Product Specification
IXD3235/36/37
TYPICAL APPLICATION CIRCUITS
IXD3235/36/37 A, B, C, E, G
Series (Fixed Output Voltage)
IXD3235/36/37 D, F Series (Adjustable Output Voltage)
EXTERNAL COMPONENTS
fOSC
1.2 MHz
3.0 MHz
L, µH
CIN, µF
CL, µF
4.7
4.7
10
1.5
4.7
10
Setting Output Voltage
The IXD3235/36/37 D, F Series allows set output voltage externally by two resistors RFB1 and RFB2 as sown on
schematic diagram above.
Output voltage can be set starting from 0.9V. However, when input voltage (VIN) is lower than the set output
voltage, output voltage (VOUT) cannot be higher than the input voltage.
VOUT = 0.8 × (RFB1+RFB2)/RFB2
RFB1 + RFB2 < 1 MΩ.
The value of the phase compensation capacitor CFB is calculated by the follow equation
fZFB = 1/(2×π×CFB×RFB1),
where fZFB < 10 kHz. For optimization, fZFB can be adjusted in the range of 1 kHz to 20 kHz depending on the
inductance L and the load capacitance CL.
Example:
When RFB1 = 470 kΩ and RFB2 = 150 k, VOUT = 0.8 × (470 k+150 k) / 150 k = 3.3 V
VOUT, V
0.9
RFB1, kΩ
100
RFB2, kΩ
820
CFB, pF
150
VOUT, V
2.5
RFB1, kΩ
510
RFB2, kΩ
240
CFB, pF
100
1.2
150
300
100
3.0
330
120
150
1.5
130
150
220
3.3
470
150
100
1.8
300
240
150
4.0
120
30
470
PS034201-0515
PRELIMINARY
13
ZILOG [ ZILOG, INC. ]
