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onsemi NCP1117DT285RK
- Part No.:
- NCP1117DT285RK
- Manufacturer:
- onsemi
- Package:
- TO-252-3, DPAK (2 Leads + Tab), SC-63
- Datasheet:
-
NCP1117DT285RK.pdf
- Description:
- IC REG LINEAR 2.85V 1A DPAK
- Quantity:
- Payment:
- Shipping:
Inventory:1,566
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Product details
Overview
NCP1117DT285RK from onsemi is a 2.85 V fixed-output, low-dropout linear voltage regulator in DPAK (TO-252) package, delivering up to 1.0 A output current with 1.2 V max dropout at 800 mA over temperature, ±1.0% output voltage accuracy, and no minimum load requirement - widely used for active SCSI termination and post-regulation in hard drive controllers.
For engineers reviewing the NCP1117DT285RK datasheet, pinout, applications, or equivalent options, key selection considerations include dropout voltage at full load, thermal performance in DPAK with PCB copper heatsinking, ripple rejection at 120 Hz, and compatibility with 4.25–10 V input range for stable 2.85 V rail generation.
Technical Context
The NCP1117DT285RK implements a bandgap-referenced feedback loop with internal trimming for ±1.0% output accuracy and features integrated thermal shutdown (activates ~175°C), safe operating area compensation, and current limiting. Its architecture supports operation with input voltages up to 20 V while maintaining regulation down to 4.25 V input for the 2.85 V variant.
Designed as a three-terminal fixed-output LDO, it requires only two external capacitors (10 µF input and 10 µF output) for stability and exhibits 62 dB ripple rejection at 120 Hz with Vin−Vout = 6.4 V and Iout = 500 mA - optimized for post-regulation of switching supplies and noise-sensitive SCSI bus termination.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.85 V ±1.0% - ensures precise SCSI bus termination voltage compliance without external resistors. |
| Max Output Current | 1.0 A - sufficient to drive multiple SCSI terminators or logic rails in storage controllers. |
| Dropout Voltage | 1.2 V max at 800 mA - enables stable regulation from 4.25 V input, critical for low-headroom post-regulation. |
| Input Voltage Range | 4.25 V to 10 V (for 2.85 V version) - defines safe operating window avoiding overvoltage stress or dropout failure. |
| Ripple Rejection | 62 dB at 120 Hz - suppresses line-frequency ripple from AC/DC supplies feeding SCSI backplanes. |
| Thermal Shutdown | ~175°C junction - protects against sustained overload or inadequate heatsinking in enclosed drives. |
| Quiescent Current | 5.5 mA typical - minimizes standby power loss in always-on storage subsystems. |
Pinout & Package
DPAK (TO-252-3) package with exposed metal tab thermally connected to Pin 2 (Output); standard 3-pin surface-mount configuration optimized for PCB copper heatsinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Ground / Adjust | Reference node for internal feedback; must be low-impedance connection to minimize ground bounce in SCSI termination. |
| 2 | Output | Regulated 2.85 V supply; tab is electrically connected to this pin - requires dedicated thermal pad tied to large copper pour. |
| 3 | Input | Unregulated input (4.25–10 V); placement near bulk capacitor essential for transient response in hard drive controllers. |
Key Features
| Feature | Design Value |
|---|---|
| No minimum load requirement | Enables stable regulation even under light/no-load conditions common in SCSI bus idle states. |
| ±1.0% output voltage accuracy | Guarantees compliance with SCSI-2/3 active termination specs (2.85 V ±30 mV) without calibration. |
| Internal current limit & thermal shutdown | Prevents catastrophic failure during short-circuit events in densely packed drive electronics. |
| 10 µF input/output capacitor support | Allows use of low-ESR ceramic or tantalum caps - reduces board space vs. legacy electrolytic solutions. |
| Operation to 20 V input | Provides design margin for input transients in industrial storage enclosures with unregulated DC rails. |
Applications
| Active SCSI Bus Termination | Hard Drive Controller Power |
|---|---|
Use Scenario: Termination of differential SCSI-2/3 parallel bus signals in server backplanes and RAID controllers. IC Role / Device Role / Timing Role: Provides precision 2.85 V bias for active termination networks, replacing passive resistor arrays. Use Value: Eliminates termination voltage drift across temperature, improving signal integrity and bus reliability up to 40 MB/s. | Use Scenario: Local regulation for ASIC/FPGA I/O banks and servo motor control logic in 3.5" and 2.5" HDDs. IC Role / Device Role / Timing Role: Low-noise post-regulator downstream of buck converters, powering timing-critical interface circuitry. Use Value: Delivers clean 2.85 V rail with 62 dB ripple rejection, reducing bit error rates in high-speed data transfers. |
| Switching Power Supply Post-Regulation | Battery Charger Reference Supply |
Use Scenario: Final-stage regulation after high-efficiency DC/DC converters in multi-rail embedded power systems. IC Role / Device Role / Timing Role: LDO post-regulator suppressing switching noise from upstream converters feeding sensitive analog circuits. Use Value: Maintains <1.2 V dropout at 1 A, enabling efficient 5 V → 2.85 V conversion with minimal heat dissipation. | Use Scenario: Stable reference voltage source for battery charge management ICs in portable storage devices. IC Role / Device Role / Timing Role: Precision voltage reference generator for charger IC feedback loops requiring tight tolerance. Use Value: ±1.0% accuracy ensures consistent charge termination thresholds across temperature and unit variance. |
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 |
|---|---|---|---|
| LD1117S285TR | STMicroelectronics part; 2.85 V fixed, SOT-223 package, 1 A rating, 1.3 V dropout at 800 mA. | SOT-223 footprint differs from DPAK - requires PCB layout change; lower thermal resistance to ambient in DPAK favors higher ambient temp operation. | Select when existing SOT-223 layout exists and thermal load is moderate; verify ripple rejection (60 dB @ 120 Hz) meets system noise floor. |
| TLV1117-285CDCYR | Texas Instruments part; 2.85 V fixed, SOT-223, 800 mA max, 1.2 V dropout at 800 mA, ±2% initial accuracy. | Lower current rating and wider voltage tolerance - unsuitable for full-load SCSI termination; better PSRR above 1 kHz. | Choose for cost-sensitive designs with <800 mA load and relaxed accuracy; not recommended for mission-critical SCSI termination. |
Compared with LD1117S285TR and TLV1117-285CDCYR, the NCP1117DT285RK offers superior output accuracy (±1.0% vs. ±2%), DPAK thermal performance for sustained 1 A loads, and guaranteed 62 dB ripple rejection at 120 Hz - making it optimal for high-reliability SCSI and storage controller applications.
Availability
NCP1117DT285RK is available at Aetrix Electronics and suitable for active SCSI termination, hard drive controller power, and switching supply post-regulation requiring stable component supply, long-term lifecycle support, and automotive-grade traceability options (NCV1117 variants).
Supply support for NCP1117DT285RK 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The NCP1117 series belongs to onsemi's precision linear regulator product line, engineered for high-accuracy, low-dropout point-of-load regulation in storage, computing, and industrial control systems where reliability and thermal robustness are critical.
FAQ
What is the maximum input voltage for the NCP1117DT285RK?
The NCP1117DT285RK supports an absolute maximum input voltage of 20 V, but its recommended operating input range for the 2.85 V output variant is 4.25 V to 10 V. Exceeding 10 V increases power dissipation and thermal stress without functional benefit, and operation above 20 V may cause permanent damage per the Absolute Maximum Ratings table.
Does the NCP1117DT285RK require an external capacitor on the output pin?
Yes, the NCP1117DT285RK requires a minimum 4.7 µF output capacitor with ESR between 33 mΩ and 2.2 Ω for stability; 10 µF tantalum or ceramic is recommended. Omitting or undersizing Cout risks oscillation, especially under dynamic load changes in hard drive controllers.
Is the NCP1117DT285RK pin-compatible with the LM317?
No - the NCP1117DT285RK is a fixed-output 3-pin LDO in DPAK package (Pin 1=Ground, Pin 2=Output, Pin 3=Input), whereas the LM317 is an adjustable regulator in TO-220/TO-263 with different pinout (Pin 1=Adjust, Pin 2=Output, Pin 3=Input). The NCP1117 series is pin-compatible with LM317 *only* in adjustable versions (e.g., NCP1117DTAG), not fixed-output variants like NCP1117DT285RK.
What thermal performance can be expected from the NCP1117DT285RK in DPAK package?
In DPAK (Case 369C), the NCP1117DT285RK has RθJA = 67°C/W (min pad) and RθJC = 6.0°C/W. With a 2 oz. copper thermal pad (≥25 mm²), it can dissipate ~1.5 W at 50°C ambient before reaching 125°C junction - sufficient for 1 A at 1.2 V dropout (1.2 W dissipation) in typical HDD PCB layouts.
Can the NCP1117DT285RK be used in automotive applications?
The NCP1117DT285RK is not AEC-Q100 qualified; for automotive use, select the NCV1117DT285RKG variant (same DPAK package, 2.85 V, AEC-Q100 Grade 1, −40°C to +125°C). The NCP prefix denotes commercial/industrial grade (0°C to +125°C ambient), unsuitable for under-hood or safety-critical vehicle systems.
NCP1117DT285RK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- 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):
- 20V
- Voltage - Output (Min/Fixed):
- 2.85V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1.2V @ 800mA
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- -
- PSRR:
- 68dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DPAK
NCP1117DT285RK FAQ
1.How can I place an order for NCP1117DT285RK through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP1117DT285RK 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 NCP1117DT285RK reliable?
The price and inventory of NCP1117DT285RK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP1117DT285RK is usually 5 days.
3.What payment methods are accepted for NCP1117DT285RK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP1117DT285RK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP1117DT285RK?
NCP1117DT285RK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP1117DT285RK 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 NCP1117DT285RK?
For technical support, including NCP1117DT285RK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP1117DT285RK requirements.
6.How does Aetrix verify that NCP1117DT285RK is sourced from the original manufacturer or authorized distributors?
All NCP1117DT285RK 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 NCP1117DT285RK meets industry standards.
7.What is the process for return or replacement of NCP1117DT285RK?
All NCP1117DT285RK units undergo pre-shipment inspection (PSI). If there is an issue with NCP1117DT285RK, 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 NCP1117DT285RK part is unused and in its original packaging.
Return procedure for NCP1117DT285RK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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