ISL8540EVAL1Z: 2A High Voltage Buck Regulator with Integrated MOSFETs ® Application Note The ISL8540 is a step down DC/DC power switching regulator which accepts a 9V to 40V input, and provides up to 2A of output current. The output voltage can be set between 1.21V and 35V by means of an external resistor divider. The device uses an internal power DMOS transistor with a typical rDS(ON) of 0.19Ω to obtain very high efficiency and high switching speed. A switching frequency in the range of 100kHz to 600kHz can be realized (the maximum power dissipation of the various packages must be observed). Notable features of this next generation DC/DC converter include pulse-by-pulse current limit for FET protection, hiccup-mode short circuit protection, voltage feedforward, frequency SYNC, soft-start, low standby current of 60µA typical in the disabled state and thermal shut-down. The device is available in a 20 Ld HTSSOP package. February 13, 2008 AN1323.1 Features • Voltage feedforward • Step down DC/DC supporting up to 2A • Input voltage range of 9V to 40V • Internal reference of 1.21V ±1% • Adjustable output voltage range of 1.21V to 35V • Adjustable switching frequency 100kHz to 600kHz • Frequency SYNC pin • Zero load current operation • Pulse-by-pulse mode current limit • Hiccup mode short-circuit protection • Low standby current of 60µA typical Ordering Information PART NUMBER (Note) ISL8540IVEZ PART MARKING • Thermal shut-down TEMP. RANGE (°C) PACKAGE (Pb-free) PKG. DWG. # ISL85 40IVEZ -40 to +85 20 Ld HTSSOP MDP0048 • Transient survival up at 60V for 400ms • Pb-free (RoHS compliant) Applications ISL8540IVEZ-T* ISL85 40IVEZ -40 to +85 20 Ld HTSSOP MDP0048 • Industrial and automotive power supplies ISL8540EVAL1Z Evaluation Board • Portable computers *Please refer to TB347 for details on reel specifications. NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate PLUS ANNEAL - e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pbfree peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. • Battery chargers • Distributed power systems Related Literature • Technical Brief TB363 “Guidelines for Handling and Processing Moisture Sensitive Surface Mount Devices (SMDs)” Pinouts ISL8540 (20 LD HTSSOP) TOP VIEW VIN 1 19 VIN LX 3 18 LX LX 4 17 LX BOOT 5 16 SS EN 6 15 PGND VCC5 7 14 PGOOD SYNC 8 13 REF RTCT 9 12 COMP SGND 10 1 20 VIN VIN 2 11 FB CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2007, 2008. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1323 What’s Inside Evaluating the Other Output Voltage The Evaluation Board Kit contains the following materials: The ISL8540EVAL1Z kit output is preset to 5V. The output voltage can be adjusted from 1.21V to 35V by Equation 1: • The ISL8540EVAL1Z REVB board. R 1 = ( R 2 ) ⁄ ( ( V OUT ⁄ V FB1 ) – 1 ) • The ISL8540 datasheet. • ISL8540 Evaluation Board Application Note. Recommended Equipment The following equipment is recommended to evaluate the performance of the board: • 0V to 60V power supply with at least 5A current sourcing capability. • Electronic Loads capable of sinking current up to 5A. • Digital Multimeters (DMMs.) • 100MHz quad-trace Oscilloscope. • Signal generator (to test the SYNC feature only). Quick Setup Guide 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. 2. Connect the bias supply to VIN, with the positive terminal connected to P1(VIN), and the return to P2(GND). 3. Connect the load across the output terminals, between pins P3 (positive) and P4 (return). 4. Verify that the jumper JP1 is connected. 5. Apply a voltage between 9V and 40V across the input. with R2 = 51.1kΩ and VFB1 = 1.21V. Note: The inductor, output capacitors and the compensation network may need to be tweaked, along with the corresponding compensation network, for optimal performance with change in output voltage and/or load. Also, additional heatsinking or airflow may required to insure that the junction temperature does not exceed +125°C. Frequency The ISL8540EVAL1Z kit is preset at 500kHz. The ISL8540EVAL1Z can be adjusted to operate at switching frequencies from 100kHz to 600kHz. Use C16 to program the switching frequency using Equation 2: 6.25 1000 C 16 [ nF ] = -------------------- ⎛ ------------------------------ – 0.3⎞ ⎠ R 7 [ kΩ ] ⎝ f OSC [ kHz ] (EQ. 2) Synchronization The ISL8540EVAL1Z circuit may be synchronized to a TTL signal that is set at a higher switching frequency than the pre-set frequency. The range of the external synchronizing frequency is from 100kHz to 600kHz. It is recommended to use and RTCT capacitor (C16) of 2700pF in this configuration. 6. Verify that the output voltage is 5V. TABLE 1. SWITCH 1 SETTINGS JP1 2 (EQ. 1) ENABLE OPERATING MODE 1 OPEN Unit Disabled 2 GND Unit Enabled AN1323.1 February 13, 2008 Schematic 3 Application Note 1323 AN1323.1 February 13, 2008 Application Note 1323 TABLE 2. COMPONENT LIST REF DES QTY VALUE TOL. VOLTAGE C5, C10, C11 3 0.10µF 10% 50V PACKAGE 0603 PART NUMBER C1608X7R1H104K-T C12-C14 3 150µF 20% 25V 8mmx10mm EEE-FK1E151P-T C1-C3 3 47µF 20 100V 12.5mmx13.5mm EEV-FK2A470Q-T C7, C9 2 100pF 5% 50V 0603 H1045-00101-50V5-T C15 1 0.01µF 10% 50V 0603 H1045-00103-50V10-T C18 1 1µF 10% 16V 0603 H1045-00105-16V10-T C19 1 390pF 5% 50V 0603 H1045-00391-50V5-T C8, C17 0 OPEN - - - H1045-DNP C6 1 1.0µF 10% 25V 0805 H1046-00105-25V10-T C4 1 0.1µF 10% 100V 1206 H1065-00104-100V10-T C16 1 470pF 5% 100V 1206 H1065-00471-100V5-T L1 1 22µH 20% - 18mmx15mm DO5010H-223MLB JP1 1 0Ω - - Header SPC02SYAN D1 1 5A 100V Power DI-5 PDS5100H U1 1 2A - 40V 20 HTSSOP ISL8540IEVZ R9 1 20Ω 1% 100V 0603 H2511-0200-1/10W1-T R5, R6, R8 3 10k 1% 100V 0603 H2511-1002-1/16W1-T R1 1 16.2k 1% 100V 0603 H2511-1622-1/16W1-T R4 1 301k 1% 100V 0603 H2511-3013-1/10W1-T R2 1 51.1k 1% 100V 0603 H2511-05112-1/16W1-T R3 1 5.62k 1% 100V 0603 H2511-5621-1/16W1-T R7 1 20k 1% 100V 0603 H2513-02002-1/4W1-T R10 1 0Ω 1% 100V 0603 H2515-00R00-1W-T 4 MANUFACTURER DESCRIPTION TDK CAPACITOR, SMD, 0603, 0.10µF, 50V, 10%, X7R PANASONIC CAP, SMD,1 0.3mm, 150µF, 25V, 20%, ROHS, ALUM. ELEC. PANASONIC CAPACITOR, SMD, H13, 47µF, 100V, 20%, ROHS, ALUM. ELEC. CAPACITOR, SMD, 0603, AVX, Samsung, 100pF, 50V, 5%, NPO, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 0603, AVX, Samsung, 0.01µF, 50V, 10%, X7R, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 0603, 1µF, AVX, Samsung, 16V, 10%, X7R, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 0603, AVX, Samsung, 390pF, 50V, 5%, NPO, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 0603, AVX, Samsung, DNP-PLACE HOLDER, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 0805, AVX, Samsung, 1.0µF, 25V, 10%, X7R, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 1206, AVX, Samsung, 0.1µF, 100V, 10%, X7R, ROHS TDK, Murata, Vishay CAPACITOR, SMD, 1206, AVX, Samsung, 470pF, 100V, 5%, NPO, ROHS TDK, Murata, Vishay COILCRAFT COIL-PWR INDUCTOR, SMD, 18x15, 22µH, 20%, 7A, ROHS, 47mΩ SULLINS CONN-JUMPER, 2 PIN, SHUNT, ROHS DIODES INC. DIODE-RECTIFIER, SMD, Power DI-5, 100V, 5A, ROHS, SCHOTTKY INTERSIL IC-STEP DOWN DC/DC CONVERTER, 20P, HTSSOP, ROHS PANASONIC RESISTOR, SMD, 0603, 20Ω, 1/10W, 1%, TF, ROHS PANASONIC RESISTOR, SMD, 0603, 10k, 1/16W, 1%, TF, ROHS PANASONIC RESISTOR, SMD, 0603, 16.2k, 1/16W, 1%, TF, ROHS YAGEO RESISTOR, SMD, 0603, 301k, 1/10W, 1%, TF, ROHS PANASONIC RESISTOR, SMD, 0603, 51.1k, 1/16W, 1%, TF, ROHS PANASONIC RESISTOR, SMD, 0603, 5.62k, 1/16W, 1%, TF, ROHS PANASONIC RESISTOR, SMD, 1206, 20k,1/4W, 1%, TF, ROHS VENKEL RESISTOR, SMD, 2512, 0Ω, 1W, TF, ROHS AN1323.1 February 13, 2008 Application Note 1323 ISL8540EVAL1Z Board Layout ISL8540EVAL1Z Rev. B FIGURE 1. TOP COMPONENTS FIGURE 2. TOP LAYER ETCH 5 AN1323.1 February 13, 2008 Application Note 1323 ISL8540EVAL1Z Board Layout (Continued) FIGURE 3. 2ND LAYER ETCH FIGURE 4. 3RD LAYER ETCH 6 AN1323.1 February 13, 2008 Application Note 1323 ISL8540EVAL1Z Board Layout (Continued) FIGURE 5. BOTTOM LAYER COMPONENTS (MIRRORED) FIGURE 6. BOTTOM LAYER ETCH (MIRRORED) 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 AN1323.1 February 13, 2008