1µA, 4-Bump UCSP/SOT23,
Precision Current-Sense Amplifier

General Description
The MAX9938 high-side current-sense amplifier offers
precision accuracy specifications of VOS less than
500μV (max) and gain error less than 0.5% (max).
Quiescent supply current is an ultra-low 1μA. The
MAX9938 fits in a tiny, 1mm x 1mm UCSP™ package
size or a 5-pin SOT23 package, making the part ideal for
applications in notebook computers, cell phones, PDAs,
and all battery-operated portable devices where accura-
cy, low quiescent current, and small size are critical.
The MAX9938 features an input common-mode voltage
range from 1.6V to 28V. These current-sense amplifiers
have a voltage output and are offered in four gain versions:
25V/V (MAX9938T), 50V/V (MAX9938F), 100V/V
(MAX9938H), and 200V/V (MAX9938W).
The four gain selections offer flexibility in the choice of
the external current-sense resistor. The very low 500μV
(max) input offset voltage allows small 25mV to 50mV
full-scale VSENSE voltage for very low voltage drop at
full-current measurement.
The MAX9938 is offered in tiny 4-bump, UCSP (1mm x
1mm x 0.6mm footprint), 5-pin SOT23, and 6-pin μDFN
(2mm x 2mm x 0.8mm) packages specified for operation
over the -40°C to +85°C extended temperature range.

Applications
Cell Phones
PDAs
Power Management Systems
Portable/Battery-Powered Systems
Notebook Computers

Features
 Ultra-Low Supply Current of 1µA (max)
 Low 500µV (max) Input Offset Voltage
 Low < 0.5% (max) Gain Error
 Input Common Mode: +1.6V to +28V
 Voltage Output
 Four Gain Versions Available
25V/V (MAX9938T)
50V/V (MAX9938F)
100V/V (MAX9938H)
200V/V (MAX9938W)
 Tiny 1mm x 1mm x 0.6mm, 4-Bump UCSP,
5-Pin SOT23, or 2mm x 2mm x 0.8mm, 6-Pin
µDFN Packages