Application Note 1703 ISL8502AEVAL1Z: 2A Synchronous Buck Regulator with Integrated MOSFETs The ISL8502A is a synchronous buck controller with internal MOSFETs packaged in a small 4mmx4mm QFN package. The ISL8502A can support a continuous load of 2A and has a very wide input voltage range. With the switching MOSFETs integrated into the IC, the complete regulator footprint can be very small and provide a much more efficient solution than a linear regulator. The ISL8502A is capable of standalone operation or it can be used in a master slave combination for multiple outputs that are derived from the same input rail. Multiple slave channels can be individually programmed such that the internal clocks are out-of-phase. This method minimizes the ripple on the input rail. The switching PWM controller drives two internal N-Channel MOSFETs in a synchronous-rectified buck converter topology. The synchronous buck converter uses voltage-mode control with fast transient response. The switching regulator provides a maximum static regulation tolerance of ±1% over line, load, and temperature ranges. The output is user-adjustable by means of external resistors down to 0.6V. The output is monitored for undervoltage events. The switching regulator also has over current protection. Thermal shutdown is integrated. The ISL8502A features a bidirectional Enable pin that allows the part to shut itself down and pull the enable pin low at the same time. PGOOD Rising Delay (measured from VOUT reaching regulation to PGOOD Rising) has been reduced from 250ms (typical) for ISL8502 to 1ms (typical) for ISL8502A (measured at 500kHz switching frequency). Pin Configuration ISL8502A (24 LD QFN) TOP VIEW Features • • • • • • • • • • • • • • • • 2A Continuous Output Current Integrated MOSFETs for Small Regulator Footprint Adjustable Switching Frequency, 500kHz to 1.2MHz Tight Output Voltage Regulation, ±1% Over-Temperature Wide Input Voltage Range, 5V ±10% or 5.5V to 14V Wide Output Voltage Range, from 0.6V Simple Single-Loop Voltage-Mode PWM Control Design Input Voltage Feed-Forward for Constant Modulator Gain Fast PWM Converter Transient Response Lossless rDS(ON) High Side and Low Side Overcurrent Protection Undervoltage Detection Integrated Thermal Shutdown Protection Power-Good Indication Adjustable Soft-Start QFN Package - Compliant to JEDEC PUB95 MO-220 QFN (Quad Flat No Leads) package outline - Near Chip Scale Package footprint, which improves PCB efficiency and has a thinner profile Pb-Free (RoHS Compliant) Applications • • • • • Point of Load Applications Graphics Cards - GPU and Memory Supplies ASIC Power Supplies Embedded Processor and I/O Supplies DSP Supplies VCC PVCC BOOT VIN VIN VIN Ordering Information 24 23 22 21 20 19 PART NUMBER PART TEMP. RANGE MARKING (°C) PGOOD 1 18 VIN ISL8502AIRZ (Notes 1, 2, 3) SGND 2 17 PHASE ISL8502AEVAL1Z Evaluation Board EN 3 16 PHASE NOTES: SYNCH 4 M/S 5 14 PHASE FS 6 13 PGND October 21, 2011 AN1703.0 GND 29 7 8 9 10 11 12 COMP FB SS PGND PGND PGND 15 PHASE 85 02AIRZ -40 to +85 PACKAGE (Pb-free) PKG. DWG. # 24 Ld 4x4 QFN L24.4x4D 1. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications. 2. 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 Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 3. For Moisture Sensitivity Level (MSL), please see device information page for ISL8502A. For more information on MSL please see tech brief TB363. 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2011. All Rights Reserved 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 1703 What’s Inside Evaluating Other Output Voltages The Evaluation Board Kit contains the following materials: • The ISL8502A datasheet The ISL8502AEVAL kit outputs are preset to 2.5V. For a quick evaluation of output voltages between 0.6V and VIN -1.7V, the following resistors need to be changed in the feedback network as shown in Equations 1 and 2: • This EVAL KIT document R 111 = ( R 108 ) ⁄ [( V OUT ⁄ V FB1 ),– 1] Recommended Equipment where R108 = 17.4kΩ; and VFB1 = 0.6V The following materials are recommended to perform testing: R 211 = ( R 208 ) ⁄ [( V OUT2 ⁄ V FB2 ),– 1] • 0V to 15V power supply with at least 5A source current capability, battery, notebook AC adapter where R208 = 17.4kΩ; and VFB2 = 0.6V • The ISL8502A EVAL REVD board • Two Electronic Loads capable of sinking current up to 5A (EQ. 1) (EQ. 2) • 100MHz quad-trace Oscilloscope However, for reliable operation over the entire load and temperature range, it is highly recommended to follow the output filter and loop compensation network design guidelines as listed in the ISL8502A datasheet. • Signal generator (only if the SYNC function needs to be evaluated) Frequency Quick Setup Guide The ISL8502AEVAL can operate at switching frequencies from 500kHz to1.2MHz. R104 and R204 are used to program the switching frequency through Equation 3: • Digital Multimeters (DMMs) 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. Plus terminal to J1(VIN) and negative return to J2(GND). (EQ. 3) R 104 and ( R 204 ) = 48000 ⁄ ( fosc [ kHz ] ) TABLE 1. SWITCH 1 SETTINGS SW1 SKIP 4. Turn on the power supply. 1 NC 5. Verify the outputs voltages are 2.5V for VOUT1 and VOUT2. 2 EN_ALL 3 EN1 Enable or disable VOUT1 4 EN2 Enable or disable VOUT2 3. Verify that all positions are ON for S1, EN_all, EN_1, EN_2. OPERATING MODE No Connect Enable or disable VOUT1 and VOUT2 Soft-start C107, C207 can be used to adjust the soft-start time. 2 AN1703.0 October 21, 2011 ON ON ON ON 8 7 6 5 GROUND CONNECTIONS FOR SCOPE PROBES IKN0403000 24 PIN PACKAGE 25 EP 1 C210 470PF 17.4K R210 2 18 17 16 15 14 13 R208 174 2 4.7UH 0 C206 OPEN 2 R205 1 1 10UF TP203 10UF 2 C200B 1 1 TP212 R105 1 J4 4 J8 1 1 J3 10UF 2 C100B 1 10UF 2 C100A 1 TP103 3 0.1UF 2 C102 1 24 23 22 21 20 19 0.1UF 2 C103 1 10K R102 10K 0 R101 R100 24 23 22 21 20 19 2 TP104 36 3 1 1 1 J1 1 J2 1 2 4 J10 J6 1 L200 100UF 4 J9 2 C200A 1 3 2 2 C204 1 3 TP200 100UF 2 C104 1 22UF 2 C105 1 2 R3 4 J7 3 1 22UF J5 18 17 16 15 14 13 1 2 2 C205 1 0.1UF 24 23 22 21 20 19 2 C202 1 U200 MLFP DNP 1 2 3 4 5 6 JP2 R207 24 23 22 21 20 19 1 1 25 1 2 TP209 1 2 3 4 5 6 7 8 9 10 11 12 R108 1 7 8 9 10 11 12 174 1 17.4K C110 R110 2 C207 1 0.01UF 2 47PF 0.1UF 2 C203 1 10K 0 C106 2 C208 1 D200 L100 R209 2 C209 1 20K 1000PF 1 2 4.7UH R202 2 1 10K 470PF 18 17 16 15 14 13 R204 18 17 16 15 14 13 DNP R107 24 PIN PACKAGE 95.3K TP109 3 U100 MLFP 1 2 DNP R201 R200 1 1 0.01UF 2 C107 1 25 EP 7 8 9 10 11 12 1 2 3 4 5 6 D1 31 R2 2 TP112 TP100 5.49K JP1 4.99K TP205 7 8 9 10 11 12 25 47PF 2 C108 1 TP105 1 1 2 3 4 5 6 5.49K 95.3K R104 DNP R103 R109 2 C109 1 20K 1000PF TP110 JP3 2 1 2 2 1 Q4 R111 1 1 75 R6 D100 TP211 TP204 2 1 1 ENABLE R203 OFF TP210 S1 1 TP111 Q6 1 2N7002 1 R211 1 2 3 4 Q1 5.49K 1 ON 1 1 D2 31 Q3 P6 TP3 1 2 1 36 Q5 R5 2N7002 1 3 R4 Q2 1 1 P1 1 AND 2 REG 1 REG 2 1 2 3 4 5.49K 1 OPEN 1 2 VOUT2 Application Note 1703 1 2 3 3 2 75 R1 ISL8502AEVAL1Z Schematic 2 VIN VOUT1 AN1703.0 October 21, 2011 Application Note 1703 TABLE 2. BILL OF MATERIALS PART NUMBER QTY UNITS REFERENCE DESIGNATOR DESCRIPTION MANUFACTURER MANUFACTURER PART ISL8502EVAL1ZREVEPCB 1 ea SEE LABELRENAME BOARD PWB-PCB, ISL8502EVAL1Z, REV E, SOIC, ROHS IMAGINEERING INC ISL8502EVAL1ZREVEPCB GRM21BR71C475KA73L 2 ea C111, C211 CAP, SMD, 0805, 4.7µF, 16V, 10%, X7R, ROHS MURATA GRM21BR71C475KA73L H1044-00104-16V10-T 2 ea C102, C202 CAP, SMD, 0402, 0.1µF, 16V, 10%, X7R, ROHS VENKEL C0402X7R160-104KNE MURATA GRM155R71C104KA88D PANASONIC ECJ-0EX1C104K TAIYO YUDEN EMK105B7104KV-F YAGEO CC0402KRX7R7BB104 KEMET C0402C104K4RACTU H1044-00105-10V10-T H1044-00150-50V5-T 2 ea 2 ea C103, C203 C108, C208 CAP, SMD, 0402, 1.0µF, 10V, 10%, X5R, ROHS CAP, SMD, 0402, 15pF, 50V, 5%, NP0, ROHS TDK C1005X7R1C104K MURATA GRM155R61A105KE15D VENKEL C0402X5R100-105KNE TAIYO YUDEN LMK105BJ105KV-F AVX 0402ZD105KAT2A MURATA GRM36COG150J050AQ PANASONIC ECU-E1H150JCQ VENKEL H1044-00153-16V10-T 2 ea C107, C207 CAP, SMD, 0402, 0.015µF, PANASONIC 16V, 10%, X7R, ROHS VENKEL C0402COG500-150JNE ECJ-0EB1C153K C0402X7R160-153KNE AVX 0402YC153KAT2A MURATA GRM155R71C153KA01D H1044-00471-50V10-T 2 ea C110, C210 CAP, SMD, 0402, 470pF, 50V, 10%, X7R, ROHS PANASONIC ECJ-0EB1H471K VENKEL C0402X74500-471KNE H1044-00821-50V10-T 2 ea C109, C209 CAP, SMD, 0402, 820pF, 50V, 10%, X7R, ROHS PANASONIC ECJ-0EB1H821K H1044-DNP 0 ea C106, C206 CAP, SMD, 0402, DNPPLACE HOLDER, ROHS H1046-DNP 0 ea C112, C113 CAP, SMD, 0805, DNPPLACE HOLDER, ROHS H1065-00106-25V10-T 4 ea C100A, C100B, C200A, C200B CAP, SMD, 1206, 10µF, 25V, 10%, X5R, ROHS VENKEL C1206X5R250-106KNE H1082-00107-10V20-T 2 ea C105, C205 CAP, SMD, 1210, 100µF, 10V, 20%, X5R, ROHS TAIYO YUDEN LMK325BJ107MM-T 111-0702-001 1 ea VIN CONN-GEN, BIND.POST, INSUL-RED, THMBNUTGND JOHNSON COMPONENTS 111-0702-001 KEYSTONE 7006 111-0703-001 1 ea GND CONN-GEN, BIND.POST, INSUL-BLK, THMBNUTGND JOHNSON COMPONENTS 111-0703-001 131-4353-00 4 ea J7-J10 CONN-SCOPE PROBE TEST TEKTRONIX PT, COMPACT, PCB MNT, ROHS 131-4353-00 1514-2 6 ea J3-J6, P1, P2 CONN-TURRET, TERMINAL POST, TH, ROHS 1514-2 4 KEYSTONE KEYSTONE 7007 AN1703.0 October 21, 2011 Application Note 1703 TABLE 2. BILL OF MATERIALS (Continued) PART NUMBER QTY UNITS REFERENCE DESIGNATOR DESCRIPTION MANUFACTURER MANUFACTURER PART 5002 17 ea a) TP3, TP100, TP103-TP105, TP109-TP112, CONN-MINI TEST POINT, VERTICAL, WHITE, ROHS KEYSTONE 5002 5002 0 ea b) TP200, TP203- CONN-MINI TEST POINT, VERTICAL, WHITE, ROHS TP205, TP209TP212 KEYSTONE 5002 69190-202HLF 3 ea JP1-JP3 CONN-HEADER, 1X2, RETENTIVE, 2.54mm, 0.230X 0.120, ROHS" BERG/FCI 69190-202HLF SPC02SYAN 1 ea JP3 CONN-JUMPER, SHORTING, 2 PIN, BLACK, GOLD, ROHS SULLINS SPC02SYAN 1N4148WS-7-F-T 2 ea D100, D200 DIODE-RECTIFIER, SMD, SOD-323, 2P, 75V, 150mA, ROHS DIODES INC. 1N4148WS-7-F BAT54-T 0 ea DNP (D1, D3) DIODE-SCHOTTKY, SMD, SOT23, 3P, 30V, 200mA, SINGLE DIODE FAIRCHILD BAT54 PDS560-13 0 ea DNP (D2, D4) DIODE-RECTIFIER, SMD, POWER DI5, 3P, 60V, 5A, ROHS DIODES INC. PDS560-13 LTST-C170CKT 2 ea LED1, LED2 LED-GaAs RED, SMD, 2mmx1.25mm, 100mW, 40mA, 10mcd, ROHS LITEON/VISHAY LTST-C170CKT ROHM SML-210LTT86 STANLEY ELECTRIC BR112H-TR CDRH8D28NP-4R7NC 2 ea L100, L200 SUMIDA COIL-PWR INDUCTOR, SMD, 8.3mm, 4.7µH, 30%, ELECTRIC, CO. 3.4A, ROHS, SHIELDED CDRH8D28NP-4R7NC ISL8502AIRZ 2 ea U100, U200 IC-2A BUCK REGULATOR, 24P, QFN, 4X4, ROHS ISL8502AIRZ 2N7002-7-F-T 2 ea Q3, Q6 TRANSISTOR, N-CHANNEL, DIODES, INC. 3 LD, SOT-23, 60V, 115mA, ROHS ON SEMICONDUCTOR MMBT2222ALT1G-T 4 ea Q1, Q2, Q4, Q5 TRANSISTOR, NPN, 3 LD, SOT23, 40V, 600mA, ROHS H2510-00360-1/16W5-T 2 ea R3, R5 RES, SMD, 0402, 36Ω, 1/16W, 5%, TF, ROHS H2510-00750-1/16W5-T H2510-00R00-1/16W-T H2510-01002-1/16W1-T 2 ea 3 ea 4 ea 5 R1, R6 R100, R105, R205 R101, R102, R201, R202 RES, SMD, 0402, 75Ω, 1/16W, 5%, TF, ROHS RES, SMD, 0402, 0Ω, 1/16W, 5%, TF, ROHS RES, SMD, 0402, 10k, 1/16W, 1%, TF, ROHS INTERSIL 2N7002-7-F 2N7002LT1G YAGEO RC0402JR-0736RL VENKEL CR0402-16W-360JT PANASONIC ERJ2GEJ0750 VENKEL CR0402-16W-750JT VENKEL CR0402-16W-00T PANASONIC ERJ-2GE0JR00 PANASONIC ERJ-2RKF1002X VENKEL CR0402-16W-1002FT ROHM MCR01MZPF1002 YAGEO RC0402FR-0710KL VISHAY/DALE CRCW040210K0FKED AN1703.0 October 21, 2011 Application Note 1703 TABLE 2. BILL OF MATERIALS (Continued) PART NUMBER H2510-01401-1/16W1-T H2510-02802-1/16W1-T QTY UNITS 2 ea 4 ea REFERENCE DESIGNATOR R110, R210 R108, R109, R208, R209 DESCRIPTION RES, SMD, 0402, 1.4k, 1/16W,1%, TF, ROHS MANUFACTURER MANUFACTURER PART VISHAY/DALE CRCW04021K40FKED STACKPOLE RMCF0402FT1K40 VENKEL CR0402-16W-1401FT RES, SMD, 0402, VENKEL 28k,1/16W, 1%, TF, ROHS PANASONIC CR0402-16W-2802FT ERJ-2RKF2802X ROHM MCR01MZPF2802 YAGEO RC0402FR-0728KL VISHAY/DALE CRCW040228K0FKED KDA RK73H1E4991F VENKEL CR0402-16W-4991FT H2510-04991-1/16W1-T 1 ea R203 RES, SMD, 0402, 4.99k, 1/16W, 1%, TF, ROHS H2510-05491-1/16W1-T 2 ea R2, R4 RES, SMD, 0402, 5.49k, 1/16W, 1%, TF, ROHS H2510-06041-1/10W1-T 2 ea R111, R211 RES, SMD, 0402, 6.04k, 1/10W, 1%, TF, ROHS PANASONIC ERJ2RKF6041X H2510-09532-1/16W1-T 2 ea R104, R204 RES, SMD, 0402, 95.3k, 1/16W, 1%, TF, ROHS YAGEO RC0402FR-0795K3L VENKEL CR0402-16W-9532FT H2510-DNP 0 ea R103, R107, R200, R207 RES, SMD, 0402, DNP, DNP, DNP, TF, ROHS H2511-00100-1/10W1-T 2 ea R112, R212 RES, SMD, 0603, 10Ω, 1/10W, 1%, TF, ROHS KOA RK73H1JT10R0F VENKEL CR0603-10W-10R0FT H2515-DNP 0 ea R113, R114 RES, SMD, 2512, DNP, DNP, DNP, TF, ROHS IKN0403000 1 ea S1 (Install according to silkscreen) SWITCH-DIP, SMD, 4P, SLIDE, SPST, LP, ROHS APEM IKN0403000 4-40X1/2-SCREW 4 ea Four corners SCREW, 4-40X1/2in, PAN, NYLON, PHILLIPS, ROHS 4-40X3/4-STANDOFF 4 ea Four corners STANDOFF, 4-40X3/4in, F/F, HEX, NYLON, ROHS KEYSTONE 1902D 5X8-STATIC-BAG 1 ea Place assy in bag BAG, STATIC, 5X8, ZIPLOC, INTERSIL ROHS DNP 0 ea C104, C204 DO NOT POPULATE OR PURCHASE LABEL-DATE CODE 1 ea LABEL-RENAME BOARD 1 ea 6 LABEL-FOR DATE CODE AND BOM REV # RENAME PCB TO: LABEL, TO RENAME ISL8502AEVAL1Z BOARD 212403-013 INTERSIL LABEL-DATE CODE INTERSIL LABEL-RENAME BOARD AN1703.0 October 21, 2011 Application Note 1703 ISL8502AEVAL1Z Board Layout ISL8502AEVAL1Z FIGURE 1. TOP COMPONENTS FIGURE 2. TOP LAYER ETCH 7 AN1703.0 October 21, 2011 Application Note 1703 ISL8502AEVAL1Z Board Layout (Continued) FIGURE 3. 2ND LAYER ETCH FIGURE 4. 3RD LAYER ETCH 8 AN1703.0 October 21, 2011 Application Note 1703 ISL8502AEVAL1Z 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 9 AN1703.0 October 21, 2011