Efficient 40-V Linear Voltage Regulators for Industrial and Automotive Applications

The LDH40 and LDQ40 are the latest additions to the lineup of low-dropout (LDO) voltage regulators designed for automotive applications. The LDH40 delivers up to 200 mA with an adjustable output voltage ranging from 1.2 V to 22 V. On the other hand, the LDQ40 regulators offer a maximum output current of 250 mA and come in a version with adjustable output voltage from 1.2 V to 12 V, as well as fixed output options of 1.8 V, 2.5 V, 3.3 V, and 5.0 V.

These LDO regulators are specifically engineered to provide efficient power conversion for energy-conscious applications. With a quiescent current as low as 2 µA at zero load and a logic-controlled shutdown mode drawing only 300 nA, these devices are ideal for always-on standby systems where preserving battery energy is crucial. Additionally, the regulators can be easily stabilized using a small ceramic capacitor on the output.

For automotive applications, the LDH40 and LDQ40 regulators are AEC-Q100 qualified and come in compact 2- x 2-mm DFN6L packages with wettable flanks that simplify PCB design and enable automated optical inspection. Their wide input-voltage range allows them to be connected to a vehicle's 12-V bus, which can experience transients of up to 40 V, making them suitable for powering infotainment systems, instrument clusters, and advanced driver-assistance systems (ADAS), particularly in electric vehicles.

These LDO regulators come equipped with various system protection and management features, including internal current limiting, thermal protection, soft-start functionality, and output active discharge. They also feature an enable pin for shutdown control and a power-good pin for diagnostic monitoring. The LDQ40 regulators further enhance safety with built-in short-circuit protection.

The LDH40 automotive-grade regulator is currently in production in the DFN6L wettable flank package, while the adjustable-output LDQ40 regulators, available in both industrial and automotive grades, are also in production in standard DFN6L and wettable-flank packages for automotive applications. The fixed-output LDQ40 regulators with 1.8 V, 2.5 V, 3.3 V, and 5.0 V options are expected to be available in the second quarter, while the industrial-grade LDQ40 regulators with 3.3 V and 5.0 V outputs are slated for release in the third quarter.

For more information on the new LDO voltage regulators for automotive applications, visit www.st.com/ldo-for-automotive.