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The L99H92 automotive gate driver

Containing two high-side and two low-side drivers, the L99H92 can control a single H bridge powering one bidirectional DC motor or two half bridges for two unidirectional motors. Typical applications for the highly integrated and easily configurable driver include an electric sunroof, window lift, powered trunk, sliding doors, and seat-belt pre-tensioners.

The charge pump powers the high-side drivers to maintain correct operation as the vehicle battery voltage fluctuates, enabling the outputs to function with a supply as low as 5.41V. The charge pump output is also available at an external pin to control a MOSFET for reverse-battery protection.

The gate-driving current is programmed through the SPI port, allowing slew-rate control to minimize electromagnetic emissions and thermal dissipation. Programming the current saves up to four external discrete components per MOSFET, typically needed for slew-rate setting with conventional drivers. The maximum drive current of 170mA gives designers flexibility to use the driver with a wide variety of external MOSFETs, including high-power devices with large gate capacitance.

With many features for system protection and diagnostics, the L99H92 is built for reliability and safety. There is overcurrent protection with a programmable threshold, detected by monitoring the MOSFET drain current. Also, cross-conduction protection with programmable dead time ensures safety and efficiency. Additional protection includes overtemperature early warning and shutdown, overvoltage and undervoltage protection on analog and digital power supply inputs, and open-load and output short-circuit detection in off-state diagnostic mode.

A fail-safe input can turn off all MOSFETs instantaneously and a dedicated diagnostic pin provides immediate fault warning without waiting for periodic SPI transfers.

Additionally, two current-sense amplifiers are integrated for system-status monitoring, helping minimize the bill of materials. Suitable for high-side, low-side, and inline sensing, the amplifiers have independently programmable gain, low offset, and low thermal drift. They can be independently disabled to reduce current consumption when unused.

The L99H92 is in production now and packaged as a TQFP32 or QFN32 with wettable flanks to facilitate inspection. Pricing starts from $1.7062 in the QFN32 package and $1.7246 in TQFP32 package, for orders of 1000 pieces.

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Automotive designs are increasingly employing brushless DC (BLDC) motors and electronic control units (ECU) for advanced driver assistance systems (ADAS). These require precision op amps for accurate analog signal conditioning. The chopper-stabilized low input offset voltage (VOS = 8µV) and almost-zero temperature drift (0.02µV/°C) of the AS333Q enable it to maintain high accuracy across the full common-mode input voltage range.

In addition, the device’s ability to handle beyond-the-rail-to-rail common-mode inputs allows the AS333Q to support both supply and ground-referenced inputs. The extremely low 1.1µV/√Hz low-frequency noise helps to improve signal-to-noise ratios (SNR), while a low quiescent current of 17μA (typical) means it can be used in equipment that must continue operating while a vehicle’s engine is off.

The AS333Q is qualified for AEC-Q100 Grade 1, manufactured in IATF 16949 certified facilities, and is PPAP capable. It is available in the SOT25 package at $0.82 in 1,000-piece quantities.

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