ECS-3951M/3953M-AU SMD Clock Oscillators ECS ECS-3951M/3953M-AU SMD Clock Oscillators are automotive grade miniature SMD oscillators. These oscillators operate at a standard temperature range from -55°C to 125°C. The ECS-3951M-AU SMD clock oscillators operate at 5V and ECS-3953M-AU operate at 3.3V respectively. These SMD oscillators are ideal for today's high temperature range applications.