STEVAL-ISA028V1 STMicroelectronics

STEVAL-ISA028V1 Single phase 20 A step-down converter evaluation board based on the L6727 Data Brief Features BOM optimized for 12 V input / 1.25 V output 20 A High flexibility to host wide range designs Customizable output voltage L6726A / L6727 compatibility Controller input voltage (V ) range from 5 V to CC 12 V Conversion input voltage (V ) up to 13.2 V IN DPAK / SO-8 / PowerSO-8 / PowerFLAT MOSFET compatibility Multi-footprint for input and output capacitors Through-hole / SMD inductor compatibility 4-layer PCB STEVAL-ISA028V1 Description This evaluation board demonstrates the key features of STMicroelectronics L6727, a new powerful new buck controller. The L6727 makes the design of complete step-down voltage regulators simple and cost effective. It provides a full solution by integrating a 0.8 V reference, control logic and protection, and NMOS drivers in an 8-pin package. The L6727 evaluation board implements a step-down DC/DC converter in a four-layer PCB and demonstrates the operation of the device in a general-purpose application. The input voltage can range from 5 V to 12 V and the output voltage is fixed at 1.25 V. The application can deliver an output current up to 20 A. Airflow must be applied with current higher than 18 A ( V = 5 V). The switching frequency is 300 kHz. IN December 2007 Rev 2 1/4 For further information contact your local STMicroelectronics sales office www.st.com 4 Obsolete Product(s) - Obsolete Product(s)Board schematic STEVAL-ISA028V1 1 Board schematic Figure 1. Schematic PHASE GND PHASE GND HSD PHASE HSDHSD 2/4 Obsolete Product(s) - Obsolete Product(s) VIN1 VIN POWER L1 PHASE 1 2 OUT GNDIN1 NC GNDIN POWER NC NC NC NC NC NC C1 C2 C3 Q1 Q2 Q3 0 R16 1800uF 1800uF NC C4 C5 C6 C7 C8 C9 NC NC NC 0 HSG 4 LSG1 4 LSG2 4 0 0 0 0 0 0 0 0 0 VCC D1 1N4148 VCC R2 VCC GND 3.3 BOOT GNDCC GND 1uF C38 100nF VIN POWER C10 0 0 UGATE 4.7uF 4.7uF 4.7uF Q4 UGATE HSG R3 1 STD55NH2LL C11 C12 C13 2.2 U1 PHASE 0 0 0 R17 L6726A/27 BOOT 1 8 PHASE BOOT PHASE VOUT1 UGATE 2 7 COMP 2.2 L2 VOUT UGATE COMP 2 1 OUT GND 3 6 FB T60-18 6Ts GND FB LGATE 4 5 VCC PIN VCC LGATE R4 C15 C16 C17 C18 C19 C20 C21 C22 LGATE VCC 1uF 3.3 Q5 Q6 1.8 R1 LGATLGE ATE R5 LSG1 1 STD90NH2LL 1 NC R18 C14 0 NC NC NC 2200uF NC NC NC NC GNDOUT1 NC GNDOUT C23 6.8nF 0 0 R15 0 0 0 0 0 0 0 0 0 0 0 NC OUT COMP FB C25 C26 C27 C28 C29 C30 C31 C32 C33 C34 R6 R10 C24 12k R7 R8 R9 R11 2200uF NC NC NC NC NC NC NC NC NC NC 0 2.2k 33k 10nF 0 C36 R14 0 0 0 0 0 0 0 0 0 0 C35 R12 R13 C37 33pF NC 3.9k NC NC NC 0 0 VCC PIN COMP FB PHASE 3 2 3 2 3 2 1 5 2 6 3 7 8 1 5 2 6 3 7 8 1 5 2 6 3 7 8