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Diodes Incorporated AS7818ADTR-G1
- Part No.:
- AS7818ADTR-G1
- Manufacturer:
- Diodes Incorporated
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
AS7818ADTR-G1.pdf
- Description:
- IC REG LINEAR 18V 1A TO252-2
- Quantity:
- Payment:
- Shipping:
Inventory:3,026
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Product details
Overview
AS7818ADTR-G1 from Diodes Incorporated is a fixed-output +18V, 1A three-terminal positive linear voltage regulator in TO-252-2 (5) / TO252 (Type CJ) package, featuring internal current limiting, thermal shutdown, and safe-area protection. It delivers stable local regulation for microprocessor power supplies and post-regulation after switching converters, with ±4% output voltage accuracy over –40°C to +125°C.
For engineers reviewing the AS7818ADTR-G1 datasheet, AS7818ADTR-G1 pinout, AS7818ADTR-G1 application, or AS7818ADTR-G1 equivalent, key selection criteria include dropout voltage (2V at 1A), load regulation (≤150mV), ripple rejection (58dB at 120Hz), and RoHS-compliant "Green" packaging with halogen/antimony-free molding compound.
Technical Context
The AS7818ADTR-G1 implements a monolithic series-pass regulator architecture with integrated bandgap reference, error amplifier, and Darlington output transistor. Its safe-area compensation ensures stable operation under transient overload without external components.
Designed for fixed-voltage operation only, it requires no external capacitors for stability but specifies 0.33µF input and 0.1µF output ceramic capacitors for optimal transient response and noise suppression across its full operating temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +18V nominal, ±4% tolerance over –40°C to +125°C - ensures compatibility with 18V logic and analog rails. |
| Output Current | Up to 1A continuous - supports mid-power digital subsystems without external current boosting. |
| Dropout Voltage | 2V at IOUT = 1A, TJ = +25°C - defines minimum input headroom needed to maintain regulation. |
| Ripple Rejection | 58dB at 120Hz - suppresses low-frequency switching noise from upstream DC/DC converters. |
| Line Regulation | ≤150mV over VIN = 20.9V to 33V - maintains output stability despite input supply variation. |
| Load Regulation | ≤150mV over IOUT = 5mA to 1A - ensures consistent voltage delivery across dynamic load profiles. |
| Quiescent Current | 3.4–6mA at VIN = 23V, IOUT = 0 - enables low-noise biasing without excessive idle power loss. |
Pinout & Package
AS7818ADTR-G1 uses the TO-252-2 (5) / TO252 (Type CJ) surface-mount package - thermally enhanced with exposed drain pad for PCB heat sinking. Package dimensions: 10.4 × 6.7 × 1.7 mm (L × W × H), weight ≈ 0.312 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (INPUT) | Voltage Input | Accepts unregulated DC input; must be ≥20.9V to sustain 18V output under full load. |
| 2 (GND) | Ground Reference | Common return path for input, output, and internal circuitry; requires low-impedance PCB connection. |
| 3 (OUTPUT) | Voltage Output | Delivers regulated +18V; connects directly to load and output capacitor (0.1µF ceramic recommended). |
Key Features
| Feature | Design Value |
|---|---|
| Fixed +18V output | Eliminates external resistor network; reduces BOM count and layout complexity for dedicated 18V rails. |
| Internal thermal shutdown | Activates at +150°C junction temperature - prevents catastrophic failure during sustained overload or poor heatsinking. |
| Safe-area protected output transistor | Prevents second breakdown during short-circuit or high-VCE/IC transients without external foldback circuitry. |
| Lead-free & "Green" packaging | TO-252-2 (5) meets RoHS 3 (2015/863/EU); halogen/antimony-free (<900ppm Br/Cl, <1000ppm Sb) - compliant for automotive and industrial end-equipment. |
| Low output noise | 10µV/√Hz typical (10Hz–100kHz) - suitable for noise-sensitive analog circuits like ADC references or op-amp supplies. |
Applications
| Microprocessor Power Supply | Post-Regulation for Switching Supplies |
|---|---|
|
Use Scenario: Providing clean, stable 18V bias to FPGA I/O banks or DSP core peripherals. IC Role / Device Role / Timing Role: Local point-of-load regulator delivering low-noise, tightly regulated voltage independent of main system rail fluctuations. Use Value: Maintains signal integrity and timing margins by suppressing switching noise from upstream DC/DC converters via 58dB ripple rejection. |
Use Scenario: Final-stage regulation after a 24V buck converter to feed analog front-end circuitry. IC Role / Device Role / Timing Role: Precision voltage clamp ensuring constant 18V supply despite input ripple and load-step-induced droop. Use Value: Enables ≤150mV load regulation across 5mA–1A, preserving ADC reference stability and sensor excitation accuracy. |
| Motherboard Local Regulation | Telecom Line Card Power |
|
Use Scenario: Dedicated 18V rail for PCIe slot auxiliary power or clock buffer ICs on server motherboards. IC Role / Device Role / Timing Role: Compact, surface-mount regulator placed near high-speed interfaces to minimize trace inductance and ground bounce. Use Value: TO-252-2 (5) package provides 100°C/W θJA, enabling 1A delivery with minimal PCB copper area versus through-hole alternatives. |
Use Scenario: Powering line interface ICs (e.g., SLICs) requiring precise 18V bias in telecom access equipment. IC Role / Device Role / Timing Role: Robust, thermally protected regulator handling repetitive surge events common in telco environments. Use Value: Internal short-circuit limiting (0.2A typical) and thermal shutdown prevent latch-up during lightning-induced transients on subscriber lines. |
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/NOPB (TI) | TO-252-3 package; same 18V/1A rating but higher quiescent current (6.5mA typ) and lower PSRR (50dB). | Lacks "Green" halogen-free certification; not qualified for automotive-grade thermal cycling per AEC-Q200. | Select if legacy TI ecosystem compatibility is required and RoHS3/halogen-free compliance is not mandated. |
| MC7818CD2TR4 (ON Semi) | TO-263-2 package; identical electrical specs but θJA = 50°C/W - better thermal performance at cost of larger footprint. | Requires larger PCB pad layout; not drop-in compatible due to different pinout (Input/GND/Output vs INPUT/OUTPUT/GND). | Choose when board-level thermal resistance exceeds 60°C/W and forced-air cooling is unavailable. |
Compared with LM7818CDT/NOPB, AS7818ADTR-G1 offers superior environmental compliance and lower noise; versus MC7818CD2TR4, it trades thermal efficiency for smaller footprint and pinout compatibility with standard TO-252-2 layouts.
Availability
AS7818ADTR-G1 is available at Aetrix Electronics and suitable for microprocessor power supplies, telecom line cards, motherboard local regulation, and post-regulation for switching supplies requiring stable component supply with full RoHS3 and halogen-free compliance.
Supply support for AS7818ADTR-G1 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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The AS78XXA series belongs to Diodes' high-reliability linear regulator product line, engineered specifically for industrial, telecom, and computing applications demanding robust thermal protection, tight output tolerance, and environmentally compliant packaging.
FAQ
What is the maximum input voltage for AS7818ADTR-G1?
The absolute maximum input voltage is 36V. However, the recommended operating range is VIN ≤ 33V to ensure reliable operation within thermal limits and maintain ±4% output accuracy across temperature. Exceeding 33V risks exceeding power dissipation limits, especially at high ambient temperatures or without adequate PCB copper pour.
Does AS7818ADTR-G1 require external capacitors?
Yes - a 0.33µF ceramic capacitor on the INPUT pin and a 0.1µF ceramic capacitor on the OUTPUT pin are mandatory per the datasheet for stability and transient response. These values are optimized for the internal compensation network; using larger or electrolytic capacitors may degrade regulation or cause oscillation.
Is AS7818ADTR-G1 suitable for automotive applications?
No - AS7818ADTR-G1 is not AEC-Q100 qualified. While it meets RoHS3 and operates from –40°C to +125°C, Diodes explicitly states that automotive-grade versions require separate qualification (PPAP, IATF 16949 manufacturing, AEC-Q200 stress testing), which this part does not carry.
How does the TO-252-2 (5) package affect thermal performance?
The TO-252-2 (5) package has a θJA of 100°C/W (no heatsink) and θJC of 16°C/W. Effective thermal management requires ≥250mm² of 2-oz copper connected to the exposed drain pad; adding thermal vias improves θJA to ~60°C/W, enabling full 1A operation at +70°C ambient.
AS7818ADTR-G1 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-G1 FAQ
1.How can I place an order for AS7818ADTR-G1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AS7818ADTR-G1 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-G1 reliable?
The price and inventory of AS7818ADTR-G1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AS7818ADTR-G1 is usually 5 days.
3.What payment methods are accepted for AS7818ADTR-G1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AS7818ADTR-G1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AS7818ADTR-G1?
AS7818ADTR-G1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AS7818ADTR-G1 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-G1?
For technical support, including AS7818ADTR-G1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AS7818ADTR-G1 requirements.
6.How does Aetrix verify that AS7818ADTR-G1 is sourced from the original manufacturer or authorized distributors?
All AS7818ADTR-G1 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-G1 meets industry standards.
7.What is the process for return or replacement of AS7818ADTR-G1?
All AS7818ADTR-G1 units undergo pre-shipment inspection (PSI). If there is an issue with AS7818ADTR-G1, 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-G1 part is unused and in its original packaging.
Return procedure for AS7818ADTR-G1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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