Component Comparison: SSM6N58NU,LF vs TB6612FNG,C,8,EL
Quick verdict
For discrete MOSFET switching applications requiring up to 4A continuous current with minimal board area and low gate charge, the SSM6N58NU,LF is clearly superior due to its low R_DS(on) and logic-level gate drive. Conversely, for integrated motor driver solutions where ease of control, half-bridge outputs, and built-in PWM-friendly functionality matter more than peak current capability, the TB6612FNG,C,8,EL is the better fit, despite its lower continuous current rating and larger package.
Spec comparison table
| Spec | SSM6N58NU,LF | TB6612FNG,C,8,EL | Notes |
|---|---|---|---|
| Configuration | 2 N-Channel MOSFETs (Dual) | Integrated Motor Driver (4 half-bridge MOSFETs) | Discrete dual MOSFET vs. integrated driver with MOSFETs and control logic |
| Continuous Drain Current (I_D) @ 25°C | 4 A | 1 A | SSM6N58NU,LF supports 4× higher continuous current, critical for power handling |
| Drain-Source Voltage Max (V_DS) | 30 V | 13.5 V (Load voltage) | SSM6N58NU,LF supports higher voltage; TB6612FNG limited to 13.5 V load voltage |
| Gate Drive Threshold (V_GS_th max) | 1 V @ 1 mA | Not specified | SSM6N58NU,LF is logic-level with 1 V threshold, suitable for low-voltage drive |
| Gate Charge (Q_g) max | 1.8 nC @ 4.5 V | Not specified | Low gate charge reduces switching losses and drive requirements for SSM6N58NU,LF |
| Input Capacitance (C_iss) max | 129 pF @ 15 V | Not specified | Lower input capacitance favors faster switching and lower gate drive current |
| Maximum Power Dissipation | 1 W | Not specified | SSM6N58NU,LF can dissipate up to 1 W; no direct data for TB6612FNG |
| R_DS(on) max @ 2A, 4.5V | 84 mΩ | Not specified | Lower R_DS(on) means lower conduction losses; no direct data for TB6612FNG |
| Operating Temperature Range | Up to 150°C (Junction) | -20°C to 85°C (Ambient) | SSM6N58NU,LF supports higher junction temperature, better for high-temp environments |
| Package | 6-UDFN (2x2 mm) | 24-LSSOP (5.6 mm width) | SSM6N58NU,LF is much smaller, suits tight board space |
| Mounting Type | Surface Mount | Surface Mount | Both are SMT but form factors differ significantly |
| Function | Discrete MOSFET Array | Fully integrated motor driver | TB6612FNG includes control logic, useful for motor control |
| Voltage Supply | N/A (MOSFETs only) | 2.7 V to 5.5 V | TB6612FNG requires logic supply, SSM6N58NU is passive device |
| Voltage Load | N/A | 2.5 V to 13.5 V | TB6612FNG load voltage limited to 13.5 V |
| Output Configuration | N/A | 4 half-bridge outputs | TB6612FNG intended for motor drive, SSM6N58NU is raw MOSFETs |
| Output Current Max | 4 A | 1 A | Significant difference in current capability |
| Technology | MOSFET (Metal Oxide) | Power MOSFET | Both use MOSFET technology, TB6612FNG integrates driver stages |
Design trade-offs
The SSM6N58NU,LF is a discrete dual N-channel MOSFET array optimized for low-voltage, moderate current switching applications. Its 84 mΩ R_DS(on) at 2A and logic-level gate drive threshold (1 V) allow direct interfacing with low-voltage logic (1.8–4.5 V drive). The low gate charge (1.8 nC) and input capacitance (129 pF) reduce switching losses and gate driver current, critical in battery-powered or high-frequency switching designs. The 6-UDFN package (2×2 mm) offers a compact footprint and exposed pad for efficient thermal dissipation, supporting up to 1 W power dissipation and junction temperatures up to 150°C. This makes the device suitable for dense, thermally constrained layouts where discrete MOSFETs can be customized for specific switching topologies.
In contrast, the TB6612FNG,C,8,EL integrates four half-bridge power MOSFETs with control logic in a 24-LSSOP package. While its maximum output current is limited to 1A, the part simplifies motor driver design by incorporating PWM control, direction, and brake logic internally. This reduces firmware complexity and BOM count but trades off raw current capacity and voltage margin (max load voltage 13.5 V) compared to discrete MOSFETs. The larger package size (5.6 mm width) increases PCB area and thermal resistance, and the maximum ambient operating temperature is limited to 85°C, requiring careful thermal management in high-load scenarios.
From a firmware perspective, the TB6612FNG,C,8,EL offers a parallel interface and integrated control, reducing gate drive complexity and eliminating the need for external MOSFET drivers. However, this also means less flexibility in gate drive timing, dead-time insertion, and switching frequency optimization compared to discrete MOSFETs like the SSM6N58NU,LF, where the designer controls all aspects of the MOSFET drive.
In terms of cost, the SSM6N58NU,LF will generally be less expensive per MOSFET but requires additional external components (gate drivers, logic) and PCB area for full motor driver implementation. The TB6612FNG,C,8,EL offers system-level integration at a higher unit cost but potentially lower overall BOM and assembly cost in low-current motor drive applications.
Use-case fit
Choose SSM6N58NU,LF when…
- Designing a compact, efficient DC-DC converter or load switch that requires up to 4A continuous current with tight thermal constraints.
- Implementing custom half-bridge or synchronous rectifier circuits where gate drive timing and switching frequency must be finely tuned.
- Operating in environments requiring high junction temperatures (up to 150°C) and power dissipation up to 1 W.
- Minimizing gate drive losses and switching energy is critical due to low gate charge and input capacitance.
- Board space is limited and a small 2×2 mm 6-UDFN package is preferred.
Choose TB6612FNG,C,8,EL when…
- Building a low-voltage (2.5–13.5 V) brushed DC motor driver requiring up to 1A continuous current with integrated PWM and direction control.
- Simplifying firmware and hardware by leveraging built-in half-bridge drivers and logic, avoiding external gate driver ICs.
- The application can tolerate a larger PCB footprint (24-LSSOP) and ambient operating temperature limited to 85°C.
- Rapid prototyping or low-volume production where integration reduces design complexity and component count.
- The load voltage and current requirements fall within the device’s specified range and no custom switching schemes are needed.
Drop-in compatibility
These parts are not pin-compatible or footprint-compatible. The SSM6N58NU,LF is a discrete dual N-channel MOSFET array in a compact 6-UDFN (2×2 mm) package, while the TB6612FNG,C,8,EL is a fully integrated motor driver IC in a substantially larger 24-LSSOP package (5.6 mm wide). The function and interface differ fundamentally: the SSM6N58NU,LF requires external gate drive and control logic, whereas the TB6612FNG,C,8,EL integrates control and power stages with a parallel interface. Substituting one for the other would require a full redesign of the PCB footprint, power and signal routing, and firmware.
Alternatives to consider
- Si2302DS (Vishay): Logic-level N-channel MOSFET with low R_DS(on) in a small SOT-23 package, suitable for compact low-voltage switching.
- DRV8833 (Texas Instruments): Dual H-bridge motor driver IC with integrated MOSFETs and control logic for up to 1.5 A continuous current, offering more current than TB6612FNG but similar integration.
- IRLB8743PBF (Infineon): Low R_DS(on) logic-level N-channel MOSFET, higher current rating (up to 30A), good for discrete power switching beyond 4A load.