User Guide 010 ISL85403EVAL2Z Evaluation Board User Guide Description Key Features The ISL85403EVAL2Z board allows quick evaluation of the ISL85403 in the noninverting buck-boost configuration. It is a cost effective solution for the low-power, wide input voltage range point-of-load application where both stepping up and stepping down voltage capabilities are required. • Small, compact design Specifications • Convenient power connection References ISL85403 Datasheet The design specifications of the ISL85403EVAL2Z are shown in Table 1. TABLE 1. SPECIFICATIONS PARAMETERS VALUES Input Voltage (VIN) 8V to 40V Output Voltage (VOUT) 12.0V Max. Output Current (IOUT_MAX) Ordering Information PART NUMBER ISL85403EVAL2Z DESCRIPTION ISL85403 Evaluation Board, buck-boost configuration 12V output 1A Switching Frequency 500kHz Output Ripple 360mV at 1A Load FIGURE 1. TOP VIEW February 2, 2015 UG010.1 • VIN range of 8V to 40V 1 FIGURE 2. BOTTOM VIEW CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2014, 2015. 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. User Guide 010 Functional Description The ISL85403 is a flexible switching regulator with an integrated 127mΩ high-side MOSFET. It can be used as a synchronous buck converter, a 2-stage boost-buck converter, or a noninverting buck-boost converter. The ISL85403EVAL2Z board demonstrates the operations of the ISL85403 in the noninverting buck-boost configuration. The ISL85403EVAL2Z board is shown in Figures 1 and 2. The schematic is shown on page 4, bill of materials on page 4, and PCB layers for reference start on page 7. Figures 4 through 15 show performance data taken from the evaluation board. Operating Range The board input voltage range is 8V to 40V. The output voltage is set to 12V and can be changed by voltage feedback resistors R11 and R13, as shown in Equation 1: V ref R 13 = R 11 -------------------------------V OUT – v ref (EQ. 1) Note: In order to change to a higher output voltage, the output capacitors have to be changed for the higher voltage rating. The board is set to a default frequency of 500kHz (FS pin/R1 is open). The switching frequency can be programmed to other values by a resistor at R1. Refer to the ISL85403 datasheet for the resistor value and the switching frequency. The switching frequency can also be synchronized to external clock by connecting the external clock to the SYNC terminal (J5). source of the MOSFET. Keep this loop (output ceramic capacitor, MOSFET and diode) as small as possible to minimize the voltage spikes induced by the trace parasitic inductance. 4. Place the output ceramic and aluminum capacitors close to the power stage components as well. 5. Place vias (at least 9) in the bottom pad of the IC. The bottom pad should be placed in ground copper plane with an area as large as possible in multiple layers to effectively reduce the thermal impedance. 6. Place the 4.7µF ceramic decoupling capacitor (C4 as shown in the “ISL85403EVAL2Z Circuit Schematic” on page 3) as close as possible to the IC’s VCC pin. Put multiple vias close to the ground pad of this capacitor. 7. Keep the bootstrap capacitor close to the IC. 8. Keep the LGATE drive trace as short as possible and try to avoid using vias in the LGATE drive path to achieve the lowest impedance. 9. Place the output voltage sense trace close to the place that is to be strictly regulated. 10. Place all the peripheral control components close to the IC. Quick Test Setup +- - LOAD + A Inductor Current In the noninverting buck-boost configuration, the inductor current (IL) can be expressed as: V OUT + V IN I L = I OUT -------------------------------V (EQ. 2) IN The maximum inductor current happens at the condition of the minimum input voltage and the maximum output current. The inductor used in this noninverting buck-boost configuration should have saturation current higher than the maximum inductor current. V OUT + V IN,min I L sat I OUT,max -----------------------------------------V IN,min (EQ. 3) PCB Layout Guidelines 1. Place the input ceramic capacitors as closely as possible to the IC VIN pin and power ground connecting to the power diode. Keep this loop (input ceramic capacitor, IC VIN pin and diode) as small as possible to minimize the voltage spikes induced by the trace parasitic inductance. A bulk capacitor, C5 (as shown in the “ISL85403EVAL2Z Circuit Schematic” on page 3), is included to support long wire connections from power supplies to the evaluation board. 2. Keep the phase node copper area small but large enough to handle the load current. FIGURE 3. ISL85403EVAL2Z BOARD SETUP 1. Connect the power supply to the input terminals VIN (J2) and GND (J8). Connect the load terminals to the output VOUT (J6) and GND (J3). Make sure the setup is correct prior to applying any power or load to the board. 2. Adjust the power supply to 8V to 40V and turn it on. 3. Verify the output voltage is 12V and use oscilloscope to monitor the phase node waveforms. 3. On the output side, place the output ceramic capacitors as closely as possible to the cathode of the power diode and the Submit Document Feedback 2 UG010.1 February 2, 2015 - & X) 9,1 9&& Submit Document Feedback ISL85403EVAL2Z Circuit Schematic & X) 9,1 & X) VIN & X) - *1' 9,1 9&& 9,1 %6 & / X) ' 3+$6( 5 4 %6=1/6* ' 9&& 5 N '13 5 & X) & X) - *1' 5 '13 N 5 N Vout & 9287 5 '13 - %6 - 9287 X+ N 5 N 5 '13 3+$6( 3+$6( (3 (;7B%2267 5 N 5 - 6<1& 6<1& &203 5 N 6*1' $8;9&& )% S) S) & & &203 /*$7( /*$7( User Guide 010 & Q) 5 02'( 3*1' ,6/ 66 )% 8 )6 3*22' 66 & X) 02'( )6 3*22' '13 9&& %227 %227 ,/,0,7 (1 ,/,0,7 (1 5 3 - %6 UG010.1 February 2, 2015 User Guide 010 Bill of Materials REF DES PART NUMBER QTY DESCRIPTION MANUFACTURER C5 HHXA630ARA330MHA0G 1 Aluminum Electrolytic Capacitor, SMD, 8x10, 33µF, 63V, 20%, 40mΩ, ROHS UNITED CHEMI-CON C6 VARIOUS 1 CAP, SMD, 0603, 0.1µF, 50V, 10%, X7R, ROHS VARIOUS C3 VARIOUS 1 CAP, SMD, 0603, 1µF, 16V, 10%, X5R, ROHS VARIOUS C9 VARIOUS 1 CAP, SMD, 0603, 0.22µF, 25V, 10%, X7R, ROHS VARIOUS C10 VARIOUS 1 CAP, SMD, 0603, 470pF, 50V, 5%, NP0, ROHS VARIOUS C7 VARIOUS 1 CAP, SMD, 0603, 4700pF, 50V, 10%, X7R, ROHS VARIOUS C8 VARIOUS 1 CAP, SMD, 0603, 68pF, 50V, 10%, NP0, ROHS VARIOUS C1, C2 VARIOUS 2 CAP, SMD, 1206, 4.7µF, 50V, 10%, X5R, ROHS VARIOUS T521X337M016ATE025 1 CAP-TANT, LOW-ESR, SMD, 7.3x4.3x4, 330µF, 16V, 20%, 25mΩ, ROHS KEMET SS6P3LHM3/86A 2 DIODE-SCHOTTKY RECTIFIER, SMD, SMPC, 60V, 3A, ROHS VISHAY L1 744770118 1 COIL-PWR INDUCTOR, SMD, 12mm, 18µH, 20%, 4.2A, 0.032Ω, ROHS WURTH U1 ISL85403IRZ 1 IC-SWITCHING REGULATOR, 20P, QFN, 4X4, ROHS INTERSIL Q1 BSZ100N06LS3G 1 TRANSIST-MOS, N-CHANNEL, 8P, PG-TSDSON-8, 60V, 20A, ROHS INFINEON R2 VARIOUS 1 RES, SMD, 0603, 348k, 1/10W, 1%, TF, ROHS VARIOUS R3 VARIOUS 1 RES, SMD, 0603, 49.9k, 1/10W, 1%, TF, ROHS VARIOUS R4 VARIOUS 1 RES, SMD, 0603, 100Ω, 1/10W, 1%, TF, ROHS VARIOUS R5 VARIOUS 1 RES, SMD, 0603, 113k, 1/10W, 1%, TF, ROHS VARIOUS R8 VARIOUS 1 RES, SMD, 0603, 200k, 1/10W, 1%, TF, ROHS VARIOUS R9 VARIOUS 1 RES, SMD, 0603, 4.7k, 1/10W, 1%, TF, ROHS VARIOUS R11 VARIOUS 1 RES, SMD, 0603, 28k, 1/10W, 1%, TF, ROHS VARIOUS R12 VARIOUS 1 RES, SMD, 0603, 0Ω, 1/10W, 1%, TF, ROHS VARIOUS R13 VARIOUS 1 RES, SMD, 0603, 2k, 1/10W, 1%, TF, ROHS VARIOUS 0 Do not populate C12 D1, D2 R1, R6, N/A R7, R10, C13 N/A 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 Submit Document Feedback 4 UG010.1 February 2, 2015 User Guide 010 Typical Performance Curves 90 12.2 VIN = 8V 70 VIN = 18V VIN = 8V 60 50 OUTPUT VOLTAGE (V) FREQUENCY (%) 80 VIN = 36V VIN = 24V 40 VIN = 18V 12.1 12.0 VIN = 24V VIN = 36V 11.9 30 20 0.0 0.2 0.4 0.6 0.8 11.8 1.0 0.0 OUTPUT CURRENT (A) 0.2 0.4 0.6 OUTPUT CURRENT (A) 0.8 1.0 FIGURE 5. LOAD REGULATION FIGURE 4. EFFICIENCY vs LOAD VOUT (AC-COUPLE) VOUT (AC-COUPLE) IL IL PHASEi PHASEi PHASEo PHASEo FIGURE 7. OUTPUT RIPPLE AT 1A LOAD (VIN = 8V) FIGURE 6. OUTPUT RIPPLE AT 0A LOAD (VIN = 8V) OUT VV OUT (AC-COUPLE) (AC-COUPLE) VOUT VOUT (AC-COUPLE) (AC-COUPLE) IL IL IL IL PHASEi PHASEi PHASEi PHASEi PHASEo PHASEo PHASEo PHASEo FIGURE 8. OUTPUT RIPPLE AT 0A LOAD (VIN = 36V) Submit Document Feedback 5 FIGURE 9. OUTPUT RIPPLE AT 1A LOAD (VIN = 36V) UG010.1 February 2, 2015 User Guide 010 Typical Performance Curves (Continued) VOUT (AC-COUPLE) VOUT (AC-COUPLE) IL IL FIGURE 10. LOAD TRANSIENT RESPONSE 0A<->1A, VIN = 8V FIGURE 11. LOAD TRANSIENT RESPONSE 0A<->1A, VIN = 36V VOUT VOUT IL VOUT IL PHASEi PHASEi IL PHASEo PHASE PHASEo FIGURE 13. SOFT-START AT 1A LOAD (VIN = 8V) FIGURE 12. SOFT-START AT 0A LOAD (VIN = 8V) VOUT VOUT VOUT IL VOUT IL IL IL PHASEi PHASEi PHASEi PHASEo PHASEo PHASEo FIGURE 14. SOFT-START AT 0A LOAD (VIN = 36V) Submit Document Feedback 6 FIGURE 15. SOFT-START AT 1A LOAD (VIN = 36V) UG010.1 February 2, 2015 User Guide 010 Board Layout FIGURE 16. SILKSCREEN TOP FIGURE 17. TOP LAYER FIGURE 18. LAYER 2 FIGURE 19. LAYER 3 FIGURE 20. BOTTOM LAYER FIGURE 21. SILKSCREEN BOTTOM Submit Document Feedback 7 UG010.1 February 2, 2015