IRDC3477 TM SupIRBuck USER GUIDE FOR IRDC3477 EVALUATION BOARD DESCRIPTION TM The IR3477 SupIRBuck is an easy-to-use, Additional features include pre-bias startup, a fully integrated and highly efficient DC/DC very precise 0.5V reference, forced continuous voltage regulator. The onboard constant on conduction mode option, over/under voltage protection, power good output, and enable input time hysteretic controller and MOSFETs make IR3477 a space-efficient solution that delivers with voltage monitoring capability. up to 15A of precisely controlled output voltage. IR3477 is housed in a 20-lead This user guide contains the schematic, bill of materials, and operating instructions of the 5mmx6mm QFN package. IRDC3477 evaluation board. Detailed product Key features offered by IR3477 include: specifications, application information and programmable switching frequency, soft start, performance curves at different operating conditions are available in the IR3477 data temperature compensated over current protection, and thermal shutdown allowing a sheet. very flexible solution suitable for many different applications and an ideal choice for battery powered applications. BOARD FEATURES V = +12V IN V = +5V CC V = +1.05V OUT I = 0 to 15A OUT F = 300kHz CCM S L = 1H C = 22F (ceramic 1210) + 68F (electrolytic) IN C = 47F (ceramic 0805) + 330F (PC-CON) OUT 1 IRDC3477 CONNECTIONS and OPERATING INSTRUCTIONS An input supply in the range of 8 to 19V should be connected from VIN to PGND. A maximum load of 15A may be connected to V and PGND. The connection diagram is shown in Fig. 1, and the OUT inputs and outputs of the board are listed in Table 1. IRDC3477 has two input supplies, one for biasing (VCC) and the other for input voltage (VIN). Separate supplies should be applied to these inputs. VCC input should be a well regulated 4.5V to 5.5V supply connected to VCC and PGND. Enable (EN) is controlled by the first switch of SW1, and FCCM option can be selected by the second switch of SW1. Toggle the switch to the ON position (marked by a solid square) to enable switching or to select FCCM. The absolute maximum voltage of the external signal applied to EN (TP4) and FCCM (TP3) is +8V. Table 1. Connections Connection Signal Name VIN (TP2) VIN PGND (TP5) Ground for VIN VCC (TP16) VCC Input PGND (TP17) Ground for VCC Input VOUT (TP7) V (+1.05V) OUT PGND (TP10) Ground for V OUT EN (TP4) Enable Input FCCM (TP3) Forced Continuous Conduction Mode Input LAYOUT The PCB is a 4-layer board. All layers are 1 oz. copper. IR3477 and other components are mounted on the top and bottom layers of the board. The power supply decoupling capacitors, bootstrap capacitor and feedback components are located close to IR3477. To improve efficiency, the circuit board is designed to minimize the length of the on- board power ground current path. 2