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.