USERS MANUAL ISL85003EVAL2Z, ISL85003AEVAL2Z AN1930 Rev.1.00 Evaluation Board User Guide Aug 28, 2014 Description Key Board Features The ISL85003 and ISL85003A kits are intended for use for Small, compact design point-of-load applications sourcing from 4.5V to 18V. The kits Switch selectable EN (enabled/disabled) are used to demonstrate the performance of the ISL85003 Switch selectable MODE (auto-DCM/forced-PWM) and ISL85003A, low quiescent current high efficiency synchronous buck regulators. Connectors and test points for easy probing The ISL85003 and ISL85003A are offered in a 4x3mm dual flat no lead (DFN) package. References ISL85003, ISL85003A datasheet Specifications The boards are designed to operate at the following operating conditions: Ordering Information Input voltage range from 4.5V to 18V PART NUMBER DESCRIPTION Resistor programmable output voltage from 0.8V, 1% ISL85003EVAL2Z Evaluation Board for ISL85003FRZ and Up to 3A output current ISL85003AFRZ Current mode control Evaluating the Other Output - DCM/CCM - Internal or external compensation options Voltage - 500kHz switching frequency option The ISL85003 and ISL85003A kit outputs are preset to 5V for - External synchronization up to 2MHz on ISL85003 V however, the output voltages are programmed using an OUT external resistor divider that scales the feedback relative to the Adjustable soft-start time on the ISL85003A internal reference voltage. The output voltage programming Operating junction temperature range: -40C to +125C resistor, R , will depend on the value chosen for the feedback 2 resistor, R , and the desired regulator output voltage, V . 1 OUT The value for the feedback resistor R is typically between Quick Setup Guide 1 10k and 400k as shown in Equation 1. 1. Ensure that the circuit is correctly connected to the supply R 0.8V 1 (EQ. 1) and loads prior to applying any power. ------------------------------- R = 2 V 0.8V OUT 2. Connect the bias supply to VIN, the plus terminal to VIN (P4) and the negative return to PGND (P5). If the output voltage desired is 0.8V, then R is left 2 unpopulated. R is still required to set the low frequency pole 3. Connect the output load to V0, the plus terminal to V0 (P8) 1 of the modulator compensation. and the negative return to PGND (P9). 4. Verify that the position is PWM or PFM for SW2. Switch Control 5. Verify that the position is ON for SW1. The ISL85003 and ISL85003A evaluation boards contain SW1 6. Turn on the power supply. and SW2 for various controls of the ISL85003 and ISL85003A circuitries. Table 1 details this function. 7. Verify the output voltage is 5V for VO. TABLE 1. SWITCH SETTINGS Recommended Equipment SW1 ENABLE FUNCTION The following materials are recommended to perform testing: 1OFF Disable V0 0V to 25V power supply with at least 10A source current capability 3ON Enable V0 Electronic loads capable of sinking current up to 7A SW2 MODE FUNCTION Digital multimeters (DMMs) 1DCM Force DCM 100MHz quad-trace oscilloscope 3 PWM Fixed PWM frequency at light load Signal generator AN1930 Rev.1.00 Page 1 of 6 Aug 28, 2014Evaluation Board User Guide ISL85003EVAL2Z, ISL85003AEVAL2Z Components Selection V 0.8V 1V 1.2V 1.5V 1.8V 2.5V 3.3V 5V OUT C , C 10F 10F 10F 10F 10F 10F 10F 10F 1 2 C 22F 22F 22F 47F 47F 47F 47F 47F 5 C 22F 22F 22F 22F 22F 22F 22F 22F 6 C Open Open Open 4.7pF 4.7pF 4.7pF 4.7pF 4.7pF 4 L 1.8H 2.2H 2.2H 3.3H 3.3H 3.3H 4.7H 4.7H 1 R 301k 301k 301k 301k 301k 301k 301k 301k 1 R Open 1.2M 604k 344k 241k 142k 96.3k 57.6k 2 NOTE: V = 12V, I = 3A The components selection table is a suggestion for typical application using internal compensation mode. For applications IN OUT that require high output capacitance greater than 200F, R should be adjusted to maintain a loop response bandwidth about 40kHz. 1 ISL85003EVAL2Z Evaluation Board FIGURE 1. TOP VIEW FIGURE 2. BOTTOM VIEW AN1930 Rev.1.00 Page 2 of 6 Aug 28, 2014