AD7689BCPZRL7

The AD7682/AD7689 are 4/8-channel, 16-bit, charge redistribution successive approximation register (SAR) ADCs operating from a single VDD supply. The AD7682/AD7689 contain all the components needed for a multichannel, low power data acquisition system, including: a true 16-bit, no missing codes SAR ADC; a 4-channel (AD7682) or 8-channel (AD7689) low crosstalk multiplexer for configuring inputs as single-ended (with or without reference ground), differential, or bipolar; an internal low drift voltage reference (selectable at 2.5V or 4.096V) and buffer; a temperature sensor; an optional single-pole filter; and a sequencer that is especially useful when multiple channels are sampled sequentially. The AD7682/AD7689 use a simple SPI interface for writing to the configuration register and retrieving conversion results. The SPI interface operates from a separate supply (VIO), which is set to the host logic level. Power consumption is proportional to throughput rate. The AD7682/AD7689 are available in a compact 20-lead LFCSP package and are rated for operation over the −40°C to +85°C temperature range.

Applications

• Multi-channel system monitoring
• Battery-powered devices
• Medical instruments: ECG/EKG
• Mobile communications: GPS
• Power line monitoring
• Data acquisition
• Seismic data acquisition systems
• Instrumentation
• Process control

Key features

• 16-bit resolution, no missing codes
• 4-channel (AD7682) / 8-channel (AD7689) multiplexer with selectable inputs: unipolar single-ended, differential (with reference GND), pseudo-bipolar
• Throughput rate: 250 kSPS
• INL: typical ±0.4 LSB, maximum ±1.5 LSB (±23 ppm of FSR)
• Dynamic range: 93.8 dB
• SINAD: 92.5 dB (20 kHz)
• THD: −100 dB (20 kHz)
• Analog input range: 0 V to VREF, VREF up to VDD
• Multiple reference options: internal selectable 2.5 V or 4.096 V reference; external buffered reference (up to 4.096 V); external reference (up to VDD)
• Internal temperature sensor (TEMP)
• Channel sequencer, selectable 1-pole filter, busy indicator
• No pipeline delay, SAR architecture
• Single-supply operation: 2.3 V to 5.5 V; logic interface voltage: 1.8 V to 5.5 V
• Serial interface compatible with SPI, MICROWIRE, QSPI, and DSP
• Power consumption: 3.5 mW (2.5 V / 200 kSPS), 12.5 mW (5 V / 250 kSPS)
• Standby current: 50 nA
• Cost-reduced grade available
• 20-lead 4 mm × 4 mm LFCSP package