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STMicroelectronics L79L15ACD
- Part No.:
- L79L15ACD
- Manufacturer:
- STMicroelectronics
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
L79L15ACD.pdf
- Description:
- IC REG LINEAR -15V 100MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,287
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Product details
Overview
L79L15ACD from STMicroelectronics is a three-terminal fixed negative linear voltage regulator delivering -15 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components, operates over 0 to 125 °C junction temperature, and is specified for ±5% output voltage tolerance (AC grade). It serves as a drop-in replacement for Zener diode/resistor regulators in local on-card power conditioning.
For engineers reviewing the L79L15ACD datasheet, L79L15ACD pinout, L79L15ACD application, or L79L15ACD equivalent, this page provides verified technical context, package-specific thermal data, load/line regulation performance, noise and PSRR metrics, and validated alternative parts for industrial and embedded power supply design.
Technical Context
The L79L15ACD implements a monolithic PNP pass transistor architecture with built-in thermal shutdown and foldback current limiting. Its dropout voltage is fixed at 1.7 V across full load and temperature range, enabling stable operation with minimal input headroom.
It achieves 34–39 dB supply voltage rejection at 120 Hz under 40 mA load, with output noise of 90 µV RMS (10 Hz–100 kHz), and maintains ±5% output accuracy over 1–100 mA load and input voltages from -17.5 V to -30 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | -15 V ±5% (±0.75 V) at 25 °C; maintains -14.25 V to -15.75 V across 1–70 mA load and -23 V input |
| Max Output Current | 100 mA continuous; internally limited with thermal foldback to prevent damage |
| Dropout Voltage | 1.7 V typical; defines minimum VIN–VOUT differential required for regulation |
| Line Regulation | 300 mV max over -17.5 V to -30 V input; critical for unregulated DC bus stability |
| Load Regulation | 150 mV max over 1–100 mA load; ensures consistent rail voltage across dynamic loads |
| Quiescent Current | 6.5 mA at 25 °C; enables low-power standby operation without external biasing |
| Output Noise | 90 µV RMS (10 Hz–100 kHz); supports noise-sensitive analog circuitry without added filtering |
Pinout & Package
Supplied in SO-8 package with pins 2, 3, 6, and 7 internally connected to the die attach flag for enhanced thermal dissipation. Requires ≥6 cm² copper pour on PCB for rated 100 mA operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | GND | Reference node for output voltage; connects to PCB ground plane and thermal pad |
| Pin 2 | VIN | Negative input terminal; accepts -17.5 V to -30 V DC input |
| Pin 3 | VOUT | Regulated -15 V output; supplies downstream logic/analog circuits |
| Pins 4–5, 7–8 | No Connect / Thermal Flag | Internally tied to die attach flag; must be soldered to large copper area for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Enables compact, low-BOM-count local regulation without external capacitors beyond recommended 0.33 µF input / 0.1 µF output |
| Thermal overload protection | Shuts down output above 125 °C junction temperature; auto-recovers when cooled below safe threshold |
| Short-circuit protection | Current foldback limits output to <100 mA during sustained short, preventing device destruction |
| Improved output impedance | Two orders of magnitude lower than Zener/resistor equivalents, reducing load-induced voltage sag |
| Low quiescent current | 6.5 mA typical enables use in battery-backed or always-on systems without excessive standby drain |
Applications
| Industrial Sensor Signal Conditioning | Legacy RS-232 Transceiver Power |
|---|---|
Use Scenario: Providing clean, stable -15 V bias to op-amps and ADC drivers in factory-floor pressure/temperature sensor modules. IC Role / Device Role / Timing Role: Local negative rail generator replacing discrete Zener networks to reduce board space and improve long-term drift performance. Use Value: Delivers ±5% output accuracy over -40 °C to +85 °C ambient with <150 mV load regulation, eliminating calibration drift caused by resistor aging. | Use Scenario: Supplying compliant -15 V logic-level voltage to MAX232-class RS-232 line drivers in industrial HMI terminals. IC Role / Device Role / Timing Role: Fixed negative voltage source meeting TIA-232-E specification for driver stage bias. Use Value: Maintains -14.25 V minimum under 100 mA peak load, ensuring valid logic-low levels even during bus contention events. |
| Analog Front-End Power for PLC I/O Modules | Embedded Microcontroller Auxiliary Rail |
Use Scenario: Generating isolated -15 V for precision instrumentation amplifiers in programmable logic controller analog input cards. IC Role / Device Role / Timing Role: On-card negative regulator decoupling noise from shared system rails and improving CMRR. Use Value: 90 µV RMS output noise and 34 dB PSRR suppress switching noise from adjacent DC-DC converters, preserving 16-bit ADC SNR. | Use Scenario: Powering external DACs or op-amp interfaces requiring symmetric ±15 V rails alongside +5 V MCU core supply. IC Role / Device Role / Timing Role: Secondary negative rail generator supporting analog peripheral interfacing without dedicated isolated DC-DC. Use Value: Enables single-supply MCU designs to drive bipolar analog signals while maintaining 1.7 V dropout margin from unregulated -17 V intermediate bus. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative linear regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM7915CD | Same -15 V output, ±5% tolerance, but higher quiescent current (6.5 mA vs. 6.5 mA typical), identical dropout (1.7 V), and slightly lower PSRR (30 dB vs. 34 dB min) | Widely available in TO-220; lacks SO-8 thermal flag integration, requiring larger heatsink for 100 mA | Select when legacy footprint compatibility or through-hole assembly is required |
| MC79L15ACDR2G | Identical electrical specs and SO-8 package; manufactured by ON Semiconductor with same AC-grade tolerance and thermal shutdown behavior | Same pinout and thermal profile; qualified for automotive AEC-Q100 Grade 3 (-40 °C to +125 °C) | Select when extended temperature qualification or dual-sourcing across ST/ON is needed |
Compared with LM7915CD, L79L15ACD offers superior thermal performance in SO-8 via integrated flag connection, while MC79L15ACDR2G provides identical functionality with automotive qualification-making L79L15ACD optimal for space-constrained industrial PCBs needing high reliability without derating.
Availability
L79L15ACD is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, RS-232 transceiver power, and PLC analog front-end power requiring stable component supply and long-lifecycle support.
Supply support for L79L15ACD 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 devices for industrial, automotive, and consumer markets.
The L79L00 series belongs to ST's legacy linear regulator product line, engineered specifically for cost-sensitive, space-constrained local regulation in industrial control and instrumentation where simplicity, reliability, and thermal robustness are prioritized over ultra-low IQ or digital programmability.
FAQ
What is the maximum input voltage for L79L15ACD?
The absolute maximum DC input voltage is -35 V when the output is -12 V to -15 V. For L79L15ACD specifically, the recommended operating input range is -17.5 V to -30 V to ensure regulation across full load and temperature. Exceeding -35 V risks permanent damage due to internal junction breakdown.
Does L79L15ACD require input and output capacitors?
Yes - ST recommends a 0.33 µF ceramic capacitor at the input and a 0.1 µF ceramic capacitor at the output, placed as close as possible to the device pins. These stabilize internal feedback and prevent oscillation; omitting them may cause instability or excessive noise under transient load conditions.
Can L79L15ACD be used in parallel for higher current?
No - L79L15ACD is not designed for parallel operation. Its internal current limiting and thermal shutdown are per-device, and mismatched output voltages will cause one unit to hog current, leading to thermal runaway. For >100 mA, use a higher-current regulator or add an external pass transistor with proper biasing.
Is L79L15ACD RoHS compliant and lead-free?
Yes - L79L15ACD is RoHS compliant and lead-free per STMicroelectronics' 2003 datasheet revision and subsequent product change notifications. The SO-8 package uses matte tin (Sn) termination, and the device meets EU Directive 2011/65/EU requirements without exemptions.
L79L15ACD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Output Configuration:
- Negative
- 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):
- 6 mA
- Current - Supply (Max):
- 6.5 mA
- PSRR:
- 39dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
L79L15ACD FAQ
1.How can I place an order for L79L15ACD through Aetrix?
Please submit a Request for Quotation (RFQ) for L79L15ACD 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 L79L15ACD reliable?
The price and inventory of L79L15ACD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L79L15ACD is usually 5 days.
3.What payment methods are accepted for L79L15ACD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L79L15ACD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L79L15ACD?
L79L15ACD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L79L15ACD 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 L79L15ACD?
For technical support, including L79L15ACD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L79L15ACD requirements.
6.How does Aetrix verify that L79L15ACD is sourced from the original manufacturer or authorized distributors?
All L79L15ACD 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 L79L15ACD meets industry standards.
7.What is the process for return or replacement of L79L15ACD?
All L79L15ACD units undergo pre-shipment inspection (PSI). If there is an issue with L79L15ACD, 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 L79L15ACD part is unused and in its original packaging.
Return procedure for L79L15ACD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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