Maxim Releases Small Current-Sense Amplifier

Maxim Integrated Products introduced the MAX9938, described as the industry’s smallest high-side, current-sense amplifier. Packaged in a 4-bump UCSP, this device is said to be 9x smaller than competitive SOT23 devices. Additionally, it is said to integrate precision resistors to minimize total solution size, eliminating the need for external gain-setting resistors.

The company’s proprietary BiCMOS process technology is said to enable this device to achieve the industry’s lowest quiescent-current consumption and highest accuracy. Designed to operate from a wide (1.6 to 28V) input-voltage range, the MAX9938 is suitable 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.

The MAX9938 is said to enable the industry’s smallest solution. Packaged in a tiny, 1 x 1 x 0.6mm, 4-bump UCSP, this IC is said to be 9x smaller than competitive SOT23 devices. Moreover, it is said to integrate 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.

The company claims that 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.

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