UM6K33NTN vs FDMA905P MOSFET Comparison

Quick verdict

For low-voltage, low-current signal switching or level shifting, the UM6K33NTN’s dual N-channel MOSFET array with 50 V rating and 200 mA current is the clear choice due to its logic-level drive and small input capacitance. Conversely, for high-current load switching up to 10 A at 12 V, the FDMA905P P-channel MOSFET offers far superior conduction losses and power handling, making it the preferred device for power rails and load switches in battery-powered or 12 V systems.

Spec comparison table

SpecUM6K33NTNFDMA905PNotes
Configuration2 N-Channel (Dual)Single P-ChannelUM6K33NTN is dual N-channel array; FDMA905P is single P-channel MOSFET, different use cases.
Continuous Drain Current (Id) @ 25°C200 mA10 AFDMA905P supports 50× higher current, better for high power switching.
Drain-Source Voltage (Vds max)50 V12 VUM6K33NTN has higher voltage rating, suitable for higher voltage domains.
Gate Drive Threshold (Vgs_th max)1 V @ 1 mA1 V @ 250 µAComparable threshold voltage; FDMA905P triggers at lower current threshold, slightly more sensitive.
Rds(on) max @ Id, Vgs2.2 Ω @ 200 mA, 4.5 V16 mΩ @ 10 A, 4.5 VFDMA905P conduction losses are orders of magnitude lower at rated current.
Gate Charge Qg max @ VgsNot specified29 nC @ 6 VFDMA905P gate charge is measurable; UM6K33NTN data absent, likely very low due to low current.
Input Capacitance (Ciss) max @ Vds25 pF @ 10 V3405 pF @ 6 VUM6K33NTN input capacitance is ~2 orders of magnitude lower, easing gate drive at low current.
Power Dissipation max120 mW2.4 W (Ta)FDMA905P handles 20× higher power dissipation, critical for thermal design in power stages.
Operating Temperature Range (TJ)Up to 150°C-55°C to 150°CBoth rated for 150°C max junction temperature; FDMA905P supports wider low-temp range.
Package / Case6-TSSOP (UMT6), SC-88, SOT-3636-WDFN Exposed PadDifferent packages; FDMA905P’s exposed pad aids thermal dissipation.
Mounting TypeSurface MountSurface MountBoth surface mount, but different footprints.
TechnologyMOSFET (Metal Oxide)MOSFET (Metal Oxide)Both standard MOSFET technology.
Gate-Source Voltage MaxNot specified±8 VFDMA905P has explicit ±8 V max gate voltage, useful for robust gate drive margin.

Design trade-offs

The UM6K33NTN and FDMA905P target fundamentally different applications as reflected in their specifications. The UM6K33NTN’s dual N-channel MOSFET array supports low-current switching up to 200 mA at 50 V, with a logic-level gate threshold of 1 V and very low input capacitance (25 pF). This low input capacitance reduces gate drive losses and switching delay when driven from low current MCU GPIOs or logic-level signals, making it suitable for signal multiplexing, level shifting, or low-side load switching in low-power applications. Its relatively high Rds(on) of 2.2 Ω at 200 mA means it’s not intended for power switching, but it can handle moderate voltage with minimal board space.

In contrast, the FDMA905P is a single high-current P-channel MOSFET optimized for load switching up to 10 A at 12 V, with an extremely low Rds(on) of 16 mΩ at 10 A and 4.5 V gate drive. This translates to conduction losses on the order of 1.6 W at full load, requiring a package with good thermal dissipation, which is provided by the 6-WDFN with an exposed pad. The FDMA905P’s gate charge of 29 nC at 6 V is substantial but typical for power MOSFETs switching high currents, so gate drivers or MCU pins need to source sufficient current to switch efficiently without excessive delay or losses. The P-channel MOSFET simplifies high-side switching in 12 V systems as it can be driven directly from a logic-level signal referenced to ground, avoiding the complexity of bootstrap or charge pump circuits needed for N-channel high-side switches.

Thermal management is a key consideration. The FDMA905P’s 2.4 W power dissipation rating at ambient temperature requires careful PCB thermal design, including exposed pad soldering and possibly thermal vias to the inner or backside copper plane. The UM6K33NTN’s 120 mW rating is much lower, and its small package and low current make it easier to manage thermally, but it cannot handle high power loads.

From a layout standpoint, the UM6K33NTN’s 6-TSSOP or SC-88 packages are compact and fine-pitch, suitable for dense signal routing, while the FDMA905P’s 6-WDFN with exposed pad demands careful soldering and thermal relief pads. Because the UM6K33NTN is dual N-channel, it can replace two discrete MOSFETs, saving BOM and board space in low-power analog or digital switching roles.

Cost-wise, the UM6K33NTN is likely cheaper due to simpler construction, lower current rating, and smaller die size, but pricing details are not provided here. The FDMA905P’s power rating and package complexity generally come at a higher cost but justify themselves in power management use cases.

Use-case fit

Choose UM6K33NTN when…

Choose FDMA905P when…

Drop-in compatibility

These devices are not pin- or footprint-compatible. The UM6K33NTN is a dual N-channel MOSFET array in a 6-TSSOP/SC-88/SOT-363 style package, while the FDMA905P is a single P-channel MOSFET in a 6-WDFN (2x2 mm) package with an exposed pad. Substituting one for the other would require significant circuit redesign, including changing from dual N-channel to single P-channel device or vice versa, adjusting gate drive circuitry, and redesigning PCB footprints. No direct drop-in substitution is possible.

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