MC34063A, MC33063A
8
1
V
out
8
1
R
V
out
7
R
sc
V
in
6
2
R
sc
V
in
7
2
6
R
³
0 for
constant V
in
Figure 8. External Current Boost Connections for I
C
Peak Greater than 1.5 A
8a. External NPN Switch
8b. External NPN Saturated Switch
(See Note 7.)
7. 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
µs
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.
http://onsemi.com
6
ONSEMI [ ON SEMICONDUCTOR ]
