MC34063A
DESCRIPTION
DC-TO-DC Converter Control Circuits
PIN CONFIGURATION
Switch
Collector
Switch
Emitter
Timing
Capacitor
GND
1
2
3
4
8
7
6
5
Diver
Collector
I
PK
Sense
V
CC
Comparator
Inverting
Input
The MC34063A is a monolithic control circuit containing
the primary functions required for DC-to-DC converters.
The device consists of an internal temperature compen-
sated reference, comparator, controlled duty cycle oscill-
ator with an active current limit circuit, driver and high
current output switch. MC34063A is specifically designed
to be incorporated in Step-Down, Step-Up and Voltage-
Inverting applications with a minimum number of extern-
al components.
(Top View)
FEATURES
Operation from
-0.3V
to 40V Input
Low Standby Current
Current Limiting
Output Switch Current to 1.5A
Output Voltage Adjustable
Frequency Operation to
42kHz
Precision 2% Reference
APPLICATION
DC-DC Converter
ORDERING INFORMATION
Temperature Range
Package
SOP8L
SOP8L
DIP8L
Orderable
Device
MC34063ADG
MC34063ADRG
MC34063APG
Package Qty
75Units/Tube
2500Units/Tape
50Units/Tube
0°C to +70°C
Pb-Free
1
MC34063A
SCHEMATIC DIAGRAM
8
Drive
Collector
DC-TO-DC Converter Control Circuits
1
Switch
Collector
S Q
R
7
I
pk
Sense
I
pk
Oscillator G
T
6
V
CC
3
Timing
Capacitor
100
Q2
Q1
2
Switch
Emitter
+
Comparator
_
5
Comparator
Inverting
Input
1,25V
Reference
Regulator
4
GND
(Bottom View)
Figure 1. Representative Schematic Diagram
ABSOLUTE MAXIMUM RATINGS
Parameter
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
Power Dissipation, T
A
= 25°C
D Package
P Package
Thermal Resistance, T
A
= 25°C
D Package
P Package
Symbol
V
CC
V
IR
V
C(switch)
V
E(switch)
V
CE(switch)
V
C(driver)
I
C(driver)
I
SW
P
D
R
θJA
T
J
T
A
T
stg
Value
40
−0.3 to +40
40
40
40
40
100
1.5
625
1.25
160
100
+150
0 to +70
−65 to +150
°C/W
°C
°C
°C
Unit
V
V
V
V
V
V
mA
A
mW
W
Operating Junction Temperature
Operating Ambient Temperature Range
Storage Temperature Range
2
MC34063A
ELECTRICAL CHARACTERISTICS
Parameter
OSCILLATOR
Frequency
Charge Current
Discharge Current
Discharge to Charge
Current Ratio
Current Limit
Sense Voltage
f
osc
I
chg
I
dischg
I
dischg
/I
chg
V
lpk(sense)
Symbol
DC-TO-DC Converter Control Circuits
(Vcc = 5.0V, T
A
=0 to +70°C, unless otherwise specified)
Test Conditions
Min
Typ Max Unit
33
33
42
42
kHz
μA
μA
V
Pin5
=0V,C
T
=1.0nF,T
A
= 25°C 24
V
CC
= 5.0V to 40V, T
A
= 25°C 24
V
CC
= 5.0V to 40V, T
A
= 25°C 140
Pin7 to V
CC
, T
A
=25°C
I
chg
= I
dischg
, T
A
= 25°C
5.2
250
200 260
6.2
7.5
300 350
mV
OUTPUT SWITCH (Note 3)
Saturation Voltage,
V
CE(sat)
Darlington Connection
Saturation Voltage,
Darlinton Connection
I
SW
= 1.0A,
Pins 1, 8 connected
I
SW
= 1.0A, Forced β = 20
R
Pin 8
= 82Ω to V
CC
I
SW
= 1.0A, V
CE
=5.0V,
T
A
= 25°C
V
CE
= 40V
1.0
1.3
V
V
V
CE(sat)
h
FE
I
C(off)
0.45 0.7
50
75
40
100
DC Current Gain
Collector Off-State
Current
COMPARATOR
Threshold Voltage
Threshold Voltage
Line Regulation
Input Bias Current
TOTAL DEVICE
Supply Current
μA
V
th
Reg
line
I
IB
T
A
= 25°C
T
A
= T
low
to T
high
V
CC
= 3.0V to 40V
V
in
= 0V
V
CC
= 5.0V to 40V,
C
T
= 10nF, V
pin7
= V
CC
,
V
Pin5
> V
th
, Pin 2 = GND,
Remaining pins open
1.225 1.25 1.275
1.21
1.4
1.29
5.0
V
mV
nA
-20 -400
I
CC
2.5
4.0
mA
NOTE 1: Maximum package power dissipation limits must be observed
NOTE 2: Low duty cycle pulse techniques are used during test to maintain juction temperature as
close to ambient temperature as possible
3
MC34063A
Assembly Information:
DC-TO-DC Converter Control Circuits
CHIP APPEARANCE
CHIP SIZE
CHIP THICKNESS
1
8
7
BONDING PAD
DIMENSION
1a
1b
2a
2b
3
4
5
6
7
8
SCRIBE LINE WIDTH
TOP METAL
BACK METAL
WAFER SIZE
SWITCH
COLLECTOR
SWITCH
EMITTER
TIMING
CAPACITOR
GROUND
COMPARATOR
INVERTING
INPUT
1,18
×
1,27 mm
460
±
20
μm
90
×
90
μm
90
×
90
μm
90
×
90
μm
90
×
90
μm
90
×
90
μm
90
×
90
μm
90
×
90
μm
90
×
90
μm
96
μm
Al
–
100 mm
2
3
4
5
6
Vcc
Ipk SENCE
DRIVER
COLLECTOR
4
MC34063A
t
on-off
.OUTPUT SWITCH ON-OFF TIME(μS)
1000
500
200
100
50
20
10
5.0
2.0
1.0
DC-TO-DC Converter Control Circuits
TYPICAL PERFORMANCE CHARACTERISTICS
V
CC
=5.0V
Pin7=V
CC
Pin5=GND
T
A
=25°C
t
on
V
OSC,
OSOCILLATOR VOLTAGE(V)
200 mV / DIV
V
CC
=5.0V Pins1,5,8=Open
Pin7=V
CC
C
T
=1.0μF
Pin2=GND T
A
=25°C
10μS / DIV
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
V
CC
=5.0V
Pin7=V
cc
Pins 2
,3,5=GND
T
A
= 25ºC
Forcedβ = 20
Darlington Connection
t
off
0.01 0.02 0.05 0.1 0.2 0.5
1.0 2.0
5.0
10
C
T
,OSCILLATOR TIMING CAPACITOR(nF)
Figure 3. Timing Capacitor Waveform
Figure 2. Output Switch On−Off Time vs.
Oscillator Timing Capacitor
1.8
V
CE
(sat),SATURATION VOTAGE(V)
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0
0.2
0.4 0.6 0.8 1.0 1.2 1.4 1.6
V
CC
=5.0V
P
ins
1,7,8=V
cc
P
ins
3,5=GND
T
A
= 25ºC
V
CE
(sat),SATURATION VOTAGE(V)
I
E
, EMITTER CURRENT(A)
Figure 4. Emitter Follower Configuration Output
Saturation Voltage vs. Emitter Current
I
C
, COLLECTOR CURRENT(A)
Figure 5. Common Emitter Configuration Output Switch
Saturation Voltage vs. Collector Current
400
3.6
V
cc
=5.0V
I
chg
=I
dischg
V
IPK
(sense),CURRENT LIMIT
I
CC
,SUPPLY CURRENT(mA)
380
360
3.2
2.8
2.4
2.0
1.6
1.2
0.8
0.4
0
0
5.0 10
15
20
25 30
35
40
C
T
=1.0nF
Pin7=V
cc
Pin2=GND
SENSE VOLTAGE(V)
340
320
300
280
260
240
220
200
-55
-25
0
25
50
75
100 125
T
A
,AMBIENT TEMPERATURE(°C)
Figure 6. Current Limit Sense Voltage vs.
Temperature
V
CC
,S UPPLY VOLTAGE(V)
Figure 7. Standby Supply Current vs. Supply Voltage
5
