AD7685 Datasheet

• 16-bit resolution with no missing codes
• Throughput: 250 kSPS
• INL: ±0.6 LSB typical, ±2 LSB maximum (±0.003% of FSR)
• SINAD: 93.5 dB @ 20 kHz
• THD: −110 dB @ 20 kHz
• Pseudo differential analog input range 0 V to V_REF with V_REF up to V_DD
• No pipeline delay
• Daisy-chain multiple ADCs, BUSY indicator
• Single-supply operation 2.3 V to 5.5 V with 1.8 V to 5 V logic interface
• Serial interface SPI^®-/QSPI^™-/MICROWIRE^™-/DSP-compatible
• Power dissipation:
  1.4 μW @ 2.5 V/100 SPS
  1.35 mW @ 2.5 V/100 kSPS, 4 mW @ 5 V/100 kSPS
• Standby current: 1 nA

• Battery-powered equipment
• Medical instruments
• Mobile communications
• Personal digital assistants (PDAs)
• Data acquisition
• Instrumentation
• Process controls

The AD7685 is a 16-bit, charge redistribution successive approximation, analog-to-digital converter (ADC) that operates from a single power supply, V_DD, between 2.3 V to 5.5 V. It contains a low power, high speed, 16-bit sampling ADC with no missing codes, an internal conversion clock, and a versatile serial interface port. The part also contains a low noise, wide bandwidth, short aperture delay, track-and-hold circuit. On the CNV rising edge, it samples an analog input IN+ between 0 V to REF with respect to a ground sense IN−. The reference voltage, REF, is applied externally and can be set up to the supply voltage.

Power dissipation scales linearly with throughput.

The SPI-compatible serial interface also features the ability, using the SDI input, to daisy chain several ADCs on a single 3-wire bus or provides an optional BUSY indicator. It is compatible with 1.8 V, 2.5 V, 3 V, or 5 V logic using the separate supply VIO.

The AD7685 is housed in a 10-lead MSOP or a 10-lead QFN (LFCSP) with operation specified from −40°C to +85°C.