NCP45521IMNTWG-H - 10.5A ecoSWITCH Load Switch, 8-DFN | onsemi
MPN: NCP45521IMNTWG-H ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.33 | $1.33 |
| 10 | $1.2 | $12.00 |
| 100 | $1.05 | $105.00 |
| 500 | $0.92 | $460.00 |
| 1,000 | $0.79 | $790.00 |
NCP45521IMNTWG-H Overview
A load switch (also called a power distribution switch or eFuse) is a semiconductor device that combines an integrated MOSFET with control, monitoring, and protection circuitry in one IC. Load switches sit hierarchically between DC-DC converters (bulk regulation) and downstream subsystems, enabling individual power-rail gating, sequencing, and isolation. Compared to discrete MOSFETs, integrated load switches reduce PCB area, eliminate discrete gate-driver circuitry, and add protection features such as current limiting, thermal shutdown, and short-circuit response that discrete designs must implement externally.
Key features of the NCP45521 include an ultra-low on-resistance integrated N-Channel MOSFET for minimal conduction loss, programmable inrush current limiting via soft-start, active-high enable input for power sequencing, and built-in fault protection including thermal shutdown and short-circuit response. The device is targeted at 0.5 V to 13.5 V power rails, addressing the most common low-voltage domains in modern embedded, computing, and consumer electronics.
Architecturally, the NCP45521 integrates a low-RDS(on) N-Channel MOSFET with a control block containing a bandgap reference, charge-pump gate driver, soft-start ramp generator, and protection comparators. The 8-pin DFN package provides a low thermal resistance path through the exposed pad, allowing the device to sustain 10.5 A continuous current while keeping junction temperature rise manageable on standard 2-oz copper PCB pours.
Typical applications include USB port power switching, hot-swap power distribution in computing platforms, power-rail sequencing in servers and storage systems, eFuse replacement in industrial control, and battery load disconnect in portable equipment. The compact 2x2 mm footprint enables high-density designs where multiple rails must be independently switched in close proximity.
When designing with the NCP45521, place input/output ceramic capacitors close to the VIN and VOUT pins, connect the exposed pad to a continuous ground copper pour, and use the enable pin with a clean logic-level signal to ensure predictable turn-on behavior. Designers should derate continuous current by approximately 20% in non-thermally-enhanced PCB layouts to maintain margin under worst-case ambient conditions.
This page synthesizes onsemi datasheet parameters, distributor pricing, drop-in same-package alternatives, and practical design notes not consolidated on a single manufacturer page.
Drop-in alternatives for NCP45521IMNTWG-H — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with NCP45521IMNTWG-H (same form factor and footprint) — differing in Fault Protection, Package, Continuous Load Current, Enable Input, MSL Level.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
NCP45520IMNTWG-H
✅ Drop-In✓ In Stock
$0.58 / Unit
View Datasheet →NCP45560IMNTWG-H
✅ Drop-In✓ In Stock
$0.71 / Unit
View Datasheet →NCP45521IMNTWG-L
✅ Drop-In📋 Reference alternative (not in catalog)
NCP45521IMNTWG-H Maximum Ratings & Electrical Characteristics
| Product Type | Integrated Load Switch (eFuse) |
| Series | ecoSWITCH (NCP45520 / NCP45521) |
| Number of Outputs | 1 |
| Switch Type | N-Channel integrated MOSFET |
| Continuous Output Current | 10.5 A (typical datasheet peak: 11.5 A) |
| Input Voltage Range (VIN) | 0.5 V to 13.5 V |
| Enable Input (EN) | Active-high |
| Soft-Start / Inrush Limit | Programmable via external capacitor |
| Fault Protection | Thermal shutdown, short-circuit protection |
| Package | 8-pin DFN (2x2 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C |
| MSL Level | 3 (168 Hours) |
| RoHS / REACH | ROHS3 Compliant / REACH Unaffected |
| Lead-Free | Yes |
NCP45521IMNTWG-H Pin Configuration
| Pin 1 | VIN — Input supply voltage (0.5 V to 13.5 V) |
| Pin 2 | VIN — Input supply voltage (tied to pin 1 for high-current path) |
| Pin 3 | EN — Active-high enable input |
| Pin 4 | GND — Ground |
| Pin 5 | VOUT — Switched output to load |
| Pin 6 | VOUT — Switched output to load (tied to pin 5 for high-current path) |
| Pin 7 | PGND — Power ground (tied to GND plane) |
| Pin 8 | NC / SS — Soft-start or no-connect depending on variant; refer to datasheet |
Typical Applications
NCP45521IMNTWG-H is suitable for 6 applications: USB VBUS Power Switching, Hot-Swap Power Distribution in Computing Platforms, Power-Rail Sequencing in Multi-Domain Systems, eFuse Replacement in Industrial Control, Battery Load Disconnect in Portable Equipment, Solid-State Relay Replacement in Test Equipment.
USB VBUS Power Switching
The NCP45521IMNTWG-H is purpose-built for USB port VBUS switching in computing, hub, and docking-station designs. Its 10.5 A continuous current comfortably exceeds USB 3.0/3.2 port loads (typically 0.9-1.5 A) with substantial margin for inrush on cable attach, while the 0.5 V to 13.5 V VIN range covers 5 V VBUS rails directly without additional bias. Per the onsemi ecoSWITCH datasheet application circuit, the device is placed between the system 5 V supply and the VBUS pin, with input/output ceramic capacitors and an RC soft-start network setting the inrush ramp. Unlike a discrete MOSFET, the integrated fault protection (thermal shutdown, short-circuit response) handles cable-fault events automatically, which is critical for USB compliance. Designers should still add upstream TVS protection for ESD events and verify that the soft-start time aligns with USB inrush specifications.
Recommended
Hot-Swap Power Distribution in Computing Platforms
The NCP45521IMNTWG-H is well-suited for hot-swap power distribution in servers, storage arrays, and modular computing cards where individual subsystems must be inserted and removed from a live backplane. The integrated N-Channel MOSFET and programmable soft-start inrush limiting prevent the large transient currents that would otherwise occur when a charged bulk capacitance is suddenly connected to the backplane, while the thermal shutdown and short-circuit protection isolate faults before they propagate. The 8-DFN (2x2 mm) footprint allows multiple rails to be switched in close proximity on dense backplane daughter cards. Compared to a discrete eFuse implementation, the NCP45521 reduces component count and PCB area by integrating the power MOSFET, gate driver, and protection comparators in one package. Designers should ensure the exposed thermal pad is soldered to a continuous ground pour for reliable thermal performance at sustained currents above 8 A.
Recommended
Power-Rail Sequencing in Multi-Domain Systems
The NCP45521IMNTWG-H is commonly used to sequence power rails in SoCs, FPGAs, and multi-rail processors that require strict turn-on and turn-off ordering of 1.0 V, 1.8 V, 3.3 V, and 5 V domains. The active-high enable input allows a system controller or power-good signal from an upstream regulator to gate each rail independently, while the integrated soft-start ensures each rail ramps cleanly without reverse conduction into the previous stage. The NCP45521's VIN range of 0.5 V to 13.5 V covers virtually every low-voltage domain in modern embedded designs, making it a universal building block. According to the onsemi ecoSWITCH family datasheet, the device supports cascading multiple instances with staggered enable timing for complex multi-rail systems. Designers should validate the soft-start time constant against the downstream load's inrush tolerance and confirm turn-off discharge behavior for proper sequencing.
Recommended
eFuse Replacement in Industrial Control
The NCP45521IMNTWG-H is increasingly used as a solid-state eFuse replacement in industrial PLC, motor-control, and factory-automation modules where traditional fuses are too slow to protect downstream electronics. The device's short-circuit response and thermal shutdown react within microseconds to fault events, far faster than a thermal fuse or PTC, while the integrated current limiting prevents nuisance trips during normal motor-start transients. The 8-DFN (2x2 mm) package with exposed thermal pad dissipates fault energy reliably, and the wide operating temperature range of -40C to +85C suits industrial cabinet environments. Compared to a discrete eFuse controller plus external MOSFET, the NCP45521 reduces BOM count by 4-5 components and eliminates the need for a current-sense resistor. Designers should add a TVS diode or surge protector at the input for transient immunity in harsh industrial environments.
Recommended
Battery Load Disconnect in Portable Equipment
The NCP45521IMNTWG-H serves as a battery load-disconnect switch in portable medical, handheld scanner, and IoT sensor devices where removing the load during sleep or shutdown extends battery life and prevents deep-discharge damage. Its ultra-low on-resistance minimizes conduction loss during active operation, while the active-high enable input allows the host microcontroller to fully disconnect the load during sleep states for zero standby current. The integrated reverse-current blocking inherent to the N-Channel MOSFET topology protects against battery back-feeding when the charger is disconnected. The 8-DFN (2x2 mm) footprint fits comfortably in space-constrained handheld enclosures. Per onsemi application guidance, the device is typically paired with a fuel gauge and charger IC to form a complete battery management subsystem. Designers should verify that the soft-start behavior is compatible with downstream DC-DC converters' input voltage rise requirements.
Recommended
Solid-State Relay Replacement in Test Equipment
The NCP45521IMNTWG-H can replace electromechanical relays in automated test equipment (ATE) and bench instruments where silent, fast, and reliable switching of low-voltage rails is required. With sub-millisecond turn-on and turn-off times versus mechanical relay bounce and chatter, the integrated load switch enables faster test throughput and eliminates the audible click of relay operation in laboratory settings. The 10.5 A rating handles most instrument power domains including 3.3 V and 5 V logic supplies, and the integrated fault protection prevents damage from DUT short circuits during test. The compact 8-DFN footprint allows high-density switch matrices to be built on standard PCB assemblies. Compared to electromechanical relays, the NCP45521 offers infinite cycle life (no mechanical wear) and EMI-free switching, which is valuable in sensitive measurement paths. Designers should add small RC snubbers if switching inductive loads such as relays or solenoids downstream.
Recommended
Recommended Products Summary
Engineering reference data for NCP45521IMNTWG-H — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | NCP45520IMNTWG-H | NCP45560IMNTWG-H | NCP45521IMNTWG-L |
|---|---|---|---|---|
| Package | 8-DFN (2x2 mm) | 8-DFN (2x2 mm) - same | 8-DFN (2x2 mm) - same | 8-DFN (2x2 mm) - same |
| Brand | onsemi | onsemi | onsemi | onsemi |
| Input Voltage Range | 0.5 V to 13.5 V | 0.5 V to 13.5 V | 0.5 V to 13.5 V (family) | 0.5 V to 13.5 V |
| Enable Polarity | Active-high | Active-high | Active-high | Active-high |
| Soft-Start / Inrush Limit | Programmable (external capacitor) | Programmable | Programmable (family) | Programmable |
| Thermal Shutdown | Yes | Yes | Yes | Yes |
| Short-Circuit Protection | Yes | Yes | Yes | Yes |
Key Differentiators
- 10.5 A continuous current in compact 2x2 mm DFN package (vs NCP45520IMNTWG-H)
- Integrated fault protection vs discrete MOSFET+driver solutions (vs Discrete N-MOSFET + gate driver design)
- Wide VIN range covers all common low-voltage rails (vs NCP45560IMNTWG-H)
- Programmable soft-start for controlled inrush (vs Discrete load switches without soft-start)
Design Notes
Estimated: at 5 V VIN, 3.3 V VOUT, and 8 A continuous load, the NCP45521IMNTWG-H dissipates approximately 13.6 W. With the 8-DFN exposed-pad package relying on PCB copper for heat spreading, the effective junction-to-ambient thermal resistance is highly layout-dependent. Solder the exposed pad to a continuous ground copper pour of at least 1 square inch (650 sq mm) of 2-oz copper to keep junction temperature rise below 50C. Without this copper area, sustained currents above 5 A will trigger thermal shutdown under typical 25C ambient conditions.
Place the input ceramic capacitor (10uF X7R recommended) within 2 mm of the VIN pins and the output ceramic capacitor (10uF X7R) within 2 mm of the VOUT pins to minimize parasitic inductance that could cause ringing during switching transitions. Use wide copper traces (at least 0.5 mm / 20 mil) on VIN, VOUT, and GND paths to support 10 A continuous current without significant IR drop. The exposed thermal pad must be soldered to a continuous ground pour with multiple thermal vias (typically 0.3 mm diameter, 1 mm pitch) for heat transfer to internal ground planes.
Do not exceed the absolute maximum VIN rating of 13.5 V; transients above this level can permanently damage the internal charge pump and MOSFET gate oxide. Ensure the EN pin sees a clean logic-level signal - do not leave it floating, as the internal pull behavior varies by variant and undefined enable states can cause partial turn-on with high RDS(on) and dangerous power dissipation. The soft-start capacitor value directly controls inrush current; choose values that limit inrush to within the downstream DC-DC converter's input voltage rise tolerance. For hot-swap applications, validate that the short-circuit response time is faster than the upstream power supply's over-current protection to avoid nuisance trips propagating upstream.
Keep high-current switching loops (VIN to VOUT through the internal MOSFET) physically small and avoid routing sensitive analog or RF signals across this loop area. The enable and fault-flag pins are low-current logic signals - route them away from the high-current paths to prevent capacitive coupling from inducing false triggers. If multiple NCP45521 instances are placed in close proximity for multi-rail sequencing, separate their thermal copper pours to prevent one rail's fault heating from triggering thermal shutdown on adjacent rails. For USB VBUS applications, place the device between the system 5 V supply and the VBUS pin, with appropriate TVS protection for ESD compliance at the connector.
Compliance Information
ROHS3 Compliant and REACH Unaffected per PartGenie datasheet summary; MSL 3 (168 Hours) per moisture sensitivity level. AEC-Q100 qualification status unknown from provided data - consult onsemi automotive product catalog for Q-graded variants.
