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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics L79L12ABD-R

Name: L79L12ABD-R
Brand: STMicroelectronics
SKU: L79L12ABD-R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L79L12ABD-R

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: L79L12ABD-R.pdf

Description:: IC REG LINEAR -12V 100MA 8SO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L79L12ABD-R from STMicroelectronics is a three-terminal fixed negative voltage regulator delivering -12 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components and is designed for local on-card regulation in industrial control, instrumentation, and embedded power subsystems where noise rejection and stable low-current biasing are critical.

For engineers reviewing the L79L12ABD-R datasheet, L79L12ABD-R pinout, L79L12ABD-R application, or L79L12ABD-R equivalent, this device serves as a drop-in replacement for Zener-diode/resistor regulators-offering two orders of magnitude lower output impedance, reduced quiescent current (6.5 mA typ.), and 80 µV RMS output noise in 10 Hz–100 kHz bandwidth.

Technical Context

The L79L12ABD-R implements a monolithic bipolar linear regulator architecture with built-in thermal shutdown and foldback current limiting. Its fixed -12 V output is trimmed at 25 °C to ±1% tolerance (−11.5 V to −12.5 V), maintaining regulation across input voltages from −14.5 V to −27 V and load currents from 1 mA to 100 mA.

It achieves 37–42 dB supply voltage rejection at 120 Hz with 1.7 V dropout voltage, enabling operation in noisy DC bus environments. The device supports extended temperature operation from −40 °C to +125 °C junction, qualifying it for industrial-grade power rail conditioning without external compensation.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	−12 V nominal; −11.5 V to −12.5 V at 25 °C ensures tight biasing for op-amp dual supplies and analog sensor interfaces
Output Current	100 mA max; sufficient for powering low-power microcontrollers, RS-232 transceivers, and analog front-ends
Input Voltage Range	−14.5 V to −27 V; enables compatibility with standard −15 V and −24 V industrial rails while maintaining regulation margin
Dropout Voltage	1.7 V typical; allows ≥2.7 V headroom above output, reducing heat dissipation vs. higher-dropout alternatives
Quiescent Current	6.5 mA at 25 °C; enables efficient standby operation in battery-backed or low-power monitoring systems
Output Noise	80 µV RMS (10 Hz–100 kHz); minimizes interference in precision ADC references and audio signal paths
SVR @ 120 Hz	37–42 dB; suppresses ripple from rectified AC-derived supplies in mixed-signal PCBs
Thermal Shutdown	Active at ~150 °C junction; protects against sustained overloads without external circuitry

Pinout & Package

Package: SO-8 (modified internal frame with pins 2, 3, 6, and 7 electrically connected to die attach flag for enhanced thermal performance; 55 °C/W junction-to-ambient thermal resistance with 6 cm² copper heatsink).

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	GND	Ground reference terminal; must be connected directly to low-impedance system ground plane
Pin 2	VIN	Negative input supply; accepts −14.5 V to −27 V; requires ≥0.33 µF ceramic bypass capacitor
Pin 3	VOUT	Regulated −12 V output; requires ≥0.1 µF ceramic output capacitor for stability and transient response
Pins 4–5, 7–8	No Connect / Thermal Flag Tie	Internally tied to die attach flag; recommended to connect to large copper pour for thermal management

Key Features

Feature	Design Value
Fixed −12 V Output	Guaranteed −11.4 V to −12.6 V over full load (1–70 mA) and input range, eliminating need for external feedback resistors
Thermal Overload Protection	Self-resetting shutdown prevents permanent damage during sustained overcurrent or high ambient temperature conditions
No External Components Required	Stable operation with only input/output capacitors; reduces BOM count and PCB area vs. adjustable regulators
Low Output Impedance	~10× lower than Zener/resistor equivalents, improving PSRR and load transient response in sensitive analog circuits
Extended Temperature Range	−40 °C to +125 °C operating junction temperature supports deployment in harsh industrial enclosures and automotive under-hood zones

Applications

Industrial Sensor Signal Conditioning

RS-232 Transceiver Bias Supply

Use Scenario: Providing clean, stable negative rail for precision instrumentation amplifiers and 16-bit ADC drivers in factory-floor pressure/temperature sensors.

IC Role / Device Role / Timing Role: Fixed negative voltage regulator supplying −12 V to analog signal chain components requiring low-noise, low-drift bias.

Use Value: 80 µV RMS output noise and 42 dB SVR ensure <0.005% measurement error contribution from power rail noise in 24-bit delta-sigma systems.

Use Scenario: Powering the negative supply pin of MAX232-class RS-232 transceivers in programmable logic controllers (PLCs) with isolated serial ports.

IC Role / Device Role / Timing Role: Local point-of-load regulator generating −12 V from a shared −15 V backplane, decoupling transceiver noise from other subsystems.

Use Value: 100 mA output capacity supports multiple transceivers per rail; thermal shutdown prevents latch-up during cable short events.

Embedded Microcontroller Auxiliary Rail

Analog Front-End for Data Acquisition

Use Scenario: Generating −12 V for op-amp bias in ARM Cortex-M4-based motor control boards where dual-supply op-amps condition current-sense signals.

IC Role / Device Role / Timing Role: Low-quiescent-current (6.5 mA) negative regulator enabling always-on analog monitoring without compromising MCU sleep-mode efficiency.

Use Value: 1.7 V dropout allows operation from −15 V rail even under brownout conditions, maintaining analog functionality during main supply dips.

Use Scenario: Supplying negative reference voltage to 12-bit DACs and anti-aliasing filters in portable test equipment with battery + DC adapter operation.

IC Role / Device Role / Timing Role: Precision voltage source for analog signal path offset calibration and bipolar DAC output swing extension.

Use Value: ±1% output tolerance at 25 °C and <100 mV load regulation error ensure <±1 LSB error in 12-bit conversion accuracy over full load range.

Equivalent & Alternatives

The following parts are listed as comparable options for similar fixed negative voltage regulation applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM7912CD	±2% output tolerance (−11.4 V to −12.6 V), 1.7 V dropout, but only rated for 0 °C to +125 °C operation	Lacks extended −40 °C low-temp capability; unsuitable for outdoor or unheated industrial deployments	Select if cost sensitivity outweighs wide-temperature requirement and board space permits TO-220 heatsinking
MC79L12ACDR2G	±5% output tolerance (−11.4 V to −12.6 V), same SO-8 package, but quiescent current 6.0 mA (typ.) and 40 dB SVR	Higher output variation and lower ripple rejection limit use in high-precision analog stages	Prefer for legacy designs already qualified with ON Semiconductor's L79L family; verify noise budget margins

Compared with LM7912CD and MC79L12ACDR2G, the L79L12ABD-R provides tighter initial tolerance (±1%), guaranteed −40 °C start-up, and superior 42 dB SVR-making it optimal for new industrial designs demanding robustness across environmental extremes and signal integrity in mixed-signal systems.

Availability

L79L12ABD-R is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded control systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for L79L12ABD-R 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, specializing in power management, analog, microcontrollers, and automotive ICs.

The L79L00 series belongs to ST's legacy linear regulator product line, engineered specifically for cost-sensitive, space-constrained industrial and consumer applications requiring reliable fixed-voltage regulation without external components.

FAQ

What is the minimum input voltage required for stable −12 V output?

The L79L12ABD-R requires a minimum input voltage of −14.5 V to maintain regulation across its full 100 mA load range and temperature span. Below this, dropout behavior occurs-output voltage drops linearly with input. At light loads (<10 mA), regulation holds down to −13.7 V, but design margin mandates −14.5 V as the absolute minimum per datasheet test conditions.

Can this regulator be used in parallel to increase output current?

No-L79L12ABD-R is not designed for parallel operation. Its internal current limiting and thermal protection are per-device; paralleling causes unequal current sharing due to output voltage mismatch (±1% tolerance), leading to thermal runaway in one unit. For >100 mA, use an external pass transistor with proper ballasting or select a higher-current regulator like L7912.

Is a heatsink required for continuous 100 mA operation?

With the SO-8 package and 6 cm² copper heatsink on the PCB, no external heatsink is needed for 100 mA at ambient ≤50 °C. Junction temperature remains below 125 °C. Without copper pour, power dissipation exceeds safe limits above ~30 mA-verify thermal design using R_thj-amb = 55 °C/W and P_diss = (V_IN − V_OUT) × I_OUT.

Does the L79L12ABD-R require input/output capacitors, and what values are recommended?

Yes-0.33 µF ceramic capacitor on VIN and 0.1 µF ceramic capacitor on VOUT are mandatory for stability per STMicroelectronics' test circuits. These values suppress high-frequency oscillation and improve transient response. Larger values (e.g., 10 µF tantalum on input) may be added for bulk filtering but do not replace the specified ceramics.

L79L12ABD-R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Configuration:: Negative

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):: 6 mA

Current - Supply (Max):: 6.5 mA

PSRR:: 42dB (120Hz)

Control Features:: -

Protection Features:: Over Temperature, Short Circuit

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

L79L12ABD-R FAQ

1.How can I place an order for L79L12ABD-R through Aetrix?

Please submit a Request for Quotation (RFQ) for L79L12ABD-R 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 L79L12ABD-R reliable?

The price and inventory of L79L12ABD-R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L79L12ABD-R is usually 5 days.

3.What payment methods are accepted for L79L12ABD-R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L79L12ABD-R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L79L12ABD-R?

L79L12ABD-R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L79L12ABD-R 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 L79L12ABD-R?

For technical support, including L79L12ABD-R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L79L12ABD-R requirements.

6.How does Aetrix verify that L79L12ABD-R is sourced from the original manufacturer or authorized distributors?

All L79L12ABD-R 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 L79L12ABD-R meets industry standards.

7.What is the process for return or replacement of L79L12ABD-R?

All L79L12ABD-R units undergo pre-shipment inspection (PSI). If there is an issue with L79L12ABD-R, 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 L79L12ABD-R part is unused and in its original packaging.

Return procedure for L79L12ABD-R:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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