EVB RT2862GSP-01 EN

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RT2862GSP
Evaluation Board
RT2862 Step-Down Converter Evaluation Board
Purpose
The RT2862 is a high-efficiency current mode synchronous step-down regulator that can deliver up to 3A output
current from a wide input voltage range of 4.5V to 36V. This document explains the function and use of the RT2862
evaluation board (EVB) and provides information to enable operation and modification of the evaluation board and
circuit to suit individual requirements.
Table of Contents
Purpose ............................................................................................................................................................... 1
Introduction.......................................................................................................................................................... 2
General Product Description ................................................................................................................................ 2
Product Features ................................................................................................................................................. 2
Application ........................................................................................................................................................... 2
Evaluation Board ................................................................................................................................................. 3
Specification ........................................................................................................................................................ 4
Schematic............................................................................................................................................................ 4
BOM .................................................................................................................................................................... 5
PCB Layout ......................................................................................................................................................... 6
Step-Down Converter Efficiency Test ................................................................................................................. 10
More Information................................................................................................................................................ 11
Important Notice for Richtek Evaluation Board ................................................................................................... 11
EVB_RT2862GSP-01
May 2016
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your power partner.
RT2862GSP
Evaluation Board
Introduction
General Product Description
The RT2862 is a high efficiency, current mode synchronous step-down DC/DC converter that can deliver up to 3A
output current over a wide input voltage range from 4.5V to 36V. The device integrates a 105mΩ high side and an
80mΩ low side MOSFET to achieve high conversion efficiency up to 95%. The current mode control architecture
supports fast transient response and uses a simple compensation circuit.
A cycle-by-cycle current limit function provides protection against a shorted output and an internal soft-start
eliminates input surge current during start-up. The RT2862 provides complete protection functions such as input
under voltage lockout, output under voltage protection, over current protection and thermal shutdown.
The RT2862 is available in the thermal enhanced SOP-8 (Exposed Pad) package.
Product Features

4.5V to 36V Input Voltage Range

3A Output Current

Internal N-MOSFETs

Current Mode Control

Frequency Operation : 300kHz to 1MHz

Adjustable Output Voltage from 0.8V to 30V

High Efficiency Up to 95%

Stable with Low ESR Ceramic Output Capacitors

Cycle-by-Cycle Current Limit
Application




Point of Load Regulator in Distributed Power Systems
Digital Set Top Boxes
Broadband Communications
Vehicle Electronics

Automotive Audio, Navigation, and Information Systems
Enterprise Datacom Platforms Point of Load (POL)

Industrial Grade General Purpose Point of Load

EVB_RT2862GSP-01
May 2016
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RT2862GSP
Evaluation Board
your power partner.
Evaluation Board
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
VIN
Signal
Input voltage
Comment (expected waveforms or voltage levels on test points)
Input voltage range = 4.5V to 36V
Default output voltage = 3.3V
VOUT
Output voltage
Output voltage range = 0.8V to 30V
(see ‘’ Output Voltage Setting’’ section for changing output voltage
level)
SW
Switch Node
SW waveform
EN
Chip Enable Operation
BOOT
Boot strap supply test point
Floating supply voltage for the high-side N-MOSFET switch
MODE
RT test point
Switching frequency setting point
GND
Ground
Ground
Enable signal. EN is automatically pulled high (by R4) to enable
operation. Connect EN low to disable operation.
Power-up & Measurement Procedure
1. Apply a 12V nominal input power supply (4.5V < VIN < 36V) to the VIN and GND terminals.
2. The EN voltage is pulled to logic high by R4 (100kΩ to VIN) to enable operation. Drive EN high (>2.0V) to enable
operation or low (<0.4V) to disable operation.
3. Verify the output voltage (approximately 3.3V) between VOUT and GND.
4. Connect an external load up to 3A to the VOUT and GND terminals and verify the output voltage and current.
EVB_RT2862GSP-01
May 2016
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RT2862GSP
Evaluation Board
your power partner.
Output Voltage Setting
Set the output voltage with the resistive divider (R1, R2) between VOUT and GND with the midpoint connected to
FB through RCAMP. The output is set by the following formula:
VOUT = 0.8 x (1 +
R1
)
R2
The installed VOUT capacitors (C4, C5) are 22μF, 16V X5R ceramic types. Do not exceed their operating voltage
range and consider their voltage coefficient (capacitance vs. bias voltage) and ensure that the capacitance is
sufficient to maintain stability and provide sufficient transient response for your application. This can be verified by
checking the output transient response as described in the RT2862 IC datasheet.
Specification
Parameter
Input Voltage Range
Symbol
Min
VIN
4.5
Output Voltage
VOUT
Oscillator Frequency
fOSC
Output Current
IOUT
High-Side Switch Current Limit
Range
UOC
Typ.
Max
Units
36
V
3.3
300k
4.25
5
V
1M
Hz
3
A
5.75
A
Schematic
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May 2016
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RT2862GSP
Evaluation Board
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BOM
Reference
Q'ty
P/N
Description
Package
Manufacture
U1
1
RT2862GSP
DC/DC Converter
PSOP-8
Richtek
C1, C2
2
C3216X5R1H106K160AB
10μF/±10%/50V/X5R
Ceramic Capacitor
1206
TDK
C4, C5
2
GRM32ER61C226KE20#
22μF/±10%/16V/X5R
Ceramic Capacitor
1210
Murata
C7
1
0603B272K500
2.7nF/±10%/50V/X7R
Ceramic Capacitor
0603
WALSIN
C3, C6, C11
3
C1608X7R1H104K080AA
0.1μF/±10%/50V/X7R
Ceramic Capacitor
0603
TDK
C8, C9, C12,
C13
0
Not Installed
0603
L1
1
4.7μH/4.1A
8 x 8 x 4.2mm
R1
1
75kΩ/±1%, Resistor
0603
R2
1
24kΩ/±1%, Resistor
0603
R3
1
13kΩ/±1%, Resistor
0603
R4
1
100kΩ/±1%, Resistor
0603
R5, D1, D2
0
Not Installed
R6, RCAMP
2
0Ω, Resistor
0603
RT
1
113kΩ/±1%, Resistor
0603
TP
4
Test Pin
GP
4
Golden Pin
EVB_RT2862GSP-01
May 2016
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TAIYO
YUDEN
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Evaluation Board
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PCB Layout
Top View (1st layer)
Bottom View (4th Layer)
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RT2862GSP
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Component Placement Guide—Component Side (1st layer)
PCB Layout—Component Side (1st Layer)
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RT2862GSP
Evaluation Board
PCB Layout—Inner Side (2nd Layer)
PCB Layout—Inner Side (3rd Layer)
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RT2862GSP
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Component Placement Guide—Bottom Side (4th Layer)
PCB Layout—Bottom Side (4th layer)
EVB_RT2862GSP-01
May 2016
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your power partner.
RT2862GSP
Evaluation Board
Step-Down Converter Efficiency Test
EVB_RT2862GSP-01
May 2016
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your power partner.
RT2862GSP
Evaluation Board
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.
EVB_RT2862GSP-01
May 2016
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