ADC121S655 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – 12-Bit, 200 kSPS to 500 kSPS, Differential Input, Micro Power A/D Converter

May 2007
ADC121S655
12-Bit, 200 kSPS to 500 kSPS, Differential Input, Micro
Power A/D Converter
General Description
The ADC121S655 is a 12-bit, 200 kSPS to 500 kSPS sam-
pling Analog-to-Digital (A/D) converter that features a fully
differential, high impedance analog input and an external ref-
erence. The reference voltage can be varied from 1.0V to
V_A, with a corresponding resolution between 244µV and V_A
divided by 4096.
The output serial data is binary 2's complement and is com-
patible with several standards, such as SPI™, QSPI™, MI-
CROWIRE™, and many common DSP serial interfaces. The
differential input, low power consumption, and small size
make the ADC121S655 ideal for direct connection to trans-
ducers 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
MSOP-8 package. Operation is guaranteed over the indus-
trial temperature range of −40°C to +105°C and clock rates
of 3.2 MHz to 8 MHz.
Features
■ ^{True Differential Inputs}
■ ^{Guaranteed performance from 200 kSPS to 500 kSPS}
■ ^{External Reference}
■ ^{Wide Input Common-Mode Voltage Range}
■ ^{SPI™/QSPI™/MICROWIRE™/DSP compatible Serial}
Interface
Key Specifications
■ ^{Conversion Rate}
■ ^INL
■ ^DNL
■ ^{Offset Error}
■ ^{Gain Error}
■ ^SINAD
■ ^{Power Consumption at V}_A ^{= 5V}
■ — ^{Active, 500 kSPS}
— Active, 200 kSPS
— Power-Down
200 kSPS to 500 kSPS
± 0.95 LSB (max)
± 0.85 LSB (max)
± 3.0 LSB (max)
± 5.5 LSB (max)
70 dB (min)
9 mW (typ)
7 mW (typ)
1.5 µW (typ)
Applications
■ ^{Automotive Navigation}
■ ^{Portable Systems}
■ ^{Medical Instruments}
■ ^{Instrumentation and Control Systems}
■ ^{Motor Control}
■ ^{Direct Sensor Interface}
Pin-Compatible Alternatives by Speed
All devices are pin compatible.
Resolution
Specified for Sample Rate Range of:
50 to 200 ksps
200 to 500 ksps
500 ksps to 1 Msps
12-bit
ADC121S625
ADC121S655
ADC121S705
Connection Diagram
TRI-STATE® is a trademark of National Semiconductor Corporation.
MICROWIRE™ is a trademark of National Semiconductor Corporation.
QSPI™ and SPI™ are trademarks of Motorola, Inc.
© 2007 National Semiconductor Corporation 300105
30010505
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