data brief for further information contact your local stmicroelectronics sales office. september 2008 rev 1 1/4 4 STEVAL-ISA024V1 20 a step-down dc-dc conver ter demonstration board with 3.3 v out and 250 khz switching freq uency, based on the l6725 features input voltage, v in : from 4.5 v to 14 v output voltage: 3.3 v selectable switching frequency: 250 khz / 500 khz over-voltage protection thermal shutdown description this 4-layer pcb demonstration board is designed as a step-down dc-dc converter to demonstrate the operation of the l6725 device in a general-purpose application. the input voltage can range from 4.5 v to 14 v with an output voltage of 3.3 v. the module can deliver an output current in excess of 20 a. the l6725 device can manage minimum on times (t on ) shorter than 100 ns. this makes possible conversions with very low duty cycles and very high switching frequencies. the switching frequency is initially set at 250 khz (controller free-running fsw), but a switching frequency of 500 khz can also be selected. STEVAL-ISA024V1 www.st.com
board schematic STEVAL-ISA024V1 2/4 1 board schematic figure 1. schematic gout r2 gin l1 q1-3 q4-6 d3 5 u1 l6725 vin vout 8 och c11 r9 c9 9 10 6 7 hgate phase lgate pgnd 3 vcc 12 vcc 2 ss c4 boot d1 11 vccd r c10 1 vfb comp r3 r1 c1 c2 c3 r4 r7 4 earef c7 r8 16 15 gnd ocl r10 r11 c12-c13 c16-c19 c5 r6 r5 c8 j1 r12 c15 ext ref j2
STEVAL-ISA024V1 revision history 3/4 2 revision history table 1. document revision history date revision changes 02-sep-2008 1 initial release.
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