A7431
DC-DC CONVERTER BUCK (STEP-DOWN)
42V 3A CC/CV
AiT Semiconductor Inc.
www.ait-ic.com
APPLICATIONS INFORMATION
Output Voltage Setting
Figure 1: Output Voltage Setting
Figure 1 shows the connections for setting the output voltage. Select the proper ratio of the two feedback
resistors RFB1 and RFB2 based on the output voltage. Adding a capacitor in parallel with RFB1 helps the system
stability. Typically, use RFB2 ≈10kΩ and determine RFB1 from the following equation:
VOUT
0.808V
RFB1 = RFB2
−1
CC Current Setting
A7431 constant current value is set by a resistor connected between the ISET pin and GND. The CC output
current is approximating linearly proportional to the current flowing out of the ISET pin. The voltage at ISET is
roughly 1V and the current gain from ISET to output is roughly 27500 (27.5mA/1μA). To determine the proper
resistor for a desired current, please refer to Figure 2 below.
Figure 2: Curve for Programming Output CC Current
REV1.1
- JAN 2016 RELEASED, SEP 2016 UPDATED -
- 7 -
AITSEMI [ AiT Semiconductor ]
