Atmel's high-temperature driver ICs in BCD-on-SOI technology open door to 150 degrees celsius applications

Atmel Corporation has announced the availability of the new high-temperature hex half-bridge driver ICs ATA6837 and ATA6839. The ATA6837 and ATA6839 are manufactured using Atmel’s high-voltage 0.8 um BCD-on-SOI technology (SMART-I.S.), which enables the use of much smaller lower-cost QFN packages. These new devices can be used in both passenger car applications (e.g., flap control of air condition systems) as well as in 24V truck applications due to their high voltage capability (up to 40V). These devices also boast a broad range of protection features.

The ATA6837 is a fully protected hex half-bridge driver IC with integrated power stages. Each of the six high-side and low-side drivers is capable of driving currents up to 650 mA via a microcontroller such as Atmel's automotive-qualified AVR® microcontroller ATmega88. External clamping diodes are not needed due to the half-bridge configuration, thus assembly efforts are substantially reduced. The ATA6839, a high-power variant, differs only in the output stages (1.0A).
The new ICs have an operating chip temperature of 200 degrees Celsius and are able to dissipate approximately twice the power of conventional driver ICs, which can normally only work up to 150 degrees Celsius chip temperatures. As a result, low-cost assembly with “poor” thermal resistance can be used for convenience electronics, and in particular for high-temperature applications such as engine-mounted electronics to control small motors or valves. Furthermore, the ICs exhibit all the advantages of Atmel’s SMART-I.S.technology, including superior latch-up immunity and reduced junction leakage.

While one of the main applications of the new driver ICs is the actuation of three fully independent DC motors in three H-bridges, the ATA6837/39 can also support the operation of up to five DC motors sharing four common lines, as long as the motors are not all actuated at the same time. Such a configuration can be used, for example, in automotive air conditioning systems, where five air-flow control flaps can be operated from one IC. Software can be used to avoid the simultaneous actuation of the DC motors. In addition, the half-bridge configuration also enables the operation of six different resistive or inductive loads.

The ATA6837/39 provide several protection features such as overtemperature warning of 170 degrees Celsius and shutdown of 200 degrees Celsius, overload and overvoltage protection, and full protection against short-circuits. The SPI output register contains a number of diagnostic bits, which can be read by the microcontroller. In the event of undervoltage at the supply pin, the power-supply fail bit in the output register is set and all outputs are disabled. If the overtemperature pre-warning bit is set, software routines to decrease the power dissipation and temperature can be implemented. Temperature increases beyond a certain level can force the IC to shut down to prevent destruction.
The ATA6837/39 feature 4 kV ESD protection, which provides maximum safety against damage during assembly. The device also meets the strict automotive qualification demands (protection against conducted interference, EMC, and ESD protection) and can withstand transients as specified in ISO/TR 7637.

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