AD7849 Analog Devices, AD7849 Datasheet
AD7849
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AD7849 Summary of contents
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... SDIN SCLK SYNC CLR BIN/ DCEN SDOUT LDAC V COMP Figure 1. The AD7849 has a versatile serial interface structure and can be controlled over three lines to facilitate opto-isolator applications. SDOUT is the output of the on-chip shift register and can be used in a daisy-chain fashion to program devices in the multi- channel system ...
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... Figure 20; Renumbered Sequentially.................................... 12 Typical Performance Characteristics ..............................................8 Terminology .................................................................................... 10 Circuit Description......................................................................... 11 Digital-to-Analog Conversion.................................................. 11 Digital Interface.......................................................................... 12 Applying the AD7849 ................................................................ 13 Microprocessor Interfacing....................................................... 15 Applications Information .............................................................. 17 Opto-Isolated Interface ............................................................. 17 Outline Dimensions ....................................................................... 18 Ordering Guide .......................................................................... 19 Rev Page ...
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... Resistance from V kΩ max Typically 34 kΩ max kΩ min max Ω typ mA typ Voltage range: − +10 V AD7849 = OFS 14 − V )/2 ; REF+ REF− 16 − V )/2 REF+ REF− REF+ REF− ...
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... Guaranteed by design and characterization, not production tested. 2 The AD7849 is functional with power supplies of ±12 V. See the Typical Performance Characteristics section. 3 Sensitivity of gain error, offset error, and bipolar zero error to V RESET SPECIFICATIONS These specifications apply when the device goes into reset mode during power-up or power-down sequence. V Table 2 ...
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... Limit (All Versions) MIN MAX 200 Rev Page AD7849 = 14. 15. −14. loaded OUT REF− loaded −5 V. OUT REF− loaded. LDAC permanently low. OUT = −5 V. REF− rms, 10 kHz sine wave. ...
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... AD7849 2 VOUT can be shorted to DGND − provided that the power dissipation of the package is not exceeded. 3 Transient currents 100 mA do not cause SCR latch-up. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only ...
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... No Connect. Leave unconnected DAC Output Voltage Pin. OUT 20 R Input to Summing Resistor of DAC Output Amplifier. This is used to select the output voltage ranges. Also, see OFS Figure 20 to Figure 23 in the Applying the AD7849 section REF+ OFS V V REF– ...
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... AD7849 TYPICAL PERFORMANCE CHARACTERISTICS V 1 REF OUT CH1 1.00V M 20.0µs CH1 CH4 1.00mV Figure 3. AC Feedthrough SYNC 1 SDIN OUT CH2 5.00V M 1.00µs CH1 5.00V CH4 200mV Figure 4. Digital-to-Analog Glitch Impulse Without Internal Deglitcher +15V ...
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... V OUT 2 C2 p-p 216mV C2 RISE 458ns LDAC C2 FALL 3 452.4ns –10mV CH1 CH3 OUT 2 14.75 16.00 CH1 15 16 Rev Page 10.0V CH2 10.0V M 10.0ms CH1 7.8mV 5.0V Figure 12. Turn-On Characteristics 7.8V 10.0V CH2 10.0V M 1.00ms CH1 7.8mV Figure 13. Turn-Off Characteristics AD7849 C1 RISE 3.808ms C2 RISE 8µs C1 FALL 4.7621ms ...
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... When the DAC is not selected ( SYNC is held high), high frequency logic activity on the digital inputs is capacitively coupled through the device to show up as noise on the V This noise is digital feedthrough. Rev Page AD7849 is connected for bipolar output and (100 … terminals to V when the DAC is loaded with all 0s. OUT pin ...
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... R-2R structure would need. Output Stage The output stage of the AD7849 is shown in Figure 14 capable of driving a 2 kΩ load in parallel with 200 pF. The feedback and offset resistors allow the output stage to be configured for gains ...
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... When DCEN is at Logic 0, standalone mode is selected. In this mode, a low SYNC input provides the frame synchronization signal that tells the AD7849 that valid serial data on the SDIN input is available for the next 16 falling edges of SCLK. An internal counter/decoder circuit provides a low gating signal so that only 16 data bits are clocked into the input shift register ...
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... V separate from the automatic power-on reset feature of the device. APPLYING THE AD7849 Power Supply Sequencing and Decoupling In the AD7849 this happens, then an internal diode is turned on, and it produces in the chain, a latch-up in the device. Care should be taken to employ the ...
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... R1 can be omitted. Pin 5 of the AD586 may be left open circuit, and Pin the AD7849 tied REF− Bipolar Configuration Figure 21 shows the AD7849 set up for ±10 V bipolar operation. The AD588 fed to the V for the circuit shown in Figure 21 is shown in Table 8. ...
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... SCLK. For all the interfaces, the DAC update can be done automatically when all data is clocked in can be done under control of LDAC . +5V Figure 24 through Figure 27 show the AD7849 configured for V interfacing to a number of popular DSP processors and CC microcontrollers ...
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... SBUF register is arranged correctly so that the most significant bits are the first to be transmitted to the AD7849, and the last bit to be sent is the LSB of the word to be loaded to the AD7849. When data is transmitted to the part, P3.3 is taken low. Data on RXD is valid on the falling edge of TXD. The 87C51 transmits its serial data in 8-bit bytes, with only eight falling clock edges occurring in the transmit cycle ...
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... The serial loading structure of the makes it ideal for opto-isolated interfaces because the number of interface lines is kept to a minimum. Figure 28 shows a 4-channel isolated interface using the AD7849. The DCEN pin must be connected high to enable the daisy-chain facility. Four channels with 14-bit or 16-bit resolution are provided in the circuit shown, but this can be expanded to accommodate any number of DAC channels without any extra isolation circuitry ...
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... AD7849 OUTLINE DIMENSIONS 0.210 (5.33) MAX 0.150 (3.81) 0.130 (3.30) 0.115 (2.92) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 1.060 (26.92) 1.030 (26.16) 0.980 (24.89 0.280 (7.11) 0.250 (6.35) 1 0.240 (6.10) 10 0.100 (2.54) BSC 0.060 (1.52) 0.015 (0.38) 0.015 (0.38) MIN GAUGE PLANE SEATING PLANE 0.005 (0.13) MIN 0.070 (1.78) 0.060 (1.52) 0.045 (1.14) COMPLIANT TO JEDEC STANDARDS MS-001 CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN ...
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... AD7849BR −40°C to +85°C AD7849BR-REEL −40°C to +85°C AD7849BRZ −40°C to +85°C AD7849BRZ-REEL −40°C to +85°C AD7849CR −40°C to +85°C AD7849CR-REEL −40°C to +85°C AD7849CRZ −40°C to +85°C AD7849CRZ-REEL −40°C to +85° RoHS Compliant Part ...
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... AD7849 NOTES ©1995–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D01008-0-3/11(C) Rev Page ...