Application Note 1647 Author: David Sorlien ISL9112IRTNEVAL1Z, ISL9112IRT7EVAL1Z Evaluation Board User Guide Evaluation Board Features • ISL9112IRTNZ high efficiency buck-boost regulator with I2C adjustable output voltage • Input voltage rating from 1.8V to 5.5V • I2C programmable output voltage, default 3.3V • I2C programmable slew rate control TABLE 2. DESCRIPTION OF CONNECTORS CONNECTOR J1 Header for connecting input power J2 Header for connecting external load J5 Header for connecting I2C interface • 1200mA output current at VIN ≥ 3V and VOUT = 3.3V • 2.5MHz switching frequency • Jumper selectable EN (enabled/disabled) • Jumper selectable MODE (auto-PFM/forced-PWM) • Connectors, test points and jumpers for easy evaluation Required Equipment • ISLUSBI2CKIT1Z (includes USB to I2C interface, USB cable and 4-pin I2C cable) • Power supply capable of delivering up to 5.5V and 3A • Electronic load • Multimeter to measure voltages and currents • Oscilloscope Test Points, Connectors and Jumpers TABLE 1. DESCRIPTION OF TEST POINTS TEST POINT(S) DESCRIPTION TP1 VOUT Kelvin connection for efficiency measurements TP2 LX1 (Input side of power inductor) TP3 PGND (Power ground) TP4 LX2 (Output side of power inductor) TP5 PVIN Kelvin connection for efficiency measurements TP6 VIN (supply input for internal reference) TP7 SCL (I2C clock) TP8 SDA (I2C data) TP9 EN (Enable input, drive high to enable device) TP10 MODE/SYNC (Mode input, drive low for forced PWM, or apply external clock between 2.75MHz and 3.25MHz for external sync) DESCRIPTION TABLE 3. DESCRIPTION OF JUMPERS JUMPER DESCRIPTION J3 Jumper to select EN input logic state. Set EN = VIN to enable device, or set EN = GND to disable device. J4 Jumper to select MODE input logic state. Set MODE = VIN to enable auto-PFM mode, or set MODE = GND to select forced PWM mode. To use external sync feature, remove this jumper and apply an external clock between 2.75MHz and 3.25MHz on the MODE test point (TP10) or center pin on the J4 header. Quick Setup Guide 1. Install jumper on J3, shorting EN to VIN. 2. Install jumper on J4, shorting MODE to VIN. 3. Connect power supply to J1, with voltage setting between 1.8V and 5.5V. 4. Connect electronic load to J2. 5. Place scope probes on VOUT test point, and other test points of interest. 6. Turn on the power supply. 7. Monitor the output voltage start-up sequence on the scope. The waveforms will look similar to those shown in Figure 2 and Figure 3. 8. Turn on the electronic load. 9. Measure the output voltage with the voltmeter. The voltage should regulate within data sheet spec limits (FN7649). 10. To determine efficiency, measure input and output voltages at the Kelvin testpoints TP5 and TP1, and measure the input and output currents. Calculate efficiency based on these measurements. 11. To test external sync, remove the jumper at J4, then apply an external clock between 2.75MHz and 3.25MHz on the MODE input (test point TP10, or the center pin of header J4). TP11, TP13, TP14 GND (Ground) TP12 July 10, 2012 AN1647.2 FB (Voltage feedback input, connected to VOUT) 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Copyright Intersil Americas Inc. 2011, 2012. All Rights Reserved. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. Application Note 1647 Evaluation Software Installation/Use 1. Check your system specs against the system requirements listed below. •Windows 98SE, Windows XP, or Windows NT •CD-ROM drive •USB port •At least 20MB free hard disk space •1024x768 or larger resolution monitor 2. Install the driver for the ISLUSB2I2C interface by double clicking on the file named “ISLUSBI2C_Driver_Installer.exe” on the ISL9112 evaluation kit CD-ROM. Follow the instructions that appear on-screen to install the driver. 3. Install the ISL9112 evaluation software by double clicking on the file named: “ISL9112_Eval_Installer.exe” on the ISL9112 eval kit CD-ROM. Follow the instructions that appear on-screen to install the application. 4. Attach the ISLUSBI2C interface to the computer using the supplied USB cable. The ‘Found New Hardware” dialog will appear. Select “Install the software automatically” and click “Next”. 5. Locate the 4-wire I2C cable that is provided with the ISLUSBI2C kit. Attach one end of this cable to the 4-pin header on the ISLUSBI2C interface, and connect the other end of this cable to the corresponding 4-pin header on the ISL9112 evaluation board. 6. Following the “Quick Setup Guide” on page 1 of this document, connect the power supply, DC load, and other test equipment to the ISL9112 evaluation board, then apply power. 7. Launch the ISL9112 evaluation software. The installer adds a shortcut in the Start menu: Start → Programs → Intersil → ISl9112 → ISL9112 Eval. Select this item to launch the evaluation software. 8. When launched, the ISL9112 evaluation software detects the ISLUSBI2C interface. At the bottom of the ISL9112 application window is a Log textbox. The message in this textbox should report: “USB-to-I2C driver initialization successful” and “USB-to-I2C interface detected.” See Figure 1. If this message is not displayed, please check connections and try reinstalling the ISLUSBI2C driver. 9. Try reading the ISL9112 device registers by clicking on the READ buttons. Observe the activity reported in the Log textbox. Successful I2C communication will be reported in this textbox. If there is a communication error, this will also be reported in the Log textbox. 10. To change the output voltage, use Table 5 to determine the DCDOUT value that corresponds to the desired output voltage. Change the value of V Control register accordingly, and also set the I2CEN bit. Click the Write button to write this value to the device. 11. To invoke Ultrasonic mode, set the ULTRA bit in the V Control register, and click the Write button to write this value to the device. 12. To change the slew rate setting, use Table 5 to determine the SLEWRATE value that corresponds to the desired slew rate. Change the value of the Slew Ctrl register accordingly, then click the Write button to write this data to the device under test. 13. To observe slew rate control behavior, set the slew rate to a value other than ‘0b000’, and then change the DCDOUT value using the evaluation software. Observe VOUT on an oscilloscope to see the slew rate limited transitions from one voltage setting to the new voltage setting. FIGURE 1. ISL9112 EVALUATION SOFTWARE WINDOW 2 AN1647.2 July 10, 2012 Application Note 1647 Typical Start-up Waveforms VIN = 2V VOUT = 3.3V LX1 I = 200mA 2V/DIV OUT Output Voltage Programming TABLE 5. ISL9112 OUTPUT VOLTAGE SETTINGS DCDOUT[4:0] OUTPUT VOLTAGE (V) 0b00000 1.9 0b00001 2.0 0b00010 2.1 0b00011 2.2 0b00100 2.3 0b00101 2.4 0b00110 2.5 0b00111 2.6 0b01000 2.7 0b01001 2.8 0b01010 2.9 0b01011 3.0 0b01100 3.1 0b01101 3.2 0b01110 3.3 0b01111 3.4 0b10000 3.5 0b10001 3.6 0b10010 3.7 0b10011 3.8 0b10100 3.9 TABLE 4. ISL9112 SLEW RATE CONTROL SETTINGS 0b10101 4.0 BIT NAME TYPE RESET 0b10110 4.1 2:0 SLEWRATE R/W 000 0b10111 4.2 0b11000 4.3 0b11001 4.4 0b11010 4.5 0b11011 4.6 0b11100 4.7 0b11101 4.8 0b11110 4.9 0b11111 5.0 LX2 2V/DIV VOUT 2V/DIV EN 2V/DIV 400µs/DIV FIGURE 2. ISL9112 START-UP WITH VIN = 2V AND VOUT = 3.3V VIN = 4V VOUT = 3.3V LX1 I = 200mA 2V/DIV OUT LX2 2V/DIV VOUT 2V/DIV EN 2V/DIV 400µs/DIV FIGURE 3. ISL9112 START-UP WITH VIN = 4V AND VOUT = 3.3V Slew Rate Control 7:3 Reserved R/W 00000 3 DESCRIPTION Slew rate control (typ), expressed as µs per LSB change in DCDOUT value: 0b000 = 0µs/ΔLSB 0b001 = 1.5µs/ΔLSB 0b010 = 3.1µs/ΔLSB 0b011 = 6.3µs/ΔLSB 0b100 = 12.5µs/ΔLSB 0b101 = 25µs/ΔLSB 0b110 = 50µs/ΔLSB 0b111 = 100µs/ΔLSB AN1647.2 July 10, 2012 Application Note 1647 Evaluation Board Schematic J2 VOUT 1 2 3 4 C2 10µF 0805 HDR4 TP12 J4 HDR3 TP10 TP1 TP2 VIN 1.8V TO 5.5V J1 TP4 1 2 3 4 C1 10µF 0805 U1 ISL9112IRTNZ/IRT7Z 1 12 VOUT FB 2 L1 2.2µH 3 4 5 6 HDR4 TP5 GND MODE LX1 EN PVIN SDA VIN SCL 11 0 TP6 VIN MODE 1 2 3 TP11 10 J3 HDR3 TP9 9 EN 8 SDA 7 SCL TP7 PD R1 LX2 PGND VOUT 3.3V (ISL9112IRTNZ) 5.0V (ISL9112IRT7Z) VIN 1 2 3 TP8 VIN C3 1µF J5 TP3 TP13 TP14 1 2 3 4 HDR4B FIGURE 4. ISL9112 EVALUATION BOARD SCHEMATIC TABLE 6. ISL9112 EVALUATION BOARD BILL OF MATERIALS ITEM# QTY DESIGNATORS PART TYPE FOOTPRINT DESCRIPTION VENDORS 1 1 U1 ISL9110IRTNZ or ISL9112IRT7Z L12.3x3C TQFN Intersil ISL9112 Buck-Boost Regulator with I2C Adjustable Output Voltage INTERSIL 2 1 L1 2.2µH 5x5x1.4 NRS5020T2R2 TAIYO YUDEN 3 2 C1, C2 10µF/10V/X5R 0805 LMK212BJ106KG TAIYO YUDEN 4 1 C3 1µF/10V/X7R 0603 LMK107BJ105KK TAIYO YUDEN 6 1 R1 0Ω 0603 Resistor, Generic ANY 7 2 J1, J2 HDR-4 HDR-4 Vert. Pin Header, 4-Pin, 0.1” Spacing, Generic ANY 8 2 J3, J4 HDR-3 HDR-3 Vert. Pin Header, 3-Pin, 0.1” Spacing, Generic ANY 9 1 J5 HDR-4POL HDR-4POL Header, 4-pin, Polarized, AMP 3-641213-4 AMP 13 14 TP1, TP2, TP3, TP4, TP5, TP6, TP7, TP8, TP9, TP10, TP11, TP12, TP13, TP14 TEST POINT TEST POINT Test Point, Thru-Hole, White, Mouser 534-5002 KEYSTONE 4 AN1647.2 July 10, 2012 Application Note 1647 Evaluation Board Layout FIGURE 5. ISL9112 EVALUATION BOARD SILKSCREEN TOP FIGURE 6. ISL9112 EVALUATION BOARD TOP COPPER 5 AN1647.2 July 10, 2012 Application Note 1647 Evaluation Board Layout (Continued) FIGURE 7. ISL9112 EVALUATION BOARD MID LAYER 1 (GND) FIGURE 8. ISL9112 EVALUATION BOARD MID LAYER 2 (VIN AND VOUT) 6 AN1647.2 July 10, 2012 Application Note 1647 Evaluation Board Layout (Continued) FIGURE 9. ISL9112 EVALUATION BOARD BOTTOM LAYER (GND) Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 7 AN1647.2 July 10, 2012