MC34063A, MC33063A, NCV33063A
R
V
out
V
out
8
7
6
1
2
8
7
6
1
2
R
R
sc
sc
V
in
V
in
R ³ 0 for
constant V
in
Figure 9. External Current Boost Connections for IC Peak Greater than 1.5 A
9a. External NPN Switch
9b. External NPN Saturated Switch
(See Note 8)
8. If the output switch is driven into hard saturation (non−Darlington configuration) at low switch currents (≤ 300 mA) and high driver currents
(≥30 mA), it may take up to 2.0 ms to come out of saturation. This condition will shorten the off time at frequencies ≥ 30 kHz, and is magnified
at high temperatures. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a
non−Darlington configuration is used, the following output drive condition is recommended.
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