ADC122S706 Datasheet, PDF (1/24 Pages) National Semiconductor (TI) – Dual 12-Bit, 500 kSPS to 1 MSPS, Simultaneous Sampling A/D Converter

November 16, 2007
ADC122S706
Dual 12-Bit, 500 kSPS to 1 MSPS, Simultaneous Sampling
A/D Converter
General Description
The ADC122S706 is a dual 12-bit, 500 kSPS to 1 MSPS si-
multaneous 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 ADC122S706 features an external
reference that can be varied from 1.0V to V_A.
The ADC122S706 offers dual high-speed serial data outputs
that are binary 2's complement and are compatible with sev-
eral standards, such as SPI™, QSPI™, MICROWIRE™, and
many common DSP serial interfaces. Channel A's conversion
result is outputted on D_OUTA while Channel B's conversion re-
sult is outputted on D_OUTB. This feature makes the AD-
C122S706 an excellent replacement for systems using two
distinct ADCs in a simultaneous sampling application. The
serial clock (SCLK) and chip select bar (CS) are shared by
both channels. For lower power consumption, a single serial
data output mode is externally selectable.
The ADC122S706 may be operated with independent analog
(V_A) and digital (V_D) supplies. V_A can range from 4.5V to 5.5V
and V_D can range from 2.7V to V_A. With the ADC122S706
operating with a V_A of 5V and a V_D of 3V, the power con-
sumption at 1 MSPS is typically 25 mW. Operating in power-
down mode, the power consumption of the ADC122S706
decreases to 3 µW. The differential input, low power con-
sumption, and small size make the ADC122S706 ideal for
direct connection to sensors in motor control applications.
Operation is guaranteed over the industrial temperature
range of −40°C to +105°C and clock rates of 8 MHz to 16 MHz.
The ADC122S706 is available in a 14-lead TSSOP package.
Features
■ ^{True Simultaneous Sampling Differential Inputs}
■ ^{Guaranteed performance from 500 kSPS to 1 MSPS}
■ ^{External Reference}
■ ^{Wide Input Common-Mode Voltage Range}
■ ^{Single or Dual High-Speed Serial Data Outputs}
■ ^{Operating Temperature Range of −40°C to +105°C}
■ ^{SPI™/QSPI™/MICROWIRE™/DSP compatible Serial}
Interface
Key Specifications
■ ^{Conversion Rate}
500 kSPS to 1 MSPS
■ ^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 1 MSPS}
■—
—
—
Converting, V_A = 5V, V_D = 3V
Converting, V_A = 5V, V_D = 5V
Power-Down
20 mW (typ)
25 mW (typ)
3 µW (typ)
Applications
■ ^{Motor Control}
■ ^{Power Meters/Monitors}
■ ^{Multi-Axis Positioning Systems}
■ ^{Instrumentation and Control Systems}
■ ^{Data Acquisition Systems}
■ ^{Medical Instruments}
■ ^{Direct Sensor Interface}
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 300171
30017105
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