1FEATURES
23• True Simultaneous Sampling Differential
Inputs
• Specified Performance from 200 kSPS to 500
kSPS
• External Reference
• Wide Input Common-Mode Voltage Range
• Single High-Speed Serial Data Output
• Operating Temperature Range of −40°C to
+105°C
• SPI™/ QSPI™/MICROWIRE/DSP Compatible
Serial Interface

APPLICATIONS
• Motor Control
• Power Meters/Monitors
• Multi-Axis Positioning Systems
• Instrumentation and Control Systems
• Data Acquisition Systems
• Medical Instruments
• Direct Sensor Interface

KEY SPECIFICATIONS
• Conversion Rate: 200 kSPS to 500 kSPS
• INL: ±1 LSB (max)
• DNL: ±0.95 LSB (max)
• SNR: 71 dBc (min)
• THD: -72 dBc (min)
• ENOB: 11.25 bits (min)
• Power Consumption at 500 kSPS
– Converting, VA = 5V, VREF = 2.5V: 11 mW
(typ)
– Power-Down, VA = 5V, VREF = 2.5V: 3 μW
(typ)

DESCRIPTION
The ADC122S655 is a dual 12-bit, 200 kSPS to 500
kSPS simultaneous sampling Analog-to-Digital (A/D)
converter. The analog inputs on both channels are
sampled simultaneously to preserve their relative
phase information to each other. The converter is
based on a successive-approximation register
architecture where the differential nature of the
analog inputs is maintained from the internal track-
and-hold circuits throughout the A/D converter to
provide excellent common-mode signal rejection. The
ADC122S655 features an external reference that can
be varied from 1.0V to VA.
The ADC122S655's serial data output is binary 2's
complement and is compatible with several
standards, such as SPI, QSPI, MICROWIRE, and
many common DSP serial interfaces. The serial clock
(SCLK) and chip select bar (CS) are shared by both
channels.
Operating from a single 5V analog supply and a
reference voltage of 2.5V, the total power
consumption while operating at 500 kSPS is typically
11 mW. With the ADC122S655 operating in power-
down mode, the power consumption reduces to 3
μW. The differential input, low power consumption,
and small size make the ADC122S655 ideal for direct
connection to sensors in motor control applications.
Operation is specified over the industrial temperature
range of −40°C to +105°C and clock rates of 6.4 MHz
to 16 MHz. The ADC122S655 is available in a 10-
lead VSSOP package.