ST MC34063AB, MC34063AC, MC34063EB, MC34063EC User Manual

MC34063AB - MC34063AC MC34063EB - MC34063EC

DC/DC converter control circuits

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.

Employing a minimum number of external components the MC34063A/E devices series is

DIP-8

SO-8

designed for step-down, step-up and voltageinverting applications.

Table 1.	Device summary
		Order codes
	DIP-8		SO-8
	MC34063ABN (1)		MC34063ABD-TR
	MC34063ACN (1)		MC34063ACD-TR
	MC34063EBN		MC34063EBD-TR
	MC34063ECN		MC34063ECD-TR

1. The "A" version is not recommended for new designs.

November 2007

Rev 10

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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

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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
6		VCC	Voltage supply
7		IPK	IPK sense
8		DRC	Voltage driver collector

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MC34063AB - MC34063AC - MC34063EB - MC34063EC							Maximum ratings
3	Maximum ratings
Table 3.	Absolute maximum ratings
Symbol		Parameter					Value		Unit
VCC	Power supply voltage						50		V
VIR	Comparator input voltage range						-0.3 to 40		V
VSWC	Switch collector voltage						40		V
VSWE	Switch emitter voltage (VSWC = 40V)						40		V
VCE	Switch collector to emitter voltage						40		V
VDC	Driver collector voltage						40		V
IDC	Driver collector current						100		mA
ISW	Switch current						1.5		A
PTOT	Power dissipation at TA = 25°C		for DIP-8				1.25		W
			for SO-8				0.625
TJ	Operating junction temperature						150		°C
TSTG	Storage temperature range						-40 to 150		°C
			for AC and EC series				0 to 70
TOP	Operating ambient temperature range		for AB series				-40 to 85		°C
			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		Thermal resistance junction-ambient (1)			100		160	°C/W
thJA
RthJC		Thermal resistance junction-case			42		20	°C/W

1. This value depends from thermal design of PCB on which the device is mounted.

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Electrical characteristics	MC34063AB - MC34063AC - MC34063EB - MC34063EC

4 Electrical characteristics

(Refer to the test circuits, VCC = 5 V, TA = TLOW to THIGH, unless otherwise specified, see

Note 2)

Table 5.	Oscillator
Symbol		Parameter	Test conditions	Min.	Typ.	Max.	Unit
fOSC		Frequency	VPIN5 = 0V, CT = 1 nF, TA = 25°C	24	33	42	kHz
ICHG		Charge current	VCC = 5 to 40V, TA = 25°C	24	33	42	µA
IDISCHG		Discharge current	VCC = 5 to 40V, TA = 25°C	140	200	260	µA
IDISCHG/ICHG		Discharge to charge	PIN 7 = VCC, TA = 25°C	5.2	6.2	7.5	µA
		current ratio
VIPK(sense)		Current limit sense voltage	ICHG = IDISCHG, TA = 25°C	250	300	350	mV

Table 6.	Output switch
Symbol	Parameter		Test conditions	Min.	Typ.	Max.	Unit
VCE(sat)	Saturation voltage, darlington	ISW = 1	A, PIN 7, 8 connected		1	1.3	V
	connection
VCE(sat)	Saturation voltage	ISW = 1	A, RPIN8 = 82 Ω to VCC		0.45	0.7	V
		Forced β ~ 20
hFE	DC current gain	ISW = 1	A,VCE = 5 V, TA = 25°C	50	120
IC(off)	Collector off-state current	VCE = 40 V			0.01	100	µA

Table 7.	Comparator
Symbol	Parameter	Test conditions	Min.	Typ.	Max.	Unit
VTH	Threshold voltage	TA = 25°C	1.225	1.25	1.275	V
		TA = TLOW to THIGH	1.21		1.29
Regline	Threshold voltage line	VCC = 3 to 40 V		1	5	mV
	regulation
IIB	Input bias current	VIN = 0 V		-5	-400	nA

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MC34063AB - MC34063AC - MC34063EB - MC34063EC				Electrical characteristics
Table 8.	Total device
Symbol	Parameter	Test conditions		Min.	Typ.	Max.	Unit
		VCC = 5 to 40 V	for MC34063A		2.5	4
		CT = 1 nF
		PIN 7 = VCC
ICC	Supply current	VPIN5 >VTH	for MC34063E		1.5	4	mA
		PIN 2 = GND
		Remaining pins
		open
VSTART-UP	Start-up voltage (Note 4)	TA = 25°C	for MC34063A		2.1		V
		CT = 1 µF, PIN 5 = 0	for MC34063E		1.5

Note: 1 Maximum package power dissipation limit must be observed.

2TLOW = 0 °C, THIGH = 70 °C (AC and EC series); TLOW = -40 °C, THIGH = 85 °C (AB series); TLOW = -40 °C, THIGH = 125 °C (EB series).

3If 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 = ICOUTPUT/(ICDRIVER - 1 mA(a)) ≥ 10

4Start-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.

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