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Diodes Incorporated AS7818ADTR-E1
- Part No.:
- AS7818ADTR-E1
- Manufacturer:
- Diodes Incorporated
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
AS7818ADTR-E1.pdf
- Description:
- IC REG LINEAR 18V 1A TO252-2
- Quantity:
- Payment:
- Shipping:
Inventory:4,774
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Product details
Overview
AS7818ADTR-E1 from Diodes Incorporated is a fixed-output +18V, 1A three-terminal positive linear voltage regulator in TO-252-2 (5) package with internal current limiting, thermal shutdown, and safe-area protection. It delivers stable local regulation for microprocessor power supplies and post-regulation of switching converters, maintaining ±4% output accuracy over –40°C to +125°C.
For engineers reviewing the AS7818ADTR-E1 datasheet, AS7818ADTR-E1 pinout, AS7818ADTR-E1 application, or AS7818ADTR-E1 equivalent, key selection considerations include dropout voltage (2V at 1A), load regulation (≤150mV), ripple rejection (≥58dB at 120Hz), and thermal resistance (θJA = 100°C/W in TO-252-2).
Technical Context
The AS7818ADTR-E1 implements a monolithic bipolar linear regulator architecture with integrated bandgap reference, error amplifier, pass transistor, and protection circuitry. Its safe-area compensation ensures robust operation under transient overload without external components.
It operates with input voltages up to 32V (recommended) and 36V (absolute max), delivering regulated +18V output across 5mA–1A load current while maintaining thermal stability via internal shutdown triggered at +150°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +18V fixed, ±4% tolerance over full temperature range - ensures predictable rail generation without external feedback. |
| Output Current | Up to 1A continuous - supports high-current digital logic and analog subsystems without external boost. |
| Dropout Voltage | 2V at 1A, TJ = +25°C - defines minimum VIN–VOUT headroom required for regulation; impacts efficiency in low-headroom designs. |
| Line Regulation | ≤150mV (VIN = 20.9V to 30V) - limits output drift due to input supply variation, critical for noisy DC-DC outputs. |
| Load Regulation | ≤150mV (IOUT = 5mA to 1A) - maintains stable voltage across dynamic loads like CPU cores or FPGA I/O banks. |
| Ripple Rejection | ≥58dB at 120Hz - suppresses low-frequency switching noise from upstream converters, reducing need for additional filtering. |
| Quiescent Current | 3.4–6mA - enables low-noise regulation without excessive idle power draw in always-on subsystems. |
Pinout & Package
AS7818ADTR-E1 is housed in a surface-mount TO-252-2 (5) package (also labeled TO252 Type CJ), featuring exposed thermal pad for enhanced heat dissipation. The package is lead-free, RoHS-compliant, and halogen/antimony-free ("Green").
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (INPUT) | Voltage Input | Accepts unregulated DC input (up to 32V recommended); requires ≥0.33µF ceramic input capacitor for stability. |
| 2 (GND) | Ground Reference | Common return path for input, output, and internal bias circuits; must be low-impedance connection to minimize noise coupling. |
| 3 (OUTPUT) | Voltage Output | Delivers regulated +18V; requires ≥0.1µF ceramic output capacitor for transient response and loop stability. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Thermal Shutdown | Activates at +150°C junction temperature to prevent permanent damage during sustained overload or poor heatsinking. |
| Safe-Area Protection | Prevents second breakdown of the output transistor under simultaneous high voltage and current stress, enabling reliable operation without external foldback. |
| Short-Circuit Current Limiting | Clamps output current to ~0.2A during hard shorts, allowing safe fault recovery and preventing PCB trace damage. |
| Low Load Regulation | ≤150mV variation from 5mA to 1A load - eliminates need for post-regulator LDOs in mid-power applications. |
| Stable Performance at High Temperature | Specified operation up to +125°C ambient (TJ ≤ +150°C) - suitable for enclosed industrial enclosures and telecom base stations. |
Applications
| Microprocessor Power Supply | Post-Regulation for Switching Supplies |
|---|---|
Use Scenario: Providing clean, low-noise 18V rail to analog front-ends or high-speed DACs adjacent to digital processors. IC Role / Device Role / Timing Role: Final-stage linear regulator isolating sensitive analog circuitry from switching noise generated by upstream DC-DC converters. Use Value: 58dB ripple rejection and 10µV/VOUT output noise ensure signal integrity in precision data acquisition systems. |
Use Scenario: Tightening output tolerance and reducing residual ripple after a 24V buck converter powering industrial I/O modules. IC Role / Device Role / Timing Role: Precision post-regulator correcting for load-induced droop and line-induced variation in primary switcher output. Use Value: ±4% output accuracy and ≤150mV load regulation maintain consistent 18V compliance across 5mA–1A load steps. |
| Motherboard Local Regulation | Telecommunication Line Card |
Use Scenario: Generating dedicated 18V supply for PCIe slot auxiliary power or fan controller ICs on server motherboards. IC Role / Device Role / Timing Role: Distributed point-of-load regulator minimizing IR drop and EMI from centralized PSUs. Use Value: TO-252-2 package enables compact layout near load; thermal resistance (θJA = 100°C/W) supports convection-cooled board-level integration. |
Use Scenario: Powering line interface ICs (e.g., SLICs, codec amplifiers) in carrier-grade DSLAM or ONU equipment. IC Role / Device Role / Timing Role: Primary analog supply regulator meeting stringent long-term reliability and thermal cycling requirements. Use Value: AEC-Q200-compatible construction (per Diodes automotive qualification pathway) and 150°C junction rating support 10+ year field life in sealed telecom housings. |
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 |
|---|---|---|---|
| LM7818CDT-TR | Higher quiescent current (6–8mA), lower PSRR (50dB), TO-252-3 package with separate GND pin. | Lacks safe-area protection; less robust under transient overload conditions. | Preferred only where legacy LM78xx footprint compatibility is mandatory and thermal margin exceeds 20°C. |
| MC7818BDTRKG | Wider VIN range (40V max), tighter initial accuracy (±2%), but higher dropout (2.5V) and larger TO-263-3 package. | Requires more board area and heatsinking; better suited for high-input-voltage industrial sensors. | Select when input voltage may exceed 32V or ±2% initial accuracy is required over production lot variance. |
Compared with LM7818CDT-TR and MC7818BDTRKG, AS7818ADTR-E1 offers superior thermal robustness (safe-area + shutdown), lower noise (10µV/VOUT), and optimized TO-252-2 footprint for space-constrained telecom and computing boards - making it the preferred choice for new designs prioritizing reliability and density.
Availability
AS7818ADTR-E1 is available at Aetrix Electronics and suitable for microprocessor power supplies, post-regulation of switching supplies, and telecommunications line cards requiring stable component supply, long-lifecycle assurance, and RoHS/Green compliance.
Supply support for AS7818ADTR-E1 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 communications markets.
The AS78XXA series targets cost-sensitive, high-volume linear regulation needs where robustness, simplicity, and regulatory compliance (RoHS/Green) are essential - particularly in motherboard, telecom, and embedded control applications.
FAQ
What is the maximum input voltage for reliable operation of AS7818ADTR-E1?
The AS7818ADTR-E1 has a recommended operating input voltage of up to 32V per the datasheet's Recommended Operating Conditions table. While its absolute maximum rating is 36V, sustained operation above 32V increases thermal stress and reduces long-term reliability - especially in TO-252-2 without heatsinking. For 24V system inputs, it provides 6V headroom, well within safe dropout margins.
Does AS7818ADTR-E1 require external capacitors, and what values are specified?
Yes - AS7818ADTR-E1 requires a minimum 0.33µF ceramic capacitor on the INPUT pin and a minimum 0.1µF ceramic capacitor on the OUTPUT pin, as shown in the Typical Applications Circuit. These values ensure stability across temperature and load; larger values (e.g., 10µF tantalum + 0.1µF ceramic) improve transient response but are not mandatory for basic regulation.
How does the thermal performance of AS7818ADTR-E1 compare across its package options?
In TO-252-2 (5), AS7818ADTR-E1 has θJA = 100°C/W (no heatsink) and θJC = 16°C/W. This is less efficient than TO-220-3 (θJA = 60°C/W) but enables surface-mount assembly. With a 2-layer PCB and 1-in² copper pour under the thermal pad, practical θJA improves to ~65°C/W - sufficient for 1A operation at +70°C ambient if power dissipation remains ≤1.5W.
Is AS7818ADTR-E1 qualified for automotive applications?
AS7818ADTR-E1 itself is not AEC-Q100 qualified; however, Diodes states that automotive-grade versions (with change control, PPAP capability, and IATF 16949 manufacturing) are available upon request. Standard AS7818ADTR-E1 meets industrial temperature range (–40°C to +125°C) and "Green" material requirements, making it suitable for non-safety-critical automotive subsystems like infotainment power rails when validated per customer qualification protocols.
AS7818ADTR-E1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 32V
- Voltage - Output (Min/Fixed):
- 18V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 2V @ 1A (Typ)
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 6 mA
- Current - Supply (Max):
- -
- PSRR:
- 57dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-252-3
AS7818ADTR-E1 FAQ
1.How can I place an order for AS7818ADTR-E1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AS7818ADTR-E1 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 AS7818ADTR-E1 reliable?
The price and inventory of AS7818ADTR-E1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AS7818ADTR-E1 is usually 5 days.
3.What payment methods are accepted for AS7818ADTR-E1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AS7818ADTR-E1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AS7818ADTR-E1?
AS7818ADTR-E1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AS7818ADTR-E1 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 AS7818ADTR-E1?
For technical support, including AS7818ADTR-E1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AS7818ADTR-E1 requirements.
6.How does Aetrix verify that AS7818ADTR-E1 is sourced from the original manufacturer or authorized distributors?
All AS7818ADTR-E1 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 AS7818ADTR-E1 meets industry standards.
7.What is the process for return or replacement of AS7818ADTR-E1?
All AS7818ADTR-E1 units undergo pre-shipment inspection (PSI). If there is an issue with AS7818ADTR-E1, 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 AS7818ADTR-E1 part is unused and in its original packaging.
Return procedure for AS7818ADTR-E1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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