STEVAL-ISA039V1 STMicroelectronics

STEVAL-ISA039V1 Single phase 5A step-down converter evaluation board based on L6727 Data Brief Features Input voltage: from 5V to 12V Output voltage: fixed 1.25V but customizable by changing resistor Output current:up to 5A Swicthing frequency: 300KHz Description The purpose of this design is to demonstrate the key features of STMicroelectronics L6727 a new powerful buck controller. The L6727 allow simple, cost effective design of complete step-down voltage regulators. Indeed it provides a full STEVAL-ISA039V1 solution by integrating a 0.8V reference, control logic and protection, and NMOS drivers in an 8- pin package. L6727 demo board realizes in a two- layer PCB a step-down DC/DC converter and shows the operation of the device in a general- purpose low-current application. The input voltage can range from 5V to 12V buses and the output voltage is fixed at 1.25V. The application can deliver an output current in excess of 5A. The switching frequency is 300 kHz. July 2007 Rev 1 1/4 For further information contact your local STMicroelectronics sales office www.st.com 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 LSG1 LSG2 4 4 4 0 0 0 0 0 0 0 0 0 VCC D1 1N4148 VCC R2 VCC GND 3.3 GNDCC BOOT 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 FB 3 6 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 LGATELGATE 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 COMP FB OUT 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 Board schematic STEVAL-ISA039V1 1 Board schematic Figure 1. Schematic 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 2/4 Obsolete Product(s) - Obsolete Product(s) PHASE GND PHASE GND HSD PHASE HSDHSD