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STMicroelectronics L78L15CD-TR
- Part No.:
- L78L15CD-TR
- Manufacturer:
- STMicroelectronics
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
L78L15CD-TR.pdf
- Description:
- IC REG LINEAR 15V 100MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:7,302
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Product details
Overview
L78L15CD-TR from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 15 V output at up to 100 mA, with ±4% output tolerance (C-grade), thermal overload protection, short-circuit protection, and no external components required. It operates across an input range of 17.5–30 V and is used for local on-card regulation in industrial control modules, sensor signal conditioning circuits, and low-power microcontroller power rails.
For engineers reviewing the L78L15CD-TR datasheet, L78L15CD-TR pinout, L78L15CD-TR application, or L78L15CD-TR equivalent, this device serves as a drop-in replacement for Zener diode/resistor regulators-offering lower quiescent current (6.5 mA typ.), improved line/load regulation (250 mV/75 mV max), and higher PSRR (34–39 dB) in compact TO-92 and SO-8 packages.
Technical Context
The L78L15CD-TR integrates internal current limiting and thermal shutdown circuitry, enabling robust operation without external protection components. Its architecture uses a bandgap reference and error amplifier to maintain stable 15 V output under varying load (1–100 mA) and input (17.5–30 V) conditions.
It features a dropout voltage of 1.7 V at 40 mA, supports operation from –40 °C to +125 °C (AB grade), and delivers 90 µV RMS output noise (10 Hz–100 kHz). The SO-8 variant includes internally connected pins 2/3/6/7 to the die attach flag for enhanced thermal performance (RthJA = 55 °C/W with 6 cm² copper pour).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 15 V nominal, ±4% tolerance (14.4–15.6 V at 25 °C); ensures stable MCU core or analog sensor supply within tight margin. |
| Max Output Current | 100 mA continuous; sufficient for powering multiple low-power ICs (e.g., op-amps, logic, sensors) on a single board node. |
| Input Voltage Range | 17.5 V to 30 V DC; compatible with unregulated 24 V industrial rails after rectification/filtering. |
| Dropout Voltage | 1.7 V at 40 mA; enables regulation even when input sags to 16.7 V, improving system resilience. |
| Quiescent Current | 6.5 mA typical at 25 °C; reduces standby power loss in battery-backed or energy-sensitive applications. |
| PSRR | 34–39 dB at 120 Hz; suppresses ripple from switching pre-regulators or noisy DC supplies. |
| Output Noise | 90 µV RMS (10 Hz–100 kHz); suitable for noise-sensitive analog front-ends like ADC references or precision amplifiers. |
Pinout & Package
Supplied in SO-8 package (D-TR suffix), with pins 2, 3, 6, and 7 internally bonded to the exposed die attach flag for low thermal resistance (RthJC = 20 °C/W). This configuration requires PCB copper area beneath the package for effective heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (IN) | Unregulated Input | Accepts 17.5–30 V DC; must be decoupled with ≥0.33 µF ceramic capacitor close to pin. |
| Pin 2 (GND) | Ground Reference | Common return for input and output paths; tied internally to die flag in SO-8 for thermal conduction. |
| Pin 3 (OUT) | Regulated Output | Delivers stable 15 V; requires ≥0.1 µF ceramic output capacitor for stability and transient response. |
| Pins 4, 5, 7, 8 | No Connect / Thermal Flag | Internally shorted to die attach flag; must be soldered to ≥6 cm² PCB copper pour for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed-output regulation | 15 V ±4% over full temperature and load range eliminates need for external feedback resistors or trimming. |
| Integrated protection | Thermal shutdown and short-circuit current limiting prevent damage during fault conditions without external circuitry. |
| No external components | Stable operation with only 0.33 µF input and 0.1 µF output capacitors-reduces BOM count and layout area. |
| Low-noise performance | 90 µV RMS output noise enables use in analog signal chains where clean biasing is critical (e.g., sensor excitation, reference buffers). |
| Wide operating temperature | Rated for –40 °C to +125 °C junction temperature, supporting deployment in automotive under-hood and industrial control environments. |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Powering isolated digital input buffers and analog sensor interfaces in modular PLC backplanes. IC Role / Device Role / Timing Role: Local 15 V rail generator for optocoupler drivers and signal-conditioning op-amps. Use Value: Eliminates distribution losses and noise coupling from centralized 24 V supply, improving signal integrity and EMC performance. |
Use Scenario: Supplying 15 V to LIN transceivers and window motor controllers in door modules. IC Role / Device Role / Timing Role: Fixed-voltage regulator for communication ICs requiring stable bias independent of battery voltage fluctuations. Use Value: Maintains reliable LIN bus operation down to 16.7 V input (1.7 V dropout), extending functional range during cold-crank events. |
| Medical Patient Monitoring Sensors | Test & Measurement Front-Ends |
Use Scenario: Biasing precision thermistor and strain gauge signal chains in portable vital sign monitors. IC Role / Device Role / Timing Role: Low-noise 15 V source for instrumentation amplifiers and 16-bit ADC references. Use Value: 90 µV RMS noise and 34–39 dB PSRR ensure sub-LSB measurement accuracy in high-resolution analog acquisition. |
Use Scenario: Providing regulated 15 V to op-amp-based active filters and calibration DACs in benchtop DMMs. IC Role / Device Role / Timing Role: Local regulation stage following switching pre-regulator to suppress switching ripple. Use Value: 250 mV line regulation and 75 mV load regulation preserve gain accuracy across varying load and input conditions. |
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 |
|---|---|---|---|
| LM78L15ACZ/NOPB | ±5% output tolerance (wider than L78L15CD-TR's ±4%), higher quiescent current (7.5 mA), TO-92 only. | Suitable for cost-sensitive, non-critical 15 V rails where tighter tolerance isn't required. | Select if TO-92 footprint is mandatory and ±5% output variation is acceptable. |
| MC78L15CPG | ±5% tolerance, 100 mA rating, but no SO-8 option; higher dropout (2.0 V) and lower PSRR (30 dB). | Better suited for legacy through-hole designs with minimal thermal constraints. | Prefer for existing TO-92 layouts needing second-source availability, not for new SO-8 designs. |
Compared with LM78L15ACZ/NOPB and MC78L15CPG, the L78L15CD-TR offers tighter output tolerance, lower quiescent current, superior PSRR, and SO-8 thermal performance-making it optimal for space-constrained, noise-sensitive, and thermally demanding applications.
Availability
L78L15CD-TR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical patient monitoring sensors, and test & measurement front-ends requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for L78L15CD-TR 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 microcontrollers, power management ICs, and analog/mixed-signal devices for industrial, automotive, and consumer markets.
The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in space- and reliability-constrained embedded systems-emphasizing simplicity, protection integration, and wide-temperature operation.
FAQ
What is the maximum allowable input voltage for L78L15CD-TR?
The absolute maximum DC input voltage is 35 V for 15 V output variants, per STMicroelectronics' DS0424 Rev 30. However, sustained operation above 30 V is not recommended due to thermal stress; the recommended operating range is 17.5 V to 30 V to ensure safe junction temperature and specified regulation performance.
Can L78L15CD-TR be used in parallel to increase output current?
No-L78L15CD-TR is not designed for parallel operation. Its output voltage tolerance (±4%) and lack of current-sharing control make load imbalance likely, risking thermal runaway. For >100 mA, use a single higher-current regulator (e.g., L7815CV) or add an external pass transistor per Figure 14 in the datasheet.
Is a heatsink required for SO-8 package operation at 100 mA?
Yes-when delivering 100 mA at full input voltage (30 V), power dissipation reaches ~1.5 W. With RthJA = 55 °C/W (6 cm² copper), junction temperature rise is ~83 °C. To stay within 125 °C max, ambient must remain ≤42 °C; otherwise, additional heatsinking or derating is necessary.
Does L78L15CD-TR require input/output capacitors, and what values are validated?
Yes-ST specifies 0.33 µF ceramic at the input and 0.1 µF ceramic at the output, placed as close as possible to the respective pins. These values ensure stability across all operating conditions; larger values improve ripple rejection but do not affect basic regulation. Tantalum or electrolytic caps are not recommended due to ESR-related instability risks.
L78L15CD-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- 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):
- 15V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 5.5 mA
- Current - Supply (Max):
- 6 mA
- PSRR:
- 39dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
L78L15CD-TR FAQ
1.How can I place an order for L78L15CD-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for L78L15CD-TR 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 L78L15CD-TR reliable?
The price and inventory of L78L15CD-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78L15CD-TR is usually 5 days.
3.What payment methods are accepted for L78L15CD-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78L15CD-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L78L15CD-TR?
L78L15CD-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L78L15CD-TR 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 L78L15CD-TR?
For technical support, including L78L15CD-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78L15CD-TR requirements.
6.How does Aetrix verify that L78L15CD-TR is sourced from the original manufacturer or authorized distributors?
All L78L15CD-TR 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 L78L15CD-TR meets industry standards.
7.What is the process for return or replacement of L78L15CD-TR?
All L78L15CD-TR units undergo pre-shipment inspection (PSI). If there is an issue with L78L15CD-TR, 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 L78L15CD-TR part is unused and in its original packaging.
Return procedure for L78L15CD-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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