DC-DC Converter Control Circuits MC34063A
ELECTRICAL CHARACTERISTICS( Refer to the test circuits, VCC=5V, Ta=TLOW to THIGH, unless
otherwise specified, see note 2)
OSCILLATOR
Frequency V
= 0 V ,C
= 1nF ,T
= 25oC
Charge Current V
= 5 to 40V ,T
= 25oC
Discharge Current V
= 5 to 40V ,T
= 25oC
Discharge to Charge Current Ratio Pin 7= V
,T
= 25oC
Current Limit Sense Voltage I
= I
,T
= 25oC
OUTPUT SWITCH
Saturation Voltage, ISW= 1A ,Pins 1,8 connected
Darlington connection
Saturation Voltage ISW= 1A ,R
in8= 82Ω to VCC,
Forced β ~ 20
DC Current Gain I
= 1A, V
= 5V, T
= 25oC
Collector Off-State Current VCE= 40V
COMPARATOR
Threshold Voltage T
= 25oC
Ta= TLOW to THIGH
Threshold Voltage Line Regulation VCC= 3 to 40V
Input Bias Current VIN= 0V
TOTAL DEVICE
Supply Current VCC= 5 to 40V, CT=1㎋
Pin7= VCC ,V
in5>Vth, Pin2=GN
Remaining pins open
for MC34063A
Start-up Voltage(note 4) T
= 25oC ,C
=1㎌ ,Pin5= 0V
for MC34063A
Notes:
1) Maximum package power dissipation limit must be observed.
2) TLOW= 0oC, THIGH
= 70oC
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:
Forced β of output current switch= ICOUTPUT
/(ICDRIVER
-1㎃*)≥10
* 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
TEST CONDITIONS MIN. TYP. MAX. UNIT
FOSC 24 33 42 KHz
SYMBOL PARAMETER
㎂
Idischg 140 200 260 ㎂
Ichg 24 33 42
Vipk(sense) 250 300 350 ㎷
Idischg/Ichg 5.2 6.2 7.5
UNIT
VCE(sat) 1 1.3 V
SYMBOL PARAMETER TEST CONDITIONS MIN.
0.45 0.7
TYP. MAX.
0.01 100
V
hFE 50 120
VCE(sat)
㎂
SYMBOL PARAMETER TEST CONDITIONS MIN. TYP. MAX. UNIT
IC(off)
Vth 1.225 1.25 1.275
15
V
1.21 1.29 V
TEST CONDITIONS MIN.
㎷
IIB -5 -400 ㎁
Regline
TYP. MAX. UNIT
ICC 2.5 4 ㎃
SYMBOL PARAMETER
VSTART-UP 2.1 V
3