ADC121S625
12-Bit, 50 ksps to 200 ksps, Differential Input, Micro
Power Sampling A/D Converter
General Description
The ADC121S625 is a 12-bit, 50 ksps to 200 ksps sampling
Analog-to-Digital (A/D) converter that features a fully differ-
ential, high impedance analog input and an external refer-
ence. While best performance is achieved with reference
voltage between 500mV and 2.5V, the reference voltage can
be varied from 100mV to 2.5V, with a corresponding resolu-
tion between 49µV and 1.22mV.
The output serial data is binary 2’s complement, and is
compatible with several standards, such as SPI™, QSPI™,
MICROWIRE™, and with many common DSP serial inter-
faces. The differential input, low power, automatic power
down, and small size make the ADC121S625 ideal for direct
connection to transducers in battery operated systems or
remote data acquisition applications.
Operating from a single +5V supply, the normal power con-
sumption is reduced to a few nanowatts in the power-down
mode. The ADC121S625 is a pin-compatible superior re-
placement for the ADS7817 and is available in the MSOP-8
package. Operation is guaranteed over the industrial tem-
perature range of −40˚C to +85˚C and clock rates of 800 kHz
to 3.2 MHz.
Features
n True Differential Inputs
n Guaranteed performance from 50ksps to 200ksps
n External Reference
n High AC Common-Mode Rejection
n SPI™/QSPI™/MICROWIRE™/DSP compatible Serial
Interface
Key Specifications
n Conversion Rate 50 to 200 ksps
n Offset Error 0.4 LSB (typ)
n Gain Error 0.05 LSB (typ)
n INL ± 1 LSB (max)
n DNL ± 0.75 LSB (max)
n CMRR 82 dB (typ)
n Power Consumption
— Active, 200ksps 2.25 mW (typ)
— Active, 50ksps 1.33 mW (typ)
— Power Down 60 nW (typ)
Applications
n Automotive Navigation
n Portable Systems
n Medical Instruments
n Instrumentation and Control Systems
n Motor Control
n Direct Sensor Interface
Connection Diagram
20132705
Ordering Information
Order Code Temperature Range Description Top Mark
ADC121S625CIMM −40˚C to +85˚C 8-Lead MSOP Package, 1000 Units Tape & Reel X0AC
ADC121S625CIMMX −40˚C to +85˚C 8-Lead MSOP Package, 3500 Units Tape & Reel X0AC
ADC121S625EVAL Evaluation Board
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.
May 2005
ADC121S625
12-Bit,
50
ksps
to
200
ksps,
Differential
Input,
Micro
Power
Sampling
A/D
Converter
© 2005 National Semiconductor Corporation DS201327 www.national.com