ISL6224EVAL1 Intersil, ISL6224EVAL1 Datasheet - Page 7

• Manufacturer Part Number: ISL6224EVAL1
• Description: EVALUATION BOARD FOR ISL6224
• Manufacturer: Intersil

Specifications of ISL6224EVAL1

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 2.5V
• Current - Output: 3A
• Voltage - Input: 4 ~ 24V
• Regulator Topology: Buck
• Frequency - Switching: 300kHz
• Board Type: Fully Populated
• Utilized Ic / Part: ISL6224
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

Shutdown by Enable
When the EN bit of S1 is moved to the DOWN position the
PWM stops and the inductor current decays to zero amps
and the output capacitors discharge. A typical shutdown
waveform is shown in Figure 19.
,
FIGURE 19. SHUT DOWN BY ENABLE PIN
7
Vin=15 V, Fs=300kHz
Vout
Inductor Current
Enable Pin
Application Note 9983
Output Voltage Setpoint Calculation
The output voltage of the converter is set by connecting a
two resistor voltage divider across the output. The feedback
voltage divider output is connected to the VSEN pin of the
IC. The voltage at the VSEN pin is 0.9V when the converter
output is in regulation. The voltage at the VSEN pin is
internally compared to a 0.9V reference voltage and passed
on to the next stage of the PWM generation circuits. On the
ISL6224EVAL1 evaluation board the two resistor voltage
divider feedback network consists of R10 (top resistor) and
(R15 or R16 or R17) bottom resistors. Each bottom resistor
chooses a different output voltage. The resistors are
selected by switch S1. The equation for the setpoint of the
output voltage is shown below.
Where Ry is bottom resistor, Vo is the required output
voltage and Vref is the reference voltage.
Some of the most popular output voltage setpoints are
calculated in Table 3.
Vo
R10
Ry
Ry
=
TABLE 3. OUTPUT VOLTAGE SETPOINT
R10
----------------------------- -
1.25V
11.8K
30.1K
Vo Vref
–
×
Vref
11.8K
17.8K
1.5V
11.8K
6.65K
2.5V
11.8K
4.42K
3.3V
11.8K
2.59K
5.0V