Datasheet AD7865 (Analog Devices)

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Four-Channel, Simultaneous Sampling, Fast, 14-Bit ADC AD7865 FEATURES FUNCTIONAL BLOCK DIAGRAM Fast (2.4 s) 14-Bit ADC Four Simultaneously Sampled Inputs AV V DV V DD VREF REFAGND DD DRIVE Four Track/Hold Amplifiers 0.35 s Track/Hold Acquisition Time 6k +2.5V STBY 2.4 s Conversion Time per Channel TRACK/HOLD REFERENCE DGND 4 HW/SW Select of Channel Sequence for Conversion AGND VIN1A SIGNAL AD7865 Single Supply Operation SCALING VIN1B RD Selection of Input Ranges: 10 V, 5 V and 2.5 V, VIN2A SIGNAL 0 V to 5 V and 0 V to 2.5 V SCALING DB13 V OUTPUT IN2B MUX 14-BIT High Speed Parallel Interface Which Also Allows ADC LATCH DB0 V Interfacing to 3 V Processors IN3A SIGNAL SCALING V CHANNEL IN3B Low Power, 115 mW Typ SELECT DB0–DB3 REGISTER Power Saving Mode, 15 W Typ V SIGNAL IN4A CS SCALING V Overvoltage Protection on Analog Inputs IN4B WR FRSTDATA APPLICATIONS BUSY CONVERSION INT/EXT INT CLOCK AC Motor Control EOC CONTROL LOGIC CLOCK SELECT Uninterruptible Power Supplies Industrial Power Meters/Monitors Data Acquisition Systems CONVST SL3 SL4 H/S CLK IN INT/EXT AGND AGND Communications SEL /SL1 CLK/SL2 GENERAL DESCRIPTION
The AD7865 is available in a small (0.3 sq. inch area) 44-lead The AD7865 is a fast, low power, four-channel simultaneous PQFP. sampling 14-bit A/D converter that operates from a single 5 V supply. The part contains a 2.4 µs successive approximation
PRODUCT HIGHLIGHTS
ADC, four track/hold amplifiers, 2.5 V reference, on-chip clock 1. The AD7865 features four Track/Hold amplifiers and a fast oscillator, signal conditioning circuitry and a high speed parallel (2.4 µs) ADC allowing simultaneous sampling and then con- interface. The input signals on four channels are sampled simul- version of any subset of the four channels. taneously thus preserving the relative phase information of the 2. The AD7865 operates from a single 5 V supply and con- signals on the four analog inputs. The part accepts analog input sumes only 115 mW typ, making it ideal for low power and ranges of ± 10 V, ± 5 V, ± 2.5 V, 0 V to 2.5 V and 0 V to 5 V. portable applications. The part allows any subset of the four channels to be converted 3. The part offers a high speed parallel interface for easy con- in order to maximize the throughput rate on the selected sequence. nection to microprocessors, microcontrollers and digital The channels to be converted can be selected either via hard- signal processors. ware (channel select input pins) or via software (programming the channel select register). 4. The part is offered in three versions with different analog input ranges. The AD7865-1 offers the standard industrial A single conversion start signal (CONVST) simultaneously places ranges of ± 10 V and ± 5 V; the AD7865-2 offers a unipolar all the track/holds into hold and initiates conversion sequence range of 0 V to 2.5 V or 0 V to 5 V and the AD7865-3 offers for the selected channels. The EOC signal indicates the end of the common signal processing input range of ± 2.5 V. each individual conversion in the selected conversion sequence. The BUSY signal indicates the end of the conversion sequence. 5. The part features very tight aperture delay matching between the four input sample and hold amplifiers. Data is read from the part via a 14-bit parallel data bus using the standard CS and RD signals. Maximum throughput for a single channel is 350 kSPS. For all four channels the maximum through- put is 100 kSPS. REV. B 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
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