R1230D251D datasheet, PDF - EEWORLD Datasheet

2001. Sep. 8

PWM/VFM step-down DC/DC converter with Synchronous

Rectifier

R1230D Series

s

OUTLINE

The R1230D Series are PWM step-down DC/DC Converters with synchronous rectifier, low supply current by CMOS

process.

Each of these ICs consists of an oscillator, a PWM control circuit, a reference voltage unit, an error amplifier, a

soft-start circuit, protection circuits, a protection against miss operation under low voltage (UVLO), PWM/VFM

alternative circuit, a chip enable circuit, and a driver transistor. A low ripple, high efficiency step-down DC/DC

converter can be easily composed of this IC with only a few kinds of external components, or an inductor and

capacitors. (As for R1230D001C/D types, divider resistors are also necessary.) In terms of Output Voltage, it is fixed

internally in the R1230DXX1A/B types. While in the R1230D001C/D types, Output Voltage is adjustable with external

divider resistors.

PWM/VFM alternative circuit is active with Mode Pin of the R1230D Series. Thus, when the load current is small,

the operation can be switching into the VFM operation from PWM operation by the logic of MODE pin and the

efficiency at small load current can be improved. As protection circuits, Current Limit circuit which limits peak current

of Lx at each clock cycle, and Latch type protection circuit which works if the term of Over-current condition keeps on

a certain time in PWM mode exist. Latch-type protection circuit works to latch an internal driver with keeping it disable.

To release the condition of protection, after disable this IC with a chip enable circuit, enable it again, or restart this IC

with power-on or make the supply voltage at UVLO detector threshold level or lower than UVLO.

s

FEATURES

q

Built-in Driver ON Resistance

• • • • • • • • • • • • •

P-channel 0.35Ω, N-channel 0.45Ω (at V

IN

=3V)

q

Built-in Soft-start Function (TYP. 1.5ms), and Latch-type Protection Function (Delay Time; TYP. 1.5ms)

q

Two choices of Oscillator Frequency

• • • • • •

500kHz, 800kHz

q

PWM/VFM alternative with MODE pin

• • • • • •

PWM operation; MODE pin at “L”,

VFM operation; MODE pin at “H”

q

High Efficiency

• • • • • • • • • • • • • • • • • •

TYP. 90%

q

Output Voltage

• • • • • • • • •Stepwise

Setting with a step of 0.1V in the range of 1.2V

∼

4.0V(XX1A/B Type)

or adjustable in the range of 0.8V to V

IN

(001C/D Type)

q

High Accuracy Output Voltage

• • • • • • • • • •±2.0%(XX1A/B

Type)

q

Package

• • • • •

SON8 (Max height 0.9mm, thin type)

s

APPLICATIONS

q

Power source for portable equipment.

Rev. 1.12

-1-

s

BLOCK DIAGRAM

qR1230DXX1A/B

V

DD

V

IN

MODE

“L”= PWM

“H”= VFM

OSC

V

OUT

Lx

PWM/VFM

CONTROL

OUTPUT

CONTROL

Phase Compensation

Vref

CE

UVLO

“H” Active

Soft Start

Chip Enable

Current Protection

CE

PGND

qR1230D001C/D

AGND

V

DD

MODE

“L”= PWM “H”= VFM

V

IN

OSC

V

FB

Lx

PWM/VFM

CONTROL

OUTPUT

CONTROL

Phase Compensation

“H” Active

Vref

Chip Enable

CE

Current Protection

UVLO

Soft Start

PGND

AGND

Rev. 1.12

-2-

s

SELECTION GUIDE

In the R1230D Series, the output voltage, the oscillator frequency, and the taping type for the ICs can be

selected at the user’s request.

The selection can be made by designating the part number as shown below;

R1230DXXXX-XX

↑ ↑↑ ↑

a

b c

d

Code

a

Contents

Setting Output Voltage(V

OUT

):

Stepwise setting with a step of 0.1V in the range of 1.2V to 4.0V is possible for A/B version.

“00” is for Output Voltage Adjustable C/D version

1 : fixed

Designation of Optional Function

A : 500kHz, Fixed Output Voltage

B : 800 kHz, Fixed Output Voltage

C : 500kHz, Adjustable Output Voltage

D : 800kHz, Adjustable Output Voltage

Designation of Taping Type; Ex. :TR,TL(refer to Taping Specification)

”TR” is prescribed as a standard.

b

c

d

s

PIN CONFIGURATION

q

SON-8

2.9±0.2

0.48TYP

8

5

(0.2)

2.8

±

0.2

3.0

±

0.2

*

1

0.13

±

0.05

4

0.9 MAX.

*Attention : Tab suspension leads in the

parts have GND level. (They are connected to

the reverse side of this IC.) Do not connect to

other wires or land patterns.

0.65

0.3±0.1

0.1

M

Unit : mm

Rev. 1.12

-3-

(0.2)

s

PIN DESCRIPTION

Pin No.

1

2

3

4

5

6

7

8

Symbol

V

IN

PGND

V

DD

CE

V

OUT

/V

FB

MODE

AGND

Lx

Description

Voltage Supply Pin

Ground Pin

Voltage Supply Pin

Chip Enable Pin (active with “H”)

Output/Feedback Pin

Mode changer Pin (PWM mode at “L”, VFM mode at “H”.)

Ground Pin

Lx Pin

s

ABSOLUTE MAXIMUM RATINGS

Symbol

V

IN

V

DD

V

LX

V

CE

V

MODE

V

FB

I

LX

P

D

Topt

Tstg

Item

V

IN

Supply Voltage

V

DD

Pin Voltage

Lx Pin Voltage

CE Pin Input Voltage

MODE Pin Input Voltage

V

FB

Pin Input Voltage

L

X

Pin Output Current

Power Dissipation

Operating Temperature Range

Storage Temperature Range

(AGND=PGND=0V)

Rating

Unit

6.5

V

6.5

V

-0.3∼V

IN

+0.3

V

-0.3∼V

IN

+0.3

V

-0.3∼V

IN

+0.3

V

-0.3∼V

IN

+0.3

-0.8

A

250

mW

°C

-40∼+85

°C

-55∼+125

Rev. 1.12

-4-

s

ELECTRICAL CHARACTERISTICS

qR1230D**1A/B

Symbol

Item

V

IN

Operating Input Voltage

V

OUT

Step-down Output Voltage

∆V

OUT

/

∆T

fosc

I

DD

I

DD

I

stb

R

ONP

Step-down Output Voltage

Temperature Coefficient

Oscillator Frequency(xx1A)

Oscillator Frequency(xx1B)

Supply Current(xx1A)

Supply Current(xx1B)

Conditions

V

IN

=V

CE

=V

SET

+1.5V, V

MODE

=0V,

I

OUT

=10mA

-40°C

≤

Topt

≤

85°C

V

IN

=V

CE

=V

SET

+1.5V

V

IN

=V

CE

=V

SET

+1.5V

V

IN

=V

CE

=V

SET

+1.5V,

V

OUT

=V

MODE

=0V

V

IN

=V

CE

=V

SET

+1.5V,

V

OUT

=V

MODE

=0V

V

IN

=5.5V, V

CE

=V

OUT

=0V

V

IN

=5.0V

V

IN

=5.0V

V

IN

=5.5V, V

CE

=0V, V

LX

=0V/5.5V

V

IN

=5.5V, V

CE

=0V, V

LX

=0V/5.5V

V

IN

=5.5V, V

MODE

=0V, V

CE

=5.5V/0V

V

IN

=5.5V, V

OUT

=0V

V

IN

=2.4V, V

OUT

=0V

V

MODE

=0V

V

MODE

= V

OUT

=0V, V

IN

=V

CE

=3.0V

MIN.

2.4

TYP.×

0.980

(Topt=25°C)

TYP.

MAX. Unit

5.5

V

SET

TYP.× V

1.020

ppm

±150

/°C

500

575 kHz

800

920 kHz

230

300

µA

250

0

0.35

0.45

0.0

350

5

0.60

0.70

0.1

0.3

100

V

IN

-0.15 V

IN

-0.35 V

IN

-

0.55

0.5

1.5

2.5

0.5

1.5

2.5

1.8

2.1

2.2

1.9

2.2

2.3

-0.1

0.1

1.5

0.3

55

65

85

µA

Ω

µA

V

%

V

ms

V

µA

V

%

425

680

Standby Current

ON Resistance of

Pch Transistor

R

ONN

ON Resistance of

Nch Transistor

I

LX

leak Lx Leakage Current

I

VOUT

V

OUT

Leakage Current

I

CE

CE Input Current

V

CEH

CE "H" Input Voltage

V

CEL

CE "L" Input Voltage

Maxdty

Oscillator Maximum Duty Cycle

V

LX

Lx Limit Voltage

T

start

T

prot

V

UVLO1

V

UVLO2

I

MODE

V

MODEH

V

MODEL

VFMdty

0.20

-0.1

1.5

Delay Time by Soft-Start function

at no load, V

IN

=V

CE

=V

SET

+1.5V

Delay Time for protection circuit

V

IN

=V

CE

=V

SET

+1.5V, V

MODE

=0V

UVLO Threshold Voltage

UVLO Released Voltage

MODE Pin Input Current

MODE ”H” Input Voltage

MODE ”L” Input Voltage

VFM Duty Cycle

V

IN

=V

CE

=2.5V->1.5V, V

OUT

=0V

V

IN

=V

CE

=1.5V->2.5V, V

OUT

=0V

V

IN

=5.5V, V

CE

=0V, V

MODE

=5.5V/0V

V

IN

=V

CE

=5.5V, V

OUT

=0V

V

IN

=V

CE

=2.4V, V

OUT

=0V

V

IN

=V

CE

= V

MODE

=2.4V, V

OUT

=0V

Rev. 1.12

-5-

R1230D251D

R1230D251D Overview

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