EVB RT5795AGQW-00 EN

RT5795AGQW
Evaluation Board
your power partner.
2A, 5.5V, Low IQ ACOT Synchronous Step-Down Converter
Purpose
The RT5795A is an Advanced Constant-On-Time (ACOT) synchronous step-down converter with the input voltage
range from 2.5V to 5.5V and provides 2A output current. This document explains the function and use of the
RT5795A 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.................................................................................................................................................... 7
Important Notice for Richtek Evaluation Board ....................................................................................................... 7
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RT5795AGQW
Evaluation Board
your power partner.
Introduction
General Product Information
The RT5795A is a full featured 5.5V, 2A, Advanced Constant-On-Time (ACOT) synchronous step-down converter
with two integrated MOSFETs. The advanced COT operation allows transient responses to be optimized over a
wide range of loads, and output capacitors to efficiently reduce external component count. The RT5795A provides
up to 2.7MHz switching frequency to minimize the size of output inductor and capacitors.
Product Feature






2.5V to 5.5V Input Voltage Range
Advanced COT Control loop design
Fast Transient Response
Internal 100m and 80m Synchronous Rectifier
Highly Accurate VOUT Regulation Over Load/Line Range
Robust Loop Stability with Low-ESR COUT
Key Performance Summary Table
Key Features
Evaluation Board Number : PCB035_V1
Default Input Voltage
3.3V
Max Output Current
2A
Default Output Voltage
1.2V
Default Marking & Package Type
RT5795AGQW, WDFN-8SL 2x2
Operation Frequency
Fixed 2.7MHz
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RT5795AGQW
Evaluation Board
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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)
VIN
Input voltage
Power input supply voltage, 2.5V to 5.5V.
EN
Enable test point
Enable control input. Pull high to enable.
PGOOD
Power Ground
The exposed pad must be soldered to a large PCB and
connected to GND for maximum thermal dissipation.
AGND
Analog Ground
Should be electrically connected to GND close to the device.
PGND
Power Ground
The exposed pad must be soldered to a large PCB and
connected to PGND for maximum power dissipation.
VOS
No internal connection
Output voltage sense pin for the Internal Control Loop. Must be
connected to output.
FB
Feedback test point
Feedback voltage input.
LX
Switch node test point
Switch node. The source of the internal high-side power
MOSFET, and drain of the internal low-side (synchronous)
rectifier MOSFET.
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Power-up & Measurement Procedure
1. Apply a 12V nominal input power supply (2.5V < VIN < 5.5V) to the VIN and GND terminals.
2. Set the jumper at JP1 to connect terminals 2 and 3, connecting EN to enable operation.
3. Verify the output voltage (approximately 1.2V) between VOUT and GND.
4. Connect an external load up to 2A to the VOUT and GND terminals and verify the output voltage and current.
Output Voltage Setting
Set the output voltage with the resistive divider (R24, R29) between VOUT and GND with the midpoint connected to
FB. The output is set by the following formula :
VOUT = 0.45 x (1 +
EVB_RT5795AGQW-00
R24
)
R29
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Evaluation Board
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Schematic, Bill of Materials & Board Layout
EVB Schematic Diagram
PGOOD
VIN
8
VIN
6
PGOOD
R31
J3
C13
C15
C14
EN
LX
1
EN
LX
VOS
L1
7
Thermal
Pad
VIN
J2
C11
MODE
C10
3
VIN
C12
AGND
VOS
5
R24
C31
SIP-2P-PW
R30
GND
2
JP1
3
2
1
PGND
FB
4
3
2
1
R29
TP4
CP1
EN
1
VOS
2
TP6
PGOOD
VOS
short
PGOOD
TP1
TP5
LX
EN
LX
EN
Bill of Materials
Reference
Qty
Part Number
Description
Package
Manufacture
U4
1
RT5795AGQW
DC/DC Converter
WDFN-8SL 2x2
RICHTEK
C12, C13,
C31
3
C10, C14
2
C1608X7R1H104K080AA
0.1μF/±10%/50V/X7R
C-0603
TDK
C15
1
GRM31CR71E106KA12L
10μF/25V/X7R
C-1206
MURATA
C11
1
GRM31CR61A226KE19L
22μF/10V/X5R
C-1206
MURATA
L1
1
PIFE25201T-R47MS
0.47μH
2.5 x 2.0 mm
CYNTEC
R24
1
65.3k
R-0603
R29
1
39.2k
R-0603
R30
1
100k
R-0603
R31
1
180k
R-0603
L
1
3.3μH/2.15A
4.5 x 4 mm
EVB_RT5795AGQW-00
NC
SR04033R3MSB
Aug 2015
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ELECTRONICS
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RT5795AGQW
Evaluation Board
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PCB Layout
Top View
Bottom View
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RT5795AGQW
Evaluation Board
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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 TO
BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL
DAMAGES.
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