AD7280AWBSTZ Analog Devices Inc, AD7280AWBSTZ Datasheet
AD7280AWBSTZ
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AD7280AWBSTZ Summary of contents
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FEATURES 12-bit ADC, 1 μs per channel conversion time 6 analog input channels, common-mode range 0 27 auxiliary ADC inputs ±1.6 mV cell voltage accuracy On-chip voltage regulator Cell balancing interface Daisy-chain interface o Internal reference: ...
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AD7280A TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Power Specifications .................................................................... 5 Timing Specifications .................................................................. 6 Absolute Maximum Ratings ............................................................ 7 Thermal ...
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SPECIFICATIONS Table 1. Parameter 1 DC ACCURACY (VIN0 TO VIN6) Resolution Integral Nonlinearity Differential Nonlinearity Offset Error Offset Error Match Gain Error Gain ...
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AD7280A Parameter REGULATOR OUTPUT (V ) REG Input Voltage Range 13 Output Voltage, V REG 14 Output Current Line Regulation Load Regulation Internal Short Protection Limit 15 CELL BALANCING OUTPUTS Output High Voltage Output Low Voltage ...
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POWER SPECIFICATIONS Table 2. Parameter POWER REQUIREMENTS V DD Master Device I During Conversion DD I During Data Readback DD I During Cell ...
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AD7280A TIMING SPECIFICATIONS Table 3. 1 Parameter Min Typ t CONV 425 560 425 t ACQ 340 400 340 t ACQ 665 800 ...
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ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 4. Parameter Rating AGND −0 + AGND, DGND −0 +0 VIN0 to VIN5 Voltage ...
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AD7280A PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 6. Pin Function Descriptions Pin No. Mnemonic Description VIN6 to VIN0 Analog Input 6 to Analog Input 0. VIN0 should be connected to the base of the series-connected ...
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Pin No. Mnemonic Description 21 CS Chip Select Input. The CS input is used to frame the input and output data on the SPI and daisy-chain interfaces. On the master AD7280A device, the CS input is supplied from the DSP/microprocessor. ...
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AD7280A Pin No. Mnemonic Description 43 SDIhi Serial Data Input in Daisy-Chain Mode. The data from each AD7280A in the daisy chain is passed through the SDOlo output and the SDIhi input of each AD7280A in the chain and is ...
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TYPICAL PERFORMANCE CHARACTERISTICS 5 10V 22. 29.9V DD 5.3 5.2 5.1 5.0 4.9 –40 – TEMPERATURE (°C) Figure 4. V vs. Temperature for Different ...
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AD7280A 10,000 8870 8000 6000 4000 2000 956 167 7 0 2660 2661 2662 2663 2664 2665 CODE Figure 10. Histogram of Codes for 10,000 Samples, Even Cell Voltage Channels 10,000 9072 8000 6000 4000 2000 692 236 0 2942 ...
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10V DD 6 16. 22. 29.9V DD 3.0 1.5 0 –1.5 –3.0 –4.5 –40 – TEMPERATURE (°C) Figure 16. Total Unadjusted ...
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AD7280A TERMINOLOGY Differential Nonlinearity (DNL) DNL is the difference between the measured and the ideal 1 LSB change between any two adjacent codes in the ADC. Integral Nonlinearity (INL) INL is the maximum deviation from a straight line passing through ...
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THEORY OF OPERATION CIRCUIT INFORMATION The AD7280A is a lithium ion (Li-Ion) battery monitoring chip that can monitor the voltage and temperature of four, five, or six series-connected Li-Ion battery cells. The AD7280A also provides an interface that can be ...
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AD7280A VIN6 VIN5 VIN4 VIN3 VIN2 VIN1 VIN0 Figure 23. Mux Configuration During VIN2 to VIN1 Sampling The ADC is a successive approximation register analog-to- digital converter (SAR ADC). The converter is composed of a comparator, a SAR, control logic, ...
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TYPICAL CONNECTION DIAGRAMS 0.1µF The AD7280A can be used to monitor four, five, or six battery cells connected in series. A typical configuration for a six-cell battery monitoring application is shown in Figure 28. However, lithium ion battery applications require ...
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AD7280A V 10µF 100nF 100nF V (n – 10kΩ 100nF 10kΩ 100nF 10kΩ 100nF 10kΩ 100nF 10kΩ 100nF 10kΩ 100nF 10kΩ 7 FERRITE V 10µF 100nF 100nF 10kΩ 100nF 10kΩ 100nF 10kΩ 100nF 10kΩ 100nF ...
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REFERENCE The internal reference is temperature compensated to 2.5 V. The reference is trimmed to provide a typical drift of ±3 ppm/°C. As shown in Figure 30, the internal reference circuitry consists of a 1.2 V band gap reference and ...
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AD7280A Note that 90 μs should be allowed before initiating any conver- sions following any change to Bits[D15:D14]. This time should be allowed between writing to the control register to change the selected conversions and initiating the first conversion. Conversions ...
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The 10 kΩ resistors in series with the inputs provide protection for the analog inputs in the event of an overvoltage or undervoltage on those inputs. The 100 nF capacitor across the differential inputs acts as a low-pass filter in ...
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AD7280A CONVERSION WINDOW As described in the Converting Cell Voltages and Auxiliary ADC Inputs section, the AD7280A converts the selected cell voltage and auxiliary ADC inputs in a defined sequence (see Figure 31). As described in the Circuit Information section, ...
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AUXILIARY ADC INPUTS The AD7280A provides six single-ended analog inputs to the ADC—AUX1 to AUX6—which can be used to convert the voltage output of a thermistor temperature measurement circuit. In the event that no temperature measurements are required or that ...
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AD7280A POWER-DOWN The AD7280A provides two power-down options. • Full power-down (hardware) • Software power-down Full Power-Down (Hardware) The AD7280A can be placed into full power-down mode, which requires only 5 μA maximum current, by taking the PD pin low. ...
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Software Power-Down The AD7280A can be placed into software power-down mode, which requires 3 current, by setting Bit D8 in the control register through the serial interface. The CNVST pin should be gated out before generating a software ...
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AD7280A An example of how damage to the external transistors can occur is a connection sequence that first provides the system ground (the ground supply to the master AD7280A in the daisy chain) followed by a connection from any of ...
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ALERT OUTPUT The alert output on the AD7280A can be used to indicate whether any of the following faults has occurred: • Cell overvoltage • Cell undervoltage • Auxiliary ADC overvoltage • Auxiliary ADC undervoltage Following each completed conversion, the ...
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AD7280A REGISTER MAP Table 13. Register Register Register Name Address Data Cell Voltage 1 0x00 D11 to D0 Cell Voltage 2 0x01 D11 to D0 Cell Voltage 3 0x02 D11 to D0 Cell Voltage 4 0x03 D11 to D0 Cell ...
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Select Conversion Inputs Bits[D15:D14] of the control register determine which cell voltages and auxiliary ADC inputs are converted following a convert start command. The default value of D15 and D14 on power-up is 00. Read Conversion Results Bits[D13:D12] of the ...
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AD7280A CELL UNDERVOLTAGE REGISTER The cell undervoltage register determines the low voltage thresh- old of the AD7280A. Cell voltage conversions lower than the undervoltage threshold trigger the alert output. The AD7280A allows the user to set the undervoltage threshold to ...
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PD TIMER REGISTER The PD timer register allows the user to configure a set time after which the AD7280A is automatically powered down. The AD7280A allows the user to set the PD timer to a value from 0 minutes to ...
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AD7280A SERIAL INTERFACE The AD7280A serial interface is Mode 1 SPI compliant, that is, the clock polarity (CPOL and the clock phase (CPHA The interface consists of four signals SCLK, SDI, and SDO. The ...
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READING FROM THE AD7280A There are two types of read operation for the AD7280A: • Conversion results read • Register data read The data returned from a conversion result read operation includes the device address, the channel address, the write ...
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AD7280A DAISY-CHAIN INTERFACE In a battery monitoring application eight AD7280As can be daisy-chained together to allow individual lithium ion cell voltages to be monitored. Each AD7280A is capable of monitoring up to six Li-Ion cells ...
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WRITE ACKNOWLEDGE For all write commands received by the AD7280A, the device internally performs a CRC calculation on Bits[D31:D11] of the received data and verifies this CRC against the CRC transmitted by the DSP/microprocessor. If there is a difference between ...
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AD7280A Read Operation CRC For reads from the AD7280A, the 8-bit CRC is generated by the AD7280A based on Bits[D31:D10] of the 32-bit read cycle and is transmitted using Bits[D9:D2] of the same read cycle. The data received is divided ...
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CRC Calculation Example 3 This example shows the breakdown of a 32-bit register read from the low byte of the control register of the master device, that is, Device 0. The CRC is computed in the AD7280A on Bits[D31:D10], that ...
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AD7280A EXAMPLES OF INTERFACING WITH THE AD7280A The AD7280A supports a number of read options. The user can read back the results from • All conversions completed on all parts in the chain • Individual registers on all parts in ...
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Example 1: Initialize All Parts in a Daisy Chain on Initial Power-Up and When Coming Out of Power-Down Example 1 shows a typical device initialization routine initialize all device addresses, set Bit D2 and Bit D0 of the ...
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AD7280A Example 3: Convert and Read All Parts, All Voltages, and Three Auxiliary ADC Inputs per Part In this example assumed that all AD7280As in the daisy chain have been initialized to their correct device addresses. 1. Write ...
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Example 4: Convert and Read a Single Voltage or Auxiliary ADC Input Result from One Part In this example assumed that all AD7280As in the daisy chain have been initialized to their correct device addresses. 1. The register ...
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AD7280A Example 5: Read a Single Configuration Register on All Parts In this example assumed that all AD7280As in the daisy chain have been initialized to their correct device addresses. 1. Set Bit D0 of the control register ...
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Example 7: Self-Test Conversion on All Parts Example 7 shows a self-test conversion routine for all parts in a daisy chain select the self-test conversion, set Bits[D15:D14] of the control register to 1, and set Bits[D13:D12] of the ...
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AD7280A EMC GUIDELINES SCHEMATIC AND LAYOUT GUIDELINES To optimize the performance of a chain of AD7280A devices under noisy conditions—for example, when experiencing electromagnetic interference—the following schematic and layout guidelines should be observed (see Figure 29). 1. All AD7280A devices ...
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If a second convert start signal is received by the AD7280A while the conversion results are being read back, the data being read back from the device, or chain of devices, can be corrupted. The corruption of data occurs at ...
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... Temperature Range AD7280ABSTZ −40°C to +105°C AD7280ABSTZ-RL −40°C to +105°C AD7280AWBSTZ −40°C to +105°C AD7280AWBSTZ-RL −40°C to +105° RoHS Compliant Part Qualified for Automotive Applications. AUTOMOTIVE PRODUCTS The AD7280AW models are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. Note that these automotive models may have specifications that differ from the commercial models ...
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NOTES Rev Page AD7280A ...
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AD7280A NOTES ©2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D09435-0-4/11(0) Rev Page ...