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onsemi NCP1521BSNT1G
- Part No.:
- NCP1521BSNT1G
- Manufacturer:
- onsemi
- Package:
- SOT-23-5 Thin, TSOT-23-5
- Datasheet:
-
NCP1521BSNT1G.pdf
- Description:
- IC REG BUCK ADJ 600MA 5TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,679
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Product details
Overview
NCP1521BSNT1G from onsemi is a synchronous step-down DC-DC converter optimized for portable battery-powered systems, delivering up to 600 mA at adjustable output voltages from 0.9 V to 3.9 V with 1.5 MHz fixed-frequency PWM/PFM operation, integrated soft-start, and thermal shutdown protection - used in smartphones, USB-powered devices, and digital cameras.
For engineers reviewing the NCP1521BSNT1G datasheet, pinout, applications, or equivalent options, key selection criteria include input voltage range (2.7–5.5 V), feedback reference voltage (0.6 V), peak inductor current limit (1200 mA), TSOP-5 package footprint, and PFM-mode ripple performance (8 mV at no load).
Technical Context
The NCP1521BSNT1G implements a constant-frequency current-mode buck architecture with internal P-channel (400 mΩ) and N-channel (400 mΩ) synchronous MOSFETs, enabling high efficiency (up to 96%) and low external component count. Its 0.6 V internal reference and resistor-divider feedback allow precise output voltage programming.
It supports automatic mode switching between PWM (for high efficiency at medium-to-heavy loads) and PFM (for ultra-low quiescent current of 30 µA at light loads), with cycle-by-cycle current limiting, undervoltage lockout (2.4 V typ), and thermal shutdown at 160°C (25°C hysteresis). The device operates across −40°C to +85°C ambient temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-ion (3.0–4.2 V) and three-cell alkaline/NiMH (3.6–4.5 V) battery inputs without external regulators. |
| Output Current | Up to 600 mA - sufficient for core logic rails in portable SoCs, PMIC subsystems, and camera modules. |
| Switching Frequency | 1.3–1.8 MHz (typ 1.5 MHz) - enables use of compact 2.2 µH inductors and 10 µF ceramic output capacitors. |
| Feedback Reference | 0.6 V ±0% - sets output voltage via external resistor divider (VOUT = 0.6 × (1 + R1/R2)), enabling accurate 0.9–3.9 V adjustment. |
| Quiescent Current | 30 µA (typ) in PFM no-switching mode - extends battery runtime in standby or low-power display modes. |
| Shutdown Current | 0.3 µA (typ) - ensures negligible drain during system sleep or power-off states. |
| Thermal Shutdown | 160°C activation with 25°C hysteresis - protects against sustained overload or poor PCB thermal design without latch-up. |
Pinout & Package
Package: TSOP-5 (3.00 × 1.50 × 0.95 mm, 0.95 mm pitch), Pb-free, surface-mount, low-profile package optimized for space-constrained portable PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power Input | Supplies all internal circuitry and power switches; requires local 4.7 µF ceramic decoupling to minimize input ripple and EMI. |
| GND (Pin 2) | Power/Analog Ground | Common return path for power stage and analog blocks; must be connected directly to system ground plane with low-inductance layout. |
| EN (Pin 3) | Digital Enable Input | Active-HIGH logic control (VIH ≥ 1.2 V); floating state is prohibited - tie to VIN or microcontroller GPIO for sequencing. |
| FB (Pin 4) | Analog Feedback Input | Connects to resistor divider midpoint; senses output voltage and compares to 0.6 V reference to regulate VOUT. |
| LX (Pin 5) | Switch Node Output | Drives external inductor; carries high di/dt switching current - requires short, wide trace and careful routing to reduce EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous Rectification | Eliminates external Schottky diode, reducing conduction loss and improving full-load efficiency to ≥90% (at 3.3 V out, 300 mA). |
| Automatic PWM/PFM Mode Switching | Maintains high efficiency across 0–600 mA load range: >85% at 10 mA (PFM), >90% at 300 mA (PWM), with seamless transition. |
| Integrated Soft-Start | 320–500 µs ramp time limits inrush current during enable, preventing input rail sag and avoiding false UVLO trips. |
| Cycle-by-Cycle Current Limit | 1200 mA peak inductor current limit prevents MOSFET overstress during startup, short-circuit, or transient overload. |
| Full ESD Protection | HBM ≥2 kV and MM ≥200 V on all pins - eliminates need for external ESD diodes in handheld product designs. |
Applications
| Smartphone Core Rail | USB-Powered IoT Sensor Hub |
|---|---|
|
Use Scenario: Powers application processor I/O or memory interface rail from single-cell Li-ion battery (3.0–4.2 V). IC Role / Device Role / Timing Role: Primary synchronous buck regulator generating stable 1.8 V or 2.8 V supply with fast load transient response. Use Value: Delivers 600 mA with <80 mV load transient deviation (200→600 mA step) and maintains regulation down to 2.7 V input. |
Use Scenario: Supplies 3.3 V rail to BLE/Wi-Fi MCU and sensors from 5 V USB source. IC Role / Device Role / Timing Role: Efficient step-down converter operating in PWM-only mode for consistent noise profile and low ripple. Use Value: Achieves >85% efficiency at 500 mA (VIN = 5.0 V, VOUT = 3.3 V) and <2 mV RMS ripple in PWM mode. |
| Digital Camera Image Sensor Bias | Portable Audio DAC Power |
|
Use Scenario: Generates clean 2.8 V bias for CMOS image sensor analog front-end in compact camera module. IC Role / Device Role / Timing Role: Low-noise, low-ripple DC-DC supply with PFM-mode capability for standby power optimization. Use Value: Provides <8 mV peak-to-peak output ripple in PFM mode (IOUT = 0 mA), minimizing sensor readout noise. |
Use Scenario: Powers stereo audio DAC and headphone amplifier from 3.7 V Li-ion battery in wireless earbuds. IC Role / Device Role / Timing Role: High-efficiency, low-quiescent-current regulator supporting dynamic volume and playback states. Use Value: Draws only 30 µA quiescent current in PFM mode, extending playback time by >15% versus non-synchronous alternatives. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | Fixed 1.8 V output (non-adjustable); 3 MHz switching frequency; 300 mA max output. | Not suitable for variable-output or >300 mA applications; better for ultra-compact, fixed-voltage point-of-load use. | Select when board space is critical and output voltage is fixed - requires redesign of feedback network and inductor selection. |
| RT8059GJ6 | Adjustable 0.6–5.0 V output; 2 A rating; 1.5 MHz frequency; requires external compensation. | Higher current capability and wider VOUT range, but larger solution size and added design complexity. | Choose for future-proofing or higher-current derivatives; not drop-in - demands loop stability analysis and layout revision. |
Compared with TPS62231DRYR and RT8059GJ6, the NCP1521BSNT1G offers optimal balance of adjustability (0.9–3.9 V), 600 mA capability, and minimal BOM count in TSOP-5 - making it ideal for cost-sensitive, space-constrained portable designs where moderate current and flexible voltage setting are required.
Availability
NCP1521BSNT1G is available at Aetrix Electronics and suitable for smartphone power management, USB-powered IoT nodes, and portable camera modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for NCP1521BSNT1G 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, and sensing technologies for automotive, industrial, and portable electronics.
The NCP1521BSNT1G belongs to onsemi's NCP15xx family of high-frequency synchronous buck converters, designed specifically for battery-powered portable equipment demanding small size, low quiescent current, and robust protection features.
FAQ
What is the minimum input voltage required for NCP1521BSNT1G to maintain regulation?
The NCP1521BSNT1G has an undervoltage lockout threshold of 2.2–2.55 V (typ 2.4 V). Regulation is maintained down to 2.7 V input per datasheet specifications; operation below this risks dropout or shutdown. For 3.3 V output, minimum functional VIN is ~3.6 V under 600 mA load due to P-channel RDS(on) and inductor DCR losses.
Can NCP1521BSNT1G be used with a 5 V USB input to generate 3.9 V output?
Yes - the NCP1521BSNT1G supports USB-powered applications with VIN = 4.3–5.5 V and delivers up to 600 mA at 3.9 V in PWM mode only. Efficiency exceeds 85% at 500 mA (VIN = 5.0 V), and load regulation remains within ±1.5% across full current range, as verified in Figure 28 of the datasheet.
What is the recommended inductor value for NCP1521BSNT1G in standard applications?
The datasheet specifies 2.2 µH as the optimized inductor value for internal compensation, paired with 10 µF output capacitance. Inductor saturation current must exceed 600 mA + (IL_ripple/2); typical ripple is ~300 mA peak-to-peak. FDK MIPW3226, TDK VLF3010AT, and Coilcraft DO1605-T series are validated choices.
Does NCP1521BSNT1G require an external compensation network?
No - the NCP1521BSNT1G uses internally fixed frequency compensation optimized for 2.2 µH / 10 µF L-C filter. External compensation is neither supported nor required. Adding external components may destabilize the control loop; the feed-forward capacitor (18 pF) is the only optional passive element specified.
How does the EN pin behavior affect system power sequencing with NCP1521BSNT1G?
The EN pin is active-HIGH with VIH ≥ 1.2 V and VIL ≤ 0.4 V. It must never float - tie to VIN through a pull-up or drive from a microcontroller GPIO. Enabling NCP1521BSNT1G before VIN reaches 2.7 V may trigger UVLO; proper sequencing ensures stable startup and avoids repeated soft-start cycles.
NCP1521BSNT1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOT-23-5 Thin, TSOT-23-5
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.9V
- Voltage - Output (Max):
- 3.9V
- Current - Output:
- 600mA
- Frequency - Switching:
- 1.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 5-TSOP
NCP1521BSNT1G FAQ
1.How can I place an order for NCP1521BSNT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP1521BSNT1G 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 NCP1521BSNT1G reliable?
The price and inventory of NCP1521BSNT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP1521BSNT1G is usually 5 days.
3.What payment methods are accepted for NCP1521BSNT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP1521BSNT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP1521BSNT1G?
NCP1521BSNT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP1521BSNT1G 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 NCP1521BSNT1G?
For technical support, including NCP1521BSNT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP1521BSNT1G requirements.
6.How does Aetrix verify that NCP1521BSNT1G is sourced from the original manufacturer or authorized distributors?
All NCP1521BSNT1G 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 NCP1521BSNT1G meets industry standards.
7.What is the process for return or replacement of NCP1521BSNT1G?
All NCP1521BSNT1G units undergo pre-shipment inspection (PSI). If there is an issue with NCP1521BSNT1G, 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 NCP1521BSNT1G part is unused and in its original packaging.
Return procedure for NCP1521BSNT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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