MAX8831EVKIT+

19-4455; Rev 0; 2/09 MAX8831 Evaluation Kit Features o 28V Step-Up DC-DC Converter The MAX8831 evaluation kit (EV kit) is a fully assembled and tested PCB for evaluating the MAX8831 white LED step-up converter. The MAX8831 EV kit operates from an input supply range of 2.7V to 5.5V and is controlled by an I2C interface. The MAX8831 features a 60mA, 28V PWM DC-DC step-up converter with five low-dropout LED current regulators. Each of the five current regulators accommodates up to 9 series LEDs (depending on LED string forward voltage), and are independently programmed using an I2C interface. The I2C interface controls all operational aspects of the current regulators, including on/off state, LED current, ramp-up/ramp-down timers, and blink rate timers (LED3, LED4, and LED5). o Two 25.25mA LED Strings (LED1, LED2) for Display Backlighting I2C-Programmable Output Current (50µA to 25.25mA) 128-Step Logarithmic Dimming Individually Programmable Ramp (Up/Down) Timers The MAX8831 EV kit also includes Windows® 2000/XPand Windows Vista®-compatible software that provides a simple graphical user interface (GUI) for exercising the features of the MAX8831. The MAX8831 EV kit features an I2C interface to control the LED current, rampup/ramp-down time, and blink on/off time. To control the MAX8831 EV kit from a PC, order the CMAXQUSB command module along with the MAX8831 EV kit. o RGB LED Module Ordering Information PART TYPE MAX8831EVKIT+ EV Kit +Denotes lead(Pb)-free and RoHS compliant. o I2C Interface Control o Three 5mA LED Strings for Keypad Lighting I2C-Programmable Output Current (50µA to 5mA) 32-Step Logarithmic Dimming Individually Programmable Ramp (Up/Down) Timers Individual Blink Rate and Duty-Cycle Timers o Alternative Power Supply (VIN2) for LED3, LED4, and LED5 Strings o Open/Short LED and Open-Circuit Diode Detection o Thermal Shutdown and Output Overvoltage Protection o Lead(Pb)-Free and RoHS Compliant o Fully Assembled and Tested PCB Component List DESIGNATION QTY C1 C2 DESCRIPTION 1 1µF ±10%, 6.3V X5R ceramic capacitor (0402) Taiyo Yuden JMK105BJ105K 1 1µF ±10%, 35V X5R ceramic capacitor (0603) Taiyo Yuden GMK107BJ105K C3 1 0.1µF ±10%, 16V X5R ceramic capacitor (0402) TDK C1005X5R1C104K C4 1 0.22µF ±10%, 16V X5R ceramic capacitor (0402) TDK C1005X5R1C224K 1 1µF ±10%, 25V X5R ceramic capacitor (0603) TDK C1608X5R1E105K C5 DESIGNATION QTY DESCRIPTION D1 1 500mA, 40V Schottky diode (SOD323) Central Semi CMDSH05-4 D2–D17 16 White LEDs Nichia NSSW061AT D18–D44 27 White LEDs Nichia NHSW046AT D45 1 RGB LED module Lumex SML-LX3632SISUGSBC J1 1 2 x 10 right-angle receptacle Methode M65S-R220-11-01W JU1–JU5, JU9, JU10, JU11 8 5-pin headers Sullins PEC36SAAN Digi-Key S1012E-36-ND Windows and Windows Vista are registered trademarks of Microsoft Corp. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 Evaluates: MAX8831 General Description Evaluates: MAX8831 MAX8831 Evaluation Kit Component List (continued) DESIGNATION QTY DESIGNATION QTY DESCRIPTION JU6, JU7, JU8 3 2-pin headers Sullins PEC36SAAN Digi-Key S1012E-36-ND JU12, JU13 2 3-pin headers Sullins PEC36SAAN Digi-Key S1012E-36-ND 1 10µH ±20% inductor TOKO 1098AS-100M (DE2812C Series, 0.92A, 290mΩ, 3mm x 3.2mm x 1.2mm) L1 DESCRIPTION R1–R4 0 Not installed, resistors (0402) R1 and R2 are open; R3 and R4 are PCB short U1 1 White LED step-up converter (16 WLP) Maxim MAX8831EWE+ — 1 PCB: MAX8831 Evaluation Kit+ Component Suppliers SUPPLIER PHONE WEBSITE Central Semiconductor Corp. 631-435-1110 www.centralsemi.com Digi-Key Corp. 800-344-4539 www.digikey.com Lumex Inc. 800-278-5666 www.lumex.com Methode Electronics 708-867-6777 www.methode.com Nichia Corp. 248-352-6575 www.nichia.com Sullins Electronics Corp. 760-744-0125 www.sullinselectronics.com Taiyo Yuden 800-348-2496 www.t-yuden.com TDK Corp. 847-803-6100 www.component.tdk.com TOKO America, Inc. 847-297-0070 www.tokoam.com Note: Indicate that you are using the MAX8831 when contacting these component suppliers. MAX8831 EV Kit Files FILE DESCRIPTION INSTALL.EXE Installs the EV kit files on your computer MAX8831.EXE Application program FTD2XX.INF USB device driver file UNINST.INI Uninstalls the EV kit software Quick Start Recommended Equipment 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 underlined refers to items from the Windows operating system. • MAX8831 EV kit • Adjustable 5V power supply capable of delivering 1A (PS1) • One digital multimeter (DMM1) • A user-supplied Windows 2000/XP- or Windows Vista-compatible PC with a spare USB port • CMAXQUSB command module (USB cable included) 2 _______________________________________________________________________________________ Procedure The MAX8831 EV kit is a fully assembled and tested surface-mount board. Follow the steps below and Figure 1 to set up and verify the MAX8831 and board operation. Note: If any of the jumpers (JU1–JU11) are removed while the step-up converter is on (VOUT > VIN), an open MAX8831 Evaluation Kit 7 LED1 STRING 8 GND VIN2 8 B R JU12 1 3 2 JU10 G LED3 STRING 9 B W JU7 9 B JU2 6 JU3 6 JU4 6 JU5 JU1–JU5 SELECT THE NUMBER OF LEDs 7 8 LED5 STRING JU8 5 7 8 LED4 STRING R JU11 G JU1 6 8 W JU6 5 6 7 LED2 STRING JU9 G Evaluates: MAX8831 JU9, JU10, JU11 SELECTS THE TYPE OF LEDS (LED3, LED4, LED5) SHUNT ON PINS 2-3: CONNECTS VIN1 TO JU6, JU7, JU8, RGB SHUNT ON PINS 1-3: CONNECTS VIN2 TO JU6, JU7, JU8, RGB W 9 R 7 VOUT + SCL MAX8831 EVALUATION KIT+ DMM1 GND VDD SDA J1 PGND VIN1 JU6, JU7, JU8 SELECT POWER TO ONE WHITE LED (LED3, LED4, LED5)* *REMOVE JU1–JU5 BEFORE USING JU13 1 3 2 + - CONNECT 20-PIN RECEPTACLE TO CMAXQUSB (P3) POWER SUPPLY (PS1) SHUNT ON PINS 1-3: CONNECTS VDD TO J1'S POWER SUPPLY SHUNT ON PINS 2-3: CONNECTS VDD TO GROUND Figure 1. Initial Test Procedure Setup for MAX8831 EV Kit LED fault occurs. Verify that the step-up converter is off (VOUT ≤ VIN) before configuring a jumper setting. 1) Visit www.maxim-ic.com/evkitsoftware to download the latest version of the EV kit software, 8831Rxx.ZIP. Save the EV kit software to a temporary folder and uncompress the ZIP file. 2) Install the EV kit software on your computer by running the INSTALL.EXE program inside the tempo- rary folder. The program files are copied and icons are created in the Windows Start | Programs menu. 3) Connect the USB cable from the PC to the CMAXQUSB command module. 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- _______________________________________________________________________________________ 3 Evaluates: MAX8831 MAX8831 Evaluation Kit nect it. Administrator privileges are required to install the USB device driver on Windows. 18) Select 8192 for both Up Time(ms) and Down Time(ms) for LED1–LED5, as shown in Figure 3. 4) 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\MAX8831 (default installation directory) using the Browse button. During device driver installation, Windows may show a warning message indicating that the device driver does not contain a digital signature. This is not an error condition and it is safe to proceed with installation. 19) Select the corresponding On/Off checkbox to enable LED1–LED5. Note that the ramp-up times for LED1–LED5 increased. 5) Preset the power supply (PS1) to 5V. Turn off the power supply. Do not turn on the power supply until all connections are completed. 22) Select 1024 for both Off Time(ms) and On Time(ms) for LED3, LED4, and LED5, as shown in Figure 4. 6) On the CMAXQUSB command module, ensure that the shunt on jumper JU1 is in the 3.3V position and the pullup resistors (R5 and R6) are enabled by SW1. 23) Check the Enabled Blink checkboxes and corresponding On/Off checkboxes for LED3, LED4, and LED5 to enable the blink control. 7) Verify that the jumpers on the MAX8831 EV kit are configured as shown in Table 1. 8) Carefully connect the boards by aligning the 20-pin connector of the MAX8831 EV kit with the 20-pin header of the CMAXQUSB interface board. Gently press them together. 20) Select the corresponding On/Off checkbox to disable LED1–LED5. Note the ramp-down times for LED1–LED5. Wait until the voltage read by DMM1 is 5V before proceeding. 21) Select 64 for both Up Time(ms) and Down Time(ms) for LED3, LED4, and LED5. 24) Verify that LED3, LED4, and LED5 are blinking and that the on and off times are the same. 25) Select the corresponding On/Off checkbox to disable LED3, LED4, and LED5. Wait until the voltage read by DMM1 is 5V before proceeding. Table 1. Default Jumper Settings (JU1–JU13) 9) Connect the positive lead of DMM1 to VOUT and the negative lead to GND. JUMPER DEFAULT SHUNT POSITION 10) Connect the positive lead of PS1 to VIN1 and the negative lead to PGND. JU1 Center pin and 7 JU2 Center pin and 7 JU3 Center pin and 8 JU4 Center pin and 8 JU5 Center pin and 8 JU6 Not installed JU7 Not installed 11) Turn on the power supply (PS1). 12) Verify that the voltage read by DMM1 is approximately 5V. 13) Start the MAX8831 EV kit software by opening its icon at Start | Programs | MAX8831 EVALUATION KIT 14) Normal device operation is verified when Command Module Connected, Device Connected is displayed at the top of the MAX8831 EV kit main window (Figure 2). 15) Configure the Brightness Control tab, as shown in Figure 2. 16) Verify that LED1 and LED2 both have 7 LEDs on and that LED3, LED4, and LED5 have 8 LEDs on for each string. Note the ramp-up times for LED1–LED5. 17) Select the corresponding On/Off checkbox to disable LED1–LED5. Note the ramp-down times for LED1–LED5. Wait until the voltage read by DMM1 is 5V before proceeding. 4 JU8 Not installed JU9 Center pin and W JU10 Center pin and W JU11 Center pin and W JU12 2-3 JU13 1-3 Table 2. RGB Configuration JUMPER DEFAULT SHUNT POSITION JU9 Center pin and B JU10 Center pin and G JU11 Center pin and R _______________________________________________________________________________________ MAX8831 Evaluation Kit 27) Select the corresponding On/Off checkbox to enable LED3, LED4, and LED5. 28) Verify that RGB LED module D45’s red, blue, and green LEDs are blinking and the on and off times are the same. 29) Select the corresponding On/Off checkbox to disable LED3, LED4, and LED5. When evaluation of the MAX8831 EV kit is completed, use the following steps to power down the EV kit: 1) Turn off the power supply (PS1). 2) Disconnect all test leads from the EV kit. Detailed Description of Software User-Interface Panel The MAX8831 EV kit uses the CMAXQUSB command module for an I2C interface to control the MAX8831 configurations. The MAX8831 EV kit software displays four tabs to set the MAX8831 configurations: Brightness Control, Ramp Rate Control, Blink Control, and Status. Changes to the controls followed by a Write/Write All updates the appropriate registers of the MAX8831. After any write or read operation, the related command and data sent are shown in the top-left box. Brightness Control Tab The Brightness Control tab sheet (Figure 2) provides on/off control and LED current control for the LED1–LED5 strings. LED1 and LED2 are programmable from 50µA to 25.25mA in 128 logarithmic steps. LED3, LED4, and LED5 are programmable from 50µA to 5mA in 32 logarithmic steps. Also under the Brightness Control tab is the powersupply selector for LED3, LED4, and LED5. If the output voltage of the step-up converter is chosen to supply LED3, LED4, and LED5, verify that Boost Convert is selected in the Boost Control section (Figure 2). If an alternate supply (VIN2) is chosen to supply LED3, LED4, and LED5, verify that the External Source is Figure 2. Brightness Control Tab _______________________________________________________________________________________ 5 Evaluates: MAX8831 26) Remove the shunts on JU9, JU10, and JU11 and install according to Table 2. Evaluates: MAX8831 MAX8831 Evaluation Kit Figure 3. Ramp Rate Control Tab selected in the Boost Control section. See Table 3 for jumper settings and the Using an Alternate Power Supply (VIN2, LED3, LED4, and LED5) section for more details. By default, the MAX8831 EV kit software selects Boost Convert. Ramp Rate Control Tab The Ramp Rate Control tab sheet (Figure 3) provides independent ramp-up and ramp-down times for each LED current regulator. Both the ramp-up and rampdown times have eight different settings ranging from 64ms to 8192ms. Blink Control Tab The Blink Control tab sheet (Figure 4) provides blinkon and blink-off times for the LED3, LED4, and LED5 current regulators. Each LED string is independent of each other and features individual enable/disable control for the blink function. The blink Off Time provides four different settings ranging from 1024ms to 8192ms. The blink On Time provides four different settings ranging from 256ms to 2048ms. See the Combining Blink 6 Timer and Ramp Functions section when combining the blink control with ramp-up/ramp-down control. Status Tab As shown in the Status tab sheet (Figure 5), the STAT1 and STAT2 read-only registers monitor the MAX8831 operating state and fault status. These registers indicate any short/open LED, output overvoltage, an open Schottky diode, and overtemperature. The STAT1 and STAT2 indicators require a Read if a fault or event has occurred, in which case the corresponding indicator flag turns red. A second Read clears the status bit if the fault or event is no longer present. The CHIP_ID1 and CHIP_ID2 registers provides die type and mask revision information. Detailed Description of Hardware The MAX8831 EV kit features a 60mA, 28V PWM DC-DC step-up converter with five low-dropout LED current regulators. Each of the five current regulators accommodate up to 9 series LEDs (depending on the LED string forward _______________________________________________________________________________________ MAX8831 Evaluation Kit Evaluates: MAX8831 Figure 4. Blink Control Tab voltage) and are independently controlled using the MAX8831 EV kit software. The MAX8831 EV kit controls all operational aspects of the current regulators, including on/off state, LED current, ramp-up/ramp-down timers, and blink rate timers (LED3, LED4, and LED5 only). High-Current Regulators (LED1, LED2) The MAX8831 EV kit contains two low-dropout (200mV, max), 25.25mA linear current regulators (LED1, LED2) that can each drive up to 9 series LEDs (depending on the LED string forward voltage) for display backlighting functions. Each high-current regulator is independently enabled and is programmable from 50µA to 25.25mA in 128 logarithmic steps (Figure 2) using the MAX8831 EV kit software. Additionally, the MAX8831 EV kit software programs the ramp-up and ramp-down timers for each regulator to one of eight different timing settings. Refer to the MAX8831 I2C Registers section in the MAX8831 IC data sheet for details on I2C control of the highcurrent regulators. Low-Current Regulators (LED3, LED4, and LED5) The MAX8831 EV kit also contains three low-dropout (150mV, max), 5mA linear current regulators (LED3, LED4, and LED5) that can each drive up to 9 series LEDs. Each current regulator is independently enabled and is programmable from 50µA to 5mA in 32 logarithmic steps (Figure 2) using the MAX8831 EV kit software. The MAX8831 EV kit software also controls individual ramp-up/ramp-down timers and individual blinkon/blink-off timers. Both the ramp and blink features can be individually enabled/disabled. Refer to the LED3, LED4, and LED5 Blink Control Registers section in the MAX8831 IC data sheet for details. Using an Alternate Power Supply (VIN2, LED3, LED4, and LED5) The LED3, LED4, and LED5 low-current regulators can be powered from an alternate external power supply. To install an alternate power supply at VIN2, first remove the shunts on JU3, JU4, and JU5 and then _______________________________________________________________________________________ 7 Evaluates: MAX8831 MAX8831 Evaluation Kit Figure 5. Status Tab install jumpers on JU6, JU7, and JU8 and install a shunt across pins 1-3 of JU12. After the jumpers are properly configured, select External Source in the MAX8831 EV kit software (Figure 2). An external power supply can now be connected to VIN2. Ensure that the voltage at VIN2 is high enough to satisfy VF of the LED plus 150mV of current regulator dropout voltage. If Boost Convert (Figure 2) is selected for LED3, LED4, and LED5, and LED1 and LED2 are not enabled, the step-up converter does not turn on when LED3, LED4, or LED5 are enabled. On/Off Control Each current regulator can be independently enabled and disabled through the appropriate On/Off checkbox in the MAX8831 EV kit software. A checked box enables the corresponding LED current regulator. Overvoltage, open Schottky diode, and thermal shutdown faults automatically disable all LED current regulators. 8 Off, Shutdown, and Standby The MAX8831 is considered off when VIN1 is below the UVLO threshold and VDD is below 1.6V. When VIN1 is above the UVLO threshold and with VDD low, the IC enters the shutdown state and disables its internal reference. During shutdown, the MAX8831 holds all registers in reset, the step-up converter and all LED current drivers are off, and supply current is reduced to 0.1µA (typ). LX and LED1–LED5 are high impedance when the step-up converter is off. While the IC’s n-channel MOSFET is turned off, the step-up regulator’s output (VOUT) is connected to IN through the external inductor and Schottky diode. With a valid supply voltage applied to VDD (> 1.6V) and with VIN above VUVLO, the IC enters a standby condition, whereby it is ready to accept I2C commands. The step-up converter turns on when any current regulator (LED1–LED5) is enabled. _______________________________________________________________________________________ MAX8831 Evaluation Kit Evaluates: MAX8831 Table 3. Jumper Settings (JU1–JU13) JUMPER JU1 JU2 JU3 JU4 JU5 JU6 JU7 JU8 JU9 MAX8831 EV KIT DEFAULT SHUNT POSITION FUNCTION Center pin and 7 Connect the center pin of JU1 to one of the pins labeled 8, 7, 6, or 5 to select the respective number of LEDs for the LED1 string. JU1 connects the output of the step-up converter to the anode of the first LED (D2, D3, D4, or D5) in the LED1 string. Center pin and 7 Connect the center pin of JU2 to one of the pins labeled 8, 7, 6, or 5 to select the respective number of LEDs for the LED2 string. JU2 connects the output of the step-up converter to the anode of the first LED (D10, D11, D12, or D13) in the LED2 string. Center pin and 8 Connect the center pin of JU3 to one of the pins labeled 9, 8, 7, or 6 to select the respective number of LEDs for the LED3 string. JU3 connects the output of the step-up converter to the anode of the first LED (D18, D19, D20, or D21) in the LED3 string. Note: JU3 and JU6 cannot be installed at the same time. Center pin and 8 Connect the center pin of JU4 to one of the pins labeled 9, 8, 7, or 6 to select the respective number of LEDs for the LED4 string. JU4 connects the output of the step-up converter to the anode of the first LED (D27, D28, D29, or D30) in the LED4 string. Note: JU4 and JU7 cannot be installed at the same time. Center pin and 8 Connect the center pin of JU5 to one of the pins labeled 9, 8, 7, or 6 to select the respective number of LEDs for the LED5 string. JU5 connects the output of the step-up converter to the anode of the first LED (D36, D37, D38, or D39) in the LED5 string. Note: JU5 and JU8 cannot be installed at the same time. Not installed Install a shunt on JU6 to connect VIN1 or VIN2 (selected by JU12, see the Using an Alternate Power Supply (VIN2, LED3, LED4, and LED5) section) to the anode of D26. The shunt on JU3 must be removed first before installing a shunt on JU6. Remove the shunt on JU6 and then install a shunt on JU3 to connect the LED3 string to the output of the step-up converter. Note: JU6 and JU3 cannot be installed at the same time. Not installed Install a shunt on JU7 to connect VIN1 or VIN2 (selected by JU12, see the Using an Alternate Power Supply (VIN2, LED3, LED4, and LED5) section) to the anode of D35. The shunt on JU4 must be removed first before installing a shunt on JU7. Remove the shunt on JU7 and then install a shunt on JU4 to connect the LED4 string to the output of the step-up converter. Note: JU7 and JU4 cannot be installed at the same time. Not installed Install a shunt on JU8 to connect VIN1 or VIN2 (selected by JU12, see the Using an Alternate Power Supply (VIN2, LED3, LED4, and LED5) section) to the anode of D44. The shunt on JU5 must be removed first before installing a shunt on JU8. Remove the shunt on JU8 and then install a shunt on JU35 to connect the LED5 string to the output of the step-up converter. Note: JU8 and JU5 cannot be installed at the same time. Center pin and W Connect the center pin of JU9 to the pin labeled W to select white LEDs for the LED3 string. Connect the center pin of JU9 to the pin labeled B to select the blue LED in the RGB LED module (D45) for the LED3 string. Connect the center pin of JU9 to the pin labeled G to select the green LED in the RGB LED module (D45) for the LED3 string. Connect the center pin of JU9 to the pin labeled R to select the red LED in the RGB LED module (D45) for the LED3 string. _______________________________________________________________________________________ 9 Evaluates: MAX8831 MAX8831 Evaluation Kit Table 3. Jumper Settings (JU1–JU13) (continued) JUMPER JU10 JU11 MAX8831 EV KIT DEFAULT SHUNT POSITION FUNCTION Center pin and W Connect the center pin of JU10 to the pin labeled W to select white LEDs for the LED4 string. Connect the center pin of JU10 to the pin labeled B to select the blue LED in the RGB LED module (D45) for the LED4 string. Connect the center pin of JU10 to the pin labeled G to select the green LED in the RGB LED module (D45) for the LED4 string. Connect the center pin of JU10 to the pin labeled R to select the red LED in the RGB LED module (D45) for the LED4 string. Center pin and W Connect the center pin of JU11 to the pin labeled W to select white LEDs for the LED5 string. Connect the center pin of JU11 to the pin labeled B to select the blue LED in the RGB LED module (D45) for the LED5 string. Connect the center pin of JU11 to the pin labeled G to select the green LED in the RGB LED module (D45) for the LED5 string. Connect the center pin of JU11 to the pin labeled R to select the red LED in the RGB LED module (D45) for the LED5 string. JU12 2-3 Install a shunt across pins 2-3 to connect VIN1 to the anodes of D45, D26, D35, and D44 when shunts are installed on JU6, JU7, and JU8. Install a shunt across pins 1-3 to connect VIN2 to the anodes of D45, D26, D35, and D44 when shunts are installed on JU6, JU7, and JU8. JU13 1-3 Install a shunt across pins 1-3 to connect VDD to J1’s power supply. Install a shunt across pins 2-3 to connect VDD to ground. Note: If any of the jumpers (JU1–JU11) are removed while the step-up converter is on (VOUT > VIN), an open LED fault occurs. Verify that the step-up converter is off (VOUT ≤ VIN before configuring a jumper setting. Combining Blink Timer and Ramp Functions When using the ramp functionality of LED3, LED4, and LED5, in combination with the blink timer, it is recommended to keep the ramp-up timer shorter than the blink-on timer and the ramp-down timer shorter than the blink-off timer. Failing to comply with this restriction results in LED_ current not reaching maximum value during blink-on time, and LED_ current not returning to minimum current before turning off during the blink-off time. Refer to Figures 3 and 4, and the Combining BLINK Timer and RAMP Functions section in the MAX8831 IC data sheet for more details. System States and Fault Handling The MAX8831 EV kit software implements two fault registers (STAT1, STAT2) to provide users with fault indication. The STAT1 register indicates a fault condition for each LED_ string, whether a shorted or open LED_ fault has occurred. In the event of an LED_ fault, the corresponding bit in the STAT1 register is latched and the 10 ON/OFF control bit for that current regulator is cleared. An I2C read of the STAT1 register causes all STAT1 bits to be cleared. If the fault is persistent, then the corresponding bit in the STAT1 register is set again. All open/short fault monitors are subject to a 16ms blanking period to ensure that the MAX8831 does not respond to a false fault occurrence. The second status register (STAT2) reports the following global system faults: output overvoltage protection detection (OVP), thermal shutdown detection (TSD), and open Schottky diode detection (OSDD). Bit 0 (OVP) of the STAT2 register is updated to a 1 to indicate that an OVP event has occurred. Bit 1 (TSD) of the STAT2 register is updated to a 1 to indicate that thermal shutdown has occurred. Bit 2 (OSDD) of the STAT2 register is updated to a 1 to indicate that an open Schottky diode event has occurred. If a TSD, OVP, or OSDD fault occurs, the IC enters standby mode, the step-up converter stops switching, and all the current regulators are shut down by clearing their ON/OFF control bits. Once standby occurs, the IC will ______________________________________________________________________________________ MAX8831 Evaluation Kit Refer to Figure 5 and the state diagram (Figure 4) in the MAX8831 IC data sheet for more details. I2C Interface Pullup resistors, typically 4.7kΩ, are required on SDA and SCL. The CMAXQUSB contains two pullup resistors (R5 and R6) that are engaged by SW1. If the CMAXQUSB is not used, pullup resistors may need to be installed for resistors R1 and R2. The MAX8831 operates as an I2C slave that receives and sends data through an I2C-compatible 2-wire interface. The MAX8831 EV kit connects to the CMAXQUSB command module to create an I 2 C serial interface between the IC and a PC preinstalled with the MAX8831 EV kit software. The I2C interface controls all operational aspects of the current regulators, including on/off state, LED current, ramp-up/ramp-down timers, and blink rate timers (LED3, LED4, and LED5 only). Refer to the MAX8831 I2 C Registers section in the MAX8831 IC data sheet for more details. ______________________________________________________________________________________ 11 Evaluates: MAX8831 not transition back to the on state until an I2C command enabling one or more current regulators is received. 12 SDA SCL VDD PGND VIN1 VDD C1 1μF VIN1 VDD C4 0.22μF R2 OPEN R1 OPEN TP7 SDA SCL R3 PCB SHORT C3 0.1μF L1 10μH A4 C3 B4 C4 D3 D1 C1 U1 D1 A2 GND MAX8831 GND COMP SDA SCL VDD IN LX LX TP6 B2 B3 A3 B1 A1 D2 C2 D4 VDD SCL 1 JU13 3 2 SDA LED5 LED4 LED3 LED2 LED1 PGND PGND OUT TP5 TP4 TP3 TP2 TP1 R4 PCB SHORT C2 1μF J1-2 J1-4 J1-6 J1-8 J1-10 J1-12 J1-14 J1-16 J1-18 J1-20 J1-1 J1-3 J1-5 J1-7 J1-9 J1-11 J1-13 J1-15 J1-17 J1-19 20-PIN HEADER J1 D9 D8 D7 D6 D5 D17 D16 D15 D14 D13 D12 D4 8 5 D11 JU2 D3 7 6 D10 8 5 D2 JU1 VOUT GREEN RED 7 6 9 6 BLUE GREEN D33 D32 D31 D30 D29 D28 B G R BLUE C5 1μF G R 1 2 3 VIN2 GND VIN2 JU8 VSUPPLY W JU11 B 8 7 BLUE D44 D43 D42 D41 D40 D39 D38 D37 VIN1 JU12 GREEN RED JU7 9 6 D36 JU5 VSUPPLY W JU10 B 8 7 VSUPPLY G R D35 JU6 D34 D45 GREEN RED 9 6 D27 JU4 VSUPPLY W JU9 B 8 7 BLUE RED G R D26 D25 D24 D23 D22 D21 D20 D19 D18 JU3 Evaluates: MAX8831 MAX8831 Evaluation Kit Figure 6. MAX8831 EV Kit Schematic ______________________________________________________________________________________ MAX8831 Evaluation Kit Evaluates: MAX8831 Figure 7. MAX8831 EV Kit Component Placement Guide—Component Side ______________________________________________________________________________________ 13 Evaluates: MAX8831 MAX8831 Evaluation Kit Figure 8. MAX8831 EV Kit PCB Layout—Component Side 14 ______________________________________________________________________________________ MAX8831 Evaluation Kit Evaluates: MAX8831 Figure 9. MAX8831 EV Kit PCB Layout—Solder Side ______________________________________________________________________________________ 15 Evaluates: MAX8831 MAX8831 Evaluation Kit Figure 10. MAX8831 EV Kit Component Bottom Placement Guide—Solder Side 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. 16 __________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2009 Maxim Integrated Products SPRINGER Maxim is a registered trademark of Maxim Integrated Products, Inc.