The AD7989-1/AD7989-5 are 18-bit, successive approximation, analog-to-digital converters (ADCs) that operate from a single power supply, VDD. The AD7989-1/AD7989-5 contain a low power, high speed, 18-bit sampling ADC and a versatile serial interface port. On the CNV rising edge, the AD7989-1/AD7989-5 sample the voltage difference between the IN+ and IN− pins. The voltages on these pins typically swing in opposite phases between 0 V and VREF. The reference voltage, VREF, is applied externally and can be set independent of the supply voltage, VDD. Its power scales linearly with throughput.
The AD7989-1/AD7989-5 are serial peripheral interface (SPI)- compatible, which features the ability, using the SDI/CS input, to daisy-chain several ADCs on a single 3-wire bus. The AD7989-1/AD7989-5 are compatible with 1.8 V, 2.5 V, 3 V, and 5 V logic, using the separate VIO supply.
The AD7989-1/AD7989-5 are available in a 10-lead MSOP or a 10-lead LFCSP with operation specified from −40°C to +85°C.
**Applications**
Battery-powered equipment
Data acquisition systems
Medical instruments
Seismic data acquisition systems
### Features and Benefits
Low power dissipation
2 mW at 500 kSPS typical (VDD only)
3.5 mW at 500 kSPS typical (total)
18-bit resolution with no missing codes
Throughput: 500 kSPS
INL: ±1 LSB typical, 2 LSB maximum
SNR: 98 dB at 1 kHz, VREF = 5 V typical
SINAD: 97 dB at 1 kHz typical
THD: −120 dB at 10 kHz typical
Dynamic range: 99 dB at VREF = 5 V typical
True differential analog input voltage range: ±VREF
0 V to VREF with VREF between 2.4 V and 5.1 V
No pipeline delay
Single-supply 2.5 V operation with 1.8 V, 2.5 V, 3 V, and 5 V logic interface
Proprietary serial interface SPI-/QSPI™-/MICROWIRE™-/DSP-compatible
