MC34713EP Freescale, MC34713EP Datasheet - Page 16

• Manufacturer Part Number: MC34713EP
• Manufacturer: Freescale

Specifications of MC34713EP

• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Pin Count: 24
• Mounting: Surface Mount
• Package Type: QFN
• Case Length: 4mm
• Screening Level: Industrial
• Lead Free Status / RoHS Status: Compliant

COMPONENT SELECTION
SWITCHING FREQUENCY SELECTION
when the FREQ pin is grounded, and 200 kHz when the
FREQ pin is connected to VDDI. Intermediate switching
frequencies can be obtained by connecting an external
resistor divider to the FREQ pin. The table below shows the
resulting switching frequency versus FREQ pin voltage.
Table 5. Switching Frequency Adjustment
SELECTION OF THE INDUCTOR
16
34713
TYPICAL APPLICATIONS
FREQUENCY
Figure 7. Resistor Divider for Frequency Adjustment
The switching frequency defaults to a value of 1.0 MHz
Inductor calculation is straight forward, being
1000
200
253
307
360
413
466
520
573
627
680
733
787
840
893
947
R
R
FQH
FQL
VOLTAGE APPLIED TO PIN FREQ
2.341 – 2.500
1.717 – 1.872
1.561 – 1.716
2.185 - 2.340
2.029 - 2.184
1.873 - 2.028
1.405 - 1.560
1.249 - 1.404
1.093 - 1.248
0.936 - 1.092
0.781 - 0.936
0.625 - 0.780
0.469 - 0.624
0.313 - 0.468
0.157 - 0.312
0.000 - 0.156
VDDI
FREQ
GND
OUTPUT FILTER CAPACITOR
more important than the actual capacitance value, the
physical size, the ESR and the voltage rating:
transient response.)
where,
D_max = Maximum ON time percentage.
I
Vin_min = Minimum input voltage at PV
O
= Rated output current.
where,
Maximum OFF time percentage
Switching period.
Drain – to – source resistance of FET
Winding resistance of Inductor
Output current ripple.
For the output capacitor, the following considerations are
Transient Response percentage, TR_%
(Use a recommended value of 2 to 4% to assure a good
Maximum Transient Voltage, TR_v_dip = Vo*TR_%
Maximum current step,
Inductor Current rise time,
As a result, it is possible to calculate
Analog Integrated Circuit Device Data
Freescale Semiconductor
IN