MC33984 - Dual 4.0 mOhm High-Side Switch | NXP Semiconductors
MPN: MC33984 ✓ Active| Qty | Unit Price | Extended |
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MC33984 Overview
A high-side switch IC is a power management device that places a protected MOSFET between a positive supply rail and the load, controlling power delivery from the supply side rather than the ground side. Within the semiconductor hierarchy, the MC33984 belongs to the class of intelligent power switches (eProtect MOSFET integrated driver + power stage), a subcategory of power management ICs that merges discrete power MOSFETs, gate drivers, and protection logic in a single device, replacing electromechanical relays, fuses, and discrete component clusters.
Key features include the 4.0 mOhm on-resistance that minimizes conduction losses at high load currents, integrated self-protection against overload, overtemperature, and fault conditions, and self-recovery behavior that automatically restores operation after transient faults clear. According to the NXP datasheet, the device is explicitly designed for harsh environments and is suitable for loads with high inrush current, motors, and all types of resistive and inductive loads.
Technically, the dual-channel architecture allows two independent loads to be controlled from one device, each channel benefiting from integrated charge pumping, current limiting, and thermal shutdown logic. The silicon switch construction eliminates relay wear-out mechanisms such as contact arcing and mechanical fatigue, improving system reliability and lifetime in automotive and industrial duty cycles.
Typical applications include replacing electromechanical relays and fuses in automotive power distribution boxes, driving high-inrush loads such as lamps and heating elements, and controlling DC motors in harsh industrial environments where self-protection and fault self-recovery are required.
When designing with the MC33984, respect the thermal design: with 4.0 mOhm per channel, conduction loss equals I-squared times R, so continuous currents near the package limit require substantial PCB copper area under the power tabs to keep junction temperature within ratings. Consult the manufacturer datasheet for exact SOA and thermal resistance values.
This page synthesizes verified datasheet data, distributor availability, drop-in alternative analysis, and practical design guidance not found in the manufacturer datasheet alone.
Drop-in alternatives for MC33984 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC33984B
✅ Drop-In📋 Reference alternative (not in catalog)
MC33984 Maximum Ratings & Electrical Characteristics
| Product Type | Dual intelligent high-current self-protected silicon high-side switch |
| Number of Channels | 2 (dual) |
| On-Resistance RDS(on) | 4.0 mOhm per channel |
| Switch Topology | High-side |
| Self-Protection | Yes (overload, overtemperature, fault protection) |
| Self-Recovery | Yes (automatic recovery after transient faults) |
| Suitable Load Types | High inrush current loads, motors, resistive and inductive loads |
| Replaces | Electromechanical relays, fuses, and discrete devices |
| Environment Rating | Designed for harsh environments |
| Mounting Type | Surface Mount |
MC33984 standard Pin Configuration Guide
Pin configuration for MC33984 (standard package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for MC33984.
Refer to the datasheet for full pin configuration.
Safe Operating Area
Typical Applications
MC33984 is suitable for 6 applications: Automotive Power Distribution, High-Inrush Lamp and Heater Loads, DC Motor Control (High-Side), Industrial Load Switching in Harsh Environments, Electronic Fuse (eFuse) Modules, Body Electronics and Comfort Loads.
Automotive Power Distribution
The MC33984 fits automotive power distribution boxes and smart junction blocks where it directly replaces electromechanical relays and fuses. Its 4.0 mOhm per-channel on-resistance keeps conduction loss low on battery-fed rails; at 20 A a channel dissipates only about 1.6 W, reducing heat in sealed modules. Integrated overload, overtemperature, and fault reporting provide electronic fuse functionality with faster response than blade fuses, and self-recovery clears transient faults without driver intervention, which is valuable in harsh underhood and chassis environments with limited service access.
Recommended
High-Inrush Lamp and Heater Loads
Incandescent lamps and resistive heating elements draw 5 to 10 times rated current cold, which destroys unprotected switches. The MC33984 is explicitly rated by NXP for loads with high inrush current; integrated current limiting clamps the switch current during the tungsten filament cold phase, and thermal shutdown with self-recovery protects against sustained stalls. The dual-channel layout lets one device control left and right lamp circuits independently. Its silicon construction avoids contact arcing that erodes relay contacts, extending service life well beyond electromechanical alternatives.
Recommended
DC Motor Control (High-Side)
The MC33984 is suited to high-side switching of DC motors such as pumps, fans, and actuators, load classes the NXP datasheet explicitly lists. Motors present both inrush at start and inductive kick at switch-off; the integrated protection clamps start current, and the device handles the inductive load class by design. With 4.0 mOhm on-resistance, conduction loss during long continuous run times stays low, and self-recovery resumes operation after a transient stall-induced overtemperature event without a power cycle, improving uptime in harsh industrial and vehicle applications.
Recommended
Industrial Load Switching in Harsh Environments
Industrial panels, agricultural machinery, and construction equipment expose power electronics to voltage transients, vibration, and wide temperature swings. NXP designed the MC33984 specifically for harsh environments: the self-protected silicon switch tolerates fault events and recovers automatically, while replacing the relay, fuse, and discrete protection cluster with one device reduces BOM count and wiring complexity. Its 4.0 mOhm channels support resistive and inductive loads as defined in the datasheet, making it a general-purpose protected power rail switch for 24 V-class industrial control boards.
Recommended
Electronic Fuse (eFuse) Modules
As a relay and fuse replacement, the MC33984 forms the core of electronic fuse modules. Its built-in overload and overtemperature protection acts like a resettable fuse with microsecond response, and fault feedback to a microcontroller enables diagnostic logging and load-shedding strategies not possible with blade fuses. The 4.0 mOhm on-resistance keeps the voltage drop negligible at high currents, so protected rails behave like solid copper during normal operation, and self-recovery clears transient trips without field service intervention, which matters in remote or vehicle-mounted power modules.
Recommended
Body Electronics and Comfort Loads
Vehicle body controllers switch many medium-to-high-current loads such as seat heaters, blower motors, and rear-window heating. The MC33984 serves the heaviest of these branches: the dual-channel format pairs naturally with two related loads, 4.0 mOhm limits self-heating during continuous duty, and the resistive and inductive load capability covers the mixed load types typical of body modules. Self-protection removes the need for per-channel discrete fusing, and the harsh-environment rating covers door and underbody mounting locations exposed to moisture and temperature cycling.
Recommended
Recommended Products Summary
Engineering reference data for MC33984 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC33984B |
|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors |
| Channels | 2 (dual) | 2 (dual) |
| On-Resistance RDS(on) | 4.0 mOhm per channel | 4.0 mOhm per channel |
| Self-Protection | Yes (overload, overtemperature) | Yes |
| Self-Recovery | Yes | Yes |
| Target Environment | Harsh environments (automotive/industrial) | Harsh environments |
| Load Types | High inrush, motors, resistive, inductive | High inrush, motors, resistive, inductive |
Key Differentiators
- Dual-channel 4.0 mOhm integration (vs Discrete MOSFET solutions)
- Self-recovery after transient faults (vs Electromechanical relays and one-shot protection)
- B-suffix successor availability (vs MC33984B)
Design Notes
Estimated: with 4.0 mOhm per channel, conduction loss is I-squared x R. At 20 A continuous per channel this is about 1.6 W; at 30 A about 3.6 W. Multiplied by the package junction-to-ambient thermal resistance (value in the NXP datasheet), this defines the PCB copper requirement. Plan generous copper pours connected to the power tabs and verify junction temperature against the datasheet rating at your maximum ambient temperature, especially for dual channels conducting simultaneously.
Do not assume all MC33984 suffixes are identical: the family includes the MC33984B revision, which consolidates the same functionality but may differ in protection threshold or fault-reporting details. Always design against the specific suffix in your BOM and download the matching NXP datasheet revision. Confirm whether your variant latches faults or self-recovers before writing diagnostics code that assumes automatic fault clearing.
Treat the MC33984 like a power stage, not a logic IC: route high-current paths as short, wide traces or polygons from the supply through the device to the load connector, keep the switch loops tight to limit inductive kick on load disconnect, and place the fault/status lines away from high dV/dt power nodes to protect the microcontroller interface. Follow the NXP datasheet recommended land pattern for thermal relief on the power tabs.
Compliance Information
Compliance status was not captured in the verified data for the specific MC33984 suffix; confirm via NXP product page or distributor compliance documentation.
