Windowed Watchdog IC draws 35 µA quiescent current.
Press Release Summary:
Manufactured in 8-pin SO8 package, EM6151 integrated microprocessor voltage supervisory IC has programmable reset threshold voltages and watchdog timer with programmable time window and system enable output. Different versions are offered for different ratios of opened/closed window of watchdog and power saving function compatible with CAN-bus sleep mode. Along with open drain reset output, product features -40 to +125°C temperature range.
Original Press Release:
EM Microelectronic Announces Low-Quiescent Current, Windowed Watchdog IC with Enhanced System Security
EM6151 also offers robustness against ESD and latch-up, operating up to 125°C
COLORADO SPRINGS, Colorado - September 6, 2005 - EM Microelectronic, an electronic systems company of the Swatch Group, introduces the EM6151, a highly-integrated microprocessor voltage supervisory IC with programmable reset threshold voltages and a watchdog timer with programmable time window and system enable output. For maximum flexibility, this circuit is available in several versions, allowing for different ratios of the opened/closed window of the watchdog and power saving function compatible with CAN-bus sleep mode. The EM6151 features an open drain reset output, comes in a compact 8-pin SO8 package and operates over the temperature range from -40 to +125 °C, making it compatible with the demanding temperature extremes in automotive and industrial environments. A low power product, EM6151 draws only 35uA quiescent current.
Surveillance functions for mission-safe applications
EM6151 features an increased confidence ENABLE output. This ENABLE output can be used to drive critical control functions or to gate motor signals; for instance, it can immediately stop the motor movement when the processor behavior can not be trusted and only allow it again when there is confidence that the processor is running properly. This signal is only asserted after the software has successfully cleared the watchdog three times.
This combined effect of supply voltage surveillance, watchdog timing surveillance and system enable output provides extreme reliability and security in critical microprocessor-controlled automotive, transportation, robotic and industrial control applications. This also eliminates the need for redundant microprocessors that supervise each other. In automotive applications, EM6151 is used to monitor the microprocessors that control electronic cockpit security and the steering column as well as other functions such as trunk closure systems, electrical spoiler control, and electrical seat, dashboard, sunroof, rear-view mirror and window controls. Industrial applications include automated teller machines (ATMs), robotics and process control equipment.
A more robust watchdog
Watchdog functions are used to ensure that system microprocessors or controllers do not operate erroneously as a result of the power supply voltage being out of specified operating range, which is especially critical during system power-up and power-down sequencing. The EM6151 features a time-windowed watchdog function that recognizes far more faults than the standard watchdogs used with microprocessors. Standard watchdogs, whether internal to the CPU or external, are dependent on the CPU hardware and software to generate a counter reset signal and therefore will not reliably prevent hardware and software errors. In contrast, the EM6151 windowed watchdog ensure that the timer clear signal occurs within the correct time window ("opened" window); otherwise it activates a system reset or other error handling. This is the most robust and reliable type of watchdog action, because it effectively covers hardware errors as well as software errors such as code executing too slowly or too quickly. Indeed, code execution may be too quick when a slave MCU conflicts with its master or when the crystal oscillator malfunctions. Such errors and malfunctions are caught by a windowed watchdog but not by a standard watchdog, thus offering increased security.
Programmability
In the EM6151, timings of the watchdog function are programmable using one external resistor to set the power-on reset delay and the watchdog time. The ratio for the close/open watchdog window is factory programmable. In addition, the reset threshold voltage is also programmable using an external two-resistor voltage divider.
Version 53 (V53) comes with a large opened watchdog window (67%), making it easier for the software programmer to issue a pulse to service the watchdog.
Version 50 (V50) has a smaller opened watchdog window (33%), offering increased security in the application.
Version 55 (V55) offers a Controller Area Network bus (CAN-bus) sleep mode detector. In a typical automotive or industrial application, a central processor can issue a general "sleep" instruction to all EM6151V55-equipped peripheral modules. In sleep mode, the EM6151V55 will greatly reduce the rate that they generate reset signals. This greatly reduces power drain when the system is off and extends battery life, which is a tremendous benefit for vehicles and equipment that is garaged or off-line for periods of days or weeks at a time.
EM6151 is a member of a family of products targeted for mission safe applications. EM6152 has the same functions as EM6151 but features a 5V automotive voltage regulator guaranteeing 400mA in output.
Availability
The EM6151 windowed watchdog IC is available in SO8 package from EM Microelectronic and its authorized distributors. More information about these circuits is available at www.emmicroelectronic.com/Line.asp?IdLine=1 .
About EM Microelectronic
EM Microelectronic is a semiconductor manufacturer that designs and produces ultra-low-power, low-voltage, digital, analog and mixed-signal integrated circuits for battery-operated and field-powered devices in consumer, automotive and industrial applications. The company's product portfolio includes RFID circuits, ultra-low-power microcontrollers, voltage reset IC and microcontroller supervisory IC supervisor, watchdog, regulator, smart card ICs, LCD drivers and displays, sensor and optoelectronic ICs, mixed analog and digital gate arrays and application-specific integrated circuits. EM also produces LCD modules and offers bumping services.
EM Microelectronic is one the electronic systems companies within the Swatch Group, producing and assembling ultra-low power, miniaturized and accurate microelectronic components and systems. Additional company and product information is available at www.emmicroelectronic.com.
Datasheet is available for download at: www.emmicroelectronic.com/webfiles/Product/Supervisory/EM6151_DS.pdf
Please send business inquiries to:
Marketing Communications Department, EM Microelectronic-US, 5475 Mark Dabling Blvd. Suite 200, Colorado Springs, CO 80918, or info@emmicroelectronic.com.
