AD7801 Analog Devices, AD7801 Datasheet
AD7801
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AD7801 Summary of contents
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... The AD7801 is a single, 8-bit, voltage out DAC that operates from a single +2 +5.5 V supply. Its on-chip precision output buffer allows the DAC output to swing rail to rail. The AD7801 has a parallel microprocessor and DSP compatible interface with high speed registers and double buffered interface logic. Data is loaded to the input register on the rising edge ...
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... AD7801–SPECIFICATIONS Parameter STATIC PERFORMANCE Resolution 2 Relative Accuracy Differential Nonlinearity Zero-Code Error @ +25 C Full-Scale Error Zero-Code Error Drift 3 Gain Error DAC REFERENCE INPUT REFIN Input Range REFIN Input Impedance OUTPUT CHARACTERISTICS Output Voltage Range Output Voltage Settling Time Slew Rate Digital-to-Analog Glitch Impulse ...
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... ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD7801 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality ...
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... AD7801 Pin No. Mnemonic Function Parallel Data Inputs. 8-bit data is loaded to the input register of the AD7801 under the control of CS and WR. 1–8 D7– Chip Select. Active low logic input. WR Write Input active low logic input used in conjunction with CS to write data to the input register. ...
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... C A 3.0 LOGIC INPUTS = 2.0 LOGIC INPUTS = V OR GND DD 1.0 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 V – Volts DD Figure 7. Typical Supply Current vs. Supply Voltage OUT 1 AD7801 POWER-UP TIME INTERNAL REFERENCE DAC IN POWER-DOWN INITIALLY CH1 = 2V/div, CH2 = 5V/Div, TIME BASE = 2 s/Div Figure 10. Exiting Power-Down (Full Power-Down) ...
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... AD7801 –Typical Performance Characteristics OUT M20.0ms CH1 5.00V CH2 5.00V CH1 Figure 11. Power-On—Reset 0 0.4 INTERNAL REFERENCE 5k 100pF LOAD 0.3 LIMITED CODE RANGE (15–245 +25 C 0.2 A 0.1 0 –0.1 –0.2 –0.3 –0.4 –0 128 160 192 224 256 INPUT CODE (15 to 245) Figure 14 ...
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... DD DD GENERAL DESCRIPTION D/A Section The AD7801 is an 8-bit voltage output digital-to-analog con- verter. The architecture consists of a reference amplifier and a current source DAC followed by a current-to-voltage converter capable of generating rail-to-rail voltages on the output of the DAC. Figure 19 shows a block diagram of the basic DAC architecture ...
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... AD7801 Reference The AD7801 has the ability to use either an external reference applied through the REFIN pin or an internal reference generated from V . Figure 20 shows the reference input arrangement DD where either the internal the externally applied reference DD can be selected. The internal reference is selected by tying the REFIN pin to V ...
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... V/ s and has a full-scale settling to eight bits with a 100 pF capacitive load in typically 1.2 s. The input coding to the DAC is straight binary. Table I shows the binary transfer function for the AD7801. Figure 26 shows the DAC transfer function for binary coding. Any DAC output voltage can be expressed as: REV ...
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... DATA BUS CONTROL INPUTS Figure 27. Typical Configuration Selecting the Internal Reference Figure 28 shows a typical setup for the AD7801 when using an external reference. The reference range for the AD7801 is from Higher values of reference can be incorporated DD but will saturate the output at both the top and bottom end of the transfer function ...
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... OR AD589 WITH V Figure 32. Bipolar Operation Using the AD7801 Decoding Multiple AD7801s in a System The CS pin on the AD7801 can be used in applications to decode a number of DACs. In this application, all DACs in the AD7801* system receive the same input data, but only the CS to one of CS the DACs will be active at any one time allowing access to one channel in the system ...
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... AGND Figure 34. Digitally Programmable Indicator Programmable Current Source Figure 35 shows the AD7801 used as the control element of a programmable current source. In this circuit the full-scale current is set to 1 mA. The output voltage from the DAC is applied across the current setting resistor of 4 series with the full-scale setting resistor of 470 ...
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... REV. 0 The power supply lines of the AD7801 should use as large a trace as possible to provide low impedance paths and reduce the effects of glitches on the supply line. Fast switching signals like clocks should be shielded with digital ground to avoid radiating noise to other parts of the board and should never be run near reference inputs ...
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... AD7801 0.0118 (0.30) 0.0040 (0.10) 0.006 (0.15) 0.002 (0.05) SEATING OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 20-Lead Wide Body SOIC (R-20) 0.5118 (13.00) 0.4961 (12.60 PIN 1 0.1043 (2.65) 0.0926 (2.35) 0.0500 0.0192 (0.49) SEATING 0.0125 (0.32) (1.27) 0.0138 (0.35) PLANE BSC 0.0091 (0.23) 20-Lead TSSOP (RU-20) 0.260 (6.60) 0.252 (6.40 PIN 1 0.0433 (1.10) MAX 0.0118 (0.30) ...
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