MC34163 MC33163
Figure 20. Step–Down Converter
RSC
8
0.25 V
+–
Current
Limit
+
Vin
12 V
0.075
Cin
+7 +
330
CT
6 Oscillator
680 pF
5
R
Q
Thermal
S
4
Latch
+
9
10
Q1
11
Q2
12
60
13
Low Voltage
Indicator Output
3
14
45 k
2
RLVI
10 k 1
CDLY
+
+
–
LVI
+ Feedback
+
+
–
Comparator
1.25 V 15 k
2.0 mA
+
1.125 V
+ 7.0 V
15
16
(Bottom View)
1N5822
0.02
CB RB
L
180 µH
Coilcraft LO451–A
2200 +CO
Vout
5.05 V/3.0 A
Test
Line Regulation
Load Regulation
Output Ripple
Short Circuit Current
Efficiency, Without Bootstrap
Efficiency, With Bootstrap
Condition
Vin = 8.0 V to 24 V, IO = 3.0 A
Vin = 12 V, IO = 0.6 A to 3.0 A
Vin = 12 V, IO = 3.0 A
Vin = 12 V, RL = 0.1 Ω
Vin = 12 V, IO = 3.0 A
Vin = 12 V, IO = 3.0 A
Results
6.0 mV = ± 0.06%
2.0 mV = ± 0.02%
36 mVpp
3.3 A
76.7%
81.2%
Figure 21. External Current Boost Connections for Ipk (Switch) Greater Than 3.4 A
Figure 21A. External NPN Switch
Figure 21B. External PNP Saturated Switch
8
9
7
+
6
5
10
Q1 11
Q2 12
4
+
13
3
14
Q3
2
15
1
16
+
(Bottom View)
8
7
+
6
5
9
Q3
10
Q1 11
Q2
12
4
+
13
3
14
2
15
1
16
+
(Bottom View)
10
MOTOROLA ANALOG IC DEVICE DATA