ISO 16750-2: Electrical Load Conditions Testing for Automotive Electronic Components

ISO 16750-2 is primarily used in the automotive industry and applies to electrical and electronic components and systems intended for use in road vehicles, including:

• Electronic Control Units (ECUs)
• Sensors and actuators
• Lighting systems (including LED drivers and control modules)
• Infotainment and telematics systems
• EV and HV battery management systems
• Charging system components
• ADAS and safety-critical control modules
• Body electronics and comfort systems

ISO 16750-2 encompasses a comprehensive set of electrical tests. The following outlines the primary test categories:

• Voltage Supply Conditions: These tests assess component performance under normal and abnormal supply voltages, including:
  • Nominal voltage operation - verifying function at standard supply voltages (e.g., 13.5V for 12V systems, 27V for 24V systems)
  • Undervoltage conditions - simulating low battery states or voltage drop during high-current events
  • Overvoltage conditions - assessing performance when supply voltage exceeds normal limits due to charging system faults or load shedding
  • Start/stop voltage profiles - replicating the voltage dip experienced during cold cranking, which can drop to as low as 6V on a 12V system
  • These tests help reveal whether a component will brown out, reset, or malfunction during engine start events.
• Superimposed Alternating Voltage (Ripple): Vehicle alternators and DC/DC converters introduce AC ripple onto the DC supply. ISO 16750-2 defines superimposed ripple voltage tests that evaluate a component's immunity to this electrical noise. Failure to account for ripple can cause logic errors, communication faults, or premature component degradation.
• Transient Voltages: Transient events represent some of the most demanding electrical stresses in a vehicle environment. ISO 16750-2 defines several transient test pulses, which are closely aligned with ISO 7637-2. Key transients include:
  • Pulse 1 - Voltage drop caused by switching off inductive loads (e.g., ignition coils, solenoids)
  • Pulse 2a/2b - Positive transients from inductive load switching
  • Pulse 3a/3b - Switching transients superimposed on the supply line
  • Pulse 4 - Voltage drop during engine cranking
  • Pulse 5a/5b (Load Dump) - One of the most severe transients, occurring when a discharged battery is suddenly disconnected during alternator charging; this can generate voltage spikes of 35V or more on a 12V system
  • Load dump is a particularly important test for any component connected to the vehicle's main power supply, as unprotected components can be permanently damaged by even a single event.
• Long-Duration Overvoltage: This test evaluates a component's ability to withstand prolonged overvoltage conditions, for example, caused by a faulty voltage regulator. While transient tests measure response to brief spikes, long-duration overvoltage tests assess sustained stress tolerance, which can be a different failure mechanism entirely.
• Reverse Polarity: Reverse polarity tests simulate incorrect battery connection. Components must either withstand reverse polarity without damage, or the test results must inform protective circuit design. Failure here can result in immediate and irreversible component destruction.
• Open Circuit (Loss of Ground or Supply): These tests simulate intermittent or complete loss of ground reference or supply voltage. Components must handle these conditions without entering unsafe states or producing erroneous outputs.
• Reset Behavior: ISO 16750-2 addresses the behavior of components during and after power interruption. Components must demonstrate predictable, controlled reset behavior. Samples must return to a known, safe state without retaining erroneous data or entering undefined operating modes.
• Coupling and Decoupling Networks (CDN): For transient testing, the standard specifies the use of defined coupling and decoupling networks to ensure test reproducibility and isolation from test equipment. Proper CDN setup is critical to generating accurate, repeatable test conditions.

Components that have not been validated against these conditions carry significant risk of field failure, warranty exposure, and in safety-critical applications, potential recall liability.

For Tier 1 and Tier 2 suppliers, ISO 16750-2 test reports are frequently a prerequisite for OEM component approval. Without documented evidence of compliance, a supplier may be unable to achieve design approval or production validation sign-off resulting in delaying programs and affecting commercial relationships.