EVB RT6242AHGQUF-00 EN

RT6242AHGQUF
Evaluation Board
your power partner.
12A, 18V, 500kHz, ACOT™ Synchronous Step-Down Converter
Purpose
The RT6242A is an Advanced Constant On-Time (ACOT™) mode step-down converter with the input voltage range
from 4.5V to 18V and provides 12A output current. This document explains the function and use of the RT6242A
evaluation board (EVB), and provides information to enable operation, modification of the evaluation board and
circuit to suit individual requirements.
Table of Contents
Purpose ................................................................................................................................................................. 1
Introduction............................................................................................................................................................ 2
Key Performance Summary Table .......................................................................................................................... 2
Bench Test Setup Conditions ................................................................................................................................. 3
Schematic, Bill of Materials & Board Layout ........................................................................................................... 5
More Information.................................................................................................................................................... 8
Important Notice for Richtek Evaluation Board ....................................................................................................... 8
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RT6242AHGQUF
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Introduction
General Product Information
The RT6242A is a synchronous step-down converter with Advanced Constant On-Time (ACOT™) mode control.
The ACOT™ provides a very fast transient response with few external components. The low impedance internal
MOSFET supports high efficiency operation with wide input voltage range from 4.5V to 18V. The proprietary circuit
of the RT6242A enables to support all ceramic capacitors. The output voltage can be adjustable between 0.7V and
8V. The soft-start time is adjustable by an external capacitor.
Product Feature
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4.5V to 18V Input Voltage Range
12A Output Current
12mΩInternal High-Side N-MOSFET and 5.4mΩInternal Low-Side N-MOSFET
Advanced Constant On-Time Control
Fast Transient Response
Support All Ceramic Capacitors
Up to 95% Efficiency
Adjustable Switching Frequency from 300kHz to 700kHz
Adjustable Output Voltage from 0.7V to 8V
Adjustable Soft-Start
Pre-bias Start-Up
Adjustable Current Limit from 6A to 16A
Cycle-by-Cycle Over Current Protection
Power Good Output
Input Under-Voltage Lockout
Hiccup Mode Under-Voltage Protection
Thermal Shutdown Protection
Key Performance Summary Table
Key Features
Evaluation Board Number : PCB055_V1
Default Input Voltage
12V
Max Output Current
12A
Default Output Voltage
1.4V
Default Marking & Package Type
RT6242AHGQUF, UQFN-16JL 3x3 (FC)
Operation Frequency
Steady 500kHz at PWM
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Bench Test Setup Conditions
Headers Description and Placement
Please carefully inspect the EVB IC and external components, comparing them to the following Bill of Materials, to ensure that all components are
installed and undamaged. If any components are missing or damaged during transportation, please contact the distributor or send e-mail to
[email protected].
Test Points
The EVB is provided with the test points and pin names listed in the table below.
Test point/
Pin name
Signal
Comment (expected waveforms or voltage levels on test points)
PVCC
Internal Regulator Output
5V bias supply output. Connect a 1µF capacitor to ground.
SS
Soft-Start Time Setting
Soft-Start Time Setting. An external capacitor should be connected
between this pin and GND.
VIN
Input voltage
Power Input. The input voltage range is from 4.5V to 18V. Must
bypass with a suitably large ceramic capacitor.
GND
Ground
Ground.
PG
Power Good Indicator
Power Good Indicator Open-Drain Output.
BOOT
Bootstrap supply test point
Bootstrap. This capacitor is needed to drive the power switch's
gate above the supply voltage. It is connected between SW and
BOOT pins to form a floating supply across the power switch driver.
A 0.1µF capacitor is recommended for use.
SW
Switch node test point
Connect this pin to an external L-C filter.
EN
Enable Control Input
A logic-high enables the converter; a logic-low forces the IC into
shutdown mode reducing the supply current to less than 10µA.
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Power-up & Measurement Procedure
1. Apply a 12V nominal input power supply (4.5V < VIN < 18V) to the VIN and GND terminals.
2. Set the jumper at JP2 to connect terminals 2 and 3, connecting EN to VIN through resistor R4, to enable
operation.
3. Verify the output voltage (approximately 1.4V) between VOUT and GND.
4. Connect an external load up to 12A to the VOUT and GND terminals and verify the output voltage and current.
Output Voltage Setting
Set the output voltage with the resistive divider (R1, R2) between VOUT and GND with the midpoint connected to
FB. The output is set by the following formula :
VOUT = VFB × (1 +
R1
)
R2
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Schematic, Bill of Materials & Board Layout
EVB Schematic Diagram
Bill of Materials
Reference
Qty
Part Number
Description
Package
Manufacture
U1
1
RT6242AHGQUF
DC/DC Converter
UQFN-16JL 3x3
(FC)
RICHTEK
C1
1
NA
C-0603
C3, C4
2
UMK325BJ106MM
10µF/50V/X5R/1210
C-1210
TAIYO
YUDEN
C5
1
C1608X5R1E105KT000E
1µF/25V/X5R/0603
C-0603
TDK
C6, C8, C12
3
C1608X7R1H104KT000N
0.1µF/50V/X7R/0603
C-0603
TDK
C7
1
0603B103K500
10nF/50V/X7R/0603
C-0603
WALSIN
C9
1
C3225X5R1E226MT
22µF/25V/X5R/1210
C-1210
TDK
C10, C11
2
C3225X5R1E226MT
22µF/25V/X5R/1210
C-1210
TDK
L1
1
7443340100
1.0µH/17A
8.4 x 7.9 x 7.2mm
Wurth
Elektronik
L2
1
NA
R1, R2
2
20k
R-0603
R6
1
150k
R-0603
R7
1
66k
R-0603
R3, R4
2
100k
R-0603
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PCB Layout
Top View (1st layer)
PCB Layout—Inner Side (2nd Layer)
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PCB Layout—Inner Side (3rd Layer)
Bottom View (4th Layer)
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More Information
For more information, please find the related datasheet or application notes from Richtek website
http://www.richtek.com.
Important Notice for Richtek Evaluation Board
THIS DOCUMENT IS FOR REFERENCE ONLY, NOTHING CONTAINED IN THIS DOCUMENT SHALL BE CONSTRUED AS RICHTEK’S WARRANTY, EXPRESS
OR IMPLIED, UNDER CONTRACT, TORT OR STATUTORY, WITH RESPECT TO THE PRESENTATION HEREIN. IN NO EVENT SHALL RICHTEK BE LIABLE T O
BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL
DAMAGES.
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