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Details, datasheet, quote on part number:AD7891-1
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| Part: | AD7891-1 |
| Category: | Data Conversion => ADC (Analog to Digital Converters) => 10-14 bit |
| Description: | True Bipolar Input, Single Supply, Parallel, 8-Channel, 12-Bit High Speed Data Acquisition System |
| Company: | Analog Devices |
| Datasheet: | Download AD7891-1 datasheet File size : 194 kB |
| Request For quote: | Find where to buy AD7891-1
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Datasheet text preview:
a
FEATURES Fast 12-Bit ADC with 1.6 s Conversion Time Eight Single-Ended Analog Input Channels Overvoltage Protection on Each Channel Selection of Input Ranges: 5 V, 10 V for AD7891-1 0 to 2.5 V, 0 to 5 V, 2.5 V for AD7891-2 Parallel and Serial Interface On-Chip Track/Hold Amplifier On-Chip Reference Single Supply, Low Power Operation (100 mW Max) Power-Down Mode (75 W Typ) APPLICATIONS Data Acquisition Systems Motor Control Mobile Communication Base Stations Instrumentation
LC2MOS 8-Channel, 12-Bit High Speed Data Acquisition System AD7891
FUNCTIONAL BLOCK DIAGRAM
VDD VDD VIN1A VIN1B VIN2A VIN2B VIN3A VIN3B VIN4A VIN4B VIN5A VIN5B VIN6A VIN6B VIN7A VIN7B VIN8A VIN8B REF OUT/ REF IN REF GND 2.5V REFERENCE
STANDBY
AD7891
M U X TRACK/HOLD ADDRESS DECODE
12-BIT ADC
DATA / CONTROL LINES
CLOCK CONTROL LOGIC
WR CS RD EOC CONVST MODE
AGND AGND DGND
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
The AD7891 is an eight-channel 12-bit data acquisition system with a choice of either parallel or serial interface structure. The part contains an input multiplexer, an on-chip track/hold amplifier, a high speed 12-bit ADC, a 2.5 V reference and a high speed interface. The part operates from a single 5 V supply and accepts a variety of analog input ranges across two models, the AD7891-1 (± 5 V and ± 10 V) and the AD7891-2 (0 V to 2.5 V, 0 V to 5 V and ± 2.5 V). The AD7891 provides the option of either a parallel interface or serial interface structure determined by the MODE pin. The part has standard control inputs and fast data access times for both the serial and parallel interfaces which ensures easy interfacing to modern microprocessors, microcontrollers and digital signal processors. In addition to the traditional dc accuracy specifications such as linearity, full-scale and offset errors, the part is also specified for dynamic performance parameters including harmonic distortion and signal-to-noise ratio. Power dissipation in normal mode is 82 mW typical while in the standby mode this is reduced to 75 µW typ. The part is available in a 44-terminal plastic quad flatpack (MQFP) and a 44-lead plastic leaded chip carrier (PLCC).
1. The AD7891 is a complete monolithic 12-bit data acquisition system combining an eight-channel multiplexer, 12-bit ADC, 2.5 V reference and track/hold amplifier on a single chip. 2. The AD7891-2 features a conversion time of 1.6 µs and an acquisition time of 0.4 µs. This allows a sample rate of 500 kSPS when sampling one channel and 62.5 kSPS when channel hopping. These sample rates can be achieved using either a software or hardware convert start. The AD7891-1 has an acquisition time of 0.6 µs when using a hardware convert start and an acquisition time of 0.7 µs when using a software convert start. These acquisition times allow sample rates of 454.5 kSPS and 435 kSPS respectively for hardware and software convert start. 3. Each channel on the AD7891 has overvoltage protection. This means that an overvoltage on an unselected channel does not affect the conversion on a selected channel. The AD7891-1 can withstand overvoltages of ± 17 V.
REV. B
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 2001
AD7891SPECIFICATIONS unless otherwise noted.)
Parameter DYNAMIC PERFORMANCE2 Signal to (Noise + Distortion) Ratio 4 @ 25°C TMIN to TMAX Total Harmonic Distortion4 Peak Harmonic or Spurious Noise4 Intermodulation Distortion4 Second Order Terms Third Order Terms Channel-to-Channel Isolation4 DC ACCURACY Resolution Minimum Resolution for Which No Missing Codes Are Guaranteed Relative Accuracy4 Differential Nonlinearity4 Positive Full-Scale Error4 Positive Full-Scale Error Match4, 5 Unipolar Offset Error Unipolar Offset Error Match5 Negative Full-Scale Error4 Negative Full-Scale Error Match4, 5 Bipolar Zero Error Bipolar Zero Error Match5 ANALOG INPUTS AD7891-1 Input Voltage Range ±5 ± 10 7.5 15 0 to 2.5 0 to 5 ± 2.5 1.5 ± 50 2.375/2.625 1.6 10 2.5 ± 10 ± 20 25 5 2.4 0.8 ± 10 10 ±5 ± 10 7.5 15 0 to 2.5 0 to 5 ± 2.5 1.5 ± 50 2.375/2.625 1.6 10 2.5 ± 10 ± 20 25 5 2.4 0.8 ± 10 10 ±5 ± 10 7.5 15 0 to 2.5 0 to 5 ± 2.5 1.5 ± 50 2.375/2.625 1.6 10 2.5 ± 10 ± 20 25 5 2.4 0.8 ± 10 10 A Version 1 B Version Y Version
( V DD = 5 V
5%, AGND = DGND = 0 V, REF IN = 2.5 V. All specifications TMIN to TMAX
Unit
Test Conditions/Comments Sample Rate = 454.5 kSPS3 (AD7891-1), 500 kSPS3 (AD7891-2). Any Channel
70 70 78 80 80 80 80 12 12 ±1 ±1 ±3 0.6 ±3 0.1 ±3 0.6 ±4 0.2
70 70 78 80 80 80 80 12 12 ± 0.75 ±1 ±3 0.6 ±3 0.1 ±3 0.6 ±4 0.2
70 70 78 80 80 80 80 12 12 ±1 ±1 ±3 0.6 ±3 0.1 ±3 0.6 ±4 0.2
dB min dB min dB max dB max fa = 9 kHz, fb = 9.5 kHz dB typ dB typ dB max Any Channel Bits Bits LSB max LSB max LSB max LSB typ LSB max LSB typ LSB max LSB typ LSB max LSB typ
1.5 LSB max Input Ranges of 0 V to 2.5 V, 0 V to 5 V 1 LSB max Input Ranges of ± 2.5 V, ± 5 V, ± 10 V 1.5 LSB max Input Ranges of ± 2.5 V, ± 5 V, ± 10 V 1.5 LSB max
AD7891-1 VINXA Input Resistance AD7891-1 VINXA Input Resistance AD7891-2 Input Voltage Range
Volts Volts k min k min Volts Volts Volts k min nA max V min/V max k min pF max V nom mV max mV max ppm/°C typ k nom V min V max µA max pF max
Input Applied to Both VINXA and VINXB Input Applied to VINXA, VINXB = AGND Input Range of ± 5 V Input Range of ± 10 V Input Applied to Both VINXA and VINXB Input Applied to VINXA, VINXB = AGND Input Applied to VINXA, VINXB = REF IN6 Input Ranges of ± 2.5 V and 0 V to 5 V Input Range of 0 V to 2.5 V 2.5 V ± 5% Resistor Connected to Internal Reference Node
AD7891-2 VINXA Input Resistance AD7891-2 VINXA Input Current REFERENCE INPUT/OUTPUT REF IN Input Voltage Range Input Impedance Input Capacitance5 REF OUT Output Voltage REF OUT Error @ 25°C TMIN to TMAX REF OUT Temperature Coefficient REF OUT Output Impedance LOGIC INPUTS Input High Voltage, VINH Input Low Voltage, VINL Input Current, IINH Input Capacitance5 CIN
See REF IN Input Impedance VDD = 5 V ± 5% VDD = 5 V ± 5%
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REV. B
AD7891
Parameter LOGIC OUTPUTS Output High Voltage, VOH Output Low Voltage, VOL DB11DB0 Floating-State Leakage Current Floating-State Capacitance5 Output Coding A Version 1 4.0 0.4 ± 10 15 B Version 4.0 0.4 ± 10 15 Y Version 4.0 0.4 ± 10 15 Unit V min V max µA max pF max Data Format Bit of Control Register = 0 Data Format Bit of Control Register = 1 1.6 0.6 0.7 0.4 5 21 80 105 400 µs max µs max µs max µs max V nom mA max µA max mW max µW max Test Conditions/Comments ISOURCE = 200 µA ISINK = 1.6 mA
Straight (Natural) Binary Two's Complement CONVERSION RATE Conversion Time Track/Hold Acquisition Time 1.6 0.6 0.7 0.4 5 20 80 100 400 1.6 0.6 0.7 0.4 5 20 80 100 400
AD7891-1 Hardware Conversion AD7891-1 Software Conversion AD7891-2 ± 5% for Specified Performance
POWER REQUIREMENTS V DD I DD Normal Mode Standby Mode Power Dissipation Normal Mode Standby Mode
Logic Inputs = 0 V or VDD VDD = 5 V Typically 82 mW Typically 75 µW
NOTES 1 Temperature Ranges for the A and B Versions: 40°C to +85°C. Temperature Range for the Y Version: 55°C to +105°C. 2 The AD7891-1's dynamic performance (THD and SNR) and the AD7891-2's THD are measured with an input frequency of 10 kHz. The AD7891-2's SNR is evaluated with an input frequency of 100 kHz. 3 This throughput rate can only be achieved when the part is operated in the parallel interface mode. Maximum achievable throughput rate in the serial interface mode is 357 kSPS. 4 See Terminology. 5 Sample tested during initial release and after any redesign or process change that may affect this parameter. 6 REF IN must be buffered before being applied to V INXB. Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS*
(TA = 25°C unless otherwise noted)
VDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +7 V VDD to DGND . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +7 V Analog Input Voltage to AGND A D 7 8 9 1 - 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 17 V AD7891-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 V, +10 V Reference Input Voltage to AGND . . . . 0.3 V to VDD + 0.3 V Digital Input Voltage to DGND . . . . . . 0.3 V to VDD + 0.3 V Digital Output Voltage to DGND . . . . . 0.3 V to VDD + 0.3 V Operating Temperature Range Commercial (A, B Version) . . . . . . . . . . . . 40°C to +85°C Automotive (Y Version) . . . . . . . . . . . . . . 55°C to +105°C Storage Temperature Range . . . . . . . . . . . . 65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C MQFP Package, Power Dissipation . . . . . . . . . . . . . . 450 mW JA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 95°C/W Lead Temperature, Soldering Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215°C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C PLCC Package, Power Dissipation . . . . . . . . . . . . . . 500 mW JA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 55°C/W Lead Temperature, Soldering Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . 215°C Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . . 220°C
*Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
CAUTION 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 AD7891 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.
WARNING!
ESD SENSITIVE DEVICE
REV. B
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AD7891 TIMING CHARACTERISTICS1, 2
Parameter tCONV Parallel Interface t1 t2 t3 t4 t5 t6 t7 t8 t9 3 t10 4 Serial Interface t11 t12 3 t13 t14 t15 3 t16 3 t17 t18 4 t18A 4 t19 t20 t21 t22 A, B, Y Versions 1.6 0 35 25 5 0 35 55 35 25 5 30 30 20 25 25 5 15 20 0 30 0 30 20 15 10 30 Unit µs max ns min ns min ns min ns min ns min ns min ns min ns min ns min ns min ns max ns min ns max ns min ns min ns min ns max ns min ns min ns max ns min ns max ns min ns min ns min ns min Test Conditions/Comments Conversion Time CS to RD/WR Setup Time Write Pulsewidth Data Valid to Write Setup Time Data Valid to Write Hold Time CS to RD/WR Hold Time CONVST Pulsewidth EOC Pulsewidth Read Pulsewidth Data Access Time after Falling Edge of RD Bus Relinquish Time after Rising Edge of RD
RFS Low to SCLK Falling Edge Setup Time RFS Low to Data Valid Delay SCLK High Pulsewidth SCLK Low Pulsewidth SCLK Rising Edge to Data Valid Hold Time SCLK Rising Edge to Data Valid Delay RFS to SCLK Falling Edge Hold Time Bus Relinquish Time after Rising Edge of RFS Bus Relinquish Time after Rising Edge of SCLK TFS Low to SCLK Falling Edge Setup Time Data Valid to SCLK Falling Edge Setup Time Data Valid to SCLK Falling Edge Hold Time TFS Low to SCLK Falling Edge Hold Time
NOTES 1 Sample tested during initial release and after any redesign or process change that may affect this parameter. All input signals are measured with tr = tf = 1 ns (10% to 90% of 5 V) and timed from a voltage level of 1.6 V. 2 See Figures 2, 3, and 4. 3 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. 4 These times 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 50 pF capacitor. This means that the times quoted in the timing characteristics are the true bus relinquish times of the part and as such are independent of external bus loading capacitances. Specifications subject to change without notice.
1.6mA
TO OUTPUT PIN
1.6V 50pF
200 A
Figure 1. Load Circuit for Access Time and Bus Relinquish Time
4
REV. B
AD7891
ORDERING GUIDE
Model AD7891AS-1 AD7891AP-1 AD7891BS-1 AD7891BP-1 AD7891YS-1 AD7891YP-1 AD7891AS-2 AD7891AP-2 AD7891BS-2 AD7891BP-2 AD7891YS-2
Input Ranges ± 5 V or ± 10 V ± 5 V or ± 10 V ± 5 V or ± 10 V ± 5 V or ± 10 V ± 5 V or ± 10 V ± 5 V or ± 10 V 0 V to 5 V, 0 V to 2.5 V or ± 2.5 V 0 V to 5 V, 0 V to 2.5 V or ± 2.5 V 0 V to 5 V, 0 V to 2.5 V or ± 2.5 V 0 V to 5 V, 0 V to 2.5 V or ± 2.5 V 0 V to 5 V, 0 V to 2.5 V or ± 2.5 V
Sample Rate 454 kSPS 454 kSPS 454 kSPS 454 kSPS 454 kSPS 454 kSPS 500 kSPS 500 kSPS 500 kSPS 500 kSPS 500 kSPS
Relative Accuracy Temperature Range ± 1 LSB ± 1 LSB ± 0.75 LSB ± 0.75 LSB ± 1 LSB ± 1 LSB ± 1 LSB ± 1 LSB ± 0.75 LSB ± 0.75 LSB ± 1 LSB 40°C to +85°C 40°C to +85°C 40°C to +85°C 40°C to +85°C 55°C to +105°C 55°C to +105°C 40°C to +85°C 40°C to +85°C 40°C to +85°C 40°C to +85°C 55°C to +105°C
Package Options* S-44 P-44A S-44 P-44A S-44 P-44A S-44 P-44A S-44 P-44A S-44
*S = Plastic Quad Flatpack (MQFP); P = Plastic Leaded Chip Carrier (PLCC).
PIN CONFIGURATIONS PLCC
STANDBY VIN1A
MQFP
STANDBY VIN1A VIN1B
VIN2A VIN2B
VIN3A VIN3B
VIN4A
VIN4B VIN5A
VIN1B VIN2A
VIN2B VIN3A
VIN3B
VIN4A
VIN4B
VIN5A
VIN5B
6
5
4
3
2
1
44 43 42 41 40 PIN 1 IDENTIFIER
44 43 42 41 40 39 38 37 36 35 34
REF GND 7 NC 8 REF OUT/REF IN 9 VDD 10 AGND 11 MODE 12 DB11/TEST 13 DB10/TEST 14 DB9/TFS 15 DB8/RFS 16 DB7/DATA IN 17
39 VIN6A 38 VIN6B 37 VIN7A 36 VIN7B
REF GND NC REF OUT/REF IN VDD AGND MODE DB11/TEST DB10/TEST DB9/TFS
1 2 3 4 5 6 7 8 9 PIN 1 IDENTIFIER
VIN5B
33 V IN6A 32 V IN6B 31 V IN7A 30 V IN7B 29 V IN8A 28 V IN8B 27 AGND 26 EOC 25 NC 24 CONVST 23 CS
AD7891 PLCC
TOP VIEW (Not to Scale)
35 VIN8A 34 VIN8B 33 AGND 32 EOC 31 NC 30 CONVST 29 CS
AD7891 MQFP
TOP VIEW (Not to Scale)
DB8/RFS 10 DB7/DATA IN 11
12 13 14 15 16 17 18 19 20 21 22
18 19 20 21 22 23 24 25 26 27 28
DB2/SWCON DB1/SWSTBY
WR
DB6/SCLK VDD
DGND
DB4/A1 DB3/A0
DB5/A2/DATA OUT
NC = NO CONNECT
NC = NO CONNECT
REV. B
5
DB5/A2/DATA OUT
DB1/SWSTBY
DB0/FORMAT
DB0/FORMAT
DGND
DB3/A0 DB2/SWCON
DB6/SCLK VDD
DB4/A1
WR RD
RD
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