STMicroelectronics L78M08CDT-TR

Product Summary — L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR from STMicroelectronics is a positive fixed linear voltage regulator, delivering a regulated 8V output at up to 500mA. This three-terminal device comes in the compact DPAK package, making it suitable for high-density PCBs and on-card local voltage regulation. As a member of the broader L78M series, this regulator addresses the need for robust and reliable voltage regulation in industrial, consumer, and instrumentation designs where precise 8V power is required.

Main Features and Protection Mechanisms — L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR is engineered for reliability, integrating multiple protective mechanisms that ensure safe operation even under stressful circuit conditions:

Thermal overload protection: Automatically shuts down the regulator if excessive power causes overtemperature, preventing damage.

Short circuit protection: Limits output current during fault conditions, reducing risk to downstream circuits.

Output transition SOA (Safe Operating Area) protection: Optimizes protection for the output stage to maintain integrity during transient and overload events.

Output voltage tolerance: Specified at ±4% for the "C" version, maintaining tight regulation.

These features allow engineers to deploy the L78M08CDT-TR in applications demanding high reliability and minimal service intervention.

Maximum Ratings and Thermal Specifications — L78M08CDT-TR STMicroelectronics

Proper power dissipation is critical for reliable long-term operation. The L78M08CDT-TR is rated for continuous output currents up to 500mA, subject to adequate heat sinking. Absolute maximum input voltages and junction temperatures must be adhered to, as exceeding these ratings may result in irreversible damage. Thermal data provided by STMicroelectronics supports engineers in calculating correct heat sinking requirements, especially under full load or elevated ambient conditions.

Pin Layout and Packaging Options — L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR is delivered in the DPAK (TO-252) surface-mount package, featuring three terminals: input, ground, and output. This configuration allows for straightforward PCB layout and integration with standard assembly procedures. The L78M series also offers variants in TO-220, TO-220FP, and IPAK formats, enabling compatibility with both through-hole and surface-mount design philosophies.

Electrical Specs and Typical Performance — L78M08CDT-TR STMicroelectronics

When powered with typical input conditions (14V input, 350mA load, recommended input/output capacitors), the L78M08CDT-TR maintains:

Stable 8V regulated output

Low output noise and ripple rejection, crucial for sensitive analog or RF circuits

Consistent regulation across temperature range (-40°C to +125°C), supporting outdoor and industrial deployment

Low dropout voltage characteristics, preserving output regulation at minimum input voltages

Fast transient response, enabling use in dynamic load scenarios

Performance graphs supplied by the manufacturer further detail dropout behavior, supply rejection, and load/line regulation, guiding optimization for specific application contexts.

Design Guidelines and Application Notes — L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR is suitable for local on-card regulation, greatly simplifying PCB power distribution. When used in low-current circuits, compensation capacitors may not be mandatory, but including a quality input bypass capacitor (≥0.33μF, low ESR) is recommended for optimal noise immunity and stability, especially if situated far from the power supply or in environments with substantial electromagnetic interference.

Engineering scenarios include:

Fixed output regulators for microcontroller analog sections

Constant current source configurations

High input voltage or power dissipation management approaches (with external dropping resistor or advanced layouts)

Adjustable voltage applications with additional circuit elements

Safe PCB design practice includes minimizing ground paths and lead resistance, ensuring direct capacitor connections to the input terminals, and understanding the impact of load and line transients.

Environmental Standards and Compliance — L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR is compliant with RoHS 3 and REACH standards, certifying its suitability for global commercial, industrial, and consumer applications where environmental responsibility is mandated. The device exhibits unlimited moisture sensitivity level (MSL1), supporting standard reflow and assembly processes without special pre-baking requirements. Furthermore, ECOPACK packaging options ensure compliance with advanced environmental grades according to STMicroelectronics' policies.

Possible Alternatives or Substitute Models — L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR is part of the L78M family, with numerous models available for different fixed output voltages (including 5V, 6V, 9V, 10V, 12V, 15V, and 24V). For 8V/500mA regulation in high-density or surface-mount applications, the L78M08CDT-TR remains the direct choice. In scenarios where identical performance and packaging are required, related L78M08 DPAK variants may be considered. For alternate voltages or packaging, other L78M series models such as L78M08 in TO-220 or TO-220FP form factors are available to suit legacy or high-power requirements.

Conclusion

— L78M08CDT-TR STMicroelectronics

The L78M08CDT-TR 8V, 500mA linear voltage regulator from STMicroelectronics is a robust choice for engineers seeking precise and reliable voltage regulation within compact PCB designs. Its integrated protection, comprehensive environmental compliance, and versatility in packaging make it suitable for a broad array of application scenarios. Combined with its proven electrical characteristics and established L78M product line heritage, the L78M08CDT-TR represents a dependable component for critical system power management across diverse electronic platforms.