A8450: Automotive Multioutput Voltage Regulator

The A8450 is a multioutput power supply intended for automotive applications. The A8450 operates from a wide input supply range and is designed to satisfy the requirements of high ambient temperature environments.

Four regulated voltage outputs provide multiple options. The 3.3 V regulator and the 1.2 to 3.3 V adjustable regulator can be used to power microcontroller or DSP cores, or for I/O, sensing, and A-to-D conversion. Two 5 V outputs, one digital and the other analog, feature output tracking within 0.5% of each other over the operating temperature range. In addition, the analog regulator is protected against short-to-battery conditions. All four regulators feature foldback current limit protection.

The device can be enabled or disabled using two input pins. The high voltage input, on the ENBAT pin, allows enable/disable using an engine ignition or battery switch signal. The logic-level input, on the ENB pin, allows enable/disable by microcontroller or DSP signals.

When disabled, the A8450 draws less than 10 µA of current. A POR (power-on-reset) block monitors the supply voltages and provides a reset signal, with an adjustable delay, for microcontroller or DSP resets. A separate fault pin signals TSD (thermal shutdown), 5 V analog short-to-supply, and 5 V analog or digital undervoltage.

The A8450 is supplied in a 24-pin SOIC package (part number suffix LB) with fused power ground pins for enhanced thermal performance. This provides an RθJA of 35°C/W on a 4-layer board.

• 6 V to 45 V input range
• DC-to-DC buck converter with 5.7 V output
• Overcurrent protection with foldback, and undervoltage lockout
• Dual 5 V outputs
• Digital 5 V ±2%, 200 mA
• Analog 5 V, 200 mA
• Short-to-supply protection on analog regulator
• Analog to digital regulator output tracking < 0.5%, throughout operating temperature range
• 3.3 V linear regulator, with foldback current limit
• Adjustable 1.2 V to 3.3 V linear regulator, adjustable foldback
• Ignition switch enable; Sleep mode
• 100% duty cycle operation for low input voltages
• Power OK output
• -40°C to 135°C ambient operating temperature range