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