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GENERAL DESCRIPTION

The AD7440/AD7450A1 are 10-bit and 12-bit high speed, low

power, successive approximation (SAR) analog-to-digital

converters with a fully differential analog input. These parts

operate from a single 3 V or 5 V power supply and use

advanced design techniques to achieve very low power

dissipation at throughput rates up to 1 MSPS. The SAR

architecture of these parts ensures that there are no pipeline

delays.

The parts contain a low noise, wide bandwidth, differential

track-and-hold amplifier (T/H) that can handle input

frequencies up to 3.5 MHz. The reference voltage is applied

externally to the VREF pin and can be varied from 100 mV to

3.5 V depending on the power supply and what suits the

application. The value of the reference voltage determines the

common-mode voltage range of the part. With this truly

differential input structure and variable reference input, the

user can select a variety of input ranges and bias points.

The conversion process and data acquisition are controlled

using CS and the serial clock, allowing the device to interface

with microprocessors or DSPs. The input signals are sampled

on the falling edge of CS; the conversion is also initiated at this

point. The SAR architecture of these parts ensures that there are

no pipeline delays. The AD7440 and the AD7450A use advanced

design techniques to achieve very low power dissipation at high

throughput rates.

FEATURES

Fast throughput rate: 1 MSPS

Specified for VDD of 3 V and 5 V

Low power at max throughput rate

4 mW max at 1 MSPS with 3 V supplies

9.25 mW max at 1 MSPS with 5 V supplies

Fully differential analog input

Wide input bandwidth

70 dB SINAD at 100 kHz input frequency

Flexible power/serial clock speed management

No pipeline delays

High speed serial interface

SPI/QSPI?/MICROWIRE?/DSP compatible

Power-down mode: 1 μA max

8-lead SOT-23 and MSOP packages

APPLICATIONS

Transducer interface

Battery-powered systems

Data acquisition systems

Portable instrumentation

Motor control