SMA4F5.0AY - 5.0V TVS Diode, SMA Flat Package | STMicroelectronics
MPN: SMA4F5.0AY ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.12 | $0.12 |
| 10 | $0.1 | $1.00 |
| 100 | $0.08 | $8.00 |
| 500 | $0.07 | $35.00 |
| 1,000 | $0.06 | $60.00 |
SMA4F5.0AY Overview
A TVS diode is a semiconductor device that clamps transient voltages to a safe level by entering avalanche breakdown when the voltage exceeds its breakdown voltage. It is a critical component in circuit protection, acting as a voltage clamp that diverts excess energy away from sensitive ICs, microcontrollers, and communication interfaces. TVS diodes are part of the broader category of circuit protection devices, which also include varistors, ESD suppressors, and gas discharge tubes. In the system hierarchy, a TVS diode is a fundamental building block in the protection layer of electronic systems, working alongside fuses and current limiters to ensure reliability and safety.
Key features of the SMA4F5.0AY include a peak pulse power dissipation of 400W (10/1000µs waveform), a low clamping factor, and a fast response time of less than 1ns. The device operates over a wide temperature range of -55°C to +150°C, making it suitable for harsh environments. Its SMAflat package is designed for automated assembly, with a height of only 1.0mm, ideal for space-constrained applications. The device is RoHS compliant and halogen-free, meeting modern environmental standards.
Technically, the SMA4F5.0AY utilizes a planar epitaxial structure that ensures low leakage current and high surge capability. The device's clamping voltage at peak pulse current is typically 9.2V, providing effective protection for 5V logic and power rails. The TVS diode's bidirectional or unidirectional configuration is determined by the application; the SMA4F5.0AY is unidirectional, making it suitable for DC power lines and signal lines where the voltage is always positive.
Typical applications include protection of power supply inputs, I/O ports, and communication lines in consumer electronics, industrial control systems, automotive electronics, and telecommunications equipment. For example, in a USB power port, the SMA4F5.0AY can be placed across the VBUS line to clamp ESD events, ensuring the downstream controller remains undamaged.
When designing with this device, it is essential to place the TVS diode as close as possible to the protected connector or IC to minimize parasitic inductance. Additionally, the PCB layout should include a low-impedance ground path to ensure effective clamping. The device's standoff voltage should be higher than the maximum operating voltage of the protected line to avoid unnecessary conduction during normal operation.
Drop-in alternatives for SMA4F5.0AY — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SMAJ5.0A
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SMAJ5.0A
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
P4SMAJ5.0A
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SMA4F5.0AY Maximum Ratings & Electrical Characteristics
| Type | TVS Diode (Unidirectional) |
| Standoff Voltage (VRWM) | 5.0 V |
| Breakdown Voltage (VBR) | 6.4 V to 7.0 V |
| Clamping Voltage (VC at IPP) | 9.2 V (typical) |
| Peak Pulse Power (PPP) | 400 W (10/1000µs) |
| Peak Pulse Current (IPP) | 43.5 A (10/1000µs) |
| Leakage Current (IR) | 1 µA (max at VRWM) |
| Capacitance (C) | 1200 pF (typical at 0V, 1MHz) |
| Response Time | < 1 ns |
| Operating Temperature Range | -55°C to +150°C |
| Package | SMAflat (SMA) |
| Mounting Type | Surface Mount |
| Height | 1.0 mm (max) |
| RoHS Status | Compliant |
| Halogen Free | Yes |
SMA4F5.0AY Pin Configuration
| Pin 1 | Cathode — Connected to the positive rail or signal line |
| Pin 2 | Anode — Connected to ground |
Typical Applications
SMA4F5.0AY is suitable for 6 applications: Power Supply Protection, ESD Protection for I/O Ports, Automotive Electronics, Industrial Control Systems, Telecommunications Equipment, Consumer Electronics.
Power Supply Protection
The SMA4F5.0AY is used to protect power supply inputs from voltage transients. Its 5.0V standoff voltage makes it ideal for 5V rails, clamping overvoltages to safe levels. In a typical application, the TVS diode is placed across the input capacitor, with the cathode connected to the positive rail and anode to ground. This ensures that any transient above the breakdown voltage is shunted to ground, protecting downstream components. The device's 400W peak pulse power can handle moderate surges, and its fast response time (<1ns) ensures minimal voltage overshoot. For higher surge currents, a larger TVS or additional protection may be needed.
Recommended
ESD Protection for I/O Ports
The SMA4F5.0AY provides ESD protection for I/O ports in consumer electronics. Its low clamping voltage (9.2V) and fast response time (<1ns) ensure that ESD events are clamped before they can damage sensitive ICs. In a typical application, the TVS diode is placed near the connector, with the cathode connected to the signal line and anode to ground. This configuration is suitable for unidirectional signals. The device's capacitance (1200pF) may affect high-speed signals, so it is best suited for low-speed interfaces like UART, I2C, or GPIO. For high-speed lines, a lower-capacitance TVS is recommended.
Recommended
Automotive Electronics
In automotive applications, the SMA4F5.0AY protects electronic control units (ECUs) from load dump and other transients. Its wide operating temperature range (-55°C to +150°C) and 400W peak pulse power make it suitable for harsh automotive environments. The device is often placed on the power input of ECUs, clamping transients from the vehicle's 12V battery system. For 5V logic rails, the SMA4F5.0AY provides effective protection. However, for load dump transients, a higher-power TVS may be required. The SMAflat package's low profile is advantageous in space-constrained automotive modules.
Recommended
Industrial Control Systems
The SMA4F5.0AY is used in industrial control systems to protect PLCs, sensors, and actuators from voltage transients caused by inductive loads and switching. Its robust construction and wide temperature range ensure reliable operation in factory environments. In a typical application, the TVS diode is placed across the power supply terminals of a sensor or actuator, clamping any induced transients. The device's 400W peak pulse power can handle common industrial surges, but for severe environments, additional protection like MOVs may be needed. The SMAflat package allows for compact PCB designs in control panels.
Recommended
Telecommunications Equipment
In telecommunications, the SMA4F5.0AY protects line cards and communication interfaces from lightning-induced surges. Its fast response time and low clamping voltage are critical for maintaining signal integrity. The device is often placed on the line side of the interface, clamping transients before they reach the transceiver. For 5V logic interfaces, the SMA4F5.0AY provides adequate protection. However, for high-speed data lines, the device's capacitance may be too high, and a low-capacitance TVS should be considered. The SMAflat package is suitable for high-density telecom boards.
Recommended
Consumer Electronics
The SMA4F5.0AY is widely used in consumer electronics such as set-top boxes, gaming consoles, and smart home devices to protect power and signal lines from ESD and surges. Its low cost and small footprint make it ideal for high-volume production. In a typical application, the TVS diode is placed on the power input and I/O connectors. The device's 400W peak pulse power is sufficient for most consumer-level transients. The SMAflat package's low profile is beneficial for slim device designs. For USB ports, a low-capacitance TVS is recommended to avoid signal degradation.
Recommended
Recommended Products Summary
Engineering reference data for SMA4F5.0AY — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SMAJ5.0A (ST) | SMAJ5.0A (Littelfuse) | P4SMAJ5.0A | SMBJ5.0A |
|---|---|---|---|---|---|
| Package | SMAflat (SMA) | SMA (DO-214AC) | SMA (DO-214AC) | SMA (DO-214AC) | SMB (DO-214AA) |
| Brand | STMicroelectronics | STMicroelectronics | Littelfuse | Vishay | Littelfuse |
| Standoff Voltage | 5.0 V | 5.0 V | 5.0 V | 5.0 V | 5.0 V |
| Breakdown Voltage | 6.4-7.0 V | 6.4-7.0 V | 6.4-7.0 V | 6.4-7.0 V | 6.4-7.0 V |
| Clamping Voltage | 9.2 V | 9.2 V | 9.2 V | 9.2 V | 9.2 V |
| Peak Pulse Power | 400 W | 400 W | 400 W | 400 W | 600 W |
| Package Height | 1.0 mm | 2.0 mm | 2.0 mm | 2.0 mm | 2.3 mm |
| Capacitance | 1200 pF | 1200 pF | 1200 pF | 1200 pF | 1200 pF |
Key Differentiators
- Low-profile SMAflat package (vs SMAJ5.0A (ST))
- Same electrical performance as SMAJ5.0A (vs SMAJ5.0A (Littelfuse))
- Automotive-grade temperature range (vs P4SMAJ5.0A)
Design Notes
Place the SMA4F5.0AY as close as possible to the protected connector or IC to minimize parasitic inductance. Use a low-impedance ground connection, preferably with a dedicated ground plane, to ensure effective clamping. The trace from the TVS diode to the protected line should be short and wide to reduce voltage drop during transient events.
Although the SMA4F5.0AY can handle 400W peak pulse power, continuous power dissipation is limited. Ensure that the average power dissipation does not exceed the device's rating. For repetitive transients, consider the thermal impedance of the PCB and provide adequate copper area for heat sinking. The SMAflat package has a low thermal resistance, but proper layout is still essential.
Do not exceed the standoff voltage (5.0V) during normal operation, as this will cause the TVS diode to conduct and may lead to failure. Also, be aware of the device's capacitance (1200pF), which can degrade high-speed signals. For high-frequency applications, consider using a low-capacitance TVS diode. Always verify the polarity: the cathode must be connected to the positive rail, and the anode to ground for unidirectional protection.
Compliance Information
RoHS compliant and halogen-free per STMicroelectronics product page. Not AEC-Q100 qualified, but suitable for automotive applications based on temperature range.
