MAX14921 Evaluation Kit Evaluates: MAX14921
General Description
The MAX14921 evaluation kit (EV kit) demonstrates
a high-accuracy 16-cell battery-management reference
design. The MAX14921 is a high-accuracy 16-cell mea-
surement analog front-end (AFE) in an 80-pin TQFP
surface-mount package. The EV kit features an ADC and
reference, and an isolated interface to a PC through a
USB port to easily measure all cell voltages. Cell stacks
up to 16 cells or 65V can be monitored, whichever is lower.
The EV kit circuit demonstrates all the features of the
device through a GUI application on a Windows®-based
PC.
Benets and Features
● 16-Cell/65V(max)StackOperatingVoltageRange
● Built-InIsolatedUSBInterfacetoaWindows-
Based PC
● Plugh-and-PlayGUIDemonstratesAlltheMajor
Features of the MAX14921
● μCFirmwareinCAvailableUponRequest
● ScrewTerminalBatteryConnector
● ProvenPCBLayout
● FullyAssembledandTested
19-6668; Rev 0; 4/13
Ordering Information appears at end of data sheet.
MAX14921 EV Kit Photo
Component List
Windows is a registered trademark and a registered service
mark of Microsoft Corporation.
Block Diagram appears at end of data sheet.
DESIGNATION QTY DESCRIPTION
C1–C16 16
1.2µF±10%,16VX7Rceramic
capacitors (0805)
KEMETC0805C125K4RACTU
C17 1
10µF±10%,10VX5Rceramic
capacitor (0805)
KEMET C0805C106K8PAC
C18–C22,
C30, C107,
C126–C129,
C135, C138
13
0.1µF±10%,16VX7Rceramic
capacitors (0603)
MurataGRM188R71C104K
C23, C31,
C108–C111,
C115, C130,
C131, C136
10
1µF±10%,16VX7Rceramic
capacitors (0603)
MurataGRM188R71C105K
C24 1
0.1µF±10%,100VX7Rceramic
capacitor (0603)
MurataGRM188R72A104KA35D
C25, C29 2
100pF±10%,16VX7Rceramic
capacitors (0603)
AVX 0603YC101KAT2A
C27, C28 2
0.01µF±5%,16VX7Rceramic
capacitors (0603)
AVX 0603YC103JAT2A
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Component List (continued)
DESIGNATION QTY DESCRIPTION
C101, C103,
C104, C132,
C137
5
4.7µF+80%/-20%,10VY5V
ceramic capacitors (0603)
MurataGRM188F51A475ZE20D
C105, C106 2
18pF ±5%, 50V NP0 ceramic
capacitors (0603)
MurataGRM1885C1H180JA01D
C112–C114,
C116–C119 0Not installed, ceramic capacitors
(0603)
C133 1
4.7µF±10%,16VX7Rceramic
capacitor (0603)
MurataGRM21BR71C475KA73L
C134 1
0.47µF±10%,16VX5Rceramic
capacitor (0603)
TDKC1608X5R1C474K
D1, D101, D102 3
100V, 200mW Schottky diodes
(SOD123)
Diodes Inc. BAT46W-7-F
D2 1
68V, 500mW zener diode
(SOD123)
ONSemiMMSZ5266BT1G
D3 0 Notinstalled,diode(SOD123)
L101 1600Ω,200mAferritechip(0805)
MurataBLM21AG601SN1
LED101,LED103 2RedLEDs
Lite-OnLTST-C150CKT
LED102 1GreenLED
Lite-OnLTST-C150GKT
P2 1 24-pin power connector
Weidmuller 1841850000
P101 0
Not installed, 72-pin dual-row
connector header, 0.1in centers
Sullins PEC36DAAN
P102, P105 2 USB micro-B connectors
HiroseZX62-B-5PA(11)
P103 0
Not installed, USB type-A
connector
Mill-Max896-43-004-00-000000
P104 0
Not installed, 9-pin header, 0.1in
centers
Samtec TSW-150-07-T-S
P106–P113 0 Not installed, test points
DESIGNATION QTY DESCRIPTION
Q1–Q16 16
30Vn-channelFETs(SOT23)
ONSemiNTR4170NT1Gor
NXP 2N7002BK,215
Q101–Q103 3
40V npn bipolar transistors
(SOT23)
ONSemiMMBT3904LT3G
R1,R40–R54 16 100Ω±5%resistors(0603)
R2,R58 2220Ω±1%resistors(0603)
R3,R4,R101,
R108,R131,
R133,R135,
R140
810kΩ±1%resistors(0603)
R7–R22 16 3.3kΩ±5%resistors(0603)
R23–R38 16 33Ω±5%,1Wresistors(2512)
R39 1100Ω±5%resistor(0805)
R56,R57 21kΩ±1%resistors(0603)
R59,R60,
R126,R129 410kΩ±1%resistors(0603)
R61,R106,
R107,R109,
R110,
R116–R128
0 Not installed, resistors (0603)
R102,R103 2137Ω±1%resistors(0805)
R111 1332Ω±1%resistor(0603)
R112 139.2kΩ±1%resistor(0603)
R113 1102kΩ±1%resistor(0603)
R114 13.92kΩ±1%resistor(0603)
R115 11.5kΩ±1%resistor(0603)
R130 11kΩ±5%resistor(0805)
R132 16.04kΩ±1%resistor(0603)
R134 13.32kΩ±1%resistor(0603)
R136,R137 2301kΩ±1%resistors(0603)
R138,R139 220kΩ±1%resistors(0603)
R141 128kΩ±1%resistor(0603)
S101, S102 2 Momentary pushbutton switches
OMRONB3FS-1000P
S103–S106 0 Not installed, momentary
pushbutton switches
T101 1
1:1:2.6:2.6 1.5kVRMS isolation
module
HALOElectronicsTGM-H281NF
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Component List (continued)
*EP = Exposed pad.
Component Suppliers
Note: Indicate that you are using the MAX14921 when contacting these component suppliers.
SUPPLIER PHONE WEBSITE
AVX North America 864-967-2150 www.avx.com
Citizen America Corp. 310-781-1460 www.citizencrystal.com
Diodes Incorporated 805-446-4800 www.diodes.com
HALOElectronics,Inc. 650-903-3800 www.haloelectronics.com
HiroseElectricCo.,Ltd. 81-3-3491-9741 www.hirose.com
KEMET Corp. 864-963-6300 www.kemet.com
Lite-On,Inc. 408-946-4873 www.us.liteon.com
Murata Americas 800-241-6574 www.murataamericas.com
OMRONCorp. — www.omron.com
ONSemiconductor 602-244-6600 www.onsemi.com
Samtec, Inc. 800-726-8329 www.samtec.com
STMicroelectronics 408-452-8585 www.us.st.com
Sullins Electronics Corp. 760-744-0125 www.sullinselectronics.com
TDK Corp. 847-803-6100 www.component.tdk.com
DESIGNATION QTY DESCRIPTION
U1 1
High-accuracy16-cell
measurement AFEs (80 TQFP)
MaximMAX14921ECS+
U2 1 4.096Vvoltagereference(8SO)
MaximMAX6126AASA41+
U3 1
16-bit analog-to-digital converter
(10MSOP)
MaximMAX11163EUB+
U4 1 Opamp(5SC70)
MaximMAX9620AXK+
U101 1
ARM-based32-bitmicrocontroller
(64LQFP)
STMicroSTM32F101RET6
U102 0
Notinstalled,quad6Mbpslevel
translator (12 TQFN)
MaximMAX3395EETC+
U103, U105 0
Not installed, 1.5A current-limit
switches (8 TDFN-EP*)
MaximMAX14523AATA+
U104 0
Notinstalled,USBperipheral/host
controller with SPI interface
(32 TQFP)
MaximMAX3421EETJ+
DESIGNATION QTY DESCRIPTION
U107, U108 2
6-channel 600VRMS digital
isolators(16SO)
MaximMAX14850ASE+
U109, U110 2
12VadjustableLDOs
(6 TDFN-EP*)
MaximMAX8880ETT+
U111 1
3W primary-side transformer
H-bridgedriver(8SO)
MaximMAX256ASA+
U112 1 USBtoserialUART(28SSOP)
FTDIFT232RL-REEL
U113, U114 2
1.5A current-limit switches
(8 TDFN-EP*)
MaximMAX14523AATA+
Y101 1 8MHz,18pFcrystal(HC49/US)
CitizenHCM49-8.000MABJ-UT
Y102 0
Notinstalled,12MHz18pFcrystal
(4 SMD)
CTS 406C35D12M00000
— 1 PCB: MAX14921 ADVANCED
EVALPCB
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Figure 1. Detachable Battery Connector
Figure 2. Files Required to Run the Application
Quick Start
Required Equipment
● MAX14921 EV kit
● The two files: The “MAX14921 Eval PCB” applica-
tion(MAX14921EVALPCB.EXE)andtheDLL
“msvcr100.dll”
● Visit www.maximintegrated.com/evkitsoftware to
download the latest version of the EV kit software
● PC running Windows, with 1 spare USB port
● USB to micro-USB cable
● Stack of batteries to test
Procedure
Step 1: Attach Battery
Note: Total battery stack voltage cannot exceed 65V.
Youriskfailureofthedeviceifyouexceedthisvoltage.
Lookatthedetachablebatteryconnector,andseehowit
mates to the EV kit, see Figure 1. Connect the bottom cell
of the battery stack (the lowest voltage) to the VC0 screw
terminalandtotheadjacentGNDscrewterminal.Besure
to use two separate wires for these connections. Connect
the top of that cell (also connected to the bottom of the
second cell) to the VC1 screw terminal.
Continue in this fashion until you connect the top of the
16th cell of the battery stack (the highest voltage) to the
VC16 screw terminal and the POWER screw terminal.
Be sure to use two separate wires for these connections.
What if you have less than 16 cells in your battery
stack?Thedevicecanhandle3–16cells.Forexample,
you have only 12 cells, in that case, connect the top of
the 12th cell (the highest voltage) to all VC12–VC16 and
POWERscrewterminals.
Why do I need to connect the top and the bottom of
the battery stack twice?Thedevicetakesjustasmall
amount of current from the battery stack to operate. This
tiny power consumption is routed through the POWER
and GND terminals. Providing a separate measurement
trace to the top and the bottom of the battery stack
ensures that even this tiny current does not affect cell
measurement accuracy.
Plug the terminal strip portion of the connector into the
mating plug on the EV kit. See Figure 1.
Step 2: Run the Application
Visit www.maximintegrated.com/evkitsoftware to
download the latest version of the EV kit software,
MAX14921EVKITSoftware.ZIP.SavetheEVkitsoftware
toatemporaryfolder.Openthe.ZIPfileandextractthe
.EXE file to your preferred location. The .EXE file is the
actual EV kit GUI and not an install program. You can
store the .EXE file wherever you like and then uninstall it
later by simply deleting the .EXE file.
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Ensure that both files the application (“MAX14921 Eval
PCB” and the DLL “msvcr100.dll”) are in the same
folder. Navigate to the folder with the files and select the
“MAX14921 Eval PCB” application. Double-click on it to
run the application. See Figure 2.
If I have the files on a separate drive, do I need to
move these files to my PC? If you have the files on a
USB memory device, there is no need to move them. As
long as the two files remain in the same folder, the applica-
tion runs anywhere, including from a USB memory device.
Does the application install a driver on my PC? No,
it does not. The application needs no drivers other than
those built into Windows.
Oncetheapplicationisrunning,youshouldseeawindow
similar to the one in Figure 3. Most of the data items are
blank and are automatically filled in when the application
detects an EV kit attached to any USB port on the computer.
Step 3: Attach the EV Kit to the PC
Use the USB cable to attach the EV kit to the PC. The
correct USB connector on the EV kit is labeled P102, and
isnearthetopleftofthePCB,underS101,RESET.
LED103,totheleftoftheisolationtransformerglowsred
when the EV kit is properly powered (see Figure 4). Also,
LED102, towards the middle of the PCB, blinks green
when the microprocessor is running the firmware.
OnceyouhavecorrectlyattachedtheEVkittothePC,the
application automatically starts reporting cell voltage data.
Detailed Description of Hardware
The MAX14921 EV kit is a fully assembled and tested cir-
cuit board demonstrating the capabilities of the MAX14921
high-accuracy 16-cell battery management AFE IC in an
80-pin surface-mount TQFP package. This EV kit works
withaPC-basedGUIdemonstratingallthemajorfeatures
of the device. The EV kit also features a MAX6126 preci-
sion voltage reference and a MAX11163 16-bit, 500ksps
serial ADC. The MAX14921 and the analog portion of the
ADC are powered by the battery cell stack. All other EV kit
circuits are powered from the USB interface.
Ensure that the total cell stack voltage does not
exceed 65V. Reduce the number of cells in the stack,
if needed, to keep to 65V or lower.
Figure 3. MAX14921 EV Kit GUI Figure 4. MAX14921 EV Kit Attachment
ATTACH
TO PC HERE
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Analog Cell Voltage Acquisition
The heart of the EV kit is the analog signal path.
The MAX14921 (U1) operates in two major phases. In
the first phase, cell voltages present at the cell stack
connector(P2)areacquiredontothesamplingcapacitors
C1–C16through100ΩseriesresistorsR1andR40–R54.
These resistors limit the current during fault conditions.
The default GUI sampling time of 4ms is optimized to
work with these resistors and capacitors. All cell voltages
are captured simultaneously.
In the second phase, captured cell voltages are level shift-
ed down and presented to the ADC (U3) for conversion.
Asmallcircuit(R2andC25)filtersthesignalbetweenthe
MAX14921 and the MAX11163 ADC. To improve accu-
racy, an external voltage reference, MAX6126 (U2), is
used to provide a stable reference to the ADC.
Auxiliary Inputs (T1–T3)
The MAX14921 also includes three general-purpose
analog inputs, ranging from 0 to 5V that can be multi-
plexedtotheADCforconversion.Measuringtemperature
through inexpensive thermistors is one common use for
these extra inputs. Inputs T2 and T3 on the EV kit are
presettoaccepta10kΩthermistor.TheMAX9620opamp
(U4)buffersthereferencevoltageto10kΩpullupresistors
(R59andR60),whilefilteringisdonewithR56,R57,C27,
and C28.
InputT1isuncommitted.Thepullupresistor(R61)forthis
inputisnotinstalled,anddifferentfiltercomponents(R58
and C29) are used, optimized for faster input signals.
Cell Balancing
TheEVkitincludestransistorsQ1–Q16and33Ωpower
resistors for cell-balancing applications. These transistors
can be enabled or disabled, using the SPI interface, in
any combination at any time for passive cell-balancing
purposes.
Power and Isolation
The EV kit accepts power from either USB con-
nector, P102 or P105. To use the supplied GUI,
connect to P102. P105 is used only when reprogram-
ming microprocessor U101. Because a different protocol
is used for reprogramming, the GUI does not recognize
the EV kit if the USB cable is plugged in to P105. Two
MAX14523A power switches (U113 and U114) auto-
matically power the EV kit from either USB connector.
A MAX8880 linear regulator (U109) provides a clean 3.3V
supply for the microprocessor (U101) and related circuitry.
The microprocessor uses the Q101 and Q102 circuit to
switchin orouta1.5kΩpullupresistoron theUSBDP
line, to implement USB suspend mode.
To avoid any damage to the PC in the case of accidental
miswiring, the cell voltage acquisition circuitry is elec-
trically isolated from the microprocessor circuitry and
USB interface. Two MAX14850 digital isolators (U107,
U108) provide this isolation for the SPI and other digital
signals and a MAX256 transformer driver (U111), along
with transformer T101 provide an isolated supply to a
MAX8880 linear regulator (U110). The MAX8880 provides
a clean 5V supply for all circuits in the analog capture
path, with the exception of the internal supply of the
MAX14921 and the analog supply of the MAX11163 ADC,
which power from the MAX14921’s internal 5V regulator.
Detailed Description of Software
The Windows-based graphical-user interface (GUI)
application is simple to use and demonstrates all the
important features of the device. The application auto-
matically detects the presence of an EV kit. If the applica-
tion is run before any EV kit is attached, the fields appear
mostly blank, as seen in Figure 3. Once an EV kit is
detected, fields are automatically filled in.
Status Section
Figure 5 shows the “Status” window, located at the
bottom-right corner of the application window. It indicates
the status of the EV kit connection to the PC.
Thetextinthewindowindicateswhethertheapplication
sees an EV kit or not. It indicates either “EVK Attached,”
or “EVK Detached.”
The third line details the real-time instructions to the EV kit
fromtheapplication.Table1includesadetailedexplana-
tion for each label.
Control Section
Much of the control and status information for the EV kit is
available in the top-right section of the application. Figure
6 and Table 2 detail the available controls and indicators.
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Figure 5. Status Section
Figure 6. Control Section
Table 1. EV Kit Status Labels
Table 2. EV Kit Control Section Details (Figure 6)
LABEL DESCRIPTION
Idling
The application has made one measurement,
and continues measuring once the user has
clicked either the “Measure” or the “Measure
Once”button.
Measuring The application is capturing data continuously
and presenting it in the application window.
OffsetCal
The device is performing an offset calibration,
asdetailedintheMAX14920/MAX14921IC
data sheet.
OpenChk
The device is performing an opens check, as
detailedintheMAX14920/MAX14921ICdata
sheet.
Streaming The application is capturing data at speed
fromthedevice,andiswritingittoadiscle.
Waiting The application is waiting for an EV kit to be
attached to the PC through a USB port.
ITEM LABEL READ/WRITE DESCRIPTION
1Number of
Cells Write
Enter the number of cells in the battery stack here, from 3–16 cells. This affects
how many cell voltages display in the application window, as well as how many
cellvoltagesarerecordedwhenstreamingdatatoale.
2Sample Time Write
Sets the sample time, from 1ms to 1,000ms. This refers to the tSAMPL
specicationintheMAX14920/MAX14921ICdatasheet.Thisisthelengthof
time that the device stays in sample phase. Setting this too low affects how
accurately the cell voltages are measured. Setting it too high limits how often the
cellvoltagescanberead.RefertoFigure5intheMAX14920/MAX14921ICdata
sheet for more details. The default value of 4ms is optimized to work with the
1.2µFsamplingcapacitorsandthe100Ωseriesresistors.
3Settling Time Write
Sets the delay from when the device provides a cell voltage sample to when the
ADC starts conversion, from 1µs to 10,000µs. This refers to the tSETspecication
inFigure5intheMAX14920/MAX14921ICdatasheet.Leaveatthedefaultof
50µs.
1) CELL SELECTION ENTRY
5) PRODUCT ID INDICATOR
6) DIE REV INDICATOR
7) LDO UV INDICATOR
8) READY BIT INDICATOR
9) OVER TEMP INDICATOR
10) MAX14921 ENABLE
11) ENGAGE OW DETECT
12) PERFORM OFFSET CAL
13) MEASURE REPEATEDLY
14) MEASURE ONCE
15) CELL BALANCE GLOBAL
2) SAMPLE TIME ENTRY
3) SETTLING TIME ENTRY
4) REPEAT TIME ENTRY
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Table 2. EV Kit Control Section Details (Figure 6) (continued)
ITEM LABEL READ/WRITE DESCRIPTION
4RepeatTime Write
Setsthedelaybetweenacquisitionsofasetofcellvoltages.Forexample,atthe
default 10ms, the device samples cell voltages 100 times per second. This entry is
ignored by the application when it updates the cell voltages directly on the window.
However,whenstreamingdatatoale,thisparametersetshowoftenanewdata
setiswrittentothele.Therepeattimemustbeatleast1msgreaterthanthe
sample time. If not, the repeat time is about 1ms greater than the sample time.
5 Product Read This value is obtained from the device when the EV kit is attached to the PC.
6DieRevision Read This value is obtained from the device when the EV kit is attached to the PC.
7VA UV Read
This status indicator is updated regularly once the EV kit is attached to the PC.
Aredindicatormeansthattheinternal5VLDOisunabletoprovidethecorrect
voltagetothedeviceortotheattachedexternalcircuitry.
8Readyto
Operate Read This status bit is updated regularly from the device when the EV kit is attached to
the PC. A red indicator means that there is something wrong with the device.
9Thermal
Shutdown Read This status bit is updated continuously from the device when the EV kit is attached
to the PC. A red indicator means that the device is too hot.
10 Power Down Action Click this control button to toggle the EN pin on the device and enable or disable
the IC.
11 DetectOpen
Wires Action
Click this control button to implement open-wire detection as detailed in the First
Method of Open-Wire DetectionsectionintheMAX14920/MAX14921ICdata
sheet. This detection is not continuous and happens once each time this control
ispushed.Itupdatestheopen-wire(OW)indicatorsinthecellvoltagereadout
section of the application window. Indicators are dimmed green or red when this
information is considered stale.
12 OffsetCal Action
Click this control button to implement the offset calibration feature, as detailed in
the Buffer Amplier Offset CalibrationsectionintheMAX14920/MAX14921IC
data sheet. The output buffer offset is minimized once calibration is complete.
13 Measure Action
Click this control button to enable continuous reading of the cell voltages, the
cellU/OVbits,andtheT1–T3voltages.Theapplicationupdates6to7timesper
second unless the sample time is set too high.
14 MeasureOnce Action Clickthiscontrolbuttontodisablecontinuousreading.Onlyonesetofdatais
measured and presented in the application window when this button is pushed.
15 Balance
Enable/Disable Selection
This global control either disables or enables cell balancing for all cells whose
balancecheckboxesarechecked.Cellbalancingcanbeindividuallyenabledwith
thebalancecheckboxes.
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Cell Readout Section
Thetop-leftsectioniswherecellvoltagesarereported.Overvoltage,undervoltage,andopen-wiredetectionare
alsoindicatedhere.Cellbalancingforindivididualcellscanbeenabled/disabledinthissectionaswell.(Figure7)
Figure 7. Cell Readout Section
Table 3. EV Kit Cell Readout Section Details (Figure 7)
ITEM LABEL READ/WRITE DESCRIPTION
1 Voltage Read These are the cell voltages. Cell voltages are reported individually with 0.1mV
resolution.
2U/OV Read These indicators are updated each time cell voltages are reported. A red indicator
means that the cell voltage is either too high (> 5V) or too low (< 1.5V).
3OW Read
These indicators report the result of the most recent open-wire detection. Gray
boxesindicatenoopen-wiredetectionhasyetbeenrequested.Refertothe
MAX14920/MAX14921ICdatasheetfordetailsregardinghowtousethestatus
indicators to determine open-wire conditions.
4 Balance Write
Checktheseboxestoenable/disablecellbalancingforindividualcells.When
theglobalcell-balancecontrolisenabled,eachcheckedboxactivatesthecell-
balancing switch for that corresponding cell. See the Detailed Description of
Hardware section for more details.
5 Pack Read Thiseldreportsthemathematicalsumoftheindividualcellvoltages.Itisthe
voltage of the entire cell stack.
1) CELL VOLTAGE READOUT
2) UV/OV INDICATOR
5) TOTAL VOLTAGE READOUT
3) LAST OW DETECT STATUS
4) INDIVIDUAL CELL BALANCE CHECK BOXES
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Auxiliary Input Section
The device also has three general-purpose analog
inputs (T1–T3) whose voltages can also be presented
to the ADC. Unlike the cell voltage inputs, the T_ inputs
are neither level shifted nor sampled. The auxiliary
input section provides a way to see these T inputs in
action. Figure 8 and Table 4 detail the available control
and actions.
Streaming Data to a File
The EV kit can collect cell and T_ input data and stream it
to a file. This is when the repeat time parameter is used.
At the default setting of 10ms, data is logged at 100 data
sets per second.
To stream cell data, push the “Stream to File” control. A
“SaveAs”dialog box opens to select a file to write the
datato.Onceafileisselected,clickthe“Save”button.
Streaming continues until the “Stop Streaming” control is
pushed.Notethatyoucanquicklyendupwithlargefiles.
Stream Data File Format
Thedataisstoredinthestreamingfileastext.Thefirst
line indicates what range of cell data is captured, up to
16 cells, and whether each T_ input is also captured or
not.Eachsubsequentlineorpairoflinesrepresentsone
captured data set.
Actual data starts with the second line. This line records
up to 16 cell voltages, starting with the highest numbered
cell down to the first cell (cell 1). If any of the T_ inputs
areenabled,thenextlineisupto3T_inputvoltages.If
noT_inputisenabled,thethirdlineisinsteadthenext
set of cell voltages, captured one repeat time later.
Forexample,inFigure10,thefirstlineofthefileindicates
that all 16 cell voltages are captured, as well as all three
auxiliaryinputs.Thesecondlineshowsthatcell16read
0.0392V and cell 15 read 0.0160V. The third line shows
that T1 read 1.1506V, T2 read 4.0587V, and T3 read
4.0950V. This occurred at one time instant. The fourth
andfifthlinewouldreportthecellandauxiliaryinputs,like
lines 2 and 3, only one repeat time later. Note that at the
default 100 samples per second (10ms repeat time), the
datafilecanquicklygrowquitelarge.
Table 4. EV Kit Auxiliary Input Section Details (Figure 8)
ITEM LABEL READ/WRITE DESCRIPTION
1 Voltage Read These are the voltages read from the corresponding T_ input. Each T_ input must
beenabledforitsvoltagetobeacquiredanddisplayed.
2 Enable Write
ChecktheboxtoenableordisablethecorrespondingT_input.Whenenabled,
the T_ input voltage is read and converted at the same repetition rate as the cell
voltages.
3 Buffer Write
ChecktheboxtoenableordisabletheoptionalbufferforeachT_input.When
unchecked, the corresponding T_ input connects directly to the ADC. Use this
setting for high-drive analog sources. When checked, the T_ input is unity-gain
buffered to the ADC. Use this for low-drive analog signals.
4 Settling Delay Write This is the delay time, in microseconds, from when the device presents a T_ signal
to when the ADC conversion begins.
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Figure 8. Auxiliary Input Section
Figure 9. Example Streaming Data Output
4) SETTLING DELAY ENTRY
3) BUFFER CONTROL
2) ENABLE CONTROL
1) AUXILIARY VOLTAGE READOUT
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Figure 10a. MAX14921 EV Kit Schematic (Sheet 1 of 5)
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Figure 10b. MAX14921 EV Kit Schematic (Sheet 2 of 5)
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Figure 10c. MAX14921 EV Kit Schematic (Sheet 3 of 5)
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Figure 10d. MAX14921 EV Kit Schematic (Sheet 4 of 5)
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Figure 10e. MAX14921 EV Kit Schematic (Sheet 5 of 5)
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Figure 11. MAX14921 EV Kit Component Placement Guide—Component Side
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Figure 12. MAX14921 EV Kit Component Placement Guide—Solder Side
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Figure 13. MAX14921 EV Kit PCB Layout—Top Copper
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Figure 14. MAX14921 EV Kit PCB Layout—Layer 2 (Ground)
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Figure 15. MAX14921 EV Kit PCB Layout—Layer 3 (Power)
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Figure 16. MAX14921 EV Kit PCB Layout—Bottom Copper
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Block Diagram
MAX256
TRANSFORMER
MAX14850
ISOLATOR
MAX14850
ISOLATOR
ARM
MICROCONTROLLER
RECTIFIER MAX8880
LDO
MAX6126
REF
MAX9620
MAX11163
ADC
V
A
V
OUT
SPI
MAX14921
CONNECTOR
MAX8880
LDO
USB
SPI
3.3V
4.096V4.096V
5V
5V
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#Denotes RoHS compliant.
Ordering Information
PART TYPE
MAX14921EVKIT# EV Kit
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time.
MAX14921 Evaluation Kit Evaluates: MAX14921
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2013 MaximIntegratedProducts,Inc.
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Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
04/13 Initial release —
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
