My Inquiry
My Account
STMicroelectronics L78L20ACD-TR
- Part No.:
- L78L20ACD-TR
- Manufacturer:
- STMicroelectronics
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
L78L20ACD-TR.pdf
- Description:
- IC REG LINEAR 20V 100MA 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,158
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
L78L20ACD-TR from STMicroelectronics is a fixed-output +20 V, 100 mA positive linear voltage regulator in SO-8 package with ±4% output voltage tolerance, thermal overload protection, short-circuit protection, and no external components required. It delivers stable local regulation for microcontroller I/O rails, sensor biasing, and low-power analog circuitry in industrial control modules.
For engineers reviewing the L78L20ACD-TR datasheet, L78L20ACD-TR pinout, L78L20ACD-TR application, or L78L20ACD-TR equivalent, key selection criteria include dropout voltage (1.7 V), quiescent current (6 mA at 25 °C), output noise (150 µV, 10 Hz–100 kHz), and supply voltage rejection (32–38 dB at 120 Hz) under 1–100 mA load conditions.
Technical Context
This three-terminal monolithic regulator integrates internal current limiting, thermal shutdown, and safe-area protection-enabling robust operation without external compensation. Its SO-8 package features pins 2, 3, 6, and 7 internally connected to the die attach flag for enhanced thermal dissipation when mounted on ≥6 cm² copper area.
The device operates across 0 to 125 °C junction temperature and supports input voltages up to 40 V (for VO = 18–24 V), maintaining regulated output with line regulation ≤300 mV and load regulation ≤100 mV over full temperature and load range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +20 V ±4% (guaranteed over 1–100 mA load and 0–125 °C) |
| Max Output Current | 100 mA (continuous, with adequate PCB copper heat-sinking) |
| Dropout Voltage | 1.7 V (enables regulation from 21.7 V min input at full load) |
| Quiescent Current | 6 mA at 25 °C (low static power draw for battery-backed systems) |
| Output Noise | 150 µV RMS (10 Hz–100 kHz; critical for precision analog front-ends) |
| SVR | 32–38 dB at 120 Hz (rejects ripple from unregulated DC/DC or rectified AC sources) |
| Thermal Resistance | RthJA = 55 °C/W (with 6 cm² PCB copper heat-sink; enables >500 mW safe dissipation) |
Pinout & Package
SO-8 package with exposed die attach flag (pins 2, 3, 6, 7 internally bonded to flag). Designed for surface-mount assembly and improved thermal performance versus TO-92 or SOT-89.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | VOUT | Regulated +20 V output; connects directly to load and local bypass capacitor (0.1 µF) |
| Pin 2 | GND | Ground reference; electrically tied to die flag for low-impedance thermal path |
| Pin 3 | VIN | Unregulated input (21.7–40 V); requires 0.33 µF input capacitor for stability |
| Pins 4, 5 | NC | No connect; isolated from die; used for mechanical anchoring only |
| Pins 6, 7 | GND | Additional ground terminals tied to die flag; must be soldered to large copper pour |
| Pin 8 | GND | Primary ground terminal; completes low-impedance return path for output current |
Key Features
| Feature | Design Value |
|---|---|
| Fixed +20 V output | Eliminates need for external feedback resistors; reduces BOM count and layout complexity |
| Internal thermal shutdown | Prevents permanent damage during sustained overload or poor heatsinking |
| No external capacitors required for stability | Guaranteed stability with only 0.33 µF input and 0.1 µF output ceramic capacitors |
| ±4% output tolerance (A grade) | Tighter than standard ±8% (C grade); suitable for applications requiring higher voltage accuracy |
| Low output noise (150 µV) | Enables clean power for op-amps, ADC references, and RF bias circuits without added filtering |
Applications
| Industrial Sensor Interface | Microcontroller I/O Power Rail |
|---|---|
Use Scenario: Powering 24-bit sigma-delta ADCs and precision temperature sensors in PLC analog input modules. IC Role / Device Role / Timing Role: Local +20 V bias supply for sensor excitation and ADC reference buffers. Use Value: 150 µV output noise and 32–38 dB SVR preserve ENOB in high-resolution data acquisition. |
Use Scenario: Supplying GPIO banks and UART transceivers in ARM Cortex-M4-based edge controllers. IC Role / Device Role / Timing Role: Dedicated low-noise rail decoupled from main 3.3 V core supply. Use Value: 1.7 V dropout allows operation from 24 V field bus with margin; ±4% tolerance ensures reliable level-shifting. |
| Programmable Logic Controller (PLC) Backplane | Analog Signal Conditioning |
Use Scenario: Generating auxiliary +20 V for analog output drivers (e.g., 4–20 mA HART modules). IC Role / Device Role / Timing Role: Fixed-voltage source for current-loop DAC stages and op-amp gain stages. Use Value: Internal short-circuit protection prevents system-wide failure during field wiring faults. |
Use Scenario: Biasing instrumentation amplifiers and active filters in medical-grade signal chains. IC Role / Device Role / Timing Role: Clean, regulated supply for precision op-amp rails where PSRR alone is insufficient. Use Value: 6 mA quiescent current minimizes self-heating drift in thermally sensitive measurement paths. |
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 |
|---|---|---|---|
| LM78L20ACM/NOPB | ±5% output tolerance; RthJA = 125 °C/W (SO-8); no internal GND-flag bonding | Higher thermal resistance limits max continuous current to ~60 mA without aggressive heatsinking | Select if legacy footprint compatibility is required and lower accuracy is acceptable |
| MC78L20ACP | TO-92 package; RthJA = 200 °C/W; ±5% tolerance; no SO-8 thermal flag | Not suitable for high-density SMT designs; limited to <30 mA continuous due to thermal constraints | Choose only for through-hole prototyping or ultra-low-cost replacements where thermal performance is secondary |
Compared with LM78L20ACM/NOPB and MC78L20ACP, L78L20ACD-TR offers tighter ±4% tolerance, superior thermal performance via integrated flag bonding, and guaranteed 100 mA delivery-making it optimal for space-constrained industrial SMT designs demanding reliability and accuracy.
Availability
L78L20ACD-TR is available at Aetrix Electronics and suitable for industrial automation, programmable logic controllers, and sensor interface modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for L78L20ACD-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, specializing in power management, microcontrollers, and automotive ICs with strong industrial and embedded market focus.
The L78L series was designed specifically for cost-sensitive, space-constrained local regulation tasks-replacing Zener/resistor networks with integrated protection, lower quiescent current, and improved noise performance.
FAQ
What is the minimum input voltage required for L78L20ACD-TR to maintain regulation?
The dropout voltage is specified as 1.7 V at 100 mA and 25 °C. Therefore, the minimum input voltage is 20 V + 1.7 V = 21.7 V under full-load, room-temperature conditions. At higher temperatures or lower loads, dropout decreases slightly-but 21.7 V is the design-minimum for guaranteed regulation across all operating conditions.
Can L78L20ACD-TR be used in parallel to increase output current?
No. The L78L20ACD-TR lacks built-in current-sharing features such as current-limit matching or thermal tracking. Parallel connection risks current imbalance, thermal runaway, and premature failure. For >100 mA, use a single higher-current regulator (e.g., L7820CD2T) or add an external pass transistor with proper biasing.
Is an input capacitor mandatory, and what value is recommended?
Yes-an input capacitor is mandatory for stability. STMicroelectronics specifies a minimum 0.33 µF ceramic capacitor placed within 10 mm of pins 3 (VIN) and 2/6/7/8 (GND). Larger values (e.g., 1–10 µF) improve transient response and ripple rejection but do not affect basic stability.
Does the SO-8 package require special PCB layout considerations for thermal performance?
Yes. Pins 2, 3, 6, and 7 are internally connected to the die attach flag. To achieve the rated RthJA = 55 °C/W, these pins must be soldered to ≥6 cm² of 2-oz copper on the PCB's inner or outer layer, with multiple thermal vias to internal ground planes. Without this, junction temperature rise will exceed specifications at full load.
L78L20ACD-TR 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:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 20V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- -
- Current - Output:
- 100mA
- Current - Quiescent (Iq):
- 6 mA
- Current - Supply (Max):
- 6.5 mA
- PSRR:
- 38dB (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
L78L20ACD-TR FAQ
1.How can I place an order for L78L20ACD-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for L78L20ACD-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 L78L20ACD-TR reliable?
The price and inventory of L78L20ACD-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78L20ACD-TR is usually 5 days.
3.What payment methods are accepted for L78L20ACD-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78L20ACD-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L78L20ACD-TR?
L78L20ACD-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L78L20ACD-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 L78L20ACD-TR?
For technical support, including L78L20ACD-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78L20ACD-TR requirements.
6.How does Aetrix verify that L78L20ACD-TR is sourced from the original manufacturer or authorized distributors?
All L78L20ACD-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 L78L20ACD-TR meets industry standards.
7.What is the process for return or replacement of L78L20ACD-TR?
All L78L20ACD-TR units undergo pre-shipment inspection (PSI). If there is an issue with L78L20ACD-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 L78L20ACD-TR part is unused and in its original packaging.
Return procedure for L78L20ACD-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
L78L20ACD-TR Tags
-
MIC5504-1.8YM5-TR
Microchip Technology
-
MIC5504-3.3YM5-TR
Microchip Technology
-
MIC5365-3.0YC5-TR
Microchip Technology
-
MIC5365-1.8YC5-TR
Microchip Technology
-
MIC5365-2.5YC5-TR
Microchip Technology
-
MIC5365-3.3YC5-TR
Microchip Technology
-
MIC5365-3.3YD5-TR
Microchip Technology
-
MIC5317-3.3YM5-TR
Microchip Technology
-
TLV1117LV33DCYR
Texas Instruments
-
MIC5317-3.3YMT-TZ
Microchip Technology
-
MIC5528-3.3YMT-TR
Microchip Technology
-
TLV75801PDRVR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
