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 part.

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 parts 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

1. The AD7475 offers 1 MSPS throughput rates with 4.5 mW power consumption.
2. Single-supply operation with V_DRIVE function. The AD7475/AD7495 operate from a single 2.7 V to 5.25 V supply. The V_DRIVE function allows the serial interface to connect directly to either 3 V or 5 V processor systems independent of V_DD.
3. Flexible power/serial clock speed management. The con-version rate is determined by the serial clock, allowing the conversion time to be reduced through the serial clock speed increase. The parts also feature shutdown modes to maximize power efficiency at lower throughput rates. This allows the average power consumption to be reduced while not converting. Power consumption is 1 μA when in full shutdown.
4. No pipeline delay. The parts 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

*Protected by U.S. Patent No. 6,681,332.