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Half-bridge driver IC fits car comfort systems

Posted: 23 Jul 2007 ?? ?Print Version ?Bookmark and Share

Keywords:half-bridge driver IC? Silicon-On-Insulator? ESD protection?

Atmel Corp. has introduced the low-cost ATA6836 hex half-bridge driver IC with a high-voltage capability of up to 40V, making the device suitable for passenger car and 24V truck applications.

ATA6836 is manufactured using Atmel's high-voltage 0.8?m BCD-on-SoI (Silicon-On-Insulator) technology, called SMARTIS. This manufacturing technology is said to enable the use of much smaller and lower-cost QFN packages, which reduces the cost of automotive comfort applications.

In contrast to standard BCDMOS bulk technology, Atmel's SMARTIS technology uses an SoI substrate. Due to the SoI technology's dielectric isolation, junction leakage, which is a major issue in high-temperature designs, is minimized, said Atmel. SOI devices are also said to provide superior latch-up immunity leading to increased circuit reliability.

The ATA6836 device is a fully protected hex half-bridge driver with integrated power stages. Each of the six high-side and low-side drivers is capable of driving currents up to 650mA via an MCU, such as Atmel's automotive-qualified MCU ATmega88. The half-bridge configuration eliminates the need for external clamping diodes.

One of the main applications of ATA6836 is the actuation of three fully independent DC motors in three H-bridges. ATA6836 also supports 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. This configuration can be used, for example, in automotive air conditioning systems, where five airflow control flaps can be operated from one ATA6836. 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. ATA6836 provides several protection features such as overtemperature warning and shutdown, overload, overvoltage protection and full protection against short circuits. The SPI output register contains a number of diagnostic bits, which can be read by the MCU.

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.

ATA6836 features 4kV ESD protection. 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.

Atmel said customers using the predecessor version, T6816, can easily switch to the SO28 package to accommodate new designs. For applications with more powerful DC motors, Atmel offers the high-power version ATA6838 with 1.5A output stages. All other features are identical to ATA6836.

Samples of the ATA6836 driver IC are available now in Pb-free QFN24 packages, measuring 5mm x 5 mm.

Pricing starts at $2 for the ATA6836 and $2.10 for the ATA6838 for 10,000-piece quantities each. An application board for development support is priced at $130.

- Gina Roos

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