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onsemi NCP5661DT18RKG
- Part No.:
- NCP5661DT18RKG
- Manufacturer:
- onsemi
- Package:
- TO-252-5, DPAK (4 Leads + Tab), TO-252AD
- Datasheet:
-
NCP5661DT18RKG.pdf
- Description:
- IC REG LINEAR 1.8V 1A DPAK-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,269
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Product details
Overview
NCP5661DT18RKG from onsemi is a fixed-output, 1.8 V, 1.0 A ultra-fast transient response low dropout linear regulator in DPAK-5 package. It features 0.9 V internal reference, 1.0 V typical dropout at 1.0 A, 26 µVrms output noise without bypass capacitor, and integrated Enable and Error Flag functions. Designed for post-regulation in high-current server and networking power supplies.
For engineers reviewing the NCP5661DT18RKG datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 1.8 V ±1% accuracy over −40°C to +125°C, thermal shutdown at 160°C, ground current ≤3.0 mA at full load, and compatibility with 10–150 µF output capacitors for stability.
Technical Context
The NCP5661DT18RKG implements a bipolar-based LDO architecture with a 0.9 V precision bandgap reference and low-impedance output stage enabling ultra-fast load transient settling (1–3 µs). Its error amplifier drives an NPN pass transistor with current-limiting and thermal foldback protection.
It integrates a dedicated Error Flag output that asserts logic-low when VOUT drops below 88% of nominal (1.584 V), with 50 µs blanking time to suppress false triggers during transients. The Enable input accepts TTL-compatible thresholds (VEN(H) ≥1.3 V, VEN(L) ≤0.3 V) and draws ≤0.5 µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±1% at TJ = 25°C; ±1.5% over −20°C to +125°C - ensures stable core voltage for 1.8 V logic rails. |
| Max Output Current | 1.0 A continuous - supports high-current FPGA I/O banks or ASIC auxiliary rails. |
| Dropout Voltage | 1.0 V typical at 1.0 A (Vin ≥ 2.8 V required) - enables operation from 3.3 V input with 1.5 V headroom. |
| Ground Current | ≤3.0 mA at 1.0 A load - minimizes quiescent power loss in always-on subsystems. |
| Output Noise | 26 µVrms (10 Hz–100 kHz) without bypass cap - eliminates need for external noise-filtering components. |
| PSRR | ≥65 dB at 1 kHz - suppresses switching noise from upstream DC-DC converters. |
| Thermal Shutdown | 160°C junction temperature - protects against sustained overload or poor heatsinking. |
Pinout & Package
DPAK-5 (Case 175AA), thermally enhanced surface-mount package with exposed tab (Pin 3/TAB) for direct PCB thermal conduction. Dimensions: 6.4 mm × 5.8 mm × 2.2 mm (L×W×H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Enable (EN) | Active-high digital control: tie to Vin for always-on; pull to GND to disable regulator output and reduce IQ to ≤300 µA. |
| 2 | Input (VIN) | Positive supply input (2.0–9.0 V); requires 150 µF OSCON input capacitor for optimal transient response. |
| 3 | Ground / Tab (GND) | Power ground and thermal pad - must be soldered to ≥0.26 in² (170 mm²) 1 oz copper area for RθJA = 100°C/W. |
| 4 | Output (VOUT) | Regulated 1.8 V output; stable with 10–150 µF ceramic or low-ESR electrolytic capacitors. |
| 5 | Error Flag (EF) | Open-drain logic-low alert when VOUT < 1.584 V; requires external 100 kΩ pull-up to VIN for proper operation. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-fast transient response | 1–3 µs settling time enables use in dynamic load applications like CPU I/O domains without bulk capacitance penalty. |
| Low-noise operation | 26 µVrms noise without bypass capacitor reduces BOM count and PCB area vs. traditional LDOs requiring 10 nF caps. |
| Load-independent ground current | ≤3.0 mA max across 10 mA–1.0 A load range - simplifies power budgeting in multi-rail systems. |
| Integrated fault signaling | Error Flag provides system-level monitoring of output regulation failure, supporting watchdog or PMIC sequencing logic. |
| Robust thermal design | DPAK-5 package with RθJC = 8.0°C/W allows >2 W dissipation with minimal heatsink - suitable for 1.0 A loads at ΔV = 1.5 V. |
Applications
| Server VRM Post-Regulation | ASIC Core Power Sequencing |
|---|---|
Use Scenario: Final-stage regulation after multiphase buck converter supplying 1.8 V I/O banks on high-end servers. IC Role / Device Role / Timing Role: Low-noise, fast-transient LDO providing clean 1.8 V rail with real-time fault detection via Error Flag. Use Value: Eliminates need for additional filtering; 1.0 V dropout enables efficient use of 3.3 V intermediate bus; Error Flag enables BIOS-level rail health monitoring. | Use Scenario: Powering configurable logic blocks in Xilinx/Intel FPGAs requiring tightly regulated 1.8 V with controlled enable timing. IC Role / Device Role / Timing Role: Enable-controlled LDO delivering precise 1.8 V with ±1% accuracy across temperature, synchronized to system power-up sequence. Use Value: TTL-compatible EN pin simplifies FPGA GPIO control; 1.0 A rating covers peak I/O switching currents; ±1.5% tolerance meets FPGA VCCIO spec. |
| Networking PHY Interface Supply | Gaming Console Memory I/O Rail |
Use Scenario: Supplying 1.8 V to Ethernet PHY transceivers (e.g., Marvell 88E1512) in enterprise switches. IC Role / Device Role / Timing Role: Low-PSRR LDO rejecting switcher ripple while maintaining fast transient response to bursty packet traffic loads. Use Value: 65 dB PSRR at 1 kHz attenuates 12 V–3.3 V buck converter noise; 26 µVrms noise prevents PHY jitter degradation. | Use Scenario: Powering GDDR6 or LPDDR5 memory interfaces in next-gen gaming consoles requiring stable 1.8 V under rapid load changes. IC Role / Device Role / Timing Role: High-current LDO with sub-µs transient response ensuring memory timing margins during GPU frame rendering bursts. Use Value: 1–3 µs settling time prevents memory read/write errors during 100 mA–1.0 A load steps; DPAK thermal performance sustains 1.0 A continuously. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A4701RGWR | 1.8 V fixed, 1.0 A, 26 µVrms noise, but uses DFN-8 (3×3 mm); no Error Flag; higher IQ (1.3 mA typ) | Lacks fault reporting; better for space-constrained designs where EF is not needed | Choose if board area is critical and system-level monitoring is handled elsewhere. |
| MCP1826T-1802E/DB | 1.8 V fixed, 1.0 A, DFN-6 (3×3 mm), no Error Flag, 45 µVrms noise, 1.2 V dropout @1A | Higher noise and dropout; lower thermal performance (RθJA = 120°C/W) | Acceptable for cost-sensitive consumer applications with relaxed noise/dropout specs. |
Compared with TPS7A4701RGWR and MCP1826T-1802E/DB, the NCP5661DT18RKG uniquely combines Error Flag functionality, ultra-low noise without bypass cap, and DPAK thermal robustness - making it optimal for industrial and telecom systems requiring fault visibility and reliability under sustained load.
Availability
NCP5661DT18RKG is available at Aetrix Electronics and suitable for server VRMs, ASIC power sequencing, and networking PHY interface supplies requiring stable component supply, long-term lifecycle support, and automotive-grade traceability (NCV variant available).
Supply support for NCP5661DT18RKG 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 IoT markets.
The NCP5661 series belongs to onsemi's high-current LDO portfolio, engineered for demanding post-regulation tasks in datacenter, telecom infrastructure, and high-reliability embedded systems where ultra-fast transient response and fault diagnostics are critical.
FAQ
What is the minimum input voltage required for NCP5661DT18RKG to regulate 1.8 V at 1.0 A?
The NCP5661DT18RKG requires a minimum input voltage of 2.8 V to maintain regulation at 1.0 A load, based on its typical 1.0 V dropout voltage. At higher temperatures or worst-case conditions, up to 3.1 V input may be needed to guarantee 1.8 V output across the full operating range. Always verify margin using the dropout vs. temperature curve in Figure 3 of the datasheet.
Does NCP5661DT18RKG require an external bypass capacitor for low-noise operation?
No, the NCP5661DT18RKG delivers 26 µVrms output noise (10 Hz–100 kHz) without any external bypass capacitor. This is enabled by its internal noise-reduction architecture. Adding a 10 nF capacitor may further reduce noise but is not necessary for meeting the specified 26 µVrms value.
How is the Error Flag pin used on NCP5661DT18RKG?
The Error Flag (Pin 5) on NCP5661DT18RKG is an open-drain output that pulls low when VOUT falls below 88% of nominal (1.584 V). It requires a 100 kΩ pull-up resistor to VIN. The flag includes 50 µs blanking to ignore brief transients, and leakage is ≤1.0 µA when inactive. This signal enables system-level fault detection in the NCP5661DT18RKG design.
Can NCP5661DT18RKG be used with ceramic output capacitors?
Yes, the NCP5661DT18RKG is stable with ceramic output capacitors ≥10 µF. Multilayer ceramic capacitors (MLCCs) are recommended and should be placed close to the VOUT and GND pins with short traces to preserve ultra-fast transient response. Stability is guaranteed across 10–150 µF, including low-ESR types.
What thermal considerations apply to NCP5661DT18RKG in DPAK-5 package?
The NCP5661DT18RKG in DPAK-5 has RθJA = 100°C/W (1 oz copper, 0.26 in² pad) and RθJC = 8.0°C/W. To sustain 1.0 A at 1.5 V dropout (1.5 W dissipation), keep ambient temperature ≤70°C or enhance copper area. Thermal shutdown activates at 160°C junction temperature, and the exposed tab (Pin 3) must be soldered to maximize heat transfer.
NCP5661DT18RKG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-252-5, DPAK (4 Leads + Tab), TO-252AD
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 9V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 1.3V @ 1A
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 3 mA
- Current - Supply (Max):
- -
- PSRR:
- 70dB ~ 65dB (120Hz ~ 1kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DPAK-5
NCP5661DT18RKG FAQ
1.How can I place an order for NCP5661DT18RKG through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP5661DT18RKG 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 NCP5661DT18RKG reliable?
The price and inventory of NCP5661DT18RKG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP5661DT18RKG is usually 5 days.
3.What payment methods are accepted for NCP5661DT18RKG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP5661DT18RKG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP5661DT18RKG?
NCP5661DT18RKG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP5661DT18RKG 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 NCP5661DT18RKG?
For technical support, including NCP5661DT18RKG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP5661DT18RKG requirements.
6.How does Aetrix verify that NCP5661DT18RKG is sourced from the original manufacturer or authorized distributors?
All NCP5661DT18RKG 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 NCP5661DT18RKG meets industry standards.
7.What is the process for return or replacement of NCP5661DT18RKG?
All NCP5661DT18RKG units undergo pre-shipment inspection (PSI). If there is an issue with NCP5661DT18RKG, 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 NCP5661DT18RKG part is unused and in its original packaging.
Return procedure for NCP5661DT18RKG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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