UM6K33NTN vs SSM6N57NU,LF: Dual N-Channel MOSFET Array Comparison
Quick verdict
For low-current, low-voltage switching or level shifting where minimal gate drive voltage and ultra-compact footprint are paramount, the UM6K33NTN is the better choice. Conversely, for power switching applications requiring significantly higher current (up to 4A) and lower conduction losses, the SSM6N57NU,LF outperforms despite its lower voltage rating and larger gate charge.
Spec comparison table
| Spec | UM6K33NTN | SSM6N57NU,LF | Notes |
|---|---|---|---|
| Configuration | 2 N-Channel (Dual) | 2 N-Channel (Dual) | Equivalent |
| Continuous Drain Current (Id @ 25°C) | 200mA | 4A | SSM6N57NU,LF supports 20x higher current, suitable for power switching |
| Drain-Source Voltage (Vds max) | 50V | 30V | UM6K33NTN supports higher voltage, better for higher-voltage logic or analog switching |
| Fet Feature | Logic Level Gate, 1.2V Drive | Not specified | UM6K33NTN optimized for low gate drive voltage |
| Gate Charge (Qg max @ Vgs) | Not specified | 4nC @ 4.5V | SSM6N57NU,LF has measurable gate charge; UM6K33NTN likely lower but unspecified |
| Input Capacitance (Ciss max @ Vds) | 25pF @ 10V | 310pF @ 10V | UM6K33NTN has ~12x lower input capacitance, enabling faster switching and lower gate drive loss |
| Mounting Type | Surface Mount | Surface Mount | Equivalent |
| Operating Temperature Range (TJ) | 150°C | 150°C | Equivalent |
| Package Case | 6-TSSOP, SC-88, SOT-363 | 6-WDFN Exposed Pad | SSM6N57NU,LF’s exposed pad aids thermal dissipation |
| Max Power Dissipation | 120mW | 1W | SSM6N57NU,LF supports ~8x higher power dissipation |
| Rds(on) max @ Id, Vgs | 2.2Ω @ 200mA, 4.5V | 46mΩ @ 2A, 4.5V | SSM6N57NU,LF has drastically lower Rds(on), critical for conduction loss at higher currents |
| Supplier Device Package | UMT6 | 6-µDFN (2x2) | Different package types; SSM6N57NU,LF smaller footprint but exposed pad |
| Technology | MOSFET (Metal Oxide) | MOSFET (Metal Oxide) | Equivalent |
| Vgs(th) max @ Id | 1V @ 1mA | 1V @ 1mA | Equivalent |
Design trade-offs
The most striking difference between these two MOSFET arrays is the current handling and conduction losses. The UM6K33NTN is specified for a modest 200mA continuous drain current with a high Rds(on) of 2.2Ω, making it unsuitable for any application requiring significant power switching. Its logic-level gate drive (1.2V) and very low input capacitance (25pF) make it ideal for low-voltage digital switching or level shifting where gate drive strength is limited, such as low-voltage microcontrollers or FPGAs.
In contrast, the SSM6N57NU,LF supports a continuous drain current of 4A and has an extremely low Rds(on) of 46mΩ at 2A and 4.5V gate drive. This translates to significantly lower conduction losses when switching moderate loads, but it requires a stronger gate drive and incurs higher gate charge (4nC at 4.5V), which will affect switching speed and driver power consumption. The much larger input capacitance (310pF) means that gate driver selection and layout must be more carefully handled to avoid slow switching or excessive EMI.
Thermally, the SSM6N57NU,LF is rated for 1W power dissipation and comes in a 6-WDFN package with an exposed pad, which facilitates efficient heat sinking on the PCB. The UM6K33NTN’s 120mW power rating and smaller UMT6 package limit its ability to dissipate heat, restricting it to low-power or signal-level applications.
From a layout perspective, the UM6K33NTN’s smaller capacitance and simpler gate drive requirements reduce PCB complexity, allowing for minimal gate drive traces and less concern over parasitic inductance or ringing. The SSM6N57NU,LF’s exposed pad requires careful thermal via placement and soldering process control to maximize heat dissipation, and its higher gate charge demands a gate driver capable of delivering short, high-current pulses.
Cost at volume is not specified here, but generally, low-current MOSFET arrays like the UM6K33NTN tend to be less expensive and simpler to integrate, while high-current parts like the SSM6N57NU,LF command a premium due to their enhanced performance and thermal packaging.
Use-case fit
Choose UM6K33NTN when…
- You need dual low-current MOSFET switches for signal-level multiplexing or level shifting below 200mA.
- Operating voltage up to 50V is required, beyond the 30V limit of the SSM6N57NU,LF.
- Gate drive voltage is limited to 1.2–1.5V logic levels (e.g., direct MCU IO pins without level shifters).
- Minimizing gate input capacitance is critical to reduce switching losses or to achieve fast switching at low power.
- PCB space is limited, and you need a small 6-TSSOP/SC-88 package with simple thermal requirements.
Choose SSM6N57NU,LF when…
- Switching loads drawing up to 4A continuous current with low conduction losses is necessary.
- Operating voltage is 30V or lower, matching typical power rails in battery management or DC-DC conversion.
- You can provide a 4.5V or higher gate drive voltage, enabling low Rds(on) performance.
- Thermal dissipation is a concern and you can take advantage of the exposed pad package and PCB thermal design.
- Gate drive power and switching speed trade-offs are acceptable for more efficient power switching.
Drop-in compatibility
These parts are not pin-compatible or footprint-compatible. The UM6K33NTN comes in a 6-TSSOP/SC-88/SOT-363 package, whereas the SSM6N57NU,LF is housed in a 6-lead WDFN (2x2mm) with an exposed pad. The pin assignments and package footprints differ significantly. Substituting one for the other would require a PCB redesign, including thermal pad layout for the SSM6N57NU,LF. Gate drive requirements and voltage ratings also differ, so the substitution is not straightforward without circuit adjustments.
Alternatives to consider
- BSS138 (NXP, etc.): Single N-channel MOSFET with logic-level gate drive, widely used for low-current switching and level shifting.
- Si2302 (Vishay): Small-signal N-channel MOSFET with low Rds(on) and low gate charge, suitable for moderate current low-voltage switching.
- AO3400A (Alpha & Omega Semiconductor): Logic-level N-channel MOSFET with low Rds(on) and moderate current rating, good for compact power switching applications.