High-Precision, Low-Voltage, Current-Sense Amplifier with Current Output and Chip Select for Multiplexing

Chip Select Allows Users to Mux Multiple MAX9934s onto a Single ADC Input

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The MAX9934 high-precision, low-voltage, high-side current-sense amplifier is ideal for both bidirectional (charge/discharge) and unidirectional current measurements in battery-powered portable and laptop devices. Input offset voltage (VOS) is a low 10µV (max) at +25°C across the -0.1V to 5.5V input common-mode voltage range, and is independent of VCC. Its precision input specification allows the use of very small sense-voltages (typically ±10mV full-scale) for minimally invasive current sensing.

The output of the MAX9934 is a current proportional to input VSENSE and is available in either 25µA/mV or 5µA/mV gain options (GM) with gain accuracy better than 0.25% (max) at +25°C. A chip select (CS) allows multiplexing of several MAX9934 current outputs to a single microcontroller ADC channel (see the Typical Operating Circuit). CS is compatible with 1.8V and 3.3V logic systems.

The MAX9934 is designed to operate from a 2.5V to 3.6V VCC supply, and draws just 120µA (typ) quiescent current. When powered down (VCC = 0V), RS+ and RS- draw less than 0.1nA (typ) leakage current to reduce battery load. The MAX9934 is robust and protected from input faults of up to ±6V input differential voltage between RS+ and RS-.

The MAX9934 is specified for operation over the -40°C to +125°C temperature range and is available in 8-pin µMAX® or a 6-bump UCSP (1mm x 1.5mm x 0.6mm), making it ideal for space-sensitive applications.
MAX9934: Typical Operating Circuit MAX9934: Typical Operating Circuit Enlarge+

Key Features

  • Input Offset Voltage: 10µV (max)
  • Gain Error Less than 0.25%
  • -0.1V to +5.5V Input Common-Mode Voltage Range
  • Chip Select Allows Multiplexing Several MAX9934 Current Monitors to One ADC
  • Current Output Allows ROUT Selection for Gain Flexibility
  • Single Supply Operation: 2.5V to 3.6V
  • Two Gain Options: GM of 25µA/mV (MAX9934T) and 5µA/mV (MAX9934F)
  • Bidirectional or Unidirectional Operation
  • Small, 6-Bump UCSP (1mm x 1.5mm x 0.6mm) and 8-Pin µMAX Packages


  • MP3 Players
  • Notebook PCs and Ultra-Mobile PCs
  • PDAs and Smartphones
  • Portable Current Monitoring
  • Sensor Instrumentation Amplifiers
Part NumberOutput FormatCMVR
Bi-Dir. Curr. SenseVSENSE_FS
VOS @25°C
GainGain Accuracy @25°C
Oper. Temp.
minmaxminmaxtyprecomm.maxmax@ -3dBSee Notes
MAX9934 Current-
5 µA/mV
25 µA/mV
0-40 to +125
$1.06 @1k
See All Current Sense Amplifiers (48)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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