Datasheet AD7701 (Analog Devices) - 7

AD7701 TIMING CHARACTERISTICS1, 2 (AVDD = DVDD = +5 V 10%; AVSS = DVSS = –5 V 10%; AGND = DGND = O V; fCLKIN = 4.096 MHz; Input Levels: Logic O = O V, Logic 1 = DVDD; unless otherwise noted.) Limit at TMIN, TMAX Limit at TMIN, TMAX Parameter (A, B Versions) (S, T Versions) Unit Conditions/Comments
f 3, 4 CLKIN 200 200 kHz min Master Clock Frequency: Internal Gate Oscillator. 5 5 MHz max Typically 4.096 MHz. 200 200 kHz min Master Clock Frequency: Externally Supplied. 5 5 MHz max t 5 r 50 50 ns max Digital Output Rise Time. Typically 20 ns. t 5 f 50 50 ns max Digital Output Fall Time. Typically 20 ns. t1 0 0 ns min SC1, SC2 to CAL High Setup Time. t2 50 50 ns min SC1, SC2 Hold Time after CAL Goes High. t 6 3 1000 1000 ns min SLEEP High to CLKIN High Setup Time. SSC MODE t 7 4 3/fCLKIN 3/fCLKIN ns max Data Access Time (CS Low to Data Valid). t5 100 100 ns max SCLK Falling Edge to Data Valid Delay (25 ns typ). t6 250 250 ns min MSB Data Setup Time. Typically 380 ns. t7 300 300 ns max SCLK High Pulsewidth. Typically 240 ns. t8 790 790 ns max SCLK Low Pulsewidth. Typically 730 ns. t 8 9 l/fCLKIN +200 l/fCLKIN +200 ns max SCLK Rising Edge to Hi-Z Delay (l/fCLKIN + 100 ns typ). t 8, 9 10 (4/fCLKIN) +200 (4/fCLKIN) +200 ns max CS High to Hi-Z Delay. SEC MODE fSCLK 5 5 MHz Serial Clock Input Frequency. t11 35 35 ns min SCLK Input High Pulsewidth. t12 160 160 ns min SCLK Low Pulsewidth. t 7, 10 13 160 160 ns max Data Access Time (CS Low to Data Valid). Typically 80 ns. t 11 14 150 150 ns max SCLK Falling Edge to Data Valid Delay. Typically 75 ns. t 8 15 250 250 ns max CS High to Hi-Z Delay. t 8 16 200 200 ns max SCLK Falling Edge to Hi-Z Delay. Typically 100 ns. AC MODE t17 40 40 ns min CS Setup Time. Typically 20 ns. t18 180 180 ns max Data Delay Time. Typically 90 ns. t19 200 200 ns max SCLK Falling Edge to Hi-Z Delay. Typically 100 ns. NOTES 1Sample tested at 25°C to ensure compliance. All input signals are specified with tr = tf = 5 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V. 2See Figures 1 to 6. 3CLKIN duty cycle range is 20% to 80%. CLKIN must be supplied whenever the AD7701 is not in SLEEP mode. If no clock is present in this case, the device can draw higher current than specified and possibly become uncalibrated. 4The AD7701 is production tested with fCLKIN at 4.096 MHz. It is guaranteed by characterization to operate at 200 kHz. 5Specified using 10% and 90% points on waveform of interest. 6In order to synchronize several AD7701s together using the SLEEP pin, this specification must be met. 7t4 and t13 are measured with the load circuit of Figure 1 and defined as the time required for an output to cross 0.8 V or 2.4 V. 8t9, t10, t15, and t16 are derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit of Figure 1. The measured number is then extrapolated back to remove the effects of charging or discharging the 100 pF capacitor. This means that the time quoted in the Timing Characteristics is the true bus relinquish time of the part and as such is independent of external bus loading capacitance. 9If CS is returned high before all 16 bits are output, the SDATA and SCLK outputs will complete the current data bit and then go to high impedance. 10If CS is activated asynchronously to DRDY, CS will not be recognized if it occurs when DRDY is high for four clock cycles. The propagation delay time may be as great as four CLKIN cycles plus 160 ns. To guarantee proper clocking of SDATA when using asynchronous CS, the SCLK input should not be taken high sooner than four CLKIN cycles plus 160 ns after CS goes low. 11SDATA is clocked out on the falling edge of the SCLK input. Specifications subject to change without notice. –6– REV. E Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM PRODUCT HIGHLIGHTS SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ORDERING GUIDE PIN CONFIGURATIONS PIN FUNCTION DESCRIPTIONS TIMING CHARACTERISTICS DEFINITION OF TERMS Linearity Error Differential Linearity Error Positive Full-Scale Error Unipolar Offset Error Bipolar Zero Error Bipolar Negative Full-Scale Error Positive Full-Scale Overrange Negative Full-Scale Overrange Offset Calibration Range Full-Scale Calibration Range Input Span GENERAL DESCRIPTION THEORY OF OPERATION DIGITAL FILTERING FILTER CHARACTERISTICS USING THE AD7701 SYSTEM DESIGN CONSIDERATIONS CLOCKING ANALOG INPUT RANGES INPUT SIGNAL CONDITIONING Source Resistance Antialias Considerations VOLTAGE REFERENCE CONNECTIONS GROUNDING AND SUPPLY DECOUPLING ACCURACY AND AUTOCALIBRATION CALIBRATION RANGE POWER-UP AND CALIBRATION POWER SUPPLY SEQUENCING GROUNDING SINGLE-SUPPLY OPERATION SLEEP MODE DIGITAL INTERFACE Synchronous Self-Clocking Mode (SSC) Synchronous External Clock Mode (SEC) Asynchronous Communications (AC) Mode DIGITAL NOISE AND OUTPUT LOADING OUTLINE DIMENSIONS Revision History