RICHTEK RT34063ACN, RT34063ACS Datasheet

RT34063A

DC-to-DC Converter Control Circuits

General Description

The RT34063A Series 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 specially designed to be incorporated in Step-down and Step-up and Voltage-inverting applications with a minimum number of external components.

Ordering Information

RT34063A

 

 

 

Package type

 

 

 

 

 

 

N : DIP-8

 

 

 

S : SOP-8

 

 

 

Operating temperature range

 

 

 

 

 

 

C: Commercial standard

Marking Information

Part Number

 

Marking

 

 

 

 

 

 

 

RT34063ACN

 

RT34063ACN

 

 

 

 

 

 

 

RT34063ACS

 

RT34063ACS

 

 

 

 

 

 

 

Features

zOperation from 3.0V to 30V Input

zLow Standby Current

zCurrent Limiting

zInternal Switch Current to 1.5A

zOutput Voltage Adjustable

zFrequency Operation to 100KHz

zPrecision 2% Reference

Applications

zSaver for Cellular Phones

zDC-DC Converter Module

Pin Configurations

Part Number

Pin Configurations

 

 

 

 

 

 

 

 

 

RT34063ACN

 

 

TOP VIEW

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Plastic DIP-8)

SC

 

 

 

 

 

DRIVER

 

 

 

 

 

 

1

 

 

 

 

8

 

SE

 

 

 

 

 

 

IPK

 

2

 

 

 

 

7

RT34063ACS

TC

 

 

 

 

 

 

VCC

3

 

 

 

 

6

 

 

 

 

 

 

(Plastic SOP-8)

GND

 

 

 

 

 

 

COMP

4

 

 

 

 

5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DS34063A-06 May 2001

www.richtek-ic.com.tw

 

1

RT34063A

Absolute Maximum Ratings

z Power Supply Voltage

30V

zFeedback Input Voltage Range -0.3 ~ +30V

zSwitch Collector Voltage 30V

zSwitch Emitter Voltage30V

zSwitch Collector to Emitter Voltage 30V

zDriver Collector Voltage30V

z Driver Collector Current (see Note 1)

100mA

zSwitch Current1.5A

zPower Dissipation, PD @ TA = 25°C

DIP-81.25W SOP-80.625W

Package Thermal Resistance

DIP-8, θJA 100°C/W

SOP-8, θJA 160°C/W

zOperating Junction Temperature Range-40 ~ +125°C

zStorage Temperature Range-65 ~ +150°C

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

Electrical Characteristics

(VCC = 5V, TA = 25°C, unless otherwise specified)

Parameter

Symbol

Test Conditions

Min

Typ

Max

Units

 

 

 

 

 

 

 

 

 

Oscillator

 

 

 

 

 

 

 

Frequency

 

VPIN5 = 0V, CT = 1.0nF

26

38

48

kHz

 

Charge Current

ICHG

5.0V ≤ VCC ≤ 30V

25

36

43

µA

 

Discharge Current

IDISCHG

5.0V ≤ VCC ≤ 30V

160

250

290

µA

 

Discharge to Charge Current Ratio

 

Pin 7 to VCC

5.5

6.9

7.9

--

 

 

 

 

 

 

 

 

 

Current Limit Sense Voltage

VLIMIT

ICHG = IDISCHG

280

330

380

mV

 

Output Switch

 

 

 

 

 

 

 

Saturation Voltage, Darlington Connection

 

ISW = 1.0A, Pins1, 8 connected

--

1.0

1.3

V

 

Saturation Voltage, Darlington Connection

 

ISW = 1.0A, RPIN8 = 82Ω to

--

0.45

0.7

V

 

 

VCC, Forced β 20

 

 

 

 

 

 

 

 

DC Current Gain

 

ISW = 1.0A, VCE = 5.0V

50

75

--

--

 

Collector Off-state Current

 

VCE = 30V

--

0.01

100

µA

 

Comparator

 

 

 

 

 

 

 

Threshold Voltage

 

 

1.225

1.25

1.275

V

 

 

 

 

 

 

 

 

 

Threshold Voltage Line Regulation

 

3.0V ≤ VCC ≤ 30V

--

1.4

5.0

mV

 

Input Bias Current

IBIAS

VIN = 0V

--

-20

-400

nA

 

Total Device

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Supply Current

 

VCC = 5.0V to 30V, CT = 1.0nF,

--

3.0

4.5

mA

 

ICC

Pin7 = VCC, VPIN5 > VTH, Pin2

 

 

 

= GND, Remaining pins open

 

 

 

 

 

 

 

 

 

 

 

 

 

www.richtek-ic.com.tw

 

 

DS34063A-06 May 2001

2

RT34063A

Function Block Diagram

DRIVER 8

 

1

SC

 

 

S Q

Q2

 

 

 

R

Q1

 

 

 

 

 

 

7

 

100

 

IPK

 

2

SE

 

 

 

IPK

CT

 

 

 

Oscillator

 

 

VCC 6

Comparator

+ _

COMP 5

3 CT

1.25V Reference Regulator

4 GND

Pin Description

Pin Name

Pin Function

 

 

SC

1.5A Switch Collector

 

 

SE

Darlington Switch Emitter

 

 

CT

Oscillator Timing Capacitor

 

 

GND

Power GND

 

 

COMP

Feedback Comparator Inverting Input

 

 

VCC

Power Supply Input

 

 

IPK

Highside Current Sense Input VCC-VIPK = 330mV

DRIVER

Driver Collector

 

 

DS34063A-06 May 2001

www.richtek-ic.com.tw

 

3

RT34063A

Typical Application Circuit

 

 

 

170 H

 

 

 

 

 

8

 

L

 

1

 

 

 

 

 

 

 

 

 

180

 

S Q

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R

 

 

 

 

 

7

 

 

 

2

1N5819

 

 

 

 

 

 

 

 

RSC

 

IPK

CT

 

 

 

 

0.22

 

 

CT

 

 

6

OSC

 

 

 

VIN

 

 

 

3

 

 

12V

+100 F

+

Comp.

1.25V

1500pF

 

 

 

_

 

Ref

 

 

 

 

5

 

 

 

4

Optional Filter

 

 

 

 

 

 

 

 

R2

 

 

 

 

1.0 H

 

 

 

 

 

VOUT

VOUT

 

 

 

 

 

 

 

R1

47k

 

 

330 F

+CO 28V/175mA

+

 

 

 

100 F

 

2.2k

 

 

 

 

 

 

Fig.1 Step-up Converter

www.richtek-ic.com.tw

DS34063A-06 May 2001

4

RICHTEK RT34063ACN, RT34063ACS Datasheet

RT34063A

8

VOUT

 

1

 

+

7

2

 

6

 

VIN

3

5

4

Fig.2a External NPN Switch

8

 

R

 

1

VOUT

 

 

+

7

2

 

 

R→0 for

 

 

6

 

Constant VIN

VIN

3

 

5

4

 

Fig.2b External NPN Saturated Switch (See Note)

Fig.2 External Current Boost Connections for IC Peak Greater than 1.5A

Note: If the output switch is driven into hard saturation (non-Darlington configuration) at low switch currents (300mA) and high driver currents (30mA), it may take up to 2.0 s to come out of saturation. This condition will shorten the off time at frequencies 30KHz, and is magnified at high temperature. This condition does not occur with a Darlington configuration, since the output switch cannot saturate. If a nonDarlington configuration is used, the following output drive condition is recommended.

DS34063A-06 May 2001

www.richtek-ic.com.tw

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