AD5940BCBZ-RL7

Part: AD5940/AD5941 (including AD5941W) — Analog Devices

Type: High Precision Impedance and Electrochemical Analog Front End

Description: High precision impedance and electrochemical front end with a 16-bit ADC (800 kSPS and 1.6 MSPS options), 12-bit high speed DAC, low power potentiostat and TIA, and a 2.8–3.6 V supply.

Operating Conditions:

• Supply voltage: 2.8–3.6 V
• Operating temperature: -40 to +85 °C (AD5940/AD5941); -40 to +105 °C (AD5941W)
• High speed TIA input bandwidth: 0.015 Hz to 200 kHz
• Active high power mode above 80 kHz; active low power mode below 80 kHz

Absolute Maximum Ratings:

• Max supply voltage: AVDD, DVDD and IOVDD each -0.3 V to +3.9 V
• Max total GPIOx pin current: 30 mA positive, -30 mA negative
• Max junction temperature: 150 °C
• Storage temperature: -65 to +150 °C
• ESD: HBM 4 kV, FICDM 750 V, MM 100 V

Key Specs:

• ADC resolution: 16 bits
• ADC data rate: 400 kSPS (high speed mode), 200 kSPS (normal mode), decimation factor = 4
• INL (normal mode, PGA gain = 1.5): ±2.0 LSB typ, -4 to +4 LSB
• DNL (normal mode, PGA gain = 1.5): ±0.9 LSB typ, -0.99 to +2.5 LSB, no missing codes
• Offset error (low power mode, PGA gain = 1.5): ±200 μV typ, ±600 μV max
• Offset drift over temperature: ±3 μV/°C typ (1.82 V internal reference)
• Full-scale error (PGA gain = 1.5, excluding internal channels and AIN3): ±400 μV typ
• Potentiostat channel current: 6.5 μA with all other blocks in hibernate mode
• Low power TIA range: 50 pA to 3 mA
• Internal references: 2.5 V and 1.82 V

Features:

• 16-bit ADC with voltage, current and impedance measurement capability
• Ultralow leakage switch matrix, input buffers and programmable gain amplifier
• Dual output voltage DAC (0.2 V to 2.4 V range) with 12-bit VBIAS0 and 6-bit VZERO0 outputs
• 12-bit high speed DAC with ±607 mV output range and PGA gain settings of 2 and 0.05
• Low noise potentiostat amplifier, low power TIA, and high speed TIA
• Digital waveform generator for sinusoid and trapezoid waveforms
• Complex impedance (DFT) engine and receive filters
• Programmable AFE sequencer with 6 kB SRAM
• Hibernate mode keeps the low power DAC and potentiostat amplifier powered to maintain sensor bias
• SPI interface, wake-up timer, interrupt controller, power-on reset
• 1.82 V input/output compliant
• AEC-Q100 qualified

Applications:

• Electrochemical measurements and gas sensors
• Potentiostat, amperometry, voltammetry and cyclic voltammetry
• Bioimpedance (skin and body impedance)
• Continuous glucose monitoring
• Battery impedance

Package:

• AD5940: 3.6 mm × 4.2 mm, 56-ball WLCSP
• AD5941: 7 mm × 7 mm, 48-lead LFCSP

• Analog input
• 16-bit ADC with both 800 kSPS and 1.6 MSPS options
• Voltage, current, and impedance measurement capability
• Internal and external current and voltage channels
• Ultralow leakage switch matrix and input mux
• Input buffers and programmable gain amplifier
• Voltage DACs
• Dual output voltage DAC with an output range of 0.2 V to 2.4 V
• 12-bit V BIAS0 output to bias potentiostat
• 6-bit V ZERO0 output to bias TIA
• Ultra low power: 1 μA
• 1 high speed, 12-bit DAC
• Output range from high-speed DAC (HSDAC): ±607 mV
• Programmable gain amplifier on HSDAC output with gain settings of 2 and 0.05
• Amplifiers, accelerators, and references
• 1 low power, low noise potentiostat amplifier suitable for potentiostat bias in electrochemical sensing
• 1 low noise, low power TIA, suitable for measuring sensor current output
• 50 pA to 3 mA range
• Programmable load and gain resistors for sensor output
• Analog hardware accelerators
• Digital waveform generator
• Receive filters
• Complex impedance measurement (DFT) engine
• 1 high speed TIA to handle wide bandwidth input signals from 0.015 Hz up to 200 kHz
• Digital waveform generator for generation of sinusoid and trapezoid waveforms
• 2.5 V and 1.82 V internal reference voltage sources
• System level power savings
• Fast power-up and power-down analog blocks for duty cycling
• Programmable AFE sequencer to minimize workload of host controller
• 6 kB SRAM to preprogram AFE sequences
• Ultra low power potentiostat channel: 6.5 μA of current consumption when powered on and all other blocks in hibernate mode
• Smart sensor synchronization and data collection
• Cycle accurate control of sensor measurement
• Sequencer controlled GPIOs

• Electrochemical measurements
• Electrochemical gas sensor measurements
• Potentiostat/amperometric/voltammetry/cyclic voltammetry
• Bioimpedance applications
• Skin impedance
• Body impedance
• Continuous glucose monitoring
• Battery impedance

Figure 4. AD5940 Pin Configuration

Figure 5. AD5941 Pin Configuration

Table 7. Pin Function Descriptions

Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability.

Thermal performance is directly linked to printed circuit board (PCB) design and operating environment. Close attention to PCB thermal design is required.

θ JA is the natural convection junction to ambient thermal resistance measured in a one cubic foot sealed enclosure.

θ JC is the junction to case thermal resistance.