AIC1594_06 Datasheet, PDF (1/5 Pages) –

The AIC1594 series Design Guidelines and Thermal Performance
The AIC1594 series are step-down PWM converter delivering up to 3A output current. It is available in
SOP-8, TO-252-5 and TO-263-5 packages. This application note provides a simple method to select
components and gives the information to design a PC board that can provide a maximum power within
thermal resistance range.
CF
R2
VIN
+
Cin
U1
IN
FB
ON/OFF OUT
GND
D1
R1
L1
Vout
+
Cout
FB pin connects to Vout directly for fix version
Fig.1 Typical application circuit
The circuit shown in Fig.1 is a cost-effective buck converter. Assuming that input voltage is 12V, output
voltage is 1.8V and maximum load current is 2A. The output ripple must be smaller than 2% of output
voltage.
The output voltage is set by R1 and R2. It can be calculated from
V_OUT = V_FB x (1+R1/R2) = 1.22 x (1+R1/R2)
In order to obtain precision V_OUT, _± 1% tolerance resistors are recommended. The CF capacitor is
required to provide additional stability when using adjustable version. Below is the table that offers the
reference values.
Output Voltage (V)
1.8
4
6
8
10
15
Choose R1=36kƸ, R2=82kƸ, CF=1000pF
R1 (Ƹ)
36k
180k
180k
180k
150k
110k
R2 (Ƹ)
82k
82k
47k
33k
22k
10k
CF (F)
1000p
360p
360p
360p
470p
560p
1