Four-Channel, Simultaneous a Sampling, Fast, 14-Bit ADC AD7865 FEATURES FUNCTIONAL BLOCK DIAGRAM Fast (2.4 s) 14-Bit ADC Four Simultaneously Sampled Inputs V AV V V DV DD DRIVE DD REF REFAGND Four Track/Hold Amplifiers 6k 0.35 s Track/Hold Acquisition Time +2.5V STBY TRACK/HOLD REFERENCE DGND 2.4 s Conversion Time per Channel 4 AGND HW/SW Select of Channel Sequence for Conversion V IN1A SIGNAL AD7865 SCALING Single Supply Operation V IN1B RD Selection of Input Ranges: 10 V, 5 V and 2.5 V, V SIGNAL IN2A DB13 0 V to 5 V and 0 V to 2.5 V SCALING OUTPUT V 14-BIT IN2B MUX LATCH ADC DB0 High Speed Parallel Interface Which Also Allows V SIGNAL IN3A Interfacing to 3 V Processors SCALING CHANNEL V IN3B SELECT DB0DB3 Low Power, 115 mW Typ REGISTER V SIGNAL IN4A CS Power Saving Mode, 15 W Typ SCALING V IN4B Overvoltage Protection on Analog Inputs WR FRSTDATA INT/EXT APPLICATIONS BUSY CONVERSION INT CLOCK CONTROL LOGIC CLOCK AC Motor Control EOC SELECT Uninterruptible Power Supplies Industrial Power Meters/Monitors Data Acquisition Systems CONVST SL3 SL4 H/S CLK IN INT/EXT AGND AGND SEL /SL1 CLK/SL2 Communications The AD7865 is available in a small (0.3 sq. inch area) 44-lead GENERAL DESCRIPTION PQFP. The AD7865 is a fast, low power, four-channel simultaneous sampling 14-bit A/D converter that operates from a single 5 V PRODUCT HIGHLIGHTS supply. The part contains a 2.4 s successive approximation 1. The AD7865 features four Track/Hold amplifiers and a fast ADC, four track/hold amplifiers, 2.5 V reference, on-chip clock (2.4 s) ADC allowing simultaneous sampling and then con- oscillator, signal conditioning circuitry and a high speed parallel version of any subset of the four channels. interface. The input signals on four channels are sampled simul- 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 4. The part is offered in three versions with different analog the channel select register). 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. 5. The part features very tight aperture delay matching between The BUSY signal indicates the end of the conversion sequence. 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. use, nor for any infringements of patents or other rights of third parties Tel: 781/329-4700 World Wide Web Site: (V = 5 V 5%, AGND = DGND = 0 V, V = Internal. Clock = Internal all specifi- DD REF cations T to T unless otherwise noted.) AD7865SPECIFICATIONS MIN MAX 1 Parameter A, Y Versions B Version Unit Test Conditions/Comments SAMPLE AND HOLD 3 dB Full Power Bandwidth 3 3 MHz typ Aperture Delay 20 20 ns max Aperture Jitter 50 50 ps typ Aperture Delay Matching 4 4 ns max 2 DYNAMIC PERFORMANCE f = 100 kHz, f = 350 kSPS IN S 3 Signal to (Noise + Distortion) Ratio 25C AD7865-1, AD7865-3 78 78 dB min Typically 80 dB AD7865-2 77 77 dB min Typically 78 dB T to T MIN MAX AD7865-1, AD7865-3 77 77 dB min AD7865-2 76 76 dB min 3, 4 Total Harmonic Distortion 86 86 dB max 3, 4 Peak Harmonic or Spurious Noise 86 86 dB max 3 Intermodulation Distortion fa = 49 kHz, fb = 50 kHz 2nd Order Terms 95 95 dB typ 3rd Order Terms 95 95 dB typ 3, 5 Channel-to-Channel Isolation 88 88 dB max f = 50 kHz Sine Wave IN DC ACCURACY Any Channel Resolution 14 14 Bits 3 Relative Accuracy (INL) 2 1.5 LSB max Typically 0.6 LSBs 3 Differential Nonlinearity (DNL) 1 1 LSB max No Missing Codes Guaranteed AD7865-1 3 Positive Gain Error 10 8 LSB max Typically 2 LSBs 3 Positive Gain Error Match 8 8 LSB max Typically 2 LSBs 3 Negative Gain Error 10 8 LSB max Typically 2 LSBs 3 Negative Gain Error Match 8 8 LSB max Typically 2 LSBs Bipolar Zero Error 12 10 LSB max Typically 2 LSBs Bipolar Zero Error Match 6 6 LSB max Typically 1.5 LSBs AD7865-2 3 16 16 LSB max Typically 2 LSBs Positive Gain Error 3 Positive Gain Error Match 8 8 LSB max Typically 2 LSBs 3 Unipolar Offset Error 10 10 LSB max Typically 2 LSBs 3 Unipolar Offset Error Match 10 10 LSB max Typically 2 LSBs AD7865-3 3 Positive Gain Error 16 14 LSB max Typically 6 LSBs 3 Positive Gain Error Match 8 8 LSB max Typically 2 LSBs 3 Negative Gain Error 16 14 LSB max Typically 6 LSBs 3 Negative Gain Error Match 8 8 LSB max Typically 2 LSBs Bipolar Zero Error 14 12 LSB max Typically 5 LSBs Bipolar Zero Error Match 8 6 LSB max Typically 2 LSBs ANALOG INPUTS AD7865-1 Input Voltage Range 5, 10 5, 10 Volts Input Current 1, 1 1, 1 mA max V = 5 V and 10 V Respectively, IN Typically 0.7 mA AD7865-2 Input Voltage Range 0 V to 2.5 V, 0 V to 2.5 V, 0 V to 5 V 0 V to 5 V Volts Input Current 10 10 A max V = 2.5 V, 0 V to 2.5 V Range, Typ 1 A IN 1 1 mA max V = 5 V, 0 V to 5 V Range, Typ 0.7 mA IN AD7865-3 Input Voltage Range 2.5 2.5 Volts Input Current 1 1 mA max V = 2.5 V, Typically 0.7 mA IN 2 REV. 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