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Texas Instruments UA78L12ACDRM3
- Part No.:
- UA78L12ACDRM3
- Manufacturer:
- Texas Instruments
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
UA78L12ACDRM3.pdf
- Description:
- 100-MA 30-VLINEAR VOLTAGE REGULA
- Quantity:
- Payment:
- Shipping:
Inventory:2,423
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Product details
Overview
UA78L12ACDRM3 from Texas Instruments is a fixed-output +12 V positive-voltage linear regulator delivering up to 100 mA output current, with input voltage range of 14.5 V to 27 V (legacy chip), dropout voltage of 1.7 V at 25°C, quiescent current of 4.3–6.5 mA, and operating junction temperature range of 0°C to +125°C. It is used in motor drives and building automation for local on-card regulation.
For engineers reviewing the UA78L12ACDRM3 datasheet, UA78L12ACDRM3 pinout, UA78L12ACDRM3 application, or UA78L12ACDRM3 equivalent, this page provides verified specifications, package mapping, thermal performance data, legacy-chip electrical characteristics, and validated alternative parts for industrial power rail design.
Technical Context
The UA78L12ACDRM3 implements a classic series-pass linear regulator architecture with internal PNP pass transistor, built-in short-circuit current limiting, and thermal shutdown protection. It operates without external compensation capacitors across its full load range (1 mA to 100 mA).
It belongs to the legacy UA78L AC variant family, characterized for TJ = 0°C to +125°C, and supports stable operation with only 0.33 µF input and 0.1 µF output ceramic capacitors - eliminating need for electrolytic or tantalum types.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +12 V nominal; min/max 11.5 V / 12.5 V at TJ = 25°C (legacy AC variant) |
| Input Voltage Range | 14.5 V to 27 V - defines minimum headroom and maximum safe DC input for reliable regulation |
| Output Current | Up to 100 mA - sufficient for powering microcontrollers, sensors, and logic ICs in low-power subsystems |
| Dropout Voltage | 1.7 V at 25°C - determines minimum VI required to maintain regulation under full load |
| Quiescent Current | 4.3–6.5 mA - impacts no-load power loss and standby efficiency in always-on systems |
| Thermal Protection | Internal thermal shutdown - prevents permanent damage during sustained overload or poor heatsinking |
| Operating Temperature | 0°C to +125°C junction - validated for industrial ambient environments without derating |
Pinout & Package
UA78L12ACDRM3 is packaged in a 3-pin SOT-89 (PK) case measuring 4.5 mm × 4.095 mm, optimized for surface-mount assembly and moderate power dissipation with bottom-side thermal pad connection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| INPUT | Input supply connection | Accepts unregulated DC input; requires 0.33 µF capacitor placed close to pin for transient stability |
| COMMON | Ground reference | System ground return path; connects internally to substrate and must be low-impedance for noise control |
| OUTPUT | Regulated output | Delivers stable +12 V; requires 0.1 µF capacitor near pin to improve load transient response |
Key Features
| Feature | Design Value |
|---|---|
| Stable without external components | Eliminates need for compensation networks or ESR-tuned output capacitors - reduces BOM count and layout complexity |
| Built-in short-circuit protection | Limits output current during fault conditions to prevent damage to regulator or upstream supply |
| Thermal shutdown | Automatically disables output when junction temperature exceeds safe limit - enables robust operation in enclosed enclosures |
| Low dropout voltage | 1.7 V dropout allows use with 15 V input rails while maintaining regulation - improves system efficiency vs. higher-dropout alternatives |
| Industrial temperature grade | Rated for 0°C to +125°C junction operation - suitable for factory automation, motor control, and building management hardware |
Applications
| Motor Drives | Building Automation |
|---|---|
Use Scenario: Powering gate drivers and logic circuitry in BLDC motor control modules. IC Role / Device Role / Timing Role: Local +12 V rail generator for isolated gate driver bias and MCU peripherals. Use Value: Stable output ensures consistent gate drive strength and timing margin under variable load transients. |
Use Scenario: Supplying HVAC controllers, occupancy sensors, and actuator interfaces in smart building nodes. IC Role / Device Role / Timing Role: On-board regulation for microcontroller I/O, analog front-ends, and communication transceivers. Use Value: Eliminates need for external filtering; 100 mA capacity supports mixed-signal SoC and sensor signal chains. |
| Factory Automation | Flow Transmitters |
Use Scenario: Providing clean auxiliary power to PLC I/O modules and fieldbus interface ICs. IC Role / Device Role / Timing Role: Dedicated low-noise +12 V source for analog-to-digital conversion and isolation barrier biasing. Use Value: Low 70 µV RMS output noise minimizes quantization error in precision 16-bit ADC applications. |
Use Scenario: Powering ultrasonic or Coriolis flow meter electronics in industrial process lines. IC Role / Device Role / Timing Role: Regulated supply for analog signal conditioning, microcontroller, and 4–20 mA loop drivers. Use Value: Input voltage regulation ≤250 mV ensures stable operation despite long cable drops and supply ripple. |
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 |
|---|---|---|---|
| LM78L12ACZ/LFT3 | Same 12 V output, 100 mA rating, TO-92 package; higher quiescent current (5.5 mA typ), wider output tolerance (±10%) | Lower thermal resistance in TO-92 limits continuous power in high-ambient environments | Preferred where through-hole assembly or legacy footprint compatibility is required |
| TL78L12ACDR | Pin-compatible SOT-89 variant; improved line regulation (≤65 mV), lower noise (55 µV), same 0°C to +125°C rating | Enhanced ripple rejection (42 dB) better suits noisy industrial power supplies | Recommended upgrade path for new designs requiring tighter regulation and lower noise |
Compared with LM78L12ACZ/LFT3 and TL78L12ACDR, the UA78L12ACDRM3 offers superior thermal performance in SOT-89 (RθJB = 9.6°C/W), tighter initial output accuracy (±4.2% vs ±10%), and proven reliability in motor-drive environments - making it optimal for space-constrained industrial PCBs needing robust local regulation.
Availability
UA78L12ACDRM3 is available at Aetrix Electronics and suitable for motor drives, building automation, and factory automation requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial OEM programs.
Supply support for UA78L12ACDRM3 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 over 50 years of linear regulator innovation.
The UA78L series was designed for cost-sensitive, space-constrained industrial applications requiring simple, robust, and capacitor-free local regulation - targeting motor control, sensor nodes, and programmable logic interfaces.
FAQ
What is the maximum input voltage for UA78L12ACDRM3?
The UA78L12ACDRM3 - as a legacy AC variant - has a maximum input voltage of 35 V per absolute ratings, but its recommended operating range is 14.5 V to 27 V. Exceeding 27 V risks increased power dissipation and thermal stress without improving regulation performance. Always verify input ripple and transient margins against the 35 V absolute max.
Does UA78L12ACDRM3 require external capacitors for stability?
No - UA78L12ACDRM3 is internally compensated and stable without external capacitors. However, TI recommends a 0.33 µF input capacitor and 0.1 µF output capacitor to suppress source impedance effects and improve transient response. These values are not for stability but for system-level noise and dynamic performance.
What is the thermal resistance of UA78L12ACDRM3 in SOT-89 package?
UA78L12ACDRM3 in the PK (SOT-89) package has RθJA = 54.7°C/W (junction-to-ambient, free-air), RθJB = 9.6°C/W (junction-to-board), and RθJC(bot) = 7.7°C/W (junction-to-case bottom). For reliable operation at 100 mA, board-level copper area and solder thermal vias are critical to leverage the low RθJB value.
Is UA78L12ACDRM3 suitable for automotive applications?
No - UA78L12ACDRM3 is specified for 0°C to +125°C junction temperature and lacks AEC-Q100 qualification, extended temperature screening, or automotive-grade reliability testing. It is intended for industrial equipment, not automotive ECUs or infotainment systems requiring -40°C startup or harsh-environment validation.
How does UA78L12ACDRM3 compare to newer LDO regulators like TPS7A47?
UA78L12ACDRM3 is a classic linear regulator with 1.7 V dropout and 70 µV noise, whereas TPS7A47 is an ultra-low-noise LDO (4.7 µV) with 300 mV dropout and adjustable output. UA78L12ACDRM3 offers simplicity, zero external components, and proven ruggedness in industrial settings - while TPS7A47 targets high-precision analog systems needing lower dropout and noise.
UA78L12ACDRM3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- UA78L
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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):
- 1.7V @ 40mA
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 4.1 mA
- Current - Supply (Max):
- -
- PSRR:
- 50dB ~ 42dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Reverse Current, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
UA78L12ACDRM3 FAQ
1.How can I place an order for UA78L12ACDRM3 through Aetrix?
Please submit a Request for Quotation (RFQ) for UA78L12ACDRM3 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 UA78L12ACDRM3 reliable?
The price and inventory of UA78L12ACDRM3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for UA78L12ACDRM3 is usually 5 days.
3.What payment methods are accepted for UA78L12ACDRM3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for UA78L12ACDRM3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for UA78L12ACDRM3?
UA78L12ACDRM3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your UA78L12ACDRM3 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 UA78L12ACDRM3?
For technical support, including UA78L12ACDRM3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your UA78L12ACDRM3 requirements.
6.How does Aetrix verify that UA78L12ACDRM3 is sourced from the original manufacturer or authorized distributors?
All UA78L12ACDRM3 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 UA78L12ACDRM3 meets industry standards.
7.What is the process for return or replacement of UA78L12ACDRM3?
All UA78L12ACDRM3 units undergo pre-shipment inspection (PSI). If there is an issue with UA78L12ACDRM3, 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 UA78L12ACDRM3 part is unused and in its original packaging.
Return procedure for UA78L12ACDRM3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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