ST MC34063A, MC34063E Service Manual

DC/DC CONVERTER CONTROL CIRCUITS

■ OUTPUT SWITCH CURRENT IN EXCESS

OF 1.5A

■ 2% REFERENCE ACCURACY

■ LOW QUIESCENT CURRENT: 2.5mA (TYP.)

■ OPERATINGFROM3VTO40V

■ FREQUENCY OPERATION TO 100KHz

■ ACTIVE CURRENT LIMITING

MC34063A

MC34063E

DESCRIPTION

The MC34063A/E series is a monolithic control
circuit delivering the main functions for DC/DC
voltage converting.
The device contains an internal temperature
compensated reference, comparator, duty cycle
controlled oscillator with an active current limit
circuit, driver and high current output switch.
Output v oltage is adjustable through two external
resistors with a 2% reference accuracy.
Employing a minimum number of ex ternal
components the MC34063A /E de vice s series is
designed for Step-Down, Step-Up and
Voltage-Inverting applications.

BLOCK DIAGRAM

DIP-8 SO-8

1/16March 2004

MC34063A/E

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

SWC

V

SWE

V
V

I

DC

I

SW

P

TOT

T

T

STG

T

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.

Power Supply Voltage

CC

Comparator Input Voltage Range

IR

Switch Collector Voltage
Switch Emitter Voltage (V
Switch Collector to Emitter Voltage

CE

Driver Collector Voltage

DC

SWC

=40V)

Driver Collector Current
Switch Current
Power Dissipation at TA= 25°C for DIP-8 1.25

for SO-8 0.625

Operating Junction Temperature

J

Storage Temperature Range
Operating Ambient Temperature Range for AC and EC SERIES 0 to 70

OP

for EB SERIES -40 to 125

50 V

-0.3 to 40 V
40 V
40 V
40 V
40 V

100 mA

1.5 A
W

150 °C

-40 to 150 °C

°Cfor AB SERIES -40 to 85

THERMAL DATA

Symbol Parameter DIP-8 SO-8 Unit

R

thj-amb

R

thj-case

(*) This value depends from thermal design of PCB on which the device is mounted.

Thermal Resistance Junction-ambient (*)
Thermal Resistance Junction-case

100 160 °C/W

42 20 °C/W

CONNECTION DIAGRAM (top view)

PIN DESCRIPTION

Pin N° Symbol Name and Function

1 SWC Switch Collector
2 SWE Switch Emitter
3 TC Timing Capacitor
4 GND Ground
5 CII Comparator Inverting Input

2/16

6V
7I

CC

PK

8 DRC Voltage Driver Collector

Voltage Supply
IPKSense

ORDERING CODES

TYPE DIP-8 SO-8 SO-8 (TAPE & REEL)

MC34063AB MC34063ABN MC34063ABD MC34063ABD-TR
MC34063AC MC34063ACN MC34063ACD MC34063ACD-TR
MC34063EB MC34063EBN MC34063EBD MC34063EBD-TR
MC34063EC MC34063ECN MC34063ECD MC34063ECD-TR

(*) The "A" version is not recommended for new designs.

MC34063A/E

ELECTRICAL CHARACTERISTICS (Refer to the t es t circuits, VCC=5V,TA=T

LOW

to T

HIGH

, unless

otherwise specified, see note 2)

OSCILLATOR

Symbol Parameter Test Conditions Min. Typ. Max. Unit

f

OSC

I

CHG

I

DISCHG

I

DISCHG

I

CHG

V

IPK(sense)

Frequency V

=0V CT=1nF TA=25°C243342KHz

PIN5

Charge Current VCC= 5 to 40V TA=25°C 243342µA
Discharge Current VCC= 5 to 40V TA= 25°C 140 200 260 µA

/

Discharge to Charge Current
Ratio

Current Limit Sense Voltage I

PIN 7 = V

CHG=IDISCHG

CC

TA= 25°C 5.2 6.2 7.5 µA

TA= 25°C 250 300 350 mV

OUTPUT S WITCH

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

CE(sat)

V

CE(sat)

Saturation Voltage, Darlington

ISW= 1 A PIN 7, 8 connected 1 1.3 V

Connection
Saturation Voltage ISW=1A R

=82Ω to V

PIN8

CC

0.45 0.7 V

Forced β ~20

h

I

C(off)

DC Current Gain ISW=1A VCE=5V TA= 25°C 50 120

FE

Collector Off-State Current VCE=40V 0.01 100 µA

COMPARATOR

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

Reg

I

Threshold Voltage TA= 25°C 1.225 1.25 1.275 V

TH

T

A=TLOW

Threshold Voltage Line

line

Regulation
Input Bias Current VIN= 0 V -5 -400 nA

IB

VCC=3to40V 1 5 mV

to T

HIGH

1.21 1.29

3/16

MC34063A/E

TOTAL DEVICE

Symbol Parameter Test Conditions Min. Typ. Max. Unit

I

V

START-UP

NOTES:

1) Maximum package power dissipation limit must beobserved.

2) T

LOW

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
* Current lessdue to a built in 1KΩ anti leakage resistor.

4) Start-up Voltage is the minimum PowerSupply Voltag e at which the internal oscillator b egins to work.

TYPICAL P E RFORMAN CE CHARACTE RISTICS

Supply Current VCC=5to40V

CC

Start-Up Voltage (Note 4) TA=25°C

=0°C,T

β of output current switch = I

= 70°C (AC and EC series); T

HIGH

COUTPUT

/(I

CDRIVER

C

=1nF

T

PIN 7 = V
V

PIN5>VTH

CC

PIN 2 = GND
Remaining pins open

C

=1µF,PIN5=0

T

=-40°C,T

LOW

-1mA*)≥ 10

= 85°C (AB series); T

HIGH

for MC34063A 2.5 4 mA

1.5 4for MC34063E

for MC34063A 2.1 V
for MC34063E 1.5

LOW

= -40°C, T

= 125°C (EB series).

HIGH

Figure1 : Emitter Follower Configuration Output
Saturation Voltage vs Emitter Current

Figure2 : Output SwitchON-OFF Time vs
Oscillator Timing Capacitor

Figure3 : Common Emitter Configuration Output
Switch Saturation Voltage vs Collector Current

Figure4 : Darlington Configuration Collector
Emitter Saturation Voltage (V

CEsat)

vs Temperat.

4/16

MC34063A/E

Figure5 : Power Collector E mi tter Saturation

Voltage (V

Figure6 : Current Limit Sense Voltage (V

vs Temperature

CEsat)

IPK

Temperature

)vs

Figure8 : Bias Current vs Temperat ure

Figure9 : Supply Current vs Temperature

Figure7 : Reference V oltage v s Temp eratu re

Figure10 : Supply Current vs Input Voltage

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