RT7285CGJ6
Evaluation Board
UG7285CGJ6-00 January 2015 1 http://www.richtek.com
your power partner.
RT7285CGJ6 Evaluation Board
Purpose
The RT7285C is a synchronous step-down converter with Advanced Constant On-Time (ACOT™) mode control. It
can deliver up to 1.5A output current from a wide input voltage range of 4.3V to 18V. This document explains the
function and use of the RT7285C 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
KEY PERFORMANCE SUMMARY TABLE ................................................................................................................................... 2
BENCH TEST SETUP CONDITIONS............................................................................................................................................ 3
SCHEMATIC, BILL OF MATERIALS AND BOARD LAYOUT ........................................................................................................... 5
MORE INFORMATION........................................................................................................................................................... 10
IMPORTANT NOTICE FOR RICHTEK REFERENCE DESIGNS ...................................................................................................... 10
RT7285CGJ6
Evaluation Board
UG7285CGJ6-00 January 2015 2 http://www.richtek.com
your power partner.
Introduction
General Product Information
The RT7285C 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 4.3V to 18V. The proprietary circuit
of the RT7285C enables to support all ceramic capacitors. The output voltage can be adjusted between 0.6V and 8V.
The RT7285C also provides output under voltage protection and thermal shutdown protection. The low current
(<4μA) shutdown mode provides output disconnection, enabling easy power management in battery-powered
systems. The RT7285C is available in TSOT-23-6 package.
Product Feature
±1.5% High Accuracy Feedback Voltage
4.3V to 18V Input Voltage Range
1.5A Output Current
Integrated N-MOSFET Switches
ACOTTM mode control
Fixed Frequency Operation : 500kHz
Output Adjustable from 0.6V to 8V
Up to 95% Efficiency
Fast Transient Response
Stable with Low-ESR Ceramic Output Capacitors
Cycle-by-Cycle Over Current Protection
Input Under Voltage Lockout
Output Under Voltage Protection
Thermal Shutdown Protection
RoHS Compliant and Halogen Free
Key Performance Summary Table
Key Features
Evaluation Board Number: PCB007_V1
Default Input Voltage
12V
Max Output Current
1.5A
Default Output Voltage
1.2V
Default Marking & Package Type
RT7285CGJ6, TSOT-23-6
Operation Frequency
Steady 500kHz at all loads
Other Key Features
ACOTTM for Fast Transient Response
Protection
Output Under-Voltage Protection (hiccup mode):
Cycle-by-cycle Current Limit
Thermal Shutdown
RT7285CGJ6
Evaluation Board
UG7285CGJ6-00 January 2015 3 http://www.richtek.com
your power partner.
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.
Test point/
Pin name
Signal
Comment (expected waveforms or voltage levels on test points)
VIN
Input voltage
Input voltage range= 4.3V to 18V
VOUT
Output voltage
Default output voltage = 1.2V
Output voltage range= 0.6V to 8V
(see ‘’ Output Voltage Setting’’ section for changing output voltage level)
SW
Switching node test point
SW waveform
EN
Enable test point
Enable signal. Drive EN or install a shorting block on Jumper JP2 to
enable operation or disable operation.
JP2
Chip enable control
Install jumper or drive EN directly to enable or disable operation
BOOT
Boot strap supply test point
Floating supply voltage for the high-side N-MOSFET switch
GND
Ground
Ground
Power-up & Measurement Procedure
1. Apply a 12V nominal input power supply (4.3V < VIN < 18V) to the VIN and GND terminals.
2. The EN voltage is pulled to logic high by R5 (100kΩ to VIN) to enable operation. Drive EN high (>1.5V) to
enable operation or low (<0.4V) to disable operation.
3. Verify the output voltage (approximately 1.2V) between VOUT and GND.
4. Connect an external load up to 1.5A to the VOUT and GND terminals and verify the output voltage and current.
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