34063A
DC-TO-DC CONVERTER CONTROL CIRCUITS
The 34063A 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
FUNCTIONAL BLOCK DIAGRAM
•
•
•
•
•
•
•
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
MAXIMUM RATINGS
Rating
Power Supply Voltage
Comparator Input Voltage Range
Switch Collector Voltage
Switch Emitter Voltage (Vpin 1 = 40 V)
Switch Collector to Emitter Voltage
Driver Collector Voltage
Driver Collector Current (Note 1)
Switch Current
Power Dissipation and Thermal Characteristics
Ceramic Package, U Suffix T
A
= +25°C
Thermal Resistance
Plastic Package, P Suffix T
A
= +25°C
Thermal Resistance
SOIC Package, D Suffix
TA
= +25°C
Thermal Resistance
Operating Junction Temperature
Operating Ambient Temperature Range
Storage Temperature Range
Symbol
V
CC
V
IR
V
C(switch)
V
E(switch)
V
CE(switch)
I
C(driver)
I
C(driver)
I
SW
P
D
R
θJA
P
D
R
θJA
P
D
R
θJA
TJ
Value
40
-0.3 to
+40
40
40
40
40
100
1.5
1.25
100
1.25
100
625
160
+150
0 to +70
-65to+150
Unit
Vdc
Vdc
Vdc
Vdc
Vdc
Vdc
mA
A
W
°C/W
W
°C/W
mW
°C/W
°C
°C
°C
T
A
Tstg
ORDERING INFORMATION
Device
Temperature
Range
34063AD 0° to +70°C
34063AP1
Package
SO-8
Plastic DIP
Pin connection
ELECTRICAL CHARACTERICISTICS
(V
CC
= 5.0 V, T
A
= 0 to +70 C unless otherwise specified.)
Characteristics
Symbol
OSCILLATOR
Frequency (V
Pin 5
= 0 V, C
T
= 1.0 nF, T
A
= 25°C)
f
osc
Charge Current (V
CC
= 5.0 V to 40 V, T
A
= 25°C)
I
chg
Discharge Current (
V
CC
= 5.0 V to 40 V, T
A
= 25°C)
I
dischg
Discharge to Charge Current Ratio (Pin7 to Vcc, T
A
=25°C)
I
dischg
/I
chg
Current Limit Sense Voltage (Ichg = Idischg, T
A
= 25°C)
V
lpk
(sense)
OUTPUT SWITCH (Note 3)
Saturation Voltage, Darlington Connection (I
SW
= 1.0 A,
V
CE
(sat)
Pins 1, 8 connected)
o
Min
24
24
140
5.2
250
—
—
50
—
1.225
1.21
1.2375
—
Typ
33
33
200
6.2
300
1.0
0.45
120
0.01
1.25
—
1.25
1.4
-40
2.5
Max
42
42
260
7.5
350
1.3
0.7
—
100
1.275
1.29
1.2625
5.0
-400
4.0
Unit
kHz
µA
µA
—
mV
V
V
—
µA
V
V
mV
nA
mA
V
CE
(sat)
Saturation Voltage (I
SW
= 1.0 A, R
Pin 8
= 82
Ω
to V
CC
.
Forced
β
= 20)
=
DC Current Gain (I
SW
= 1.0 A, V
CE
5.0 V, T
A
= 25°C) h
FE
Collector Off-State Current (V
CE
= 40V)
I
C
(off)
COMPARATOR
Threshold Voltage (T
A
= 25°C)
Vth
(T
A
= T
LOW
to T
HIGH
)
Threshold Voltage (T
A
= 25°C) **
Threshold Voltage Line Regulation (V
CC
= 3.0 V to 40 V)
Input Bias Current (Vin=0V)
Vth
V
REG line
I
IB
TOTAL DEVICE
Supply Current (V
CC
= 5 0 V to 40 V, C
T
= 1 0 nF, V
pin7
=
I
CC
V
CC
. V
Pin5
> Vth, Pin 2 = Gnd, Remaining pins open)
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
3.
If the output switch is driven into hard saturation (non Darlington configuration) at low switch currents (< 300 mA) and
high driver
currents (>30 mA), it may take up to 2.0
µs
to come out of saturation This condition will shorten the off' time
at frequencies > 30 kHz, and is magnified at high temperatures This condition does not occur with a Darlington configuration,
since the output switch cannot
saturate If a non Darlington configuration is used, the following output drive condition is
recommended
Forced
β
of output switch = I
C
, output/(Ic, driver -7.0 mA*) > 10
*The 100
Ω.
resistor in the emitter of the driver device requires about 7.0 mA before the output switch conducts
**Possible
version for shipment
Embedded System
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