06 Oct 2005 | Geneva

STMicroelectronics Delivers Dual/Triple Microprocessor Supervisor Family with Innovative Manual Reset Delay Option

Geneva / 06 Oct 2005

– STMicroelectronics (NYSE: STM) , one of the world’s leading semiconductor suppliers and the second largest supplier of analog ICs*, has introduced a family of dual/triple microprocessor supervisor circuits that offers a wide range of voltage combinations, a compact 5/6-pin SOT23 package, and a new manufacturing flow that ensures short lead times. Several devices in the family also incorporate a Manual Reset Delay function. This new feature, which helps protect equipment such as set-top boxes against inadvertent resets, has been specifically included at the request of leading set-top box manufacturers.

Besides set-top boxes, the new STM6717/18/19/20 and STM6777/78/79/80 supervisors are aimed at applications such portable battery-powered systems, networking, and communication systems, where the processor core (microprocessor, DSP, or ASIC) typically requires a 1.8V or lower voltage supply and the on-chip peripherals typically require a 3V or 3.3V supply. Such systems typically need to simultaneously monitor at least two power rails and many require monitoring an additional third rail.

The STM67xx family initially comprises eight generic devices, all of which monitor the system supply (VCC1) against a fixed threshold value and provide an active-low reset output when they detect an out-of-tolerance condition. The supervisors integrate a reset function that is guaranteed to be asserted for VCC down to 0.8V, with a minimum duration of 140ms. Four of the devices have open drain outputs while the other four have push-pull outputs. Six of the eight devices (STM6717/18/19/20 and STM6777/78) also monitor a second supply input (VCC2) against a second, fixed threshold value and generate a reset if either of the two monitored VCC rails goes out of tolerance. The threshold voltages for these two monitored rails are factory-set and customer-selectable. Currently, ST offers some 23 combinations of VCC1 and VCC2 thresholds, with many more possible. Reset thresholds for VCC1 range from 4.625V down to 1.575V (nominal), while thresholds for VCC2 range from 3.075V down to 0.788V (nominal), allowing the customer to select all popular combinations of power supply rails.

In addition, the STM6719/20 and STM6779/80 include an adjustable input which is compared to a 0.625V internal reference. Using an external resistor divider, these devices can monitor an additional supply rail and they will generate a reset signal if any of the fixed or adjustable rails goes out of tolerance. With two fixed inputs and one adjustable one, the STM6719/20 can monitor three supply rails.

All eight devices include an active-low Manual Reset input for push-button reset use. The STM6717/18/19/20 family provides drop-in replacements for the MAX6717/18/19/20 supervisors but offer lower power consumption; the supply current for the STM67xx devices is typically 11µA, compared with 14µA for the competitive products at the same supply voltage. In addition, four of the family (STM6777/78/79/80) include a Manual Reset Delay function whereby the assertion of the reset can be delayed, using an external capacitor, by up to 10 seconds. If the input is not held true for the entire period of the delay, the output is not asserted, thus avoiding inadvertent resets.

Another key benefit of the new family is that all the devices are manufactured using a production flow that ensures short lead times through the optimized use of laser trimming to customize the devices at a late stage in the fabrication process: after a full electrical test of the generic dice, laser trimming is used both to blow fusible links that convert the generic device into the specific part and to trim the analog circuitry. After the laser stage, a final test is performed on the specific device. This production flow allows a large number of different devices to be obtained from a single mask set in a cost-effective and flexible manner.

The STM67xx dual/triple supervisors augment ST’s rich portfolio of supervisory and security products, which includes a comprehensive range of serial Real Time Clocks and the recently introduced STM140x series, the world’s first security supervisors to integrate all the functions by the major international security standards for detecting physical and environmental intrusion attempts.

All of the new STM67xx devices are now available for production starting at $0.40 in volume.

Further information on ST’s range of microprocessor supervisors and reset ICs, is available at www.st.com/supervisor


About STMicroelectronics
STMicroelectronics is a global leader in developing and delivering semiconductor solutions across the spectrum of microelectronics applications. An unrivalled combination of silicon and system expertise, manufacturing strength, Intellectual Property (IP) portfolio and strategic partners positions the Company at the forefront of System-on-Chip (SoC) technology and its products play a key role in enabling today's convergence markets. The Company's shares are traded on the New York Stock Exchange, on Euronext Paris and on the Milan Stock Exchange. In 2004, the Company's net revenues were $8.76 billion and net earnings were $601 million. Further information on ST can be found at www.st.com.

* iSuppli “2004 Annual Semiconductor Market Share”, May 2005

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