1FEATURES
23• True Differential Inputs
• Specified Performance from 200 kSPS to 500
kSPS
• External Reference
• Wide Input Common-Mode Voltage Range
• SPI™/ QSPI™/MICROWIRE/DSP Compatible
Serial Interface

APPLICATIONS
• Automotive Navigation
• Portable Systems
• Medical Instruments
• Instrumentation and Control Systems
• Motor Control
• Direct Sensor Interface

KEY SPECIFICATIONS
• Conversion Rate: 200 kSPS to 500 kSPS
• INL: ± 0.95 LSB (max)
• DNL: ± 0.85 LSB (max)
• Offset Error: ± 3.0 LSB (max)
• Gain Error: ± 5.5 LSB (max)
• SINAD: 70 dB (min)
• Power Consumption at VA = 5 V
– Active, 500 kSPS: 9 mW (typ)
– Active, 200 kSPS: 7 mW (typ)
– Power-Down: 1.5 μW (typ)

DESCRIPTION
The ADC121S655 is a 12-bit, 200 kSPS to 500 kSPS
sampling Analog-to-Digital (A/D) converter that
features a fully differential, high impedance analog
input and an external reference. The reference
voltage can be varied from 1.0V to VA, with a
corresponding resolution between 244μV and VA
divided by 4096.
The output serial data is binary 2's complement and
is compatible with several standards, such as SPI,
QSPI, MICROWIRE, and many common DSP serial
interfaces. The differential input, low power
consumption, and small size make the ADC121S655
ideal for direct connection to transducers in battery
operated systems or remote data acquisition
applications.
Operating from a single 5V supply, the supply current when operating at 500 kSPS is typically 1.8 mA. The
supply current drops down to 0.3 μA typically when
the ADC121S655 enters power-down mode. The
ADC121S655 is available in the VSSOP-8 package.
Operation is specified over the industrial temperature
range of −40°C to +105°C and clock rates of 3.2 MHz
to 8 MHz.