Datasheet AD7475, AD7495 (Analog Devices)

1 MSPS,12-Bit ADCs Data Sheet AD7475/ AD7495 FEATURES FUNCTIONAL BLOCK DIAGRAM Fast throughput rate: 1 MSPS VDD Specified for VDD of 2.7 V to 5.25 V V T/H 12-BIT Low power IN SUCCESSIVE APPROXIMATION 4.5 mW max at 1 MSPS with 3 V supplies REF IN ADC 10.5 mW max at 1 MSPS with 5 V supplies Wide input bandwidth: 68 dB SNR at 300 kHz input frequency SCLK CONTROL Flexible power/serial clock speed management SDATA LOGIC No pipeline delays CS High speed serial interface AD7475 VDRIVE SPI-/QSPI™-/MICROWIRE-/DSP-compatible GND On-board reference: 2.5 V (AD7495 only) VDD Standby mode: 1 μA max 8-lead MSOP and SOIC packages T/H 12-BIT VIN SUCCESSIVE APPROXIMATION APPLICATIONS ADC REF OUT Battery-powered systems BUF Personal digital assistants SCLK CONTROL Medical instruments LOGIC SDATA 2.5V REFERENCE CS Mobile communications V Instrumentation and control systems AD7495 DRIVE
01684-B-001
Data acquisition systems GND Optical sensors
Figure 1.
GENERAL DESCRIPTION PRODUCT HIGHLIGHTS
The AD7475/AD74951 are 12-bit, high speed, low power, 1. The AD7475 offers 1 MSPS throughput rates with 4.5 mW successive-approximation ADCs that operate from a single power consumption. 2.7 V to 5.25 V power supply with throughput rates up to 1 MSPS. 2. Single-supply operation with V They contain a low noise, wide bandwidth track-and-hold DRIVE function. The AD7475/AD7495 operate from a single 2.7 V to 5.25 V amplifier that can handle input frequencies above 1 MHz. supply. The VDRIVE function allows the serial interface to The conversion process and data acquisition are controlled connect directly to either 3 V or 5 V processor systems using CS and the serial clock, allowing the devices to interface independent of VDD. with microprocessors or DSPs. The input signal is sampled on 3. Flexible power/serial clock speed management. The the falling edge of CS and conversion is initiated at this point. conversion rate is determined by the serial clock, allowing The conversion time is determined by the SCLK frequency. the conversion time to be reduced through the serial clock There are no pipeline delays associated with the device. speed increase. The devices also feature shutdown modes The AD7475/AD7495 use advanced design techniques to to maximize power efficiency at lower throughput rates. achieve very low power dissipation at high throughput rates. This allows the average power consumption to reduce while With 3 V supplies and a 1 MSPS throughput rate, the AD7475 not converting. Power consumption is 1 μA when in full consumes just 1.5 mA, while the AD7495 consumes 2 mA. With shutdown. 5 V supplies and 1 MSPS, the current consumption is 2.1 mA 4. No pipeline delay. The devices feature a standard successive for the AD7475 and 2.6 mA for the AD7495. approximation ADC with accurate control of the sampling The analog input range for the devices is 0 V to REF IN. The instant via a CS input and once-off conversion control. 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. 1Protected by U.S. Patent No. 6,681,332
Rev. C Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 ©2001-2015 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com
Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS REVISION HISTORY AD7475 SPECIFICATIONS AD7495 SPECIFICATIONS TIMING EXAMPLE 1 TIMING EXAMPLE 2 ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS TERMINOLOGY TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION CONVERTER OPERATION ADC TRANSFER FUNCTION TYPICAL CONNECTION DIAGRAM Analog Input Digital Inputs VDRIVE Reference Section OPERATING MODES NORMAL MODE PARTIAL POWER-DOWN MODE Power-Up Time FULL POWER-DOWN MODE POWER VS. THROUGHPUT RATE SERIAL INTERFACE MICROPROCESSOR INTERFACING AD7475/AD7495 TO TMS320C5x/C54x AD7475/AD7495 TO ADSP-21xx AD7475/AD7495 TO DSP56xxx AD7475/AD7495 TO MC68HC16 OUTLINE DIMENSIONS ORDERING GUIDE