DC-DC Converter Control Circuits
MC34063A
ELECTRICAL CHARACTERISTICS(
Refer to the test circuits, V
CC
=5V, T
a
=T
LOW
to T
HIGH
, unless
otherwise specified, see note 2)
OSCILLATOR
SYMBOL
F
OSC
I
chg
I
dischg
I
dischg
/I
chg
V
ipk(sense)
PARAMETER
Frequency
Charge Current
Discharge Current
Discharge to Charge Current Ratio
Current Limit Sense Voltage
TEST CONDITIONS
MIN.
o
V
pin5
= 0 V ,C
T
= 1nF ,T
a
= 25 C 24
o
24
V
CC
= 5 to 40V ,T
a
= 25 C
o
140
V
CC
= 5 to 40V ,T
a
= 25 C
o
5.2
Pin 7= V
CC
,T
a
= 25 C
o
250
I
chg
= I
dischg
,T
a
= 25 C
TYP.
33
33
200
6.2
300
MAX. UNIT
42 KHz
42
㎂
260
㎂
7.5
350 ㎷
OUTPUT SWITCH
SYMBOL
PARAMETER
V
CE(sat)
Saturation Voltage,
Darlington connection
V
CE(sat)
Saturation Voltage
h
FE
I
C(off)
DC Current Gain
Collector Off-State Current
TEST CONDITIONS
I
SW
= 1A ,Pins 1,8 connected
I
SW
= 1A ,R
pin8
= 82Ω to V
CC
,
Forced β ~ 20
I
SW
= 1A, V
CE
= 5V, T
a
= 25
o
C
V
CE
= 40V
MIN.
TYP.
1
0.45
50
120
0.01
MAX. UNIT
1.3
V
0.7
V
100
㎂
COMPARATOR
SYMBOL
PARAMETER
V
th
Threshold Voltage
Reg
line
I
IB
Threshold Voltage Line Regulation
Input Bias Current
TEST CONDITIONS
T
a
= 25
o
C
T
a
= T
LOW
to T
HIGH
V
CC
= 3 to 40V
V
IN
= 0V
MIN. TYP.
1.225 1.25
1.21
1
-5
MAX. UNIT
1.275 V
1.29
V
5
㎷
-400 ㎁
TOTAL DEVICE
SYMBOL
PARAMETER
I
CC
Supply Current
TEST CONDITIONS
MIN.
V
CC
= 5 to 40V, C
T
=1㎋
Pin7= V
CC
,V
pin5
>V
th
, Pin2=GND
Remaining pins open
for MC34063A
T
a
= 25
o
C ,C
T
=1㎌ ,Pin5= 0V
for MC34063A
TYP.
2.5
MAX. UNIT
4
㎃
V
START-UP
Start-up Voltage(note 4)
2.1
V
Notes:
1) Maximum package power dissipation limit must be observed.
2) T
LOW
= 0
o
C, T
HIGH
70
o
C
=
3) If Darlington configuration is not used, care must be taken to avoid deep saturation of output switch.
The resulting switch-off time may be adversely affected.
In a Darlington configuration the following output driver condition is suggested:
/(I
-1㎃
*
)≥10
Forced β of output current switch= I
COUTPUT CDRIVER
*
Current less due to a built in 1KΩ antileakage resistor.
4) Start-up Voltage is the minimum Power Supply Voltage at which the internal oscillator begains to work.
HTC
3
ETC [ ETC ]
