Purpose
The RT6219A is an ACOTTM synchronous Buck converter with the input voltage range from 5V to 23V and provides 4A output current. This document explains the function and use of the RT6219A evaluation board (EVB), and provides information to enable operation, modification of the evaluation board and circuit to suit individual requirements.
Introduction
General Product Information
The RT6219A is a synchronous Buck converter with Advanced Constant On-Time (ACOTTM) mode control which provides a very fast transient response with no external compensators. The RT6219A operates from 5V to 23V input voltage, provides complete protection functions including Over Current Protection (OCP), Under Voltage Protection (UVP) and Over Voltage Protection (OVP). This IC also provides a 1.5ms internal soft-start function and an open-drain power good indicator.
Product Feature
-
5V to 23V Input Voltage Range
-
Adjustable from 0.6V to 5V Output Range
-
Up to 98% Duty for 2S Battery Application
-
500kHz Switching Frequency
-
Fixed Switching Frequency: 500kHz
-
ACOT™ Mode Performs Fast Transient Response
-
Integrated MOSFETs
►
67mΩ of High-Side MOSFET
►
41mΩ of Low-Side MOSFET
-
Supports MLCC Output Capacitors
-
Internal Soft-Start (1.5ms typ)
-
Built-in OVP/UVP/OCP
-
Power Good Indicator
-
Thermal Shutdown
Key Performance Summary Table
|
Key Features
|
Evaluation Board Number : PCB049_V1
|
|
Input Voltage Range
|
5V to 23V
|
|
Max Output Current
|
4A
|
|
Default Output Voltage
|
5V
|
|
Default Marking & Package Type
|
RT6219AGQW, WDFN-10L 3x3
|
|
Operation Frequency
|
500kHz at CCM
|
Bench Test Setup Conditions
Headers Description and Placement
|
|
|
|
Top View
|
Bottom View
|
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)
|
|
EN
|
Enable test point
|
Enable Control Input. Do not leave this pin floating. The slew rate of EN is recommended to be slower than 4.8V/µs.
|
|
GND
|
Ground
|
Ground.
|
|
PG
|
Power good indicator
|
Open-Drain Power Good Indicator Output.
|
|
VBYP
|
External 5V supply
|
Switch Over Input Supply Voltage for VCC. A low pass filter shoulde be connected to GND, if VBYP is applied. If VBYP is not used, then connect to GND.
|
|
VCC
|
Internal regulator output
|
5V Linear Regulator Output for Internal Control Circuit. Bypass VCC to AGND with a 2.2µF capacitor. VCC can only supply internal circuits. Do not connect to external loads.
|
|
BOOT
|
Bootstrap supply test point
|
Bootstrap Supply for High-Side Gate Driver. A capacitor is needed to drive the power switch's gate above the supply voltage. It is connected between the SW and BOOT pins to form a floating supply across the power switch driver.
|
|
SW
|
Switch node test point
|
Switch Node.
|
Power-up & Measurement Procedure
1. Connect input power (5V < VIN < 23V) and input ground to VIN and GND test pins respectively.
2. Connect positive end and negative terminals of load to VOUT and GND test pins respectively.
3. There is a 3-pin header “J5” for enable control. To use a jumper at “VDD” option to tie EN test pin to input power VIN for enabling the device. Inversely, to use a jumper at “GND” option to tie EN test pin and ground GND for disabling the device.
4. Verify the output voltage (approximately 5V) between VOUT and GND.
5. Connect an external load up to 4A to the VOUT and GND terminals and verify the output voltage and current.
Output Voltage Setting
Set the output voltage with the resistive divider (R8, R4) between VOUT and GND with the midpoint connected to FB. The output is set by the following formula :
Schematic, Bill of Materials & Board Layout
EVB Schematic Diagram
Bill of Materials
|
Reference
|
Qty
|
Part Number
|
Description
|
Package
|
Manufacture
|
|
U2
|
1
|
RT6219AGQW
|
DC/DC Converter
|
WDFN-10L 3x3
|
RICHTEK
|
|
C1, C2
|
2
|
|
4.7µF/25V
|
C-1206
|
|
|
C4
|
1
|
|
22pF/50V
|
C-0603
|
|
|
C9
|
1
|
|
220nF/50V
|
C-0603
|
|
|
C10, C11, C12, C14, C18, R3
|
6
|
NC
|
NC
|
NC
|
NC
|
|
C13
|
1
|
|
2.2µF/50V
|
C-0603
|
|
|
C15, C16, C17
|
3
|
|
22µF/6.3V/0805
|
C-0805
|
|
|
C19
|
1
|
|
0.1µF/50V
|
C-0603
|
|
|
L1
|
1
|
|
2.2µH
|
|
|
|
R1, R5
|
2
|
|
100K
|
R-0603
|
|
|
R2, R9
|
2
|
|
0
|
R-0603
|
|
|
R4
|
1
|
|
22k
|
R-0603
|
|
|
R6
|
1
|
|
10M
|
R-0603
|
|
|
R8
|
1
|
|
3k
|
R-0603
|
|
PCB Layout
Top View (1st layer)
PCB Layout—Inner Side (2nd Layer)
PCB Layout—Inner Side (3rd Layer)
Bottom View
Bottom View (4th Layer)