MAX8798EVCMAXQU+ [MAXIM]
Resistor-Adjustable Switching Regulator and Op-Amp Output Range;型号: | MAX8798EVCMAXQU+ |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | Resistor-Adjustable Switching Regulator and Op-Amp Output Range |
文件: | 总13页 (文件大小:250K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
19-1004; Rev 1; 9/08
MAX8798 Evaluation Kit/Evaluation System
Evluate:MAX798
General Description
Features
The MAX8798 evaluation system (EV system) consists
of the MAX8798 evaluation kit (EV kit) and the Maxim
CMAXQUSB command module. A Windows® 2000/XP/
Vista®-compatible software is also available for use with
the EV system (MAX8798EVCMAXQU+) and can be
downloaded from www.maxim-ic.com/evkitsoftware.
o +1.8V to +6V Input Range
o Output Voltages
+8V Output at 300mA (+2.2V Input Step-Up
Switching Regulator)
+21V Output at 20mA (Positive Charge Pump)
-13V Output at 20mA (Negative Charge Pump)
150mA High-Current Op-Amp Output
The MAX8798 EV kit (MAX8798EVKIT+) is a fully
assembled and tested surface-mount printed-circuit
board (PCB) that provides the features required for
active-matrix, thin-film transistor (TFT) liquid-crystal dis-
plays (LCDs). The EV kit contains a step-up switching
regulator, positive two-stage charge pump, negative
two-stage charge pump, digitally adjustable VCOM cali-
bration device with nonvolatile memory, SMBus™-com-
patible interface, high-speed operational amplifier (op
amp), and high-voltage, level-shifting scan driver for
thin TFT-LCD applications.
o Resistor-Adjustable Switching Regulator and Op-
Amp Output Range
o Digitally Programmable Op-Amp Output Voltage
o +35V to -25V High-Voltage Level-Shifting Drivers
o Greater than 85% Efficiency (Step-Up Switching
Regulator)
o 1.2MHz Step-Up Switching Frequency
o SMBus-Compatible Interface
o Windows 2000/XP/Vista (32-Bit)-Compatible
The EV kit operates from a DC supply voltage from
+1.8V to +6V. The step-up switching regulator is con-
figured for a +8V output providing at least 300mA from
a +2.2V input. The positive charge pump is configured
for a +21V output providing at least 20mA. The nega-
tive charge pump is configured for a -13V output pro-
viding at least 20mA. The op amp is capable of provid-
ing up to 1ꢀ0mA peak and features a programmable
output voltage initially configured for +3.2V. The high-
voltage level-shifting scan driver buffers inputs from
STV, CPV, and OE pads and shifts them to a desired
level to drive TFT-LCD row logic.
Software
o 1.2mm Low-Profile Surface-Mount Components
o Lead-Free and RoHS Compliant
o Fully Assembled and Tested
Ordering Information
PART
TYPE
EV Kit
MAX8798EVKIT+
MAX8798EVCMAXQU+
+Denotes lead-free and RoHS compliant.
EV System
The MAX8798 EV kit demonstrates low quiescent cur-
rent and high efficiency (> 8ꢀ%) for maximum battery
time per charge. Operation at 1.2MHz allows the use of
tiny surface-mount components. The MAX8798 thin
QFN package (0.8mm max height), with low-profile
external components, allows this circuit to be less than
1.2mm high.
Note: The Maxim command module (CMAXQUSB) is required
when using the MAX8798 EV kit software.
Component List
DESIGNATION QTY
DESCRIPTION
The Maxim CMAXQUSB command module provides
the SMBus-compatible interface and is connected to a
PC through the universal serial bus (USB) port. The
MAX8798 EV kit software provides a graphical user
interface (GUI) for exercising the MAX8798 features.
10µF 20%, 6.3V XꢀR ceramic
capacitor (0603)
TDK C1608XꢀR0J106M or equivalent
C1
1
0
C2, C18,
C19, C20
Not installed, ceramic capacitors
(0603)
220pF 10%, ꢀ0V X7R ceramic
capacitor (0603)
Murata GRM188R71H221KA
TDK C1608X7R1H221K or equivalent
C3
C4
1
1
0.047µF 10%, ꢀ0V XꢀR ceramic
capacitor (0603)
Murata GRM188R71H473K
TDK C1608X7R1H473K or equivalent
Windows and Windows Vista are registered trademarks of
Microsoft Corp.
SMBus is a trademark of Intel Corp.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX8798 Evaluation Kit/Evaluation System
Component List (continued)
DESIGNATION QTY
DESCRIPTION
DESIGNATION QTY
DESCRIPTION
0.22µF 20%, 16V XꢀR ceramic
capacitor (0603)
TDK C1608XꢀR1C224M or equivalent
Dual-row (2 x 10) right-angle
receptacle
J1
JU1, JU2
L1
1
2
1
Cꢀ
1
2
2-pin headers
1µF 20%, 10V XꢀR ceramic
capacitors (0603)
TDK C1608XꢀR1A10ꢀM or equivalent
3.6µH, 1.8A power inductor
Sumida CMD6D11BHPNP-3R6MC
C6, C7
OECON
R1, R6, R7
R2
0
3
1
1
1
2
1
1
2
3
Not installed, test point
0.1µF 10%, ꢀ0V X7R ceramic
capacitors (0603)
TDK C1608X7R1H104K or equivalent
200kΩ 1% resistors (0603)
36.ꢀkΩ 1% resistor (0603)
60.4kΩ 1% resistor (0603)
10Ω ꢀ% resistor (0603)
100kΩ ꢀ% resistors (0603)
24.9kΩ 1% resistor (080ꢀ)
20kΩ ꢀ% resistor (0603)
200Ω ꢀ% resistors (0603)
10kΩ ꢀ% resistors (0603)
C8–C16
C17
9
0
R3
Not installed, electrolytic capacitor
(6.3mm x ꢀmm)
R4
Rꢀ, R1ꢀ
R8
4.7µF 10%, 16V XꢀR ceramic
capacitors (1206)
Murata GRM319R61C47ꢀKA88D
TDK C3216XꢀR1C47ꢀK
C21, C22
C23
2
0
1
R9
Evluate:MAX798
R10, R11
R12, R13, R14
Not installed, ceramic capacitor
(1206)
Not installed, resistor—short
(PC trace) (0603)
1A, 30V Schottky diode (S-Flat)
Central CMMSH1-40LEADFREE
Nihon EP10QY03
R16
0
D1
Maxim internal-switch boost regulator
MAX8798ETX+
U1
1
Toshiba CRS02(TE8ꢀL)
(36-pin thin QFN, 6mm x 6mm)
200mA, 100V dual diodes (SOT23)
Fairchild MMBD4148SE (Top Mark: D4)
Central CMPD7000LEADFREE
(Top Mark: CꢀC)
—
—
2
1
Shunts
D2–Dꢀ
4
PCB: MAX8798 Evaluation Kit+
Component Suppliers
SUPPLIER
PHONE
WEBSITE
Central Semiconductor
Fairchild Semiconductor
631-43ꢀ-1110
888-ꢀ22-ꢀ372
770-436-1300
847-843-7ꢀ00
847-ꢀ4ꢀ-6700
847-803-6100
949-623-2900
www.centralsemi.com
www.fairchildsemi.com
www.murata-northamerica.com
www.niec.co.jp
Murata Electronics North America, Inc.
Nihon Inter Electronics Corp.
Sumida Corp.
www.sumida.com
TDK Corp.
www.component.tdk.com
www.toshiba.com/taec
Toshiba America Electronic Components, Inc.
Note: Indicate that you are using the MAX8798 when contacting these component suppliers.
MAX8798 EV Kit Files
FILE
DESCRIPTION
INSTALL.EXE
MAX8798.EXE
Installs the EV kit files on your computer
Application program
USB device driver file
FTD2XX.INF
UNINST.INI
Uninstalls the EV kit software
USB driver installation help file
TROUBLESHOOTING_USB.PDF
2
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MAX8798 Evaluation Kit/Evaluation System
Evluate:MAX798
2) To enable the MAX8798, ensure that a shunt is
Quick Start
Recommended Equipment
Before beginning, the following equipment is needed:
installed on jumper JU1 of the MAX8798 EV kit.
3) Visit www.maxim-ic.com/evkitsoftware to down-
load the latest version of the MAX8798 EV kit soft-
•
•
+1.8V to +6V, 2A DC power supply for PIN
ware, MAX8798Rxx.ZIP. Save the EV kit software to
a temporary folder and uncompress the ZIP file.
MAX8798 EV system
MAX8798 EV kit
4) Install the EV kit software on your computer by run-
ning the INSTALL.EXE program inside the tempo-
rary folder. The program files are copied and icons
are created in the Windows Start | Programs
menu.
CMAXQUSB command module (USB cable
included)
•
•
A user-supplied Windows 2000/XP/Vista-compatible
PC with a spare USB port
ꢀ) Carefully connect the boards by aligning the
MAX8798 EV kit’s 20-pin J1 connector with the
CMAXQUSB board’s 20-pin P3 connector. Gently
press them together. The two boards should be
flush against each other.
Voltmeter
Note: In the following sections, software-related items
are identified by bolding. Text in bold refers to items
directly from the EV kit software. Text in bold and under-
lined refers to items from the Windows operating system.
Hardware Procedure
The MAX8798 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power supply until all
connections are completed.
1) Verify that a shunt is installed across jumper JU1.
2) Verify that no shunt is installed across jumper JU2.
6) Connect the USB cable from the PC to the
CMAXQUSB board. A Building Driver Database
window pops up in addition to a New Hardware
Found message when installing the USB driver for
the first time. If you do not see a window that is
similar to the one described above after 30s,
remove the USB cable from the board and recon-
nect it. Administrator privileges are required to
install the USB device driver on Windows
2000/XP/Vista.
3) Connect the positive terminal of the power supply to
the PIN pad. Connect the negative terminal of the
power supply to the GND pads closest to PIN.
7) Follow the directions of the Add New Hardware
Wizard to install the USB device driver. Choose the
Search for the best driver for your device option.
Specify the location of the device driver to be
C:\Program Files\MAX8798 (default instal-
lation directory) using the Browse button. During
device driver installation, Windows may show a
warning message indicating that the device driver
Maxim uses does not contain a digital signa-
ture. This is not an error condition and it is safe
to proceed with installation. Refer to the
TROUBLESHOOTING_USB.PDF document for
additional information.
4) Turn on the power supply and verify that the step-
up switching regulator output (MAIN) is +8V.
ꢀ) Verify that the gate-on supply (GON) is approxi-
mately +21V.
6) Verify that the gate-off supply (GOFF) is approxi-
mately -13V.
7) Verify that the output of the high-speed op amp
(VCOM) is approximately +3.2V.
For instructions on selecting the step-up switching regu-
lator feedback and op-amp divider resistors for other out-
put voltages, see the Output-Voltage Selection section.
8) Start the MAX8798 EV kit software by opening its
icon in the Start | Programs menu.
9) Normal device operation is verified when MAX8798
connected is displayed in the status bar on the
MAX8798 EV kit main window (Figure 1).
Software Procedure
With the EV kit powered on, perform the following steps
to verify software operation:
1) On the CMAXQUSB command module, ensure that
the shunt on jumper JU1 is in the +3.3V position.
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MAX8798 Evaluation Kit/Evaluation System
Evluate:MAX798
Figure 1. MAX8798 EV Kit Software Main Window
The op-amp output (VCOM) is SMBus programmable
Detailed Description of Hardware
and is configured for an output-voltage range of +2.4V
The MAX8798 EV kit contains a step-up switching regu-
to +4V. VCOM can source or sink peak current up to
lator, positive two-stage charge pump, negative two-
1ꢀ0mA. The output-voltage range can be reconfigured
stage charge pump, digitally adjustable VCOM calibra-
to other voltages with voltage-divider resistors R6 and
tion device with nonvolatile memory, SMBus-compati-
R7. Refer to the Setting the VCOM Adjustment Range
ble interface, high-speed operational amplifier (op
section in the MAX8798 IC data sheet for more details.
amp), and high-voltage level-shifting scan driver for
The MAX8798 includes a 3-channel, high-voltage level-
shifting driver for driving row-driver functions on the
panel glass. CKV, CKVB, and STVP pads are the out-
puts of the driver. The outputs swing between GON
and GOFF according to the input logic levels on the
STV, CPV, and OE pads and the IC’s internal logic.
Refer to the High-Voltage Level-Shifting Scan Driver
section in the MAX8798 IC data sheet for more details.
thin TFT-LCD applications. The EV kit can operate from
a single DC power supply between +1.8V to +6V that
can provide at least 2A.
As configured, the step-up switching regulator (MAIN)
generates a +8V output and can provide at least
200mA from a +1.8V input. It also provides at least
300mA from a +2.2V input and 600mA from a +4.ꢀV
input. The step-up switching-regulator output voltage
can be adjusted up to +18V with different feedback
resistors (see the Output-Voltage Selection section).
Jumper Selection (JU1, JU2)
The MAX8798 EV kit incorporates jumper JU1 to
enable/disable the IC outputs and jumper JU2 to
enable/disable write protection. When write protection
is enabled, all SMBus commands are ignored by the
device. This prevents device detection and changing of
the VCOM calibrator settings. See Table 1 for jumper
JU1 functions and Table 2 for jumper JU2 functions.
The GON consists of two positive charge-pump stages
to generate approximately +21V and can provide greater
than 20mA. The GOFF consists of two negative charge-
pump stages to generate approximately -13V and can
provide greater than 20mA. Loading GON and GOFF
reduces the available MAIN current proportionally.
4
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MAX8798 Evaluation Kit/Evaluation System
Evluate:MAX798
Table 1. Jumper JU1 Functions
SHUNT POSITION
SHDN PIN
EV KIT OUTPUTS
Installed*
SHDN connected to PIN
Outputs enabled (MAIN = +8V)
Outputs disabled (MAIN ≈ PIN)
Not installed
SHDN connected to GND through Rꢀ
*Default position.
Table 2. Jumper JU2 Functions
SHUNT POSITION
WPN PIN
VCOM CALIBRATOR WRITE PROTECTION
Installed
WPN connected to GND
Enabled
Disabled
Not installed*
*Default position.
WPN connected to VDD through R1ꢀ
priate DAC setting into the DAC edit box. The DAC set-
ting can be set from 0x00 (VCOM ) to 0x7F
Output-Voltage Selection
The MAX8798 EV kit’s step-up switching-regulator out-
put (MAIN) is set to +8V by feedback resistors R1 and
R2. To generate output voltages other than +8V (up to
+18V), select different external voltage-divider resis-
tors, R1 and R2.
MAX
(VCOM
). The DAC setting is written to the device by
MIN
pressing the Load DAC button (Figure 1).
Reading 7-Bit DAC
The MAX8798 7-bit DAC is read by either pressing the
Read DAC button or by checking the DAC polling
checkbox. When checked, the software will continuously
read and display the DAC’s current setting.
Note that changing the MAIN voltage setting changes the
GON and GOFF charge-pump output voltages. The volt-
age range on GOFF is limited to -2ꢀV and the voltage
range of GON is limited to +3ꢀV. Setting the MAIN voltage
above +12V will require reconfiguring the charge pumps
to avoid exceeding +3ꢀV on GON and -2ꢀV on GOFF.
Programming EEPROM
The current DAC setting can be programmed into the
device’s internal EEPROM by entering an appropriate
DAC setting into the DAC edit box and pressing the
Program button. Pressing the Program button will also
load the current setting into the DAC. Each time the
device is powered on, the DAC is loaded with the set-
ting stored in the device’s EEPROM. Programming is
only possible when GON is greater than +16V.
In addition, output capacitors C21 and C22 are rated
for +16V. To set MAIN for greater than +16V, use high-
er voltage-rated capacitors. Refer to the Main Step-Up
Regulator, Output-Voltage Selection section in the
MAX8798 IC data sheet for instructions on selecting
resistors R1 and R2.
Detailed Description of Software
Simple SMBus Commands
There are two methods for communicating with the
MAX8798: through the MAX8798 EV kit software main
window (Figure 1), or through the interface window
available by selecting the Options | Interface menu
item from the menu bar. The Maxim command module
interface window (Figure 2) includes a 2-wire interface
tab that allows for execution of the SMBusSendByte(),
SMBusReceiveByte(), and SMBusQuick() commands.
See Table 3 for details regarding SMBus commands.
The MAX8798 device includes a calibrator that is used
for adjusting an LCD’s backplane voltage (VCOM) in
TFT-LCD displays. The VCOM voltage is adjusted by
controlling the amount of sink current drawn by the cali-
brator. This is accomplished by programming the
desired setting into the device’s 7-bit internal DAC. The
software also facilitates reading of the device and pro-
gramming of the device’s internal EEPROM. Refer to
the MAX8798 IC data sheet for further details.
Loading 7-Bit DAC Setting
The DAC setting corresponds to a certain sink-current
level, which in turn corresponds to a specific VCOM
voltage. With the MAX8798 EV kit software, the device’s
7-bit internal DAC is configured by entering an appro-
The Command byte combo box accepts numeric data
in binary, decimal, or hexadecimal. Hexadecimal num-
bers should be prefixed by $ or 0x. Binary numbers
must be exactly eight digits. See Figure 2 for an illustra-
tion of this tool.
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MAX8798 Evaluation Kit/Evaluation System
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Figure 2. Command Module Interface Window
Table 3. SMBus Commands
CONTROL
SMBus COMMAND
FORMAT
Input the desired 7-bit DAC setting into the Command byte
combo box. The 7-bit DAC value should be stored in the upper 7
bits (b7-b1) of the byte, with the LSB = 1.
Load DAC
SMBusSendByte
Input the desired 7-bit DAC setting into the Command byte
combo box. The 7-bit DAC value should be stored in the upper 7
bits (b7-b1) of the byte, with the LSB = 0.
Load DAC/program EEPROM
SMBusSendByte
Receives 8 bits from the device. The upper 7 bits correspond to
the current DAC setting and the LSB = 0.
Read DAC
SMBusReceiveByte
SMBusQuick
Search for device address shown in the Target Device Address
combo box. The MAX8798 device address is 0x9E.
Device search
6
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MAX8798 Evaluation Kit/Evaluation System
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Figure 3. MAX8798 EV Kit Schematic
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MAX8798 Evaluation Kit/Evaluation System
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Figure 4. MAX8798 EV Kit Component Placement Guide—Component Side
8
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Figure ꢀ. MAX8798 EV Kit PCB Layout—Component Side
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MAX8798 Evaluation Kit/Evaluation System
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Figure 6. MAX8798 EV Kit PCB Layout—Layer 2
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MAX8798 Evaluation Kit/Evaluation System
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Figure 7. MAX8798 EV Kit PCB Layout—Layer 3
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MAX8798 Evaluation Kit/Evaluation System
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Figure 8. MAX8798 EV Kit PCB Layout—Solder Side
12 ______________________________________________________________________________________
MAX8798 Evaluation Kit/Evaluation System
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Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
1
9/07
9/08
Initial release
Corrected part number for component L1.
—
2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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