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Data Sheet
1 MSPS, 14-Bit, Simultaneous Sampling SAR ADC with PGA and Four Comparators
AD7264
FEATURES
Dual, simultaneous sampling, 14-bit, 2-channel ADC True differential analog inputs Programmable gain stage: ×1, ×2, ×3, ×4, ×6, ×8, ×12, ×16,
×24, ×32, ×48, ×64, ×96, ×128 Throughput rate per ADC
1 MSPS for AD7264 Analog input impedance: >1 GΩ Wide input bandwidth
−3 dB bandwidth: 1.7 MHz at gain = 2 4 on-chip comparators SNR: 78 dB typical at gain = 2, 71 dB typical at gain = 32 Device offset calibration System gain calibration On-chip reference: 2.5 V −40°C to +105°C operation High speed serial interface
Compatible with SPI, QSPI™, MICROWIRE™, and DSP 48-lead LFCSP and LQFP packages
GENERAL DESCRIPTION
The AD7264 is a dual, 14-bit, high speed, low power, successive approximation ADC that operates from a single 5 V power supply and features throughput rates of up to 1 MSPS per on-chip ADC. Two complete ADC functions allow simultaneous sampling and conversion of two channels. Each ADC is preceded by a true differential analog input with a PGA. There are 14 gain settings available: ×1, ×2, ×3, ×4, ×6, ×8, ×12, ×16, ×24, ×32, ×48, ×64, ×96, and ×128.
The AD7264 contains four comparators. Comparator A and Comparator B are optimized for low power, whereas Comparator C and Comparator D have fast propagation delays. The AD7264 features a calibration function to remove any device offset error and programmable gain adjust registers to allow input path (for example, sensor) offset and gain compensation. The AD7264 has an on-chip 2.5 V reference that can be disabled if an external reference is preferred. The AD7264 is available in 48-lead LFCSP and LQFP packages.
The AD7264 is ideally suited for monitoring small amplitude signals from a variety of sensors. The devices include all the functionality needed for monitoring the position feedback signals from a variety of analog encoders used in motor control systems.
FUNCTIONAL BLOCK DIAGRAM
AVCC
VREFA
REF
BUF
AD7264
14-BIT
VA+ VA–
PGA
T/H
SUCCESSIVE APPROXIMATION
ADC
OUTPUT DRIVERS
CONTROL LOGIC
VB+ VB–
VREFB
CA_CBVCC CA+ CA– CB+ CB–
CA_CB_GND CC_CDVCC CC+ CC– CD+ CD–
CC_CD_GND
PGA
14-BIT
T/H
SUCCESSIVE
OUTPUT
APPROXIMATION DRIVERS
ADC
BUF
COMP
OUTPUT DRIVERS
COMP
OUTPUT DRIVERS
COMP
OUTPUT DRIVERS
COMP
OUTPUT DRIVERS
DOUTA
SCLK CAL CS REFSEL G0 G1 G2 G3 VDRIVE
DOUTB PD0/DIN PD1 PD2
COUTA
COUTB
COUTC
COUTD
AGND
Figure 1.
DGND
PRODUCT HIGHLIGHTS
1. Integrated PGA with a variety of flexible gain settings to allow detection and conversion of low level analog signals.
2. Each PGA is followed by a dual simultaneous sampling ADC, featuring throughput rates of 1 MSPS per ADC. The conversion result of both ADCs is simultaneously available on separate data lines or in succession on one data line if only one serial port is available.
3. Four integrated comparators that can be used to count signals from pole sensors in motor control applications.
4. Internal 2.5 V reference.
06732-001
Rev. E
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AD7264
TABLE OF CONTENTS
Features .............................................................................................. 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Product Highlights ........................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3
Timing Specifications .................................................................. 6 Absolute Maximum Ratings............................................................ 7
ESD Caution.................................................................................. 7 Pin Configurations and Function Descriptions ........................... 8 Typical Performance Characteristics ........................................... 10 Terminology .................................................................................... 14 Theory of Operation ...................................................................... 15
Circuit Info.