MAX4209:Ultra-Low Offset/Drift, Precision Instrumentation Amplifiers with REF Buffer

Instrumentation Amplifiers Use Autozero to Achieve 20µV (max) Offset

The MAX4208/MAX4209 ultra-low offset and drift instrumentation amplifiers feature exceptional precision specifications, low power consumption, rail-to-rail output, excellent gain-bandwidth product, and buffered REFIN/MODE input in a very small µMAX® package. These devices use a spread-spectrum, autozeroing technique that constantly measures and corrects the input offset, eliminating drift over time and temperature and the effect of 1/f noise. This technique achieves less than 20µV offset voltage, allows ground-sensing capability, provides ultra-low CMOS input bias current and increased common-mode rejection performance. The MAX4208/MAX4209 provide high-impedance inputs optimized for small-signal differential voltages (±100mV). All devices provide a gain-bandwidth product of 750kHz. The MAX4208 provides an adjustable gain with two external resistors or unity gain with FB connected to OUT. The MAX4209 is available with a fixed gain of 100V/V with ±0.03% (typ) accuracy. Both devices include a reference input (REF) to level-shift the output, allowing for bipolar signals in single-supply applications. In both devices, REFIN/MODE is an input to a precision unity-gain buffer, which sets the REF voltage to level-shift the output. The internal REF buffer allows the reference to be set by a simple resistive divider or an ADC reference without any loading error. The MAX4208/MAX4209 operate with a 2.85V to 5.5V single-supply voltage and consume only 750µA of quiescent current (when the internal buffer is off) and only 1.4µA in shutdown mode. These amplifiers also operate with ±2.5V dual supplies with REF connected to ground and REFIN/MODE to VSS. The MAX4208/MAX4209 are available in space-saving 8-pin µMAX packages and are specified over the automotive operating temperature range (-40°C to +125°C).

Key Features
  • Spread-Spectrum, Auto-Zero Instrumentation Amplifiers Improve DC Characteristics to Maximize Sensor Performance
    • Input Offset Voltage: ±20µV (max) at +25°C
    • ±0.25% (max) Gain Error
    • Low 0.2µV/°C Offset Voltage Drift
    • 1pA CMOS Input Bias Current
    • True Ground Sensing with Rail-to-Rail Output
    • 750kHz Gain-Bandwidth Product
  • Buffered REF Input for High Accuracy and Bipolar Operation
  • Low Power Operation Supports Remote Sensing and Battery-Powered Applications
    • 2.85V to 5.5V Single-Supply Operation (or ±1.425V to ±2.75V Dual Supplies)
    • 750µA Supply Current
    • 1.4µA Shutdown Mode
  • Adjustable (MAX4208) and Fixed Gain of 100 (MAX4209) Provide Design Flexibility
MAX4208, MAX4209: Application Circuit
MAX4208, MAX4209: Application Circuit
Applications/Uses
  • Battery-Powered Medical Equipment
  • Differential Voltage Amplification
  • Industrial Process Control
  • Notebook Computers
  • Precision Low-Side Current Sense
  • Strain-Gauge Amplifiers
DataSheet
titleDownload file
MAX4208-MAX4209 Data SheetMAX4208-MAX4209.pdf
Parametrics
Part NumberArchitectureAmps.VCMVRRail to RailAV
(V/V)
VSUPPLY (Total)
(V)
VSUPPLY (Total)
(V)
ICC per Amp.
(mA)
ICC per Amp.
(mA)
VOS
(µV)
CMRR @DC
(dB)
PSRR @DC
(dB)
Input IBIAS
(nA)
Unity Gain BW
(MHz)
Slew Rate
(V/µs)
VCMVR
(V)
en
(nV/√Hz)
Noise Spec'd @Low Pwr. ShutdnOper. Temp.
(°C)
Package/PinsBudgetary
Price
to Neg. Railminmaxtypmaxmaxtyptypmaxtyptyp<See Notes
MAX4208Indirect Current-Feedback1YesOutput OnlyAdj.2.855.50.751.3201351250.010.750.08VSS-0.1 to VDD-1.31401kHzYes-40 to +125µMAX/8$1.65 @1k
MAX420910
100
1000
µMAX/8$1.62 @1k
Design kits & evaluation modules
Quality and Environmental Data
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX4209HAUA+ActiveµMAX,;8 pin;15.6 mm²-40°C to +125°CLead Free
MAX4209HAUA+TActiveµMAX,;8 pin;15.6 mm²-40°C to +125°CLead Free
MAX4208-MAX4209.pdf MAX4209
Reduce the Chances of Human Error: Part 2, Super Amps and Filters for Analog Interface MAX5492
Introduction to Ventilators and Ventilation Rate Measurements MAX1162
Important Design Considerations for Heart-Rate and Fitness Monitors MAXQ622
Drive the REF Pin of New Generation Instrumentation and Current-Sense Amplifiers Without an Op Amp MAX4462
MAX4209.pdf MAX4209