34063
Description
The MC34063A Series is a monolithic control circuit containing the primary functions required for DC-to-DC converters.
These devices consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator
with an active current limit circuit, driver and high current output switch. This series was specifically designed to be
incorporated in Step-Down and Step-Up and Voltage-Inverting applications with a minimum number of external
components.
Features
•
•
•
•
•
•
•
Operation from 3.0 V to 40 V Input
Low Standby Current
Current Limiting
Output Switch Current to 1.5 A
Output Voltage Adjustable
Frequency Operation to 100 kHz
Precision 2% Reference
Plastic Package
Pin Connections
Internal Block Digram
Driver
Collector
1
S
R
I
pk
Sense
I
pk
Oscillator
Comparator
1.25 V
Reference
4
Gnd
C
T
7
100
2
3
V
CC
Comparator
Inverting
Input
6
Switch
Emitter
Timing
Capacitor
Q
Q2
Q1
8
Switch
Collector
5
BEIJING ESTEK ELECTRONICS CO.,LTD
1
34063
Absolute Maximum Ratings
Symbol
V
CC
V
IR
V
C(switch)
V
E(switch)
V
CE(switch)
V
C(driver)
I
C(driver)
I
SW
T
J
T
A
Tstg
Power Supply Voltage
Comparator Input Voltage Range
Switch Collector Voltage
Switch Emitter Voltage (V
PIN1
= 40 V)
Switch Collector to Emitter Voltage
Driver Collector Voltage
Driver Collector Current (Note 1)
Switch Current
Operating Junction Temperature
Operating Ambient Temperature Range
Storage Temperature Range
Parameter
Maximum
40
-0.3 to +40
40
40
40
40
100
1.5
+150
0 to +70
-65 to +150
Units
Vdc
Vdc
Vdc
Vdc
Vdc
Vdc
mA
A
°
C
°
C
°
C
Electrical Characteristics
(Vcc=5.0V, Ta=T
low
specified)
to T
high
, unless otherwise
Characteristics
OSCILLATOR
Frequency (V
pin5
= 0V, C
T
= 1.0 nF, T
A
= 25°
C)
Charge Current(V
CC
= 5.0V to 40V, T
A
= 25°
C)
Discharge Current (V
CC
= 5.0V to 40V, T
A
= 25°
C)
Discharge to Charge Current Ratio (Pin 7 to V
CC
, T
A
= 25°
C)
Current Limit Sense Voltage (I
chg
= I
dischg
, T
A
= 25°
C)
OUTPUT SWITCH (NOTE 2)
Saturation Voltage, Darlington Connection (I
SW
= 1.0 A, Pins 1, 8 connected)
Saturation Voltage, Darlington Connection (I
SW
= 1.0 A, R
pin 8
= 82Ω to V
CC
, Forced
β
≅
20)
DC Current Gain (I
SW
= 1.0 A, V
CE
= 5.0 V, T
A
= 25°
C)
Collector Off-State Current (V
CE
= 40 V)
COMPARATOR
Threshold Voltage
(T
A
=25°
C)
(T
A
=T
low
to T
high
)
Threshold Voltage Line Regulation
(Vcc=3.0 V to 40 V)
Input Bias Current
(Vin=0 V)
TOTAL DEVICE
Supply Current (Vcc = 5.0 V to 40 V, C
T
= 1.0 nF, Pin 7 = V
CC
, Vpin 5 > Vth, Pin 2 =
Gnd, remaining pins open)
Symbol
f
OSC
I
chg
I
dischg
I
dischg
/
I
chg
V
ipk(sence)
V
CE(sat)
V
CE(sat)
h
FE
I
C(off)
Vth
1.225 1.25
1.21
–
–
1.4
–
-20
1.275
1.29
5.0
-400
Min
24
24
140
5.2
250
–
–
50
–
Typ
33
35
220
6.5
300
1.0
0.45
75
40
Max
42
42
260
7.5
350
1.3
0.7
–
100
Units
kHz
µA
µA
–
mV
V
V
–
µA
V
Reg
line
I
IB
mV
nA
I
CC
–
–
4.0
mA
NOTES :
1.Maximum package power dissipation limits must be observed.
2.Low duty cycle pulse techniques are used during test to maintain junction temperature
as close to ambient temperature as possible
BEIJING ESTEK ELECTRONICS CO.,LTD
2
34063
Typical Performance Characteristics
Figure 1. Output Switch On-Off Time versus
Oscillator Timing Capacitor
Figure 2. Timing Capacitor Waveform
A
Figure 3. Emitter Follower Configuration Output
Saturation Voltage versus Emitter Current
versus
Figure 4. Common Emitter Configuration
Output Switch Saturation Voltage
Collector Current
Figure 5. Current Limit Sense Voltage
versus Temperature
Figure 6. Standby Supply Current versus
Supply Voltage
BEIJING ESTEK ELECTRONICS CO.,LTD
3
34063
Typical Applications Circuit
Figure 1.
Step-Up Converte
.
r
Note: R to 0 for constant V
in
Figure 2a.
External NPN Switch.
Figure 2.
External Current Boost Connections for I
P
Figure 2b.
External NPN Saturated Switch.
eak Greater than
1.5
A
.
BEIJING ESTEK ELECTRONICS CO.,LTD
4
34063
Figure 3.
Step-Down Converte
.
r
Figure 4a.
External NPN Switch.
Figure 4.
External Current Boost Connections for I
P
Figure 4b.
External PNP Suturated Switch.
eak Greater than
1.5
A
.
BEIJING ESTEK ELECTRONICS CO.,LTD
5
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