Datasheet AD7856 (Analog Devices) - 5

AD7856 TIMING SPECIFICATIONS1 (VDD = 5 V; TA = TMIN to TMAX, unless otherwise noted. A Grade: fCLKIN = 6 MHz; K Grade: fCLKIN = 4 MHz.) ␣ ␣ ␣ Limit at TMIN, TMAX Parameter A Version K Version Units Description
f 2 CLKIN 500 500 kHz min Master Clock Frequency 6 4 MHz max fSCLK 6 4 MHz max t 3 1 100 100 ns min CONVST Pulsewidth t2 50 50 ns max CONVST↓ to BUSY↑ Propagation Delay tCONVERT 3.5 5.25 µs max Conversion Time = 20 tCLKIN t3 –0.4 tSCLK –0.4 tSCLK ns min SYNC↓ to SCLK↓ Setup Time (Noncontinuous SCLK Input) ±0.4 t ± SCLK 0.4 tSCLK ns min/max SYNC↓ to SCLK↓ Setup Time (Continuous SCLK Input) t 4 4 30 50 ns max Delay from SYNC↓ Until DOUT 3-State Disabled t 4 5 30 50 ns max Delay from SYNC↓ Until DIN 3-State Disabled t 4 6 45 75 ns max Data Access Time After SCLK↓ t7 30 40 ns min Data Setup Time Prior to SCLK↑ t8 20 20 ns min Data Valid to SCLK Hold Time t9 0.4 tSCLK 0.4 tSCLK ns min SCLK High Pulsewidth t10 0.4 tSCLK 0.4 tSCLK ns min SCLK Low Pulsewidth t11 30 30 ns min SCLK↑ to SYNC↑ Hold Time (Noncontinuous SCLK) 30/0.4 tSCLK 30/0.4 tSCLK ns min/max (Continuous SCLK) t 5 12 50 50 ns max Delay from SYNC↑ Until DOUT 3-State Enabled t13 90 90 ns max Delay from SCLK↑ to DIN Being Configured as Output t 6 14 50 50 ns max Delay from SCLK↑ to DIN Being Configured as Input t15 2.5 tCLKIN 2.5 tCLKIN ns max CAL↑ to BUSY↑ Delay t16 2.5 tCLKIN 2.5 tCLKIN ns max CONVST↓ to BUSY↑ Delay in Calibration Sequence tCAL 41.7 62.5 ms typ Full Self-Calibration Time, Master Clock Dependent (250026 tCLKIN) tCAL1 37.04 55.5 ms typ Internal DAC Plus System Full-Scale Cal Time, Master Clock Dependent (222228 tCLKIN) tCAL2 4.63 6.94 ms typ System Offset Calibration Time, Master Clock Dependent (27798 tCLKIN) NOTES 1Sample tested at +25°C to ensure compliance. All input signals are specified with tr = tf = 5 ns (10% to 90% of V DD) and timed from a voltage level of 1.6 V. See Table X and timing diagrams for different interface modes and calibration. 2Mark/Space ratio for the master clock input is 40/60 to 60/40. 3The CONVST pulsewidth here only applies for normal operation. When the part is in power-down mode, a different CONVST pulsewidth will apply (see Power-Down section). 4Measured with the load circuit of Figure 1 and defined as the time required for the output to cross 0.8 V or 2.4 V. 5t12 is derived form 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, t 12, quoted in the timing characteristics is the true bus relinquish time of the part and is independent of the bus loading. 6t14 is derived form 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, t 14, quoted in the Timing Characteristics is the true delay of the part in turning off the output drivers and configuring the DIN line as an input. Once this time has elapsed the user can drive the DIN line knowing that a bus conflict will not occur. Specifications subject to change without notice. –4– REV. A