
| Current limiting | Clamps peak output to 140mA at 25°C, protecting both IC and downstream circuitry from short-circuit faults |
| Zener-replacement functionality | Provides two-order-of-magnitude lower output impedance vs discrete Zener+resistor, improving load regulation and PSRR |
| Legacy-chip reliability | Manufactured to mature process with documented long-term stability; widely used in field-deployed industrial equipment |
Applications
| Servo & Stepper Drives | Battery Chargers |
|---|---|
Use Scenario: Powering gate drivers, position feedback circuitry, and MCU peripherals in compact motor control modules. IC Role / Device Role / Timing Role: Local +12V regulator for isolated logic-level signal conditioning and level-shifting circuits. Use Value: Eliminates need for separate DC-DC converter; TO-92 footprint allows direct integration into space-constrained drive PCBs. |
Use Scenario: Providing regulated bias for charge management ICs and status LEDs in 12V lead-acid or Li-ion charger designs. IC Role / Device Role / Timing Role: Fixed +12V supply for analog front-end comparators and microcontroller I/O rails. Use Value: Stable output under variable input (9–28V battery range) ensures accurate voltage sensing and LED brightness consistency. |
| Portable Instrumentation | LED Lighting |
Use Scenario: Supplying precision op-amps, ADC references, and display drivers in handheld test meters and data loggers. IC Role / Device Role / Timing Role: Low-noise local regulator for analog signal chain components requiring clean 12V rails. Use Value: 80μV RMS output noise (10Hz–100kHz) preserves measurement accuracy without added filtering. |
Use Scenario: Biasing constant-current LED driver ICs or powering indicator arrays in appliance control panels. IC Role / Device Role / Timing Role: Dedicated +12V source for LED string current-setting resistors and enable logic. Use Value: Load regulation ≤100mV ensures uniform LED brightness across varying load conditions and temperature drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM78L12ACM | SOIC-8 package; same electrical specs but higher RθJA (128.8°C/W vs 158.7°C/W for TO-92); operates from –40°C to 125°C | Preferred for automated SMT assembly and extended cold-temperature operation; requires PCB thermal relief design | Select when surface-mount compatibility or wider temperature range is required; not drop-in compatible with TO-92 footprint |
| MC78L12ACP | ON Semiconductor equivalent; identical TO-92 pinout and 12V/100mA spec; 35V abs max input; 0°C–125°C TJ range | Valid second-source for supply chain diversification; same thermal and electrical behavior in legacy systems | Drop-in replacement with verified qualification for industrial control and medical devices per ON Semi documentation |
Compared with LM78L12ACZ/LFT4, LM78L12ACM offers superior thermal performance in SMT layouts but requires rework for through-hole designs, while MC78L12ACP provides identical mechanical and electrical interoperability as a qualified second source without layout changes.
Availability
LM78L12ACZ/LFT4 is available at Aetrix Electronics and suitable for servo drives, battery chargers, and portable instrumentation requiring stable component supply with long-lifecycle assurance and legacy-process consistency.
Supply support for LM78L12ACZ/LFT4 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of experience in linear regulator design and manufacturing.
The LM78Lxx series was developed for cost-effective, reliable local regulation in industrial, instrumentation, and consumer systems-emphasizing simplicity, ruggedness, and broad compatibility over ultra-low quiescent current or high PSRR.
FAQ
What is the maximum input voltage rating for LM78L12ACZ/LFT4?
The LM78L12ACZ/LFT4 is a legacy-chip variant with an absolute maximum input voltage of 35V and a recommended operating maximum of 30V. Exceeding 35V risks permanent damage, and operation above 30V may degrade regulation performance or trigger thermal shutdown under load. Always observe derating guidelines per ambient temperature.
Does LM78L12ACZ/LFT4 require external capacitors for stability?
No-LM78L12ACZ/LFT4 is internally compensated and does not require external capacitors to maintain stability. However, TI recommends a 0.33µF input capacitor and 0.1µF output capacitor to improve transient response and suppress high-frequency ringing caused by source inductance or load steps. These values are optional for stability but strongly advised for robust operation.
What is the thermal performance of LM78L12ACZ/LFT4 in its TO-92 package?
LM78L12ACZ/LFT4 in TO-92 (LP) has a junction-to-ambient thermal resistance (RθJA) of 158.7°C/W. At 100mA output and 20V input (800mW dissipation), junction temperature rise is ~127°C above ambient-so operation is limited to 0°C–125°C ambient to stay within the 125°C max junction rating. PCB copper area significantly improves real-world thermal performance.
Is LM78L12ACZ/LFT4 pin-compatible with other LM78Lxx variants?
Yes-LM78L12ACZ/LFT4 shares the identical TO-92 pinout (VOUT–GND–VIN) with all LM78Lxx ACZ variants (e.g., LM78L05ACZ, LM78L15ACZ). This allows direct substitution within the same voltage family when board layout permits, provided input/output voltage margins and thermal limits are verified for the new output voltage.
What are the key differences between LM78L12ACZ/LFT4 and the newer LM78L12ACZ (SOIC) version?
LM78L12ACZ/LFT4 is the TO-92 packaged legacy version, while the SOIC variant (e.g., LM78L12ACM) uses an 8-pin surface-mount package. Key differences include: wider operating temperature (–40°C to 125°C vs 0°C to 125°C), lower RθJA (128.8°C/W vs 158.7°C/W), and slightly tighter output tolerance (±2.5% typical vs ±5%). Electrical specs otherwise match closely, but pinout and thermal design are not interchangeable.
LM78L12ACZ/LFT4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 35V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 3 mA
- Current - Supply (Max):
- -
- PSRR:
- 54dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
LM78L12ACZ/LFT4 FAQ
1.How can I place an order for LM78L12ACZ/LFT4 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM78L12ACZ/LFT4 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 LM78L12ACZ/LFT4 reliable?
The price and inventory of LM78L12ACZ/LFT4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM78L12ACZ/LFT4 is usually 5 days.
3.What payment methods are accepted for LM78L12ACZ/LFT4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM78L12ACZ/LFT4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM78L12ACZ/LFT4?
LM78L12ACZ/LFT4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM78L12ACZ/LFT4 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 LM78L12ACZ/LFT4?
For technical support, including LM78L12ACZ/LFT4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM78L12ACZ/LFT4 requirements.
6.How does Aetrix verify that LM78L12ACZ/LFT4 is sourced from the original manufacturer or authorized distributors?
All LM78L12ACZ/LFT4 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 LM78L12ACZ/LFT4 meets industry standards.
7.What is the process for return or replacement of LM78L12ACZ/LFT4?
All LM78L12ACZ/LFT4 units undergo pre-shipment inspection (PSI). If there is an issue with LM78L12ACZ/LFT4, 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 LM78L12ACZ/LFT4 part is unused and in its original packaging.
Return procedure for LM78L12ACZ/LFT4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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