Pseudo Differential, 555 kSPS

12-Bit ADC in an 8-Lead SOT-23

AD7453

Rev. B

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FEATURES

Low power at max throughput rate:

Pseudo 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 package

APPLICATIONS

Transducer interface

Battery-powered systems

Data acquisition systems

Portable instrumentation

GENERAL DESCRIPTION

The AD74531 is a 12-bit, high speed, low power, successive

approximation (SAR) analog-to-digital converter that features a

pseudo differential analog input. This part operates from a

single 2.7 V to 5.25 V power supply and features throughput

rates up to 555 kSPS.

The part contains a low noise, wide bandwidth, differential

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

cies up to 3.5 MHz. The reference voltage for the AD7453 is

application.

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 this part ensures that there are no

pipeline delays. The AD7453 uses advanced design techniques

to achieve very low power dissipation.

FUNCTIONAL BLOCK DIAGRAM

T/H

CONTROL LOGIC

12-BIT

SUCCESSIVE

ADC

GND

SCLK

SDATA

CS

AD7453

APPROXIMATION

Figure 1.

PRODUCT HIGHLIGHTS

1.

Operation with 2.7 V to 5.25 V Power Supplies.

2.

High Throughput with Low Power Consumption. With a

3 V supply, the AD7453 offers 3.3 mW max power

consumption for a 555 kSPS throughput rate.

3.

Pseudo Differential Analog Input.

4.

Flexible Power/Serial Clock Speed Management. The

conversion rate is determined by the serial clock, allowing

the power to be reduced as the conversion time is reduced

through the serial clock speed increase. This part also

features a shutdown mode to maximize power efficiency at

lower throughput rates.

5.

Variable Voltage Reference Input.

6.

No Pipeline Delay.

7.

Accurate control of the sampling instant via a CS input and

once-off conversion control.

8.

ENOB > 10 bits Typically with 500 mV Reference.