My Inquiry
My Account
Diodes Incorporated AP1084T18L-U
- Part No.:
- AP1084T18L-U
- Manufacturer:
- Diodes Incorporated
- Package:
- TO-220-3
- Datasheet:
-
AP1084T18L-U.pdf
- Description:
- IC REG LINEAR 1.8V 5A TO220-3
- Quantity:
- Payment:
- Shipping:
Inventory:343
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
AP1084T18L-U from Diodes Incorporated is a 5A low-dropout linear regulator in TO220-3L package, delivering fixed 1.8V output with ≤1.4V dropout at full load, ±1.5% output voltage tolerance at 10mA, and integrated thermal shutdown and current limiting. It powers high-speed bus termination and low-current 3.3V logic supplies in VGA cards and embedded systems.
For engineers reviewing the AP1084T18L-U datasheet, AP1084T18L-U pinout, AP1084T18L-U application, or AP1084T18L-U equivalent, key selection criteria include dropout voltage under 5A load, thermal resistance (θJA = 78°C/W), fixed-output stability with 10µF output capacitor, and compatibility with 4.7–12V input rails for 1.8V rail generation.
Technical Context
The AP1084T18L-U operates as a three-terminal fixed-output LDO using an internal 1.25V reference and error amplifier to regulate output against line and load variations. Its dropout voltage remains ≤1.4V at 5A, enabling stable 1.8V output from inputs as low as 3.2V.
It features built-in current limiting (5.1A typical) and thermal shutdown triggered at 150°C junction temperature. Output stability requires a minimum 10µF capacitor (ESR 0.15–20Ω) connected directly to VOUT, with fast transient response validated for 0–5A load steps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.800V ±1.5% at 10mA, 3.3V≤VIN≤12V - ensures precise core voltage for 1.8V logic interfaces. |
| Dropout Voltage | 1.4V max at 5A load - enables regulation from 3.2V input, critical for multi-rail systems with tight input margins. |
| Output Current | 5.0A continuous - supports high-current digital loads like FPGA I/O banks or GPU memory interfaces. |
| Thermal Resistance θJA | 78°C/W (TO220-3L, FR-4, 2oz Cu) - dictates heatsink requirement: ~15W max dissipation at 125°C TJ. |
| Load Regulation | 15–18mV over 0–5A (at 3.3V VIN) - maintains voltage accuracy during dynamic CPU/GPU load transients. |
| Reference Voltage | 1.250V ±2% - sets precision of internal feedback loop; determines fixed-output accuracy and adjust-mode flexibility. |
| Shutdown Threshold | 150°C junction temperature - protects against thermal runaway during sustained overload or poor heatsinking. |
Pinout & Package
AP1084T18L-U uses the TO220-3L package with exposed thermal tab electrically connected to VOUT. The tab must be mounted to a heatsink or copper pour for thermal management. Pin 1 is Adj (GND in fixed mode), Pin 2 is VOUT (connected to tab), Pin 3 is VIN.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Adj) | Adjust/Ground | Grounded internally in fixed 1.8V mode; unused externally - simplifies layout by eliminating external resistor network. |
| Pin 2 (VOUT) | Regulated Output | Delivers 1.8V/5A; electrically tied to metal tab - requires low-impedance connection to output capacitor and load return path. |
| Pin 3 (VIN) | Input Supply | Accepts 3.3–12V DC; must remain ≥3.2V to maintain regulation - mandates input bulk capacitance near pin to suppress sag during 5A transients. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 1.8V output | Eliminates external resistors and layout sensitivity - reduces BOM count and improves long-term voltage stability vs. adjustable variants. |
| 1.4V dropout @ 5A | Enables efficient 1.8V rail generation from 3.3V or 5V sources - minimizes power loss (ΔP = 1.4V × 5A = 7W) vs. higher-dropout regulators. |
| Integrated thermal shutdown | Automatically disables output above 150°C junction - prevents catastrophic failure during heatsink detachment or airflow loss. |
| Current limiting (5.1A) | Clamps fault current during short-circuit or overcurrent events - protects upstream supply and PCB traces without external sensing. |
| Fast transient response | Stabilizes within microseconds after 0–5A load steps - reduces required output capacitance and avoids undershoot-induced logic errors. |
Applications
| VGA Graphics Card Power | FPGA I/O Bank Supply |
|---|---|
|
Use Scenario: Providing clean 1.8V power to DDR2/DDR3 memory interfaces on discrete graphics cards. IC Role / Device Role / Timing Role: Primary LDO regulator delivering stable 1.8V to memory VDDQ pins with minimal noise coupling. Use Value: 15–18mV load regulation over 0–5A ensures memory timing margins are preserved during GPU shader load bursts. |
Use Scenario: Supplying configurable I/O banks on Xilinx Spartan-6 or Intel Cyclone IV FPGAs. IC Role / Device Role / Timing Role: Fixed-output LDO generating 1.8V for LVCMOS18 or SSTL18 I/O standards. Use Value: 1.4V dropout allows direct derivation from 3.3V rail, reducing system-level voltage conversion stages and board area. |
| Industrial PLC Digital I/O Module | Embedded ARM Cortex-A8/A9 SoC Core Rail |
|
Use Scenario: Powering opto-isolated digital input/output circuits requiring tightly regulated 1.8V logic levels. IC Role / Device Role / Timing Role: Local point-of-load regulator decoupling field-side logic from noisy 24V industrial bus. Use Value: Built-in thermal shutdown prevents latch-up during ambient temperature spikes in unventilated enclosures. |
Use Scenario: Delivering 1.8V to ARM processor core domains in automotive infotainment head units. IC Role / Device Role / Timing Role: Secondary LDO supplying core voltage after primary DC-DC conversion from 12V battery. Use Value: Fast transient response mitigates voltage droop during CPU frequency scaling, avoiding instruction pipeline stalls. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AP1084K18L-13 | Same silicon, TO263-3L package (θJA = 60°C/W), tape-and-reel packaging | Better thermal performance in space-constrained PCB layouts; requires SMT assembly | Select when board real estate is limited and thermal budget demands lower θJA, not for through-hole prototyping. |
| TLV1117-18CDCY | 1A output, 1.2V dropout @ 1A, SOIC-8 package, no thermal shutdown | Lower current capacity; lacks overtemperature protection; unsuitable for >2A loads | Choose only for low-power auxiliary rails where 1A suffices and thermal risk is managed externally. |
Compared with AP1084T18L-U, the AP1084K18L-13 offers superior thermal performance in surface-mount designs but requires reflow-compatible layout, while TLV1117-18CDCY trades current capability and safety features for compactness-making it viable only in sub-2A, thermally benign applications.
Availability
AP1084T18L-U is available at Aetrix Electronics and suitable for VGA graphics card power delivery, FPGA I/O bank supply, and industrial PLC digital I/O modules requiring stable component supply with lead-free TO220 packaging and full production traceability.
Supply support for AP1084T18L-U 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.
The AP1084 product line delivers high-current, low-dropout linear regulation for demanding point-of-load applications where precision, thermal robustness, and fast transient response are essential - particularly in graphics, FPGA, and embedded processing subsystems.
FAQ
What is the minimum input voltage required for AP1084T18L-U to maintain 1.8V regulation?
The AP1084T18L-U requires VIN ≥ VOUT + dropout voltage. With a maximum dropout of 1.4V at 5A, the minimum input is 3.2V. At lighter loads, dropout decreases - e.g., 1.3V at 5A typ means 3.1V suffices under typical conditions. Input must also meet datasheet's 3.3V minimum specified for 1.8V fixed mode testing.
Can AP1084T18L-U be used without an external output capacitor?
No. A minimum 10µF aluminum or tantalum capacitor (ESR 0.15–20Ω) is mandatory between VOUT and GND for stability and transient response. Omitting it causes oscillation, excessive output ripple, and potential thermal shutdown due to instability-induced power dissipation.
Is the thermal tab of AP1084T18L-U electrically isolated?
No. The metal tab is internally connected to the VOUT pin. When mounting to a heatsink, electrical isolation (e.g., mica washer + thermal paste) is required unless the heatsink is referenced to the 1.8V output rail - otherwise, short circuits or ground-loop currents may occur.
How does load regulation performance change across temperature?
Load regulation degrades slightly with temperature: at 125°C junction, deviation increases up to ±0.8% (vs. ±0.5% at 25°C) for 1.5A load. This is due to thermal drift in the internal reference and error amplifier - design margin should account for worst-case deviation across the full 0–125°C operating range.
AP1084T18L-U Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 12V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1.4V @ 5A
- Current - Output:
- 5A
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- -
- PSRR:
- -
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- 0°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-3
AP1084T18L-U FAQ
1.How can I place an order for AP1084T18L-U through Aetrix?
Please submit a Request for Quotation (RFQ) for AP1084T18L-U 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 AP1084T18L-U reliable?
The price and inventory of AP1084T18L-U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP1084T18L-U is usually 5 days.
3.What payment methods are accepted for AP1084T18L-U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP1084T18L-U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP1084T18L-U?
AP1084T18L-U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP1084T18L-U 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 AP1084T18L-U?
For technical support, including AP1084T18L-U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP1084T18L-U requirements.
6.How does Aetrix verify that AP1084T18L-U is sourced from the original manufacturer or authorized distributors?
All AP1084T18L-U 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 AP1084T18L-U meets industry standards.
7.What is the process for return or replacement of AP1084T18L-U?
All AP1084T18L-U units undergo pre-shipment inspection (PSI). If there is an issue with AP1084T18L-U, 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 AP1084T18L-U part is unused and in its original packaging.
Return procedure for AP1084T18L-U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AP1084T18L-U 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
Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.
Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
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 …
