The RT5710A is a high efficiency synchronous step-down DC-DC converter. Its input voltage range is from 2.5V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 1A of output current. This document explains the function and use of the RT5710A evaluation board (EVB), and provides information to enable operation, modification of the evaluation board and circuit to suit individual requirements.
The RT5710A is a high efficiency synchronous step-down DC-DC converter. Its input voltage range is from 2.5V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 1A of output current. The internal synchronous low on-resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The Current Mode Constant-On-time (CMCOT) operation with internal compensation allows the transient response to be optimized over a wide range of loads and output capacitors.
Evaluation Board Number : PCB104_V1
Default Input Voltage
Max Output Current
Default Output Voltage
Default Marking & Package Type
RT5710AHGQW, WDFN-6L 2x2
1.5MHz in CCM mode
The EVB is provided with the test points and pin names listed in the table below.
Comment (expected waveforms or voltage levels on test points)
No Internal Connection
No internal connection.
Enable Control Input
Enable control input.
Supply Voltage Input
The RT5710A operates from a 2.5V to 6V input.
Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum thermal dissipation.
1. Apply a 3.3V nominal input power supply (2.5V < VIN < 6V) to the VIN and GND terminals.
2. Set the jumper at JP1 to connect terminals 2 and 3, connecting EN to VIN through resistor R2 (100kΩ). The Enable pin can connected to VIN directly as well to enable operation.
3. Verify the output voltage (approximately 1.2V) between VOUT and GND.
4. Connect an external load up to 1A to the VOUT and GND terminals and verify the output voltage and current.
Set the output voltage with the resistive divider (R1, R3) between VOUT and GND with the midpoint connected to FB. The output is set by the following formula :
The placement of the resistive divider should be within 5mm of the FB pin. The resistance of R3 is suggested between 10kΩ and 150kΩ to minimize power consumption, and noise pick-up at the FB pin. The resistance of R1 can then be obtained as below :
For better output voltage accuracy, divider resistors (R1 and R3) should have tolerance of ±1% tolerance or better.
1. Do not hot-plug a live 3.3V supply to the board; if hot-plugging is required, add ~100µF electrolytic capacitor at the input.
A small feedforward capacitor (C4) can be introduced into the feedback network to speed up the transient response of high output voltage circuits. Adding C4 can also improve the light load PSM switching behavior. The feedforward capacitor is added across the upper FB divider.
To optimize transient response, C4 value is chosen so that the gain and phase boost of the feedback network increases the bandwidth of the converter, while still maintaining an acceptable phase margin. Generally, larger C4 values provide higher bandwidth, but may result in an unacceptable phase margin or instability.
3.3V to 1.2V
R1, R2, R3
Top View (1st layer)
PCB Layout—Inner Side (2nd Layer)
PCB Layout—Inner Side (3rd Layer)
Bottom View (4th Layer)