USER'S MANUAL ISL8018EVAL3Z UG053 Rev.2.00 Aug 3, 2017 Evaluation Board Description Key Features The ISL8018EVAL3Z evaluation board is intended for point-ofload applications sourcing from 2.7V to 5.5V. The ISL8018EVAL3Z is used for a complete performance evaluation of the ISL8018 low quiescent, high efficiency synchronous buck regulator. * High efficiency synchronous buck regulator with up to 97% efficiency The ISL8018EVAL3Z evaluation board is a 76.2mmx76.2mm 4-layer FR4 board with 2oz copper in all layers. The complete converter occupies 438.71mm2 area. * 10% output voltage margining * Adjustable current limit * Start-up with prebiased output * Internal soft-start - 1ms or adjustable * Soft-stop output discharge during disable * Adjustable frequency from 500kHz to 4MHz - default at 1MHz Specifications This board has been configured and optimized for the following operation conditions: * VIN = 2.7 to 5.5V * External synchronization up to 4MHz - master to slave phase shifting capability Related Literature * For a full list of related documents, visit our website - ISL8018 product page * VOUT = 1.8V * IOUTMAX = 8A * fSW = 1MHz Ordering Information * Efficiency at 50% load: >90% * Output ripple: <1% of output voltage (PWM mode) PART NUMBER * Operating junction temperature range: -40C to +125C ISL8018EVAL3Z DESCRIPTION Evaluation board ISL8018 VIN GND VIN FS EN VOUT PHASE GND PG EPAD PGND SYNCIN SGND SYNCOUT COMP ISET VSET SS PHASE FB FIGURE 1. BLOCK DIAGRAM UG053 Rev.2.00 Aug 3, 2017 Page 1 of 11 ISL8018EVAL3Z Recommended Equipment Frequency Control The following materials are recommended for testing: The ISL8018 has an FS pin that controls the frequency of operation. Programmable frequency allows for optimization between efficiency and external component size. Default switching frequency is 1MHz when FS is tied to VIN (R6 = 0 and R5 is open). By connecting R5 to GND, the switching frequency could be changed from 500kHz (R5 = 386k) to 4MHz (R5 = 36k) according to Equation 1: * 0V to 10V power supply with at least 15A source current capability or 5V battery * Electronic loads capable of sinking current up to 10A * Digital Multimeters (DMMs) * 100MHz quad-trace oscilloscope 200 10 3 R T k = ------------------------------ - 14 f OSC kHz * Signal generator Quick Setup Guide 1. Ensure that the circuit is correctly connected to the supply and loads before applying any power. 2. Connect the bias supply to VIN, the plus terminal to VIN (J1), and the negative return to PGND (J2). 3. Connect the output load to VOUT, the plus terminal to VOUT1 (J3), and the negative return to PGND (J4). 4. Verify that the position is PWM for S1. 5. Verify the position is OPEN for S2 and S3. 6. Verify that the position is ON for S4 and S5. 7. Turn on the power supply. 8. Verify the output voltage is 1.8V for VOUT1. Switches Control The ISL8018 evaluation board contains S1 through S5 for various controls of the ISL8018 circuitries. Table 1 details this function. TABLE 1. SWITCH SETTINGS S1 MODE FUNCTION 1 PWM Fixed PWM frequency at light load 3 PFM Force continuous mode S2 ISET 1 LOW Set output load to 3A. - OPEN Set output load to 8A. 3 HIGH Set output load to 5A. S3 VSET 1 LOW Set output voltage -10%. - OPEN No output voltage margin 3 HIGH Set output voltage +10%. S4 ENABLE 1 OFF Disable VOUT1 3 PFM Enable VOUT1 S5 ENABLE 1 OFF Disable VOUT2 3 PFM Enable VOUT2 PROGRAM OUTPUT CURRENT SET OUTPUT MARGIN FUNCTION FUNCTION UG053 Rev.2.00 Aug 3, 2017 (EQ. 1) When using R5 to adjust the operational frequency, this also sets external compensation mode. Refer to the ISL8018 datasheet for more details. Soft-Start Control Short CSS1 to SGND for internal soft-start (approximately 1ms). Populate CSS1 to adjust the soft-start time. This capacitor, along with an internal 1.8A current source, sets the soft-start interval of the converter, tSS as shown in Equation 2. CSS1 F = 3.33 t SS s (EQ. 2) CSS must be less than 33nF to ensure proper soft-start reset after fault condition. For proper use, do not prebias the output voltage more than regulation point. Synchronization Control The ISL8018 can be synchronized from 500kHz to 4MHz by an external signal applied to the SYNCIN pin. The rising edge on the SYNCIN triggers the rising edge of the PHASE pulse. Make sure that the minimum on-time of the PHASE node is greater than 140ns. SYNCOUT is a 250A current pulse signal output triggered by the rising edge of the clock or the SYNCIN signal (whichever is greater in frequency) to drive the other ISL8018 and avoid the system's beat frequencies effects. To implement time shifting between the master circuit to the slave, it is recommended to add a capacitor, C13, as shown in Figure 4 of the schematic. The time delay from SYNCOUT_Master to SYNCIN_Slave is calculated in pF using Equation 3: C 13 pF = 0.333 t - 20 ns (EQ. 3) where t is the desired time shift between the master and the slave circuits in ns. Care must be taken to include PCB parasitic capacitance of ~3pF to 10pF. The maximum should be limited to 1/Fs-100ns to ensure that SYNCOUT has enough time to discharge before the next cycle starts. Evaluating the Other Output Voltage The ISL8018EVAL3Z evaluation board output is preset to 1.8V for VOUT1, however, output voltages can be adjusted from 0.6V to 5V. The output voltage programming resistor, R1, will depend on the desired output voltage of the regulator. The value for the Page 2 of 11 ISL8018EVAL3Z feedback resistor is typically between 0 and 200k as shown in Equation 4. VFB R 2 = R 1 --------------------------- VO - VFB (EQ. 4) If the output voltage desired is 0.6V, then R2 is left unpopulated and R1 is shorted. For faster response performance, add 10pF to 47pF in parallel to R1, feedforward capacitor C4. Check bode plot to ensure optimum performance. When internal compensation is used, we only need a few external components: input capacitance, the output capacitance, inductor, upper feedback resistor, and lower feedback resistor. Feedforward capacitor is optional. The ceramic capacitor is recommended to be X5R or X7R. the voltage rating has a large effect on the actual capacitance value for ceramic technology. The effective capacitance varies with different VOUT, therefore, it is better to use a high voltage rating capacitor or a set of parallel lower voltage rating capacitors. Additional output capacitance may be added to improve transient response and start-up performance. With additional capacitance, use external compensation for better loop response design. See the datasheet compensation section for more detail. Refer to Figures 11 through 17 for examples of 1.2VOUT and 3.3VOUT soft-start waveforms, load transient, and relevant bode plot with external compensation configuration". In Table 2, the minimum output capacitor value is given for different output voltages with internal compensation. Notice that TABLE 2. COMPONENT VALUE SELECTION (REFER TO "ISL8018EVAL3Z Schematic" on page 4) VOUT 1.2V 1.5V 1.8V 2.5V 3.3V C1, C2 22F 22F 22F 22F 22F C7, C8 66F 66F 47F 47F 47F C4 33pF 33pF 10pF 10pF 10pF L1 0.47H 0.47~1H 0.68~1.5H 1~1.5H 1~2.2H R1 100k 150k 200k 316k 450k R2 100k 100k 100k 100k 100k ISL8018EVAL3Z Evaluation Board 1 FIGURE 2. FRONT VIEW UG053 Rev.2.00 Aug 3, 2017 FIGURE 3. BACK VIEW Page 3 of 11 9,1 9,1 9,1 9,1 /; 5 & 2)) 3* 3*1' 6<1&,1 811$0('BB1B,B' 96(7 3* 96(7 3* 4 3* 3* & 3) &66 X) 4 3* $ & 811$0('BB1B,B' /; 5 $ 5 5 '13 66 & & 8) 3) $ & 8) &203 . . 9,1 $ 23(1 811$0('BB60&$3B,B% '13 3* &203 5 2)) (1 )6 '13 $ $ $ 9287 / & 3* 3*1' 6<1&287 6*1' ,6/,5$-= . 811$0('BB,6/B,B 96(7 ,6(7 (1 )6 9)% & 8) 8) 23(1 9287 & 23(1 & . $ 5 - . 3*1' )% $ )% 127( 3/($6(.((3&2033,175$&(66+257 &203 3/($6(.((3)%)%3,1675$&(66+257 &203 '5$:1%< 66 $ 3) 66 7,0./(0$11 '$7( (1*,1((5 5(/($6('%< '$7( $ 5 5 83'$7('%< '$7( ,6/ '13 &66 23(1 (9$/8$7,21%2$5' 9,1 '$7( -81;,$2 7,7/( 66 (1 66 & 6<1&287 )6 66 6*1' 6<1&,1 &203 ,6(7 )6 96(7 (1 6<1&287 811$0('BB,6/B,B 6<1&,1 3*1' 811$0('BB,6/B,B 5 3* ,6(7 9)% ,6/,5$-= 6<1&,1 3*1' 6/$9( (1 6<1&,1 $ 9,1 &203 811$0('BB,6/B,B 8 811$0('BB,6/B,B & 3) & 5 3* 5 . - 9287 $ 23(1 3*1' 3*1' 9,1 3+$6( 23(1 3+$6( 8) $ 96(7 8) & 3+$6( & (3 3*1' 3+$6( 3+$6( (3 3+$6( 9,1 9,1 & 811$0('BB,6/B,B . & 9,1 9,1 9287 8+ 9,1 811$0('BB,6/B,B 9,1 / $ 8+ 8) 5 $ & 8) - 3*1' $ 66 5 ' ,6(7 5 . )6 811$0('BB/767&&.7B,B$ ' 96(7 5 (1 5 . 21(; 811$0('BB*706&.(B,B1& 3) )% ,6/,5$-= . $ . . 9)% . 96(7 $ & 5 5 6*1' 6<1&,1 6<1&287 23(1 &203 5 5 . 23(1 & 811$0('BB60&$3B,B$ 3*1' 6<1&287 9,1 8) 811$0('BB,6/B,B 811$0('BB605(6B,B% 8) & 66 5 $ (1 3*1' 0$67(5 3* & )% 9,1 ,6(7 (1 9,1 $ 5 - 5 '13 $ 6 8) $ (1 $ $ & 8) $ 5 & '13 6 (1 - 9287 5 3*1' 2)) (1 3+$6( 6 8+ 9,1 3+$6( 3)0 & 23(1 21(; 811$0('BB*706&.(B,B1& 3+$6( 6 811$0('BB*706&.(B,B1& 9287 / 811$0('BB,6/B,B (3 6<1&,1 ,6(7 811$0('BB*706&.(B,B1& 9,1 - 9,1 2)) 3:0 9,1 ,6(7 ,6(7 6<1&,1 6 $ . 6<1&,1 811$0('BB*706&.(B,B1& 21(; 5 . 21(; '13 5 . 5 . 9287 23(1 5 6&+(0$7,& 7(67(5 9,1 Page 4 of 11 $ $ FIGURE 4. ISL8018EVAL3Z SCHEMATIC 0$6. +5':5,' ,6/ 5(9 ISL8018EVAL3Z UG053 Rev.2.00 Aug 3, 2017 ISL8018EVAL3Z Schematic ISL8018EVAL3Z TABLE 3. BILL OF MATERIALS MANUFACTURER PART NUMBER REFERENCE DESIGNATOR QTY DESCRIPTION MANUFACTURER ISL8018EVAL3ZREVAPCB 1 SEE LABEL-RENAME BOARD PWB-PCB, ISL8018EVAL3Z, REVA, ROHS GRM39COG150J050AD 1 C4, C14 CAP, SMD, 0603, 15pF, 50V, 5%, NP0, MURATA ROHS C0603COG500-221JNE 1 C5 CAP, SMD, 0603, 220pF, 50V, 5%, C0G, ROHS VENKEL 06035C333JAT2A 1 CSS1 CAP, SMD, 0603, 0.033F, 50V, 5%, X7R, ROHS AVX 0 C3, C6, CSS2 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS C3216X5R0J226M160AA 5 C1, C2, C7, C8, C10 CAP, SMD, 1206, 22F, 6.3V, 20%, X5R, 1.6mm Height, ROHS TDK GRM31CR60J476ME19L 1 C9 CAP, SMD, 1206, 47F, 6.3V, 20%, X5R, ROHS MURATA 0 C19, C20, C23, C24 CAP, SMD, 1206, DNP-PLACE HOLDER, ROHS IHLP5050CEER1R0M01 1 L1 COIL-PWR INDUCTOR,SMD, 13mm, 1.0H, 20%, 24A, ROHS VISHAY 111-0702-001 2 J1, J3 CONN-GEN, BIND.POST, INSUL-RED, THMBNUT-GND JOHNSON COMPONENTS 111-0703-001 2 J2, J4 CONN-GEN, BIND.POST, INSUL-BLK, THMBNUT-GND JOHNSON COMPONENTS 131-4353-00 2 LX1, VOUT1 CONN-SCOPE PROBE TEST PT, COMPACT, PCB MNT, ROHS TEKTRONIX 1514-2 2 J5, J6 CONN-TURRET, TERMINAL POST, TH, KEYSTONE ROHS 5000 14 EN1, EN2, FB2, PG1, PG2, SS2, ISET, VSET, CONN-MINI TEST PT, VERTICAL, RED, KEYSTONE ROHS COMP2, SYNCIN1-SYNCIN3, SYNCOUT1, SYNCOUT2 LTST-C170CKT 2 D1, D2 LED-GaAs RED, SMD, 2x1.25mm, 100mW, 40mA, 10mcd, ROHS LITEON/VISHAY ISL8018IRAJZ 1 MASTER IC-ADJ. 6A BUCK REGULATOR, 20P, QFN, 3x4, ROHS INTERSIL 2N7002-7-F 2 Q1, Q2 TRANSISTOR, N-CHANNEL, 3LD, SOT- DIODES, INC. 23, 60V, 115mA, ROHS 0 R6, R9, R20, R28 RESISTOR,SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER 0 R4, R7, R13, R14, R19, R21, R22, R25, R29 RES, SMD, 0402, DNP, DNP, DNP, TF, ROHS ERJ-3EKF20R0V 1 R24 RES, SMD, 0603, 20, 1/10W, 1%, TF, ROHS PANASONIC CR0603-10W-000T 1 R18 RES, SMD, 0603, 0, 1/10W, TF, ROHS VENKEL UG053 Rev.2.00 Aug 3, 2017 IMAGINEERING INC Page 5 of 11 ISL8018EVAL3Z TABLE 3. BILL OF MATERIALS (Continued) MANUFACTURER PART NUMBER REFERENCE DESIGNATOR QTY DESCRIPTION MANUFACTURER CR0603-10W-1003FT 8 R2, R8, R10, R11, R12, R16, R23, R26 RES, SMD, 0603, 100k, 1/10W, 1%, VENKEL TF, ROHS CR0603-10W-2003FT 2 R1, R5 RES, SMD, 0603, 200k, 1/10W, 1%, VENKEL TF, ROHS RC0603FR-0747KL 1 R3 RES, SMD, 0603, 47k, 1/10W, 1%, TF, ROHS 0 R17, R27 RES, SMD, 0603, DNP-PLACE HOLDER, ROHS 0 R15 RES, SMD, 1210, DNP, DNP, DNP, TF, ROHS GT11MSCBE 3 S1, S4, S5 SWITCH-TOGGLE, SMD, 6PIN, SPDT, 2POS, ON-NONE-ON, ROHS ITT INDUSTRIES/C&K DIVISION GT13MSCBE 2 S2, S3 SWITCH-TOGGLE, SMD, 6PIN, SPDT, 3POS, ON-OFF-ON, ROHS C&K COMPONENTS SJ-5003SPBL 4 Bottom four corners. BUMPONS, 0.44inW x 0.20inH, DOMETOP, BLACK 3M 212403-013 1 Place assembly in bag. BAG, STATIC, 5x8, ZIPLOC, ROHS INTERSIL 0 C11, C12, C13, C14, C17, C18, C21, C22, DO NOT POPULATE OR PURCHASE C25, C26, C27 0 L2, L3 DO NOT POPULATE OR PURCHASE 0 LX2, VOUT2 DO NOT POPULATE OR PURCHASE 0 U3, SLAVE DO NOT POPULATE OR PURCHASE YAGEO PCB Layout Recommendation The PCB layout is a very important design step to ensure the converter works well. For ISL8018, the power loop is composed of the output inductor L's, the output capacitor COUT, the PHASE pins, and the PGND pin. It is necessary to make the power loop as small as possible and the connecting traces among them should be direct, short, and wide. The switching node of the converter, the PHASE pins, and the traces connected to the node are very noisy, so keep the voltage feedback trace away from these noisy traces. The input capacitor should be placed as close as possible to the VIN pin and the ground of the input and output capacitors should be connected as close as possible. The heat of the IC is mainly dissipated through the thermal pad. Maximizing the copper area connected to the thermal pad is preferable. In addition, a solid ground plane is helpful for better EMI performance. It is recommended to add at least five vias ground connection within the pad for the best thermal relief. UG053 Rev.2.00 Aug 3, 2017 Page 6 of 11 ISL8018EVAL3Z ISL8018EVAL3Z Board Layout ISL8018EVAL3Z FIGURE 5. TOP LAYER COMPONENTS FIGURE 6. TOP LAYER ETCH UG053 Rev.2.00 Aug 3, 2017 Page 7 of 11 ISL8018EVAL3Z ISL8018EVAL3Z Board Layout (Continued) FIGURE 7. SECOND LAYER ETCH FIGURE 8. THIRD LAYER ETCH UG053 Rev.2.00 Aug 3, 2017 Page 8 of 11 ISL8018EVAL3Z ISL8018EVAL3Z Board Layout (Continued) FIGURE 9. BOTTOM LAYER ETCH FIGURE 10. BOTTOM LAYER COMPONENTS UG053 Rev.2.00 Aug 3, 2017 Page 9 of 11 ISL8018EVAL3Z Typical Performance Curves Unless noted: VIN = 5.5V, fSW = 1MHz, internal (soft-start). VOUT 500mV/DIV VOUT 2V/DIV IOUT 5A/DIV IOUT 5A/DIV 500s/DIV 500s/DIV FIGURE 12. 1.2VOUT, R3 = 70k, C5 = 220pF, COUT = 144F (EFFECTIVE CAPACITANCE), C4 = 33pF, L = 1H FIGURE 11. 3.3VOUT, R3 = 25k, C5 = 470pF, COUT = 100F (EFFECTIVE CAPACITANCE), C4 = 47pF, L = 2.2H IOUT 5A/DIV IOUT 5A/DIV VOUT RIPPLE 20mV/DIV VOUT RIPPLE 100mV/DIV 1ms/DIV 1ms/DIV FIGURE 13. LOAD TRANSIENT 5.5VIN/3.3VOUT, R3 = 25k, C5 = 470pF, COUT = 100F (EFFECTIVE CAPACITANCE), C4 = 47pF, L = 2.2H, SLEW RATE: 0.1A/s FIGURE 14. LOAD TRANSIENT 5.5VIN/1.2VOUT, R3 = 70k, C5 = 220pF, COUT = 144F (EFFECTIVE CAPACITANCE), C4 = 33pF, L = 1H, SLEW RATE: 0.1A/s 100 95 EFFICIENCY (%) 90 85 80 75 70 65 60 VIN = 3.3V 55 VIN = 5.0V 50 0 1 2 3 4 5 6 7 8 OUTPUT CURRENT (A) FIGURE 15. EFFICIENCY vs LOAD (1MHz PWM) UG053 Rev.2.00 Aug 3, 2017 Page 10 of 11 ISL8018EVAL3Z Typical Performance Curves Unless noted: VIN = 5.5V, fSW = 1MHz, internal (soft-start). (Continued) FIGURE 16. BODE PLOT 5.5VIN/3.3VOUT WITH FULL LOAD, R3 = 25k, C5 = 470pF, COUT = 100F (EFFECTIVE CAPACITANCE), C4 = 47pF, L = 2.2H FIGURE 17. BODE PLOT 5.5VIN/1.2VOUT WITH FULL LOAD, R3 = 70k, C5 = 220pF, COUT = 144F (EFFECTIVE CAPACITANCE), C4 = 33pF, L = 1H (c) Copyright Intersil Americas LLC 2015-2017. All Rights Reserved. All trademarks and registered trademarks are the property of their respective owners. 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 document is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com UG053 Rev.2.00 Aug 3, 2017 Page 11 of 11