Purpose
The RT6208 is a high voltage Buck converter that can deliver up to 100mA output current from a wide input voltage range of 4.5V to 36V. This document explains the function and use of the RT6208 evaluation board (EVB) and provides information to enable operation and modification of the evaluation board and circuit to suit individual requirements.
Introduction
General Product Information
The RT6208 is a high-efficiency, monolithic synchronous step-down DC/DC converter that can deliver up to 100mA output current from a 4.5V to 36V input supply. It requires only 25µA typical supply current at no load while maintaining output voltage regulation. The RT6208 achieves Boundary Conduction Mode (BCM) operation, low quiescent current and programmable high-side peak current limit, providing high efficiency over a wide range of load currents. It also provides soft-start protection to eliminate input current surge during start-up. The low current (3µA) shutdown mode provides output disconnect, enabling easy power management in battery-powered systems. The RT6208 is available in a SOT-23-6, SOT-23-8 and SOP-8 (Exposed Pad, with power good function) packages.
Product Feature
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Achieves Very High Efficiency in Low Load Conditions
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±1% High Accuracy Feedback Voltage
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4.5V to 36V Input Voltage Range
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100mA Output Current
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Integrated High-Side and Low-Side Switches
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No Compensation Required
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Low Quiescent Current
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Adjustable Peak Current Limit
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Cycle-by-Cycle Over Current Protection
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Input Under Voltage Lockout
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Internal Soft-Start
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Thermal Shutdown Protection
Key Performance Summary Table
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Key Features
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Evaluation Board Number : PCB051_V1
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Default Input Voltage
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12V
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Max Output Current
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100mA
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Default Output Voltage
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1.8V, 3.3V, 5V Optional
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Default Marking & Package Type
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RT6208GE, SOT-23-6
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Operation Mode
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Boundary Conduction Mode (BCM)
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Other Key Features
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4.5V to 36V Input Voltage Range
Support duty up to 95%
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Protection
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Cycle-by-Cycle Over Current Protection
Thermal Shutdown
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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 evb_service@richtek.com
Test Points
The EVB is provided with the test points and pin names listed in the table below.
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Test point/
Pin name
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Signal
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Comment (expected waveforms or voltage levels on test points)
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VIN
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Input voltage
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Input voltage range = 4.5V to 36V
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VOUT
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Output voltage
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Default output voltage : 1.8V, 3.3V, 5V Optional
Output voltage range = 0.8V to 5V
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SW
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Switching node test point
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SW waveform
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EN
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Enable test point
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Driving the EN pin high (>1.4V) will turn on the device again. Leaving the EN pin floating will pull the EN pin up to 2V internally and enable RT6208.
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ISET
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High-Side Peak Current Set Pin
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A resistor from this pin to GND sets the high-side peak current limit. Leave floating for the maximum peak current, 225mA. Short this pin to GND for the minimum peak current, 50mA.
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GND
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Ground
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Ground
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Power-up & Measurement Procedure
1. Apply a 12V nominal input power supply (4.5V < VIN < 36V) to the VIN and GND terminals.
2. There are 2-pin header 1.8V, 3.3V and 5V for output voltage. To use a jumper choose the output voltage level.
3. Verify the output voltage (approximately 1.8V, 3.3, 5.0V) between VOUT and GND.
4. Connect an external load up to 100mA to the VOUT and GND terminals and verify the output voltage and current.
Schematic, Bill of Materials & Board Layout
EVB Schematic Diagram
Bill of Materials
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Reference
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Qty
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Part Number
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Description
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Package
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Manufacture
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C1
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1
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0603NPO100pF+-5%50V
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100pF/0603
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C-0603
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WALSIN
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C3
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1
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C2012X7R1H224KT
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0.22µF/1206/50V
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C-1210
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TDK
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C4
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1
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GRM319R61H475KA12
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4.7µF/1206/50V
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C-1206
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muRata
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C9, C10
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2
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CL31A226KAHNNE
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22µF/1206/25V
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C-1210
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SAMSUNG
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C12
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1
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0603B104K500CT
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0.1µF/0603/50V
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C-0603
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WALSN
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Golden Pin
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5
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SIP-1P-GP
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VIN, GND, VOUT
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SIP-1P-GP
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J1
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1
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1.8V
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SIP-2P
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J2
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1
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3.3V
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SIP-2P
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J3
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1
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5V
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SIP-2P
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L1
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1
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744052101
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100µH
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5.8x5.8mm
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Wurth
Elektronik
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RFB1
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1
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0603 750K 1%
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750k/0603
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R-0603
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WALSIN
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RFB2
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1
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0603 143K 1%
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143k/0603
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R-0603
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WALSIN
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RFB3
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1
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CR0603F240KP05
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240k/0603
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R-0603
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EVER OHMS
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RFB4
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1
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0603T-1-604K
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604k/0603
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R-0603
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WALSIN
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RSET
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1
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NC
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OPTION/0603
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R-0603
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R4
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1
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0603 4R70 1%
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4.7R/0603
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R-0603
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WALSIN
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Test Pin
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5
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EN, SW, FB, VOUT, ISET
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sip-1p-tp
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U1
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1
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RT6208GE
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DC/DC Converter
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SOT-23-6
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Richtek
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EVB Layout
Top View
Bottom View