Current-Sense Amplifier offers reverse-battery protection.
Press Release Summary:
Using external resistors to set voltage gain, MAX9937 offers protection against accidental application of automotive battery voltage in reverse direction, as well as from inductive spikes and transients from -20 to +40 V. It features common-mode input range of 4-28 V, input offset voltage (VOS) of ±1.2 mV, and comes in 3 x 3 mm, 5-pin SC70 package that is lead- and halide-free, and RoHS-compliant. Applications include ECUs in power steering and antilock braking systems.
Original Press Release:
Tiny, Automotive-Grade Current-Sense Amplifier Has Reverse-Battery and Load-Dump Protection
o The MAX9937 is a high-side, current-sense amplifier for automotive applications that uses external resistors to set the voltage gain for maximum design flexibility.
o This amplifier provides protection against accidental application of the automotive battery voltage in the reverse (wrong) direction. It also features protection from inductive spikes and transients (load dump) from -20V to +40V.
o The MAX9937 features core-clamps and ESD components, along with in-circuit application components, to provide this high level of protection from major areas of concern in automotive applications.
o The MAX9937 is used in electronic control units (ECUs) to monitor current flowing inside the modules for power steering, 4-wheel drive selection, and antilock braking systems, even watching the fuse array to monitor problems.
SUNNYVALE, CA-November 13, 2008-Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX9937, a tiny, high-side current-sense amplifier that uses external resistors to set the voltage gain for maximum design flexibility. The MAX9937 protects against accidental application of battery voltage in the reverse (wrong) direction and against inductive kickback transients and spikes (load dump) of -20V to +40V. These safeguards are a major concern in automotive electronic control units (ECUs), which are used to monitor currents in the modules that control electronic power steering, 4-wheel drive, and antilock braking systems; it even watches the fuse box so as to monitor problems.
The MAX9937 input common-mode range is 4V to 28V and is independent of the VCC supply voltage, which can operate at 2.7V to 5.5V. When VCC is 5V, the supply current is a low 20µA. When VCC is 0V, the input bias current at the sense resistor is only 1µA to minimize battery drain when the ECU is off.
Voltage gain is set by the ratio of two external resistors to their accuracy. Input offset voltage (VOS) is a low ±1.2mV (max).
The MAX9937 is available in tiny, 3mm x 3mm, 5-pin SC70 package that is lead- and halide-free, thereby RoHS-compliant. This amplifier is fully specified over the -40°C to +125°C automotive temperature range. Prices start at $0.58 (1000-up, FOB USA).
Maxim Integrated Products is a publicly traded company that designs, manufactures, and sells over $2 billion of high-performance semiconductor products annually. It was founded over 25 years ago with the mission to deliver innovative analog and mixed-signal engineering solutions that add value to its customers' products. To date, Maxim has developed over 5900 products serving the industrial, communications, consumer, and computing markets. For more information, go to www.maxim-ic.com.
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