AD7871TQ Analog Devices Inc, AD7871TQ Datasheet

IC ADC 14BIT SAMPLING 28-CDIP

AD7871TQ

Manufacturer Part Number
AD7871TQ
Description
IC ADC 14BIT SAMPLING 28-CDIP
Manufacturer
Analog Devices Inc
Datasheet

Specifications of AD7871TQ

Rohs Status
RoHS non-compliant
Number Of Bits
14
Sampling Rate (per Second)
83k
Data Interface
Serial, Parallel
Number Of Converters
1
Power Dissipation (max)
95mW
Voltage Supply Source
Dual ±
Operating Temperature
-55°C ~ 125°C
Mounting Type
Through Hole
Package / Case
28-CDIP (0.600", 15.24mm)
a
GENERAL DESCRIPTION
The AD7871 and AD7872 are fast, complete, 14-bit analog-to-
digital converters. They consist of a track/hold amplifier,
successive-approximation ADC, 3 V buried Zener reference and
versatile interface logic. The ADC features a self-contained, laser
trimmed internal clock, so no external clock timing components
are required. The on-chip clock may be overridden to synchronize
ADC operation to the digital system for minimum noise.
The AD7871 offers a choice of three data output formats: a sin-
gle, parallel, 14-bit word; two 8-bit bytes or a 14-bit serial data
stream. The AD7872 is a serial output device only. The two
parts are capable of interfacing to all modern microprocessors
and digital signal processors.
The AD7871 and AD7872 operate from 5 V power supplies,
accept bipolar input signals of 3 V and can convert full power
signals up to 41.5 kHz.
In addition to the traditional dc accuracy specifications, the
AD7871 and AD7872 are also fully specified for dynamic perfor-
mance parameters including distortion and signal-to-noise ratio.
Both devices are fabricated in Analog Devices’ LC
technology process. The AD7871 is available in 28-pin plastic DIP
and PLCC packages. The AD7872 is available in a 16-pin plastic
DIP, hermetic DIP and 16-lead SOIC packages.
REV. D
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.
FEATURES
Complete Monolithic 14-Bit ADC
2s Complement Coding
Parallel, Byte and Serial Digital Interface
80 dB SNR at 10 kHz Input Frequency
57 ns Data Access Time
Low Power—50 mW typ
83 kSPS Throughput Rate
16-Lead SOIC (AD7872)
APPLICATIONS
Digital Signal Processing
High Speed Modems
Speech Recognition and Synthesis
Spectrum Analysis
DSP Servo Control
2
MOS mixed
Complete 14-Bit, Sampling ADCs
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
PRODUCT HIGHLIGHTS
1. Complete 14-Bit ADC on a Chip.
2. Dynamic Specifications for DSP Users.
3. Low Power.
FUNCTIONAL BLOCK DIAGRAMS
World Wide Web Site: http://www.analog.com
AD7871/AD7872
© Analog Devices, Inc., 1997
LC
2
MOS

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AD7871TQ Summary of contents

Page 1

FEATURES Complete Monolithic 14-Bit ADC 2s Complement Coding Parallel, Byte and Serial Digital Interface 80 dB SNR at 10 kHz Input Frequency 57 ns Data Access Time Low Power—50 mW typ 83 kSPS Throughput Rate 16-Lead SOIC (AD7872) APPLICATIONS ...

Page 2

AD7871/AD7872–SPECIFICATIONS Parameter 2 DYNAMIC PERFORMANCE 3 Signal-to-Noise Ratio (SNR MIN MAX Total Harmonic Distortion (THD) Peak Harmonic or Spurious Noise Intermodulation Distortion (IMD) Second Order Terms Third Order Terms Track/Hold Acquisition Time DC ACCURACY ...

Page 3

TIMING CHARACTERISTICS Limit MIN MAX Parameter ( Versions) (T Version ...

Page 4

AD7871/AD7872 AD7871 PIN FUNCTION DESCRIPTION DIP No. Mnemonic Function 1 CONVST Convert Start. A low to high transition on this input puts the track/hold into the hold mode. This input is asynchronous to the CLK. CS and RD must be ...

Page 5

AD7872 PIN FUNCTION DESCRIPTION DIP No. Mnemonic Function 1 CONTROL Control Input. With this pin the SCLK is noncontinuous; with this pin at –5 V, the SCLK is continuous. 2 CONVST Convert Start. A low to high ...

Page 6

AD7871/AD7872 CONVERTER DETAILS The AD7871/AD7872 is a complete 14-bit A/D converter, re- quiring no external components apart from power supply decoupling capacitors comprised of a 14-bit successive ap- proximation ADC based on a fast settling voltage-output DAC, a ...

Page 7

Gain error can be adjusted at either the first code transition (ADC negative full scale) or the last code transition (ADC posi- tive full scale). The trim procedures for both cases are as follows (see Figure 6). Positive Full-Scale Adjust ...

Page 8

AD7871/AD7872 placed on the data bus. These six bits are right justified and thereby occupy the lower six bits of the byte while the upper two bits are zeros. Serial Output Format Serial data is available on the AD7871 when ...

Page 9

Figure 10. Mode 1 Timing Diagram, Byte or Serial Read Figure 11. Mode 2 Timing Diagram, 14-Bit Parallel Read Figure 12. Mode 2 Timing Diagram, Byte or Serial Read REV. D AD7871/AD7872 –9– ...

Page 10

AD7871/AD7872 DYNAMIC SPECIFICATIONS The AD7871/AD7872 is specified and tested for dynamic per- formance specifications as well as traditional dc specifications such as Integral and Differential Nonlinearity. These ac specifi- cations are required for signal processing applications such as Speech Recognition, ...

Page 11

Using the CCIF standard where two input frequencies near the top end of the input bandwidth are used, the second and third or- der terms are of different significance. The second order terms are usually distanced in frequency from the ...

Page 12

AD7871/AD7872 Serial Interfacing Both the AD7871 and the AD7872 have an identical serial in- terface. The diagrams that follow show the AD7872 interfaces only, but the AD7871 could just as easily be used in these cir- cuits. Figures 19, 20 ...

Page 13

LAYOUT HINTS Ensure that the layout for the printed circuit board has the digi- tal and analog signal lines separated as much as possible. Take care not to run a digital track alongside an analog signal track. Guard (screen) the ...

Page 14

AD7871/AD7872 Figure 24. Data Acquisition Circuit Using the AD7871/AD7872 Figure 25. PCB Silkscreen for Figure 24 –14– REV. D ...

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Figure 26. PCB Component Side Layout for Figure 24 REV. D Figure 27. PCB Solder Side Layout for Figure 24 –15– AD7871/AD7872 ...

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... dBs min AD7871JP + dBs min AD7871KP + dBs min 4 AD7871TQ – +125 C 79 dBs min NOTES 1 To order MIL-STD-883, Class B, processed parts, add /883B to part number. Contact local sales office for military data sheet. 2 Contact local sales office for LCCC availability Plastic DIP Plastic Leaded Chip Carrier (PLCC);Q = Cerdip. ...

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