1 MSPS, 12-Bit A/D Converter in MSOP-8 or SOIC-8

The AD7475 / AD7495 are 12-bit, high speed, low power, successive-approximation ADCs that operate from a single 2.7 V to 5.25 V power supply with throughput rates up to 1 MSPS. They contain a low noise, wide bandwidth track-and-hold amplifier that can handle input frequencies above 1 MHz.

The conversion process and data acquisition are controlled using CS and the serial clock, allowing the devices to interface with microprocessors or DSPs. The input signal is sampled on the falling edge of CS and conversion is initiated at this point. The conversion time is determined by the SCLK frequency. There are no pipeline delays associated with the device.

The AD7475 / AD7495 use advanced design techniques to achieve very low power dissipation at high throughput rates. With 3 V supplies and a 1 MSPS throughput rate, the AD7475 consumes just 1.5 mA, while the AD7495 consumes 2 mA. With 5 V supplies and 1 MSPS, the current consumption is 2.1 mA for the AD7475 and 2.6 mA for the AD7495.

The analog input range for the devices is 0 V to REF IN. The 2.5 V reference for the AD7475 is applied externally to the REF IN pin, while the AD7495 has an on-board 2.5 V reference.

PRODUCT HIGHLIGHTS

* The AD7475 offers 1 MSPS throughput rates with 4.5 mW

power consumption.

* Single-supply operation with VDRIVE function. The

AD7475 / AD7495 operate from a single 2.7 V to 5.25 V

supply. The VDRIVE function allows the serial interface to

connect directly to either 3 V or 5 V processor systems

independent of VDD.

* Flexible power/serial clock speed management. The

conversion rate is determined by the serial clock, allowing

the conversion time to be reduced through the serial clock

speed increase. The devices also feature shutdown modes

to maximize power efficiency at lower throughput rates.

This allows the average power consumption to reduce while

not converting. Power consumption is 1 μA when in full

shutdown.

* No pipeline delay. The devices feature a standard successive

approximation ADC with accurate control of the sampling

instant via a CS input and once-off conversion control.

APPLICATIONS

* Battery-powered systems

* Personal digital assistants

* Medical instruments

* Mobile communications

* Instrumentation and control systems

* Data acquisition systems

* Optical sensors

* Fast throughput rate: 1 MSPS

* Specified for VDD of 2.7 V to 5.25 V

* Low power:

4.5 mW max at 1 MSPS with 3 V supplies

10.5 mW max at 1 MSPS with 5 V supplies

* Wide input bandwidth: 68 dB SNR at 300 kHz input frequency