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

Features

z

Operation from 3.0V to 30V Input

z

Low Standby Current

z

Current Limiting

z

Internal Switch Current to 1.5A

z

Output Voltage Adjustable

z

Frequency Operation to 100KHz

z

Precision 2% Reference

Applications

Saver for Cellular Phones

z

DC-DC Converter Module

z

Pin Configurations

Part Number Pin Configurations

SC

SE

TC

GND

TOP VIEW

1

2

3

4

RT34063ACN

(Plastic DIP-8)

RT34063ACS

(Plastic SOP-8)

8

7

6

5

DRIVER

IPK

VCC

COMP

Marking Information

Part Number Marking

RT34063ACN RT34063ACN

RT34063ACS RT34063ACS

DS34063A-06 May 2001 www.richtek-ic.com.tw

1

RT34063A

g p

Absolute Maximum Ratings

Power Supply Voltage 30V

z

Feedback Input Voltage Range -0.3 ~ +30V

z

Switch Collector Voltage 30V

z

Switch Emitter Voltage 30V

z

Switch Collector to Emitter Voltage 30V

z

Driver Collector Voltage 30V

z

Driver Collector Current (see Note 1) 100mA

z

Switch Current 1.5A

z

Power Dissipation, PD @ T

z

DIP-8 1.25W

SOP-8 0.625W

• Package Thermal Resistance DIP-8, θ SOP-8, θ Operating Junction Temperature Range -40 ~ +125°C

z

Storage Temperature Range -65 ~ +150°C

z

JA

= 25°C

A

100°C/W 160°C/W

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

Charge Current

Discharge Current

I

CHG

I

DISCHG

Discharge to Charge Current Ratio Pin 7 to VCC

Current Limit Sense Voltage

V

LIMITICHG

Output Switch

Saturation Voltage, Darlington Connection

DC Current Gain

Collector Off-state Current

Comparator

= 0V, CT = 1.0nF

V

PIN5

5.0V ≤ VCC ≤ 30V

= I

DISCHG

= 1.0A, Pins1, 8 connected

I

SW

= 1.0A, R

I

SW

PIN8

VCC, Forced β ≅ 20

I

= 1.0A, VCE = 5.0V

SW

= 30V

V

CE

= 82Ω to

26 38 48 kHz

25 36 43

160 250 290

µA µA

5.5 6.9 7.9 --

280 330 380 mV

-- 1.0 1.3 V

-- 0.45 0.7 V

50 75 -- --

-- 0.01 100

µA

Threshold Voltage

Threshold Voltage Line Regulation

Input Bias Current

I

BIAS

3.0V ≤ VCC ≤ 30V

VIN = 0V

1.225 1.25 1.275 V

-- 1.4 5.0 mV

-- -20 -400 nA

Total Device

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

Supply Current

www.richtek-ic.com.tw DS34063A-06 May 2001

I

CC

Pin7 = VCC, V

PIN5

= GND, Remainin

> VTH, Pin2

ins open

,

-- 3.0 4.5 mA

2

RT34063A

Function Block Diagram

Pin Description

Pin Name Pin Function

DRIVER

IPK

VCC

COMP

8

100

Reference Regulator

Q2

1.25V

SQ

R

7

I

PK

Oscillator

6

Comparator

5

C

T

+

_

Q1

1

SC

2

SE

3

CT

4

GND

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-V

DRIVER Driver Collector

= 330mV

IPK

DS34063A-06 May 2001 www.richtek-ic.com.tw

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RT34063A

Typical Application Circuit

170µH

R

0.22

V

IN

12V

SC

180

+

100µF

8

7

6

5

2.2k

R1

L

SRQ

I

C

R2

47k

+ _

PK

OSC

Comp.

T

1.25V

Ref

Fig.1 Step-up Converter

1

2

C

T

3

1500 pF

4

330µF

1N5819

+

C

O

V

OU T

28V/17 5mA

Optional Filter

1.0µH

+

100µF

V

OUT

www.richtek-ic.com.tw DS34063A-06 May 2001

4

RT34063A

V

8

1

OU T

+

7

V

IN

6

5

2

3

4

Fig.2a External NPN Switch

8

7

V

IN

6

R

1

2

3

V

OU T

+

R→0 for Constant V

IN

5

4

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

Fig.2 External Current Boost Connections for I

Peak Greater than 1.5A

C

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 2.0µs 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 non-

Darlington configuration is used, the following output drive condition is recommended.

DS34063A-06 May 2001 www.richtek-ic.com.tw

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