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 Symbol Value Unit
Power Supply Voltage V
CC
40 Vdc
Comparator Input Voltage Range V
IR
-0.3 to
+40
Vdc
Switch Collector Voltage V
C(switch)
40 Vdc
Switch Emitter Voltage (Vpin 1 = 40 V) V
E(switch)
40 Vdc
Switch Collector to Emitter Voltage V
CE(switch)
40 Vdc
Driver Collector Voltage I
C(driver)
40 Vdc
Driver Collector Current (Note 1) I
C(driver)
100 mA
Switch Current I
SW
1.5 A
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

P
D

R
θJA

P
D
R
θJA

P
D

R
θJA


1.25
100
1.25
100
625
160

W
°C/W
W
°C/W
mW
°C/W
Operating Junction Temperature TJ +150 °C
Operating Ambient Temperature Range T
A
0 to +70 °C
Storage Temperature Range Tstg -65to+150 °C