MC34063EB STMicroelectronics, MC34063EB Datasheet - Page 13

• Manufacturer Part Number: MC34063EB
• Description: DC-DC CONVERTER CONTROL CIRCUITS
• Manufacturer: STMicroelectronics

Specifications of MC34063EB

• Low Quiescent Current: 2.5 mA (typ.)

Table 12.
Note:
t
(t
C
I
R
C
L
on
PK(switch)
on
(min)
T
SC
O
/t
Parameter
off
+ t
off
) max
Calculation
V
V
The following power supply characteristics must be chosen:
V
V
I
f
V
value will and to be increased due to its equivalent series resistance and board layout. The
ripple voltage should be kept to a low value since it will directly affect the line and load
regulation.
OUT
MIN
OUT
SAT
F
IN
RIPPLE
= Forward voltage drop of the output rectifier
= Nominal input voltage
= Minimum desired output switching frequency at the selected values of V
= Desired output current
= Saturation voltage of the output switch
= Desired output voltage, |V
V
= Desired peak to peak output ripple voltage. In practice, the calculated capacitor
(Discontinuous mode)
-----------------------------------
IN min
2I
I
------------------------------------------------
PK switch
OUT
(
out(max)
V
(
0.3/I
IN min
4.5x10
------------------------------ -
V
)
Step-Up
+
ripple p p
(
–
I
1/f
V
PK(switch)
out
V
[(t
F
min
)
sat
)
t
–
on
(
-5
on
–
V
t
/t
×
V
–
on
off
IN mi
sat
t
)
on mi
(
)+1]
(
OUT
N min
------------------------------------------------ -
| = 1.25 (1 + R
(
(Continuous mode)
I
----------------------------------------------------- -
I
---------------------------------------------------
N min
PK switch
PK switch
(
)
–
(
0.3/I
(
8V
Step-Down
V
4.5x10
V
2I
OUT
)
ripple p p
sat
–
1/f
out(max)
PK(switch)
V
min
)
–
)
+
sat
(
-5
t
V
(
V
on
t
out
on
–
F
–
2
+
/R
V
)
×
t
OU
off
1
t
)
on(
)
V
(Discontinuous mode)
-----------------------------------
IN min
2I
I
PK switch
Voltage Inverting
(
out(max)
(
0.3/I
4.5x10
------------------------------ -
V
------------------------------ -
)
V
ripple p p
V
–
I
1/f
OUT
IN
PK(switch)
out
V
[(t
min
)
sat
–
t
on
IN
(
-5
on
V
+
t
/t
×
–
sat
on
and I
off
V
t
)
F
on mi
)+1]
(
O
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