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Diodes Incorporated AP1084D18L-U
- Part No.:
- AP1084D18L-U
- Manufacturer:
- Diodes Incorporated
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
AP1084D18L-U.pdf
- Description:
- IC REG LINEAR 1.8V 5A TO252-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,845
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Product details
Overview
AP1084D18L-U from Diodes Incorporated is a 5A low-dropout positive fixed-mode voltage regulator with 1.8V output, TO252-3L package, 1.4V max dropout at full load, thermal shutdown, and output current limiting. It delivers stable 1.8V supply for high-speed bus termination and low-current logic in VGA cards and embedded systems requiring tight regulation under fast load transients.
For engineers reviewing the AP1084D18L-U datasheet, AP1084D18L-U pinout, AP1084D18L-U application, or AP1084D18L-U equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, confirmed application use cases, and two rigorously cross-checked alternative parts with documented functional differences.
Technical Context
The AP1084D18L-U operates as a fixed-output LDO regulator with internal 1.25V reference and feedback network preset for 1.8V output. Its control loop maintains regulation with ≤1.4V VIN–VOUT differential at 5A, enabling operation from 3.3V to 12V input while delivering stable 1.8V output.
It integrates thermal shutdown (150°C trip), foldback current limiting (5.1A typical), and requires ≥10μF output capacitor (ESR 0.15–20Ω) for stability. The device uses a single-stage pass transistor architecture with no external compensation required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.800 V ±1.2% (25°C, 10mA–5A load), enabling direct replacement of 1.8V logic rails without resistor networks. |
| Dropout Voltage | 1.4 V max at 5A load, allowing 1.8V output from as low as 3.2V input-critical for battery-powered or multi-rail systems with tight headroom. |
| Output Current | 5.0 A continuous, supporting high-current FPGA I/O banks or GPU memory interfaces without external parallel devices. |
| Line Regulation | 0.2% typical (3.3V ≤ VIN ≤ 12V), ensuring <±3.6mV output shift across input range-sufficient for DDR2/3 VDDQ tolerance budgets. |
| Load Regulation | 15–18 mV (0–5A), meeting Intel VRE-compliant transient windows when paired with 100μF output capacitance. |
| Thermal Resistance θJA | 73°C/W (TO252-3L on FR-4, 2oz Cu), requiring minimal heatsinking for ≤3W dissipation in ambient ≤70°C. |
| Shutdown Threshold | 150°C junction temperature, providing fail-safe protection during sustained overload or poor PCB thermal layout. |
Pinout & Package
AP1084D18L-U uses the TO252-3L (DPAK) surface-mount package with exposed thermal pad (Tab = VOUT). Pin 1 is Adj/GND, Pin 2 is VOUT, Pin 3 is VIN. The tab must be soldered to a large copper pour for thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Adj (GND) | Adjust/ground terminal | Internally tied to ground for fixed 1.8V mode; must be connected to system GND-no external resistors needed. |
| 2 - VOUT | Regulated output | Delivers 1.8V at up to 5A; tab is electrically connected to this pin-requires low-inductance connection to output capacitor. |
| 3 - VIN | Input supply | Accepts 3.3–12V DC; must remain ≥1.4V above VOUT at all times to maintain regulation during 5A load steps. |
Key Features
| Feature | Design Value |
|---|---|
| Fast transient response | ≤50mV deviation for 0→5A step (COUT=100μF), eliminating need for additional bulk capacitance in space-constrained VGA card designs. |
| Low-noise operation | 65dB PSRR at 120Hz, suppressing ripple from switching pre-regulators feeding 1.8V FPGA core rails. |
| Lead-free & green compound | RoHS-compliant (EU 2002/95/EC), halogen-free molding compound-meets IPC-J-STD-020 moisture sensitivity level 3 (MSL3). |
| Stability with low-ESR caps | Compatible with 0.15–20Ω ESR electrolytic/tantalum capacitors, avoiding costly polymer or ceramic-only solutions. |
| Fixed-mode simplicity | No external feedback resistors required-reduces BOM count and layout area versus adjustable LDOs in production 1.8V power rails. |
Applications
| VGA Graphics Card Power | FPGA I/O Bank Supply |
|---|---|
|
Use Scenario: Providing clean 1.8V to DDR2 memory interfaces and TMDS transmitter circuitry on discrete graphics cards. IC Role / Device Role / Timing Role: Primary 1.8V LDO regulator delivering stable voltage during rapid pixel clock transitions and memory bursts. Use Value: 15–18mV load regulation ensures signal integrity margins are maintained across 0–5A dynamic current swings. |
Use Scenario: Powering bank-specific 1.8V I/O on Xilinx Spartan-6 or Intel Cyclone IV FPGAs in industrial control modules. IC Role / Device Role / Timing Role: Dedicated low-noise, high-current rail generator with fast transient recovery for configurable I/O standards. Use Value: 1.4V dropout enables use of 3.3V intermediate bus, reducing system-level conversion losses by ~35% vs. higher-dropout alternatives. |
| Embedded System Core Logic | High-Speed Bus Termination |
|
Use Scenario: Supplying 1.8V to ARM Cortex-A8/A9 application processors and associated peripherals in medical imaging front-ends. IC Role / Device Role / Timing Role: Main logic rail regulator with thermal shutdown protecting against processor thermal runaway events. Use Value: 73°C/W θJA allows operation at full 5A load in sealed enclosures up to 70°C ambient without active cooling. |
Use Scenario: Biasing 1.8V termination resistors on PCI Express Gen2 x4 links in server backplanes. IC Role / Device Role / Timing Role: Low-noise, low-impedance source maintaining precise termination voltage during high-frequency data toggling. Use Value: 0.2% line regulation prevents >3mV shift during PCIe link training, avoiding re-negotiation failures. |
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 electrical specs, TO263-3L package (θJA = 60°C/W), tape-and-reel packaging. | Better thermal performance for high-power density PCBs; requires larger footprint and different reflow profile. | Select when board space permits larger package and thermal dissipation exceeds TO252 limits. |
| TLV1117-18CDCY | 1A max output, 1.2V dropout at 1A, SOT-223 package, 2% output tolerance. | Limited to low-current logic; unsuitable for 5A VGA or FPGA loads. | Only viable for cost-sensitive, low-power subsystems where 1.8V rail current stays below 800mA. |
Compared with AP1084D18L-U, AP1084K18L-13 offers superior thermal management but increases PCB area and assembly complexity, while TLV1117-18CDCY sacrifices 80% output current capacity and cannot support the same class of high-performance graphics or programmable logic applications.
Availability
AP1084D18L-U is available at Aetrix Electronics and suitable for VGA graphics cards, FPGA-based industrial controllers, embedded medical imaging systems, and high-speed bus termination circuits requiring stable component supply with guaranteed long-term sourcing.
Supply support for AP1084D18L-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 semiconductor company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and connectivity applications.
The AP1084 series belongs to Diodes' high-current LDO product line, engineered specifically for low-voltage, high-current IC supply in graphics, computing, and communications infrastructure where dropout voltage and transient response are critical.
FAQ
Is AP1084D18L-U pin-compatible with adjustable AP1084 variants?
Yes-AP1084D18L-U shares identical TO252-3L pinout (Pin 1 = Adj/GND, Pin 2 = VOUT, Pin 3 = VIN) with adjustable AP1084 versions. In fixed-mode operation, Pin 1 is internally grounded, so no external resistor network is needed, simplifying layout versus adjustable variants.
What is the minimum output capacitance required for stability?
The AP1084D18L-U requires a minimum 10μF aluminum or tantalum capacitor (ESR 0.15–20Ω) between VOUT and GND. For optimal transient response in VGA or FPGA applications, 100μF is recommended-verified in Diodes' typical application circuits and transient response graphs.
Can AP1084D18L-U operate from a 3.3V input supplying 1.8V at 5A?
Yes-its 1.4V max dropout ensures regulation at 5A with VIN ≥ 3.2V. At 3.3V input, power dissipation is (3.3V − 1.8V) × 5A = 7.5W, requiring adequate PCB copper area per Diodes' TO252-3L thermal guidelines (θJA = 73°C/W).
Does AP1084D18L-U support remote voltage sensing?
No-it is a 3-terminal LDO without dedicated sense pins. Load regulation accuracy depends on PCB trace resistance between VOUT pin and load; Diodes recommends routing high-current paths directly from the thermal tab (VOUT) to minimize voltage drop under 5A load.
AP1084D18L-U Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- Surface Mount
- Supplier Device Package:
- TO-252-3
AP1084D18L-U FAQ
1.How can I place an order for AP1084D18L-U through Aetrix?
Please submit a Request for Quotation (RFQ) for AP1084D18L-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 AP1084D18L-U reliable?
The price and inventory of AP1084D18L-U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP1084D18L-U is usually 5 days.
3.What payment methods are accepted for AP1084D18L-U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP1084D18L-U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP1084D18L-U?
AP1084D18L-U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP1084D18L-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 AP1084D18L-U?
For technical support, including AP1084D18L-U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP1084D18L-U requirements.
6.How does Aetrix verify that AP1084D18L-U is sourced from the original manufacturer or authorized distributors?
All AP1084D18L-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 AP1084D18L-U meets industry standards.
7.What is the process for return or replacement of AP1084D18L-U?
All AP1084D18L-U units undergo pre-shipment inspection (PSI). If there is an issue with AP1084D18L-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 AP1084D18L-U part is unused and in its original packaging.
Return procedure for AP1084D18L-U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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