Maxim : Current-sense amplifier minimizes total solution size

Maxim Integrated Products introduces the MAX9938, the industry’s smallest high-side, current-sense amplifier. Packaged in a 4-bump UCSP, this device is 9x smaller than competitive SOT23 devices. Additionally, it integrates precision resistors to minimize total solution size, eliminating the need for external gain-setting resistors. The Company’s proprietary BiCMOS process technology enables this device to achieve the industry’s lowest quiescent-current consumption and highest accuracy. Designed to operate from a wide (1.6V to 28V) input-voltage range, the MAX9938 is ideal for smartphones, digital cameras, PDAs, MP3 players, notebook computers, and other battery-operated devices in which small size, low quiescent current, and high accuracy are critical.

Portable devices require smaller, more precise current-sense amplifiers

Current-sense amplifiers are critical components in portable devices. These small integrated circuits (ICs) are typically used to measure battery charge and discharge currents. They also monitor supply rails that may need to be powered down to control heat and power dissipation. Consequently, high accuracy is paramount to ensuring reliability and extending battery life.

Providing very high input-offset and gain accuracy has proven difficult, especially in the ever-smaller form factors required by today’s portable applications. It is precisely in these performance areas that the MAX9938 excels.

Space-saving solution offers superior performance

The MAX9938 enables the industry’s smallest solution. Packaged in a tiny, 1mm x 1mm x 0.6mm, 4-bump UCSP, this IC is 9x smaller than competitive SOT23 devices. Moreover, it integrates precision resistors, thereby eliminating the two to three external gain-setting resistors required by competitive devices. In fact, the MAX9938 is so tiny that it is 12% smaller than a single resistor!

In addition to dramatic space savings, the MAX9938 achieves the industry’s highest accuracy. Competitive devices typically offer an input-offset voltage (VOS) of ±2mV to ±5mV and gain error of 2% to 5%, for a total error of 3% to 5%. In contrast, the MAX9938 features an ultra-low, ±0.5mV (max) VOS and 0.5% (max) gain error, for a total error of less than 1% (max). This high accuracy simplifies designs, eliminating the need to worry about worst-case error tolerances.

Additionally, the MAX9938’s low VOS allows the use of a lower full-scale VSENSE voltage and, therefore, smaller RSENSE resistor. The device thus minimizes voltage-drop loss in the line and power dissipation in the sense resistor, which otherwise could create a hot spot behind the LCD display of a notebook computer.

Lowest IQ device is the smartest choice for portable devices

The MAX9938 is specifically designed for power-sensitive applications. Whereas competitive devices typically consume 100µA to 500µA of quiescent current (IQ), this precision IC consumes an industry-low 1µA IQ.
Combining significant space savings with unmatched accuracy and current consumption, the MAX9938 is the ideal choice for space-constrained, battery-operated applications.

Summary of MAX9938 key features
– Ultra-low 1µA (max) supply current
– Low ±0.5mV (max) input-offset voltage
– Less than 0.5% (max) gain error
– Less than 1% (max) total error
– Tiny, 1mm x 1mm x 0.6mm, 4-bump UCSP or 5-pin SOT23 package

The MAX9938 is offered in three voltage-gain versions (25V/V, 50V/V, and 100V/V). It is available in 4-bump UCSP (1mm x 1mm x 0.6mm) and 5-pin SOT23 packages. All versions are fully specified for operation over the -40°C to +85°C extended temperature range. Prices start at $0.64 (1000-up, FOB USA).

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Note: The above text is the public part of the press release obtained from the manufacturer (with minor modifications). EETimes Europe cannot be held responsible for the claims and statements made by the manufacturer. The text is intended as a supplement to the new product presentations in EETimes Europe magazine.

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