MC34063A Datasheet, PDF (6/12 Pages) ON Semiconductor – DC-to-DC CONVERTER CONTROL CIRCUITS

MC34063A MC33063A
Figure 9. Step–Down Converter
8
1
S Q _Q2
R
Q1
7
Rsc
0.33
Vin
6
25 V
+
100
5
Ipk
Osc
CT
VCC
+
– ^Comp.
1.25 V
Ref
Reg
2
1N5819
3
CT ^L
220 µH
470
pF
4
R2
3.6 k
R1 1.2 k
Vout
5.0 V/500 mA
+
470 CO
1.0 µH
Vout
+
100
Optional Filter
Test
Line Regulation
Load Regulation
Output Ripple
Short Circuit Current
Efficiency
Output Ripple With Optional Filter
Conditions
Vin = 15 V to 25 V, IO = 500 mA
Vin = 25 V, IO = 50 mA to 500 mA
Vin = 25 V, IO = 500 mA
Vin = 25 V, RL = 0.1 Ω
Vin = 25 V, IO = 500 mA
Vin = 25 V, IO = 500 mA
Results
12 mV = ±0.12%
3.0 mV = ±0.03%
120 mVpp
1.1 A
83.7%
40 mVpp
Figure 10. External Current Boost Connections for IC Peak Greater than 1.5 A
10a. External NPN Switch
10b. External PNP Saturated Switch
8
7
Rsc
Vin ₆
1
8
2
7
Vout
Rsc
Vin ₆
1
Vout
2
6
MOTOROLA ANALOG IC DEVICE DATA