Part A
P6SMB300A
Meritek
- Lifecycle
- Active
- Stock
- 4102 PCS
- Package
- DO-214AA-2
- Series
- TVS - Diodes
Replacement verdict
Not a drop-in replacement
The P6SMBJ26A and P6SMB300A are not functionally interchangeable. Although both are 600 W unidirectional SMBJ-series TVS diodes in the same SMB (DO-214AA) package, their standoff, breakdown, and clamping voltages differ by roughly an order of magnitude, so each device protects a fundamentally different circuit rail. Substituting one for the other would either leave the target rail unprotected or clamp at a voltage the downstream circuitry cannot tolerate.
Different standoff voltage
Different breakdown voltage
Different clamping voltage
Different protection rail
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | P6SMBJ26A | P6SMB300A | Why it matters |
|---|---|---|---|
| Reverse Standoff Voltage (V_RWM) | 26 V | 300 V | Defines the maximum continuous DC voltage the device can withstand without conducting; must exceed the normal operating voltage of the circuit being protected. |
| Breakdown Voltage (V_BR) | 28.9 V to 31.9 V | 333 V to 368 V | The voltage range at which the TVS begins to conduct; determines the clamping threshold relative to the protected circuit's supply rail. |
| Clamping Voltage (V_C) at Peak Pulse Current | 42.1 V at 14.3 A | 486 V at 1.3 A | The maximum voltage seen by the protected load during a surge; must remain below the absolute maximum rating of downstream components. |
| Peak Pulse Power (P_PPM, 10/1000 µs) | 600 W | 600 W | Indicates the surge energy the device can absorb; both share the same 600 W rating, so energy handling capability is equivalent. |
| Peak Pulse Current (I_PPM, 10/1000 µs) | 14.3 A | 1.3 A | The maximum surge current the device can shunt; lower-voltage parts handle higher currents for the same power rating. |
| Test Current (I_T) | 1 mA | 1 mA | The current at which breakdown voltage is specified; identical test conditions allow direct comparison of V_BR values. |
| Reverse Leakage Current (I_R) at V_RWM | 1 µA max | 1 µA max | Leakage below breakdown affects standby power and signal integrity; both parts share the same low leakage specification. |
| Package / Mounting | SMB (DO-214AA), Surface Mount | SMB (DO-214AA), Surface Mount | Identical footprint and mounting style allow drop-in PCB replacement without layout changes. |
| Operating Junction Temperature Range | -55 °C to +150 °C | -55 °C to +150 °C | Defines the thermal envelope for reliable operation; matching ranges ensure equivalent environmental capability. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | P6SMB300A | P6SMBJ26A |
|---|---|---|
| Series | P6SMB | - |
| Part Status | Active | Active |
| Type | Zener | Zener |
| Unidirectional Channels | 1 | 1 |
| Voltage - Reverse Standoff (Typ) | 256V | 26V |
| Voltage - Breakdown (Min) | 285V | 28.9V |
| Voltage - Clamping (Max) @ Ipp | 414V | 42.1V |
| Current - Peak Pulse(10 / 1000µs) | 1.45A | 14.3A |
| Power - Peak Pulse | 600W | 600W |
| Applications | General Purpose | General Purpose |
| Operating Temperature | -55°C ~ 150°C | -50°C ~ 150°C (TJ) |
| Mounting Type | Surface Mount | Surface Mount |
| Power Line Protection | - | No |
Frequently asked questions
What are the key differences between P6SMBJ26A and P6SMB300A?
The P6SMBJ26A is a 26 V standoff transient voltage suppressor (TVS) diode, while the P6SMB300A is a 300 V standoff TVS diode. Both are unidirectional 600 W peak pulse power devices in the SMB (DO-214AA) package, but their breakdown voltages, clamping voltages, and intended operating voltage rails differ significantly.
What is the standoff voltage and breakdown voltage for each part?
The P6SMBJ26A has a reverse standoff voltage (VRWM) of 26 V and a minimum breakdown voltage (VBR) of 28.9 V. The P6SMB300A has a reverse standoff voltage of 300 V and a minimum breakdown voltage of 333 V. These values are per the P6SMBJ series datasheet specifications.
What is the peak pulse power rating for these devices?
Both the P6SMBJ26A and P6SMB300A are rated for 600 W peak pulse power dissipation (10/1000 µs waveform). This rating is consistent across the P6SMBJ series.
What is the maximum clamping voltage of each device?
The P6SMBJ26A has a maximum clamping voltage (VC) of 42.1 V at the specified peak pulse current. The P6SMB300A has a maximum clamping voltage of 486 V. These clamping voltages apply at the respective peak pulse currents defined in the datasheet.
Are P6SMBJ26A and P6SMB300A pin-to-pin compatible?
Yes, both devices are housed in the same SMB (DO-214AA) package with identical pinout and footprint. However, pin-to-pin compatibility does not imply electrical interchangeability; the standoff and clamping voltages differ by more than an order of magnitude.
Can P6SMBJ26A and P6SMB300A be used interchangeably in a design?
No. The P6SMBJ26A is intended for circuits with operating voltages up to 26 V, while the P6SMB300A is intended for circuits with operating voltages up to 300 V. Substituting one for the other would either fail to protect the circuit or cause excessive leakage and potential damage due to inappropriate standoff voltage.
What are the typical applications for each device?
The P6SMBJ26A is typically used for transient protection on low-voltage DC rails such as 24 V industrial or automotive circuits. The P6SMB300A is used for protection on higher-voltage rails, such as 277 V AC or 300 V DC systems, where the standoff voltage must exceed the normal operating voltage.
Do both parts have the same polarity and configuration?
Yes, both the P6SMBJ26A and P6SMB300A are unidirectional TVS diodes with a single PN junction. The "A" suffix in the part number indicates a unidirectional device with a 5% breakdown voltage tolerance.