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Texas Instruments LM78L12ACZ
- Part No.:
- LM78L12ACZ
- Manufacturer:
- Texas Instruments
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
LM78L12ACZ.pdf
- Description:
- IC REG LINEAR 12V 100MA TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,518
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Product details
Overview
LM78L12ACZ 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 low-cost, no-external-components replacement for Zener-diode/resistor regulators in local on-card power conditioning.
For engineers reviewing the LM78L12ACZ datasheet, LM78L12ACZ pinout, LM78L12ACZ application, or LM78L12ACZ equivalent, this page provides verified technical context, package-specific pin functions, real-world application cards, and two validated alternative parts with documented functional and thermal differences.
Technical Context
The LM78L12ACZ is a legacy-chip variant of the LM78Lxx series, implemented as a monolithic IC with internal pass transistor, error amplifier, reference, and protection circuitry. It operates without external compensation components and maintains regulation across an input range of 14.5V–27V at junction temperatures from 0°C to 125°C.
Its architecture includes current-limiting that caps peak output current at 140mA (TJ = 25°C) and thermal shutdown triggered by internal power dissipation exceeding safe limits. Output noise is specified at 80μV RMS (10Hz–100kHz), and ripple rejection reaches 54dB at 120Hz under full-range conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +12V ±5% (11.4V–12.6V over full temperature and load range) |
| Max Input Voltage | 30V operating; 35V absolute maximum (legacy chip rating) |
| Output Current | 100mA continuous; 140mA peak (TJ = 25°C) |
| Operating Junction Temp | 0°C to 125°C (TO-92 package, ACZ suffix) |
| Line Regulation | 20–110mV over VIN = 16V–27V (TJ = 25°C) |
| Load Regulation | 10–50mV over IO = 1mA–40mA (TJ = 25°C) |
| Ripple Rejection | 40–54dB at 120Hz (VIN = 15V–25V, full temp range) |
Pinout & Package
LM78L12ACZ uses the TO-92 (LP) package: 3-pin through-hole plastic case measuring 5.20mm × 3.68mm, with leads arranged in straight-line configuration and pin 1 (VOUT) at the left when flat side faces viewer.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VOUT) | Regulated output voltage terminal | Delivers stable +12V; requires 0.1µF ceramic capacitor placed adjacent to pin and GND 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 terminal | Accepts 14.5V–27V DC input; requires 0.33µF capacitor near pin to suppress source inductance-induced ringing |
Key Features
| Feature | Design Value |
|---|---|
| No external stability components | Eliminates need for external compensation capacitors-reduces BOM count and layout complexity |
| Internal current limiting | Clamps peak output to 140mA (25°C), preventing damage during short-circuit or overload events |
| Thermal shutdown protection | Automatically disables output if junction temperature exceeds 125°C (TO-92), enabling safe recovery |
| Low quiescent current | 3–5mA typical (25°C), minimizing standby power loss in battery-backed or low-power systems |
| Zener-replacement functionality | Provides >100× lower output impedance and <50% quiescent current vs discrete Zener+resistor solutions |
Applications
| Servo & Stepper Drives | Battery Chargers |
|---|---|
Use Scenario: Powering logic-level interface circuitry (e.g., optocouplers, level shifters) in motor control boards where clean, isolated 12V bias is required. IC Role / Device Role / Timing Role: Local +12V regulator supplying gate drivers and feedback comparators; not involved in timing or PWM generation. Use Value: Eliminates need for separate 12V winding or switching converter, reducing cost and EMI in compact drive modules. | Use Scenario: Providing regulated 12V bias to charge management ICs and status LEDs in portable Li-ion charger adapters. IC Role / Device Role / Timing Role: Standby power source for supervisory circuits; remains active during charging cycles and sleep modes. Use Value: Maintains accurate LED indication and microcontroller wake-up capability even under variable wall-input conditions. |
| Portable Instrumentation | LED Lighting |
Use Scenario: Supplying analog front-end op-amps and ADC reference buffers in handheld multimeters or data loggers. IC Role / Device Role / Timing Role: Low-noise analog rail generator; output noise ≤80μV RMS ensures sub-12-bit measurement integrity. Use Value: Enables direct use of precision analog ICs without additional LDO filtering stages, saving board space and cost. | Use Scenario: Biasing constant-current LED driver ICs in architectural accent lighting fixtures with 12V string configurations. IC Role / Device Role / Timing Role: Stable 12V supply for driver enable pins and internal logic; no PWM or dimming signal involvement. Use Value: Prevents LED flicker or color shift caused by input ripple, improving visual consistency in commercial installations. |
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; wider operating temp (–40°C to 125°C); same electrical specs | Requires surface-mount assembly; better thermal performance via PCB copper area | Select when automated SMT production, higher ambient temps, or improved thermal management are required |
| MC78L12ACP | ON Semiconductor variant; identical TO-92 pinout; ±4% VO tolerance (11.52–12.48V) | Same mechanical fit; slightly tighter output spec; compatible with legacy LM78L12ACZ layouts | Select when sourcing diversification is needed and tighter initial output accuracy is beneficial |
Compared with LM78L12ACZ, LM78L12ACM offers superior thermal dissipation in SOIC but requires PCB rework, while MC78L12ACP delivers tighter output tolerance in the same TO-92 footprint-making it a drop-in upgrade for precision-sensitive analog rails.
Availability
LM78L12ACZ is available at Aetrix Electronics and suitable for servo drives, battery chargers, portable instrumentation, and LED lighting requiring stable component supply with long-term industrial availability.
Supply support for LM78L12ACZ 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.
The LM78Lxx product line was designed for cost-sensitive, low-current local regulation in industrial controls, consumer electronics, and instrumentation-emphasizing simplicity, reliability, and minimal external component count.
FAQ
What is the maximum input voltage for LM78L12ACZ?
The LM78L12ACZ supports up to 30V DC input during normal operation, with an absolute maximum rating of 35V. Exceeding 35V risks permanent damage. This rating applies specifically to the legacy-chip TO-92 variant-new-chip versions have higher 45V absolute max ratings, but LM78L12ACZ is not among them.
Does LM78L12ACZ require external capacitors for stability?
No, the LM78L12ACZ does not require external capacitors for loop stability. However, TI recommends a 0.33µF input capacitor and 0.1µF output capacitor to improve transient response and suppress high-frequency ringing-especially important in systems with long input traces or fast-switching loads.
What is the operating temperature range of LM78L12ACZ?
The LM78L12ACZ (TO-92, ACZ suffix) is rated for junction temperatures from 0°C to 125°C. Its ambient operating range depends on PCB layout and power dissipation, but derating is required above 70°C ambient to stay within the 125°C TJ limit. Thermal shutdown activates if this limit is exceeded.
How does LM78L12ACZ compare to LM78L12ACM in terms of thermal performance?
The LM78L12ACM (SOIC-8) has a lower junction-to-ambient thermal resistance (128.8°C/W vs 158.7°C/W for LM78L12ACZ), enabling ~20% higher continuous power dissipation on identical PCBs. This makes LM78L12ACM preferable in thermally constrained designs, though LM78L12ACZ remains viable for lower-power or naturally cooled applications.
Can LM78L12ACZ be used as a direct replacement for older LM78L12 variants?
Yes-LM78L12ACZ is functionally and pin-compatible with prior LM78L12 devices in TO-92 packages, including identical pinout (VOUT-GND-VIN), output voltage tolerance (±5%), and protection features. No PCB or schematic changes are needed when replacing legacy LM78L12 units with LM78L12ACZ.
LM78L12ACZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Packaging:
- Box
- Product Status:
- Obsolete
- 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 FAQ
1.How can I place an order for LM78L12ACZ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM78L12ACZ 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 reliable?
The price and inventory of LM78L12ACZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM78L12ACZ is usually 5 days.
3.What payment methods are accepted for LM78L12ACZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM78L12ACZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM78L12ACZ?
LM78L12ACZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM78L12ACZ 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?
For technical support, including LM78L12ACZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM78L12ACZ requirements.
6.How does Aetrix verify that LM78L12ACZ is sourced from the original manufacturer or authorized distributors?
All LM78L12ACZ 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 meets industry standards.
7.What is the process for return or replacement of LM78L12ACZ?
All LM78L12ACZ units undergo pre-shipment inspection (PSI). If there is an issue with LM78L12ACZ, 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 part is unused and in its original packaging.
Return procedure for LM78L12ACZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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