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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

Product Details

Key Features

Applications/Uses

Parametric specs for Current Sense Amplifiers
VSENSE_FS (mV) (recomm.) 5
25
VOS @25°C (µV) (max) 10
Output Format Current
CMVR (V) (min) -0.1
CMVR (V) (max) 5.5
VCC (V) (min) 2.5
VCC (V) (max) 3.6
ICC (µA) (typ) 120
Bi-Dir. Curr. Sense Yes
Gain 25 µA/mV
5 µA/mV
Gain Accuracy @25°C (%) (max) 0.25
Oper. Temp. (°C) -40 to +125
Package/Pins UMAX/8
Budgetary
Price (See Notes)
1.11
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Simplified Block Diagram

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Parameters

Parametric specs for Current Sense Amplifiers
VSENSE_FS (mV) (recomm.) 5
25
VOS @25°C (µV) (max) 10
Output Format Current
CMVR (V) (min) -0.1
CMVR (V) (max) 5.5
VCC (V) (min) 2.5
VCC (V) (max) 3.6
ICC (µA) (typ) 120
Bi-Dir. Curr. Sense Yes
Gain 25 µA/mV
5 µA/mV
Gain Accuracy @25°C (%) (max) 0.25
Oper. Temp. (°C) -40 to +125
Package/Pins UMAX/8
Budgetary
Price (See Notes)
1.11

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

Applications/Uses

  • MP3 Players
  • Notebook PCs and Ultra-Mobile PCs
  • PDAs and Smartphones
  • Portable Current Monitoring
  • Sensor Instrumentation Amplifiers

Description

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.

Simplified Block Diagram

MAX9934: Typical Operating Circuit MAX9934: Typical Operating Circuit Zoom icon

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .