UM6K33NTN vs SSM6L56FE,LM: Component Comparison for MOSFET Arrays
Quick verdict
For low-voltage, low-current level shifting or load switching at up to 50 V with minimal gate drive, the UM6K33NTN is the better choice due to its higher voltage rating and simpler dual N-channel configuration. For applications requiring complementary push-pull stages or higher current handling under 20 V, the SSM6L56FE,LM is preferable thanks to its N- and P-channel pair, lower RDS(on), and 800 mA current rating.
Spec comparison table
| Spec | UM6K33NTN | SSM6L56FE,LM | Notes |
|---|---|---|---|
| Configuration | 2 x N-Channel | 1 x N-Channel + 1 x P-Channel | SSM6L56FE,LM supports complementary stages, enabling half-bridge or push-pull topologies. |
| Max Drain-Source Voltage (V) | 50 V | 20 V | UM6K33NTN allows higher voltage operation, critical for 30–50 V rails. |
| Continuous Drain Current (mA) | 200 mA @ 25°C | 800 mA (Ta) | SSM6L56FE,LM supports 4x current, beneficial for higher load currents. |
| Max Power Dissipation (mW) | 120 mW | 150 mW (Ta) | SSM6L56FE,LM can dissipate more power, easing thermal design at higher currents. |
| Gate Drive Voltage Threshold (Vgs_th max) | 1 V @ 1 mA | 1 V @ 1 mA | Equivalent logic-level threshold for both devices. |
| Gate Drive Voltage (Logic Level) | 1.2 V drive | 1.5 V drive | UM6K33NTN can switch fully on at slightly lower gate voltage, useful for low-voltage logic. |
| Max RDS(on) @ Id, Vgs | 2.2 Ω @ 200 mA, 4.5 V | 235 mΩ N, 390 mΩ P @ 800 mA, 4.5 V | SSM6L56FE,LM offers significantly lower on-resistance, improving efficiency and thermal margin. |
| Input Capacitance (Ciss) | 25 pF @ 10 V | 55 pF (N), 100 pF (P) @ 10 V | UM6K33NTN has lower input capacitance, resulting in lower gate charge and faster switching. |
| Gate Charge (Qg) | Not specified | 1 nC @ 10 V | SSM6L56FE,LM’s 1 nC gate charge is moderate; UM6K33NTN missing data but likely lower due to lower Ciss. |
| Package | 6-TSSOP / SC-88 / SOT-363 | SOT-563 / SOT-666 | Different standard small-outline packages; footprint compatibility unlikely. |
| Operating Temperature Range | Up to 150°C (TJ) | Up to 150°C | Equivalent maximum junction temperature. |
| Technology | MOSFET (Metal Oxide) | MOSFET (Metal Oxide) | Both use standard MOSFET technology. |
| Mounting Type | Surface Mount | Surface Mount | Both parts are surface mount, compatible with modern PCB assembly processes. |
Design trade-offs
The primary difference between the UM6K33NTN and SSM6L56FE,LM lies in their voltage and current handling capabilities, as well as device configuration. UM6K33NTN’s 50 V rating and dual N-channel MOSFETs make it suitable for switching or level shifting in moderate voltage rails where only N-channel devices are needed, such as load switches or simple high-side switches with a suitable driver. However, its relatively high RDS(on) of 2.2 Ω at 200 mA means conduction losses become significant above a few hundred milliamps, limiting efficiency and thermal headroom. Designers should expect to limit continuous current well below 200 mA for thermal reliability or provide adequate PCB copper area for dissipation.
The SSM6L56FE,LM supports 20 V maximum but offers a complementary N- and P-channel pair, enabling half-bridge or push-pull stage designs without external complementary MOSFETs. Its dramatically lower RDS(on) — 235 mΩ for the N-channel and 390 mΩ for the P-channel at 800 mA — allows significantly higher current throughput with lower losses, improving efficiency and reducing heat generation. The 150 mW power dissipation rating and 800 mA current rating at ambient temperature reflect this capability. The trade-off is the lower voltage rating, limiting this part to lower-voltage rails.
Gate drive requirements differ slightly: UM6K33NTN fully enhances at 1.2 V logic level gate drive, which is beneficial if supply voltages or logic signals are constrained to 1.8–3.3 V domains. The SSM6L56FE,LM requires 1.5 V gate drive for full enhancement, still logic-level but potentially less optimal for ultra-low-voltage logic. Input capacitance is significantly lower in the UM6K33NTN (25 pF vs 55/100 pF), which can reduce switching losses and EMI in high-frequency applications, though the SSM6L56FE,LM gate charge of 1 nC is not excessive for typical switching speeds.
Package and footprint differences are non-trivial. UM6K33NTN’s 6-TSSOP/SC-88/SOT-363 package is common for dual MOSFET arrays, but the SSM6L56FE,LM uses SOT-563 or SOT-666, which have different pinouts and sizes. This means direct PCB footprint swaps will require re-layout, limiting drop-in substitution.
Cost at volume is not specified here, but typically Toshiba parts like the SSM6L56FE,LM with complementary devices and higher current ratings may carry a price premium over simpler dual N-channel arrays like the UM6K33NTN.
Use-case fit
Choose UM6K33NTN when:
- You need to switch or level-shift signals or loads up to 50 V but currents stay below 200 mA.
- Application requires only N-channel MOSFETs (e.g., low-side switches, simple load switches).
- Logic-level gate drive voltage is limited to around 1.2 V, such as low-voltage microcontroller outputs.
- Minimizing gate input capacitance to reduce switching losses or EMI is critical.
- PCB space is constrained and the SC-88/SOT-363 package footprint matches existing designs.
Choose SSM6L56FE,LM when:
- The application requires complementary MOSFET pairs for half-bridge or push-pull configurations at ≤ 20 V.
- Higher continuous current up to 800 mA is needed with lower conduction losses.
- Power dissipation up to 150 mW at ambient temperatures is acceptable, enabling higher power handling.
- The design can afford a slightly higher gate drive voltage (1.5 V) and larger input capacitance.
- You need a surface-mount MOSFET array optimized for load drivers, DC-DC converters, or battery protection circuits at low voltage.
Drop-in compatibility
There is no indication from the datasheets or package information that these parts are pin-compatible or footprint-compatible. The UM6K33NTN uses a 6-TSSOP/SC-88/SOT-363 package, while the SSM6L56FE,LM uses SOT-563/SOT-666. The difference in package outline and pin count/arrangement means substitution requires PCB redesign. Additionally, the internal MOSFET configurations differ (dual N-channel vs complementary N/P), so even if pin-compatible, circuit behavior would change.
Alternatives to consider
- BSS138 (ON Semiconductor): Single N-channel logic-level MOSFET with low gate charge, suitable for low-current switching up to 50 V.
- Si2302 (Vishay): N-channel MOSFET with low RDS(on) and logic-level gate drive, useful for low-voltage power switching.
- FDC855N (Fairchild): Logic-level N-channel MOSFET with moderate current capability and low gate charge, suitable for load switching in 20–30 V rails.