How External Voltage Spikes Affect ATSHA204A-SSHDA-B and How to Prevent It

How External Voltage Spikes Affect ATSHA204A-SSHDA-B and How to Prevent It

How External Voltage Spikes Affect ATSHA204A-SSHDA-B and How to Prevent It

The ATSHA204A-SSHDA-B, an Advanced Cryptographic Secure Element from Microchip Technology, is designed to provide hardware-based security for embedded systems. It features a range of protective features but is still susceptible to certain external factors, such as voltage spikes. Let's break down how these spikes affect the device and provide detailed solutions on how to address and prevent such issues.

1. How External Voltage Spikes Affect ATSHA204A-SSHDA-B

Voltage spikes, also known as transients or surges, are sudden increases in voltage that last for a brief period of time. These spikes can originate from several sources such as nearby lightning strikes, switching Power supplies, or inductive load switching in the system.

Damage to Internal Circuits: The ATSHA204A-SSHDA-B operates within a specific voltage range, typically 2.7V to 5.5V. When exposed to external voltage spikes that exceed its tolerance, the internal circuits can be damaged, leading to malfunctions or even complete failure of the device. Memory Corruption: Voltage spikes can disrupt the internal memory or cryptographic operations of the chip, leading to unexpected behavior or incorrect security operations. This could potentially compromise the integrity of secure data stored or transmitted by the device. Reduced Lifespan: Repeated exposure to voltage spikes can wear down the internal components, shortening the lifespan of the ATSHA204A-SSHDA-B and causing intermittent failures or erratic behavior over time. 2. Causes of Voltage Spikes

Several external and internal factors can cause voltage spikes:

Power Supply Issues: Unstable power sources, particularly those with poor regulation or noisy outputs, can generate voltage spikes. If the voltage exceeds the rated tolerance of the ATSHA204A, damage can occur. Inductive Loads: Devices like motors, solenoids, or relays that use inductive components can generate high-voltage spikes when they are turned off. These spikes can easily affect nearby sensitive electronics like the ATSHA204A-SSHDA-B. Electrostatic Discharge (ESD): Electrostatic buildup in the environment, caused by friction or improper grounding, can discharge and affect sensitive components. Lightning Strikes: Nearby lightning strikes or sudden electrical surges in the power grid can create large spikes that exceed the voltage limits of many devices, including the ATSHA204A-SSHDA-B. 3. How to Prevent Voltage Spike Damage

To protect the ATSHA204A-SSHDA-B from voltage spikes, several strategies can be employed:

A. Use of Voltage Suppression Components

TVS (Transient Voltage Suppression) Diodes : TVS Diode s are designed to protect sensitive electronic circuits from voltage spikes. They are placed in parallel with the power supply to clamp the voltage when a spike occurs, diverting the excess energy away from the device.

Solution: Install a bidirectional TVS diode across the power supply lines (Vcc and GND) to absorb any voltage spikes. Choose a TVS diode with a clamping voltage slightly above the maximum operating voltage of the ATSHA204A-SSHDA-B (e.g., around 6V).

Zener Diodes: In situations where spikes are expected to be less severe, a Zener diode can also be used to clamp voltage above a certain threshold, protecting the chip from excess voltage.

B. Proper Power Supply Filtering

Decoupling capacitor s: Place capacitors close to the ATSHA204A-SSHDA-B power pins to filter out noise and smooth out voltage spikes. A combination of ceramic capacitors (0.1µF for high-frequency noise) and electrolytic capacitors (10µF or higher for low-frequency filtering) is recommended.

Low-pass filters : Use low-pass filters (LC filters or RC filters) to block high-frequency spikes from reaching the ATSHA204A-SSHDA-B.

C. Grounding and Shielding

Proper Grounding: Ensure that the system is properly grounded to prevent the buildup of static charges and reduce the potential for electrostatic discharge (ESD). Use a single-point ground for the ATSHA204A and other sensitive components to minimize the risk of voltage spikes.

Shielding: For environments prone to high electromagnetic interference ( EMI ), consider using shielding around the device to protect it from external electrical disturbances.

D. Using an Isolated Power Supply

If your system is prone to significant voltage spikes (e.g., industrial environments with motors or heavy machinery), consider using isolated power supplies. These supplies can prevent spikes from reaching the ATSHA204A-SSHDA-B by electrically isolating the device from the noisy power source.

E. Design Redundancies and Monitoring

Redundant Protection Circuits: Implement additional layers of protection, such as an extra TVS diode or a secondary filtering network, to ensure that if one protective component fails, another will take over.

Voltage Monitoring: Use a voltage supervisor circuit that monitors the input power voltage. If a spike occurs, the supervisor can disable the ATSHA204A or alert the system, allowing for protective measures to be taken.

4. How to Resolve Voltage Spike Issues

If you are encountering issues related to voltage spikes on the ATSHA204A-SSHDA-B, here are the steps you should take:

Assess the Situation: Check the power supply voltage and investigate any sources of noise or spikes in your environment. Use an oscilloscope to detect transient voltage spikes. Add Protection Components: If you haven't already, install TVS diodes, capacitors, or filters as outlined above. Test the System: After implementing protective measures, test the system to ensure the ATSHA204A-SSHDA-B is functioning properly. Monitor its operation for any signs of instability or failure. Check for Damage: If the device has already been exposed to excessive voltage spikes, you may need to replace it. In this case, inspect the circuit for visible signs of damage (e.g., burnt components, damaged traces) and replace any faulty parts. Conclusion

External voltage spikes can cause significant damage to the ATSHA204A-SSHDA-B, affecting its reliability and lifespan. By understanding the sources of voltage spikes and implementing preventive measures like TVS diodes, proper power supply filtering, and good grounding practices, you can protect your device and ensure the longevity of your system. If voltage spike damage has already occurred, replacing the affected components and reinforcing the protection strategy is key to restoring functionality.