ST MC34063AB, MC34063AC, MC34063EB, MC34063EC User Manual
Features
■ Output switch current in excess of 1.5 A
■ 2 % reference accuracy
■ Low quiescent current: 2.5 mA (typ.)
■ Operating from 3 V to 40 V
■ Frequency operation to 100 kHz
■ Active current limiting
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 voltage is adjustable through two external
resistors with a 2 % reference accuracy.
MC34063AB - MC34063AC
MC34063EB - MC34063EC
DC/DC converter control circuits
DIP-8
designed for step-down, step-up and voltageinverting applications.
SO-8
Employing a minimum number of external
components the MC34063A/E devices series is
Table 1. Device summary
Order codes
DIP-8 SO-8
MC34063ABN
MC34063ACN
MC34063EBN MC34063EBD-TR
MC34063ECN MC34063ECD-TR
1. The "A" version is not recommended for new designs.
November 2007 Rev 10 1/23
(1)
(1)
MC34063ABD-TR
MC34063ACD-TR
www.st.com
23
Contents MC34063AB - MC34063AC - MC34063EB - MC34063EC
Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6 Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
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MC34063AB - MC34063AC - MC34063EB - MC34063EC Diagram
1 Diagram
Figure 1. Block diagram
3/23
Pin configuration MC34063AB - MC34063AC - MC34063EB - MC34063EC
2 Pin configuration
Figure 2. Pin connections
Table 2. 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
6VCCVoltage supply
7I
8 DRC Voltage driver collector
PK
IPK sense
4/23
MC34063AB - MC34063AC - MC34063EB - MC34063EC Maximum ratings
3 Maximum ratings
Table 3. Absolute maximum ratings
Symbol Parameter Value Unit
V
V
V
V
SWC
SWE
V
V
I
DC
I
SW
CC
IR
CE
DC
Power supply voltage 50 V
Comparator input voltage range -0.3 to 40 V
Switch collector voltage 40 V
Switch emitter voltage (V
= 40V) 40 V
SWC
Switch collector to emitter voltage 40 V
Driver collector voltage 40 V
Driver collector current 100 mA
Switch current 1.5 A
for DIP-8 1.25
P
T
TOT
T
STG
Power dissipation at TA = 25°C
for SO-8 0.625
Operating junction temperature 150 °C
J
Storage temperature range -40 to 150 °C
W
for AC and EC series 0 to 70
T
OP
Operating ambient temperature range
°Cfor AB series -40 to 85
for EB series -40 to 125
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 4. Thermal data
Symbol Parameter DIP-8 SO-8 Unit
R
thJA
R
thJC
1. This value depends from thermal design of PCB on which the device is mounted.
Thermal resistance junction-ambient
Thermal resistance junction-case 42 20 °C/W
(1)
100 160 °C/W
5/23
Electrical characteristics MC34063AB - MC34063AC - MC34063EB - MC34063EC
4 Electrical characteristics
(Refer to the test circuits, V
= 5 V, TA = T
CC
LOW
to T
, unless otherwise specified, see
HIGH
Note 2)
Table 5. Oscillator
Symbol Parameter Test conditions Min. Typ. Max. Unit
f
OSC
I
CHG
I
DISCHG
I
DISCHG/ICHG
V
IPK(sense)
Frequency V
Charge current V
Discharge current V
Discharge to charge
current ratio
Current limit sense voltage I
= 0V, CT = 1 nF, TA = 25°C 24 33 42 kHz
PIN5
= 5 to 40V, TA = 25°C 24 33 42 µA
CC
= 5 to 40V, TA = 25°C 140 200 260 µA
CC
PIN 7 = V
= I
CHG
, TA = 25°C 5.2 6.2 7.5 µA
CC
DISCHG, TA
= 25°C 250 300 350 mV
Table 6. Output switch
Symbol Parameter Test conditions Min. Typ. Max. Unit
V
CE(sat)
V
CE(sat)
h
I
C(off)
Saturation voltage, darlington
connection
Saturation voltage
DC current gain ISW = 1 A,V
FE
Collector off-state current V
= 1 A, PIN 7, 8 connected 1 1.3 V
I
SW
= 1 A, R
I
SW
Forced β ~ 20
= 40 V 0.01 100 µA
CE
= 82 Ω to V
PIN8
= 5 V, TA = 25°C 50 120
CE
CC
0.45 0.7 V
Table 7. Comparator
Symbol Parameter Test conditions Min. Typ. Max. Unit
T
= 25°C 1.225 1.25 1.275
V
Reg
I
Threshold voltage
TH
Threshold voltage line
line
regulation
Input bias current V
IB
6/23
A
= T
T
A
V
CC
IN
to T
LOW
HIGH
= 3 to 40 V 1 5 mV
= 0 V -5 -400 nA
1.21 1.29
V
MC34063AB - MC34063AC - MC34063EB - MC34063EC Electrical characteristics
Table 8. Total device
Symbol Parameter Test conditions Min. Typ. Max. Unit
V
= 5 to 40 V
CC
for MC34063A 2.5 4
CT = 1 nF
PIN 7 = V
I
CC
Supply current
V
PIN5
PIN 2 = GND
>V
TH
CC
mA
1.5 4for MC34063E
Remaining pins
open
V
START-UP
Start-up voltage (Note 4)
= 25°C
T
A
= 1 µF, PIN 5 = 0
C
T
for MC34063A 2.1
V
for MC34063E 1.5
Note: 1 Maximum package power dissipation limit must be observed.
2T
T
LOW
LOW
= 0 °C, T
HIGH
= -40 °C, T
= 70 °C (AC and EC series); T
= 125 °C (EB series).
HIGH
= -40 °C, T
LOW
= 85 °C (AB series);
HIGH
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
β of output current switch = I
COUTPUT
/(I
CDRIVER
- 1 mA
(a)
) ≥ 10
4 Start-up voltage is the minimum power supply voltage at which the internal oscillator begins
to work.
a. Current less due to a built in 1 kΩ anti leakage resistor.
7/23
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