USERS MANUAL ISL8002BDEMO1Z UG008 Rev 0.00 Demonstration Board User Guide January 22, 2015 Description Key Features The ISL8002BDEMO1Z kit is intended for use by individuals with Small, compact design requirements for point-of-load applications sourcing from 2.7V V range of 2.7V to 5.5V IN to 5.5V. The ISL8002BDEMO1Z board is used to demonstrate V adjustable from 0.6V up to 80% of V OUT IN the performance of the ISL8002B low quiescent current mode converter. I maximum is 2A OUT External soft-start programmable The ISL8002B is offered in a 8 pin 2mmx2mm TDFN package with 1mm maximum height. The complete converter occupies Output tracking and sequencing 2 less than 64mm area. Overcurrent and short-circuit protection Over-temperature/thermal protection Specifications This board has been configured and optimized for the following References operating conditions: ISL8002B Datasheet V = 2.7V to 5.5V IN V = 1.8V OUT Ordering Information VTRACK = 1.8V PART NUMBER DESCRIPTION I maximum is 2A OUT ISL8002BDEMO1Z 2A Demonstration Board Switching frequency is 2MHz Up to 95% peak efficiency Selectable PFM or PWM operation option FIGURE 2. ISL8002BDEMO1Z BOTTOM SIDE FIGURE 1. ISL8002BDEMO1Z TOP SIDE UG008 Rev 0.00 Page 1 of 8 January 22, 2015ISL8002BDEMO1Z Whats Inside PCB Layout Guidelines The demonstration kit contains the following: The PCB layout is a very important converter design step to make sure the designed converter works well. The power loop is The ISL80O2BDEMO1Z composed of the output inductor Ls, the output capacitor C , OUT ISL8002B Datasheet the PHASEs 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 Test Steps node of the converter, the PHASE pins, and the traces connected If tracking feature is not used, connect SS/TR to VIN for 1ms to the node are very noisy, so keep the voltage feedback trace internal soft-start and follow the test steps below: away from these noisy traces. The input capacitor should be placed as closely as possible to the VIN pin and the ground of the 1. Ensure that the circuit is correctly connected to the supply and input and output capacitors should be connected as closely as loads prior to applying any power. possible. The heat of the IC is mainly dissipated through the IN. Plus terminal to VIN (TP1) and 2. Connect the bias supply to V thermal pad. Maximizing the copper area connected to the negative return to PGND (TP2). thermal pad is preferable. In addition, a solid ground plane is 3. Connect the output load to VO (TP3), and the negative return helpful for better EMI performance. It is recommended to add at to PGND (TP4). least 4 vias ground connection within the pad for the best thermal relief. 4. Turn on the power supply. 5. Verify the output voltage is 1.8V for V . OUT Functional Description The ISL8002BDEMO1Z provides a simple platform to evaluate performance of the ISL8002B. The ISL8002B is a highly efficient, monolithic, synchronous step-down DC/DC converter that can deliver up to 2A of continuous output current from a 2.7V to 5.5V input supply. It uses peak current mode control architecture to allow very low duty cycle operation. The ISL8002B operates at a 2MHz switching frequency, thereby providing superior transient response and allowing for the use of small inductor. The ISL8002B can be configured for either PFM (discontinuous conduction) or PWM (continuous conduction) operation at light load. PFM provides high efficiency by reducing switching losses at light loads and PWM reduces noise susceptibility and RF Tied MODE pin to high for PWM or to Ground for interference. PFM. The ISL8002B can be programmable for external soft-start or output tracking and sequencing. Adding a resistor divider from VIN to SS/TR (R R ) and a 5 4 capacitor (C6) from the SS/TR pin to ground determines the output ramp rate, maximum soft-start cap value is 1 F. Adding a resistor divider across SS/TR can be use for outputs tracking. Populate R and R if Tracking feature is used. Ratio 3 4 between R /R should equal R /R . Otherwise connect SS/TR 1 2 3 4 to VIN for 1ms internal soft-start. UG008 Rev 0.00 Page 2 of 8 January 22, 2015