LX1553 MICROSEMI [Microsemi Corporation], LX1553 Datasheet

LX1553

Manufacturer Part Number

LX1553

Description

ULTRA-LOW START-UP CURRENT, CURRENT-MODE PWM

Manufacturer

MICROSEMI [Microsemi Corporation]

Datasheet

1.LX1553.pdf (18 pages)

Available stocks

Company

Part Number

Manufacturer

Quantity

Price

Company:

Meier Automation Equipment Co., Limited

Part Number:

LX1553C

Manufacturer:

LMI

Quantity:

20 000

Current page: 1 of 18
Download datasheet (378Kb)

Rev. 1.0a 1/01

H E

INPUT

-55 to 125

The LX155X family of ultra-low start-up

current (250µA max.), current mode

control IC's offer new levels of energy

efficiency for offline converter applica-

tions. They are ideally optimized for

personal computer and CRT power

supplies although they can be used in

any number of off-line applications

where energy efficiency is critical.

Coupled with the fact that the LX155X

series requires a minimal set of external

components, the series offers an

excellent value for cost conscious

consumer applications.

LX155X series demonstrates a signifi-

cant power reduction as compared with

other similar off-line controllers. Table 1

compares the SG384X, UC384XA and

the LX155X start-up resistor power

dissipation. The LX155X offers an

overall 4X reduction in power dissipa-

-40 to 85

0 to 70

Optimizing energy efficiency, the

(°C)

N F I N I T E

Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. LX1552CDMT)

Plastic DIP

8-pin

YPICAL

LX155xCM

LX155xIM

O W E R

—

P R O D U C T H I G H L I G H T

LX1552

LX1554

ICRO

PPLICATION OF

F O R F U R T H E R I N F O R M A T I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1

D E S C R I P T I O N

O F

OWER

11861 W

P A C K A G E O R D E R I N F O R M A T I O N

N N O V A T I O N

TART

Plastic SOIC

8-pin

LX155xCDM

LX155xIDM

Note: Calculation is done for universal AC input speci-

fication of V

following equation: (Resistor curr ent is selected to be

2 * I

LX155X U

Max. Start-up Current

Specification (I

Typical Start-Up

Resistor Value (R

Max. Start-Up Resistor

Power Dissipation (P

tion. Additionally, the precise oscillator

discharge current gives the power

supply designer considerable flexibility

in optimizing system duty cycle

consistency.

demonstrates improved load regulation,

pulse by pulse current limiting and

inherent protection of the power supply

output switch. The LX155X includes a

bandgap reference trimmed to 1%, an

error amplifier, a current sense com-

parator internally clamped to 1V, a high

current totem pole output stage for fast

switching of power mosfet's, and an

externally programmable oscillator to

set operating frequency and maximum

duty cycle. The undervoltage lock-out

circuitry is designed to operate with as

little as 250µA of supply current

permitting very efficient bootstrap

designs.

Design Using

ESTERN

-U

The current mode architecture

—

at V

ACMIN

EATURE

ACMIN

VENUE

= 90V

)

SING

2 * I

AC MIN

)

RMS

A B L E

, G

1000µA 500µA

SG384x UC384xA LX155x

2.26W 1.13W

62K

to V

, P

ARDEN

Plastic SOIC

14-pin

ACMAX

LX155xCD

LX155xID

= 265V

124K

—

LTRA

ROVE

MAX

RMS

-L

R O D U C T I O N

using the

250µA

248K

0.56W

, CA. 92841

TART

-U

Ceramic DIP

8-pin

LX155xMY

LX1552

LX1553

LX1554

LX1555

p CURRENT SENSE DELAY TO OUTPUT

p AUTOMATIC FEED FORWARD

p PULSE-BY-PULSE CURRENT LIMITING

p ENHANCED LOAD RESPONSE

p UNDER-VOLTAGE LOCKOUT WITH

p DOUBLE PULSE SUPPRESSION

p HIGH CURRENT TOTEM POLE OUTPUT

p 500kHz OPERATION

V A I L A B L E

Part #

URRENT

—

ULTRA-LOW START-UP CURRENT

(150µA typ.)

TRIMMED OSCILLATOR DISCHARGE

CURRENT (±2% typ.)

INITIAL OSCILLATOR FREQUENCY BETTER

THAN ±4%

OUTPUT PULLDOWN DURING UVLO

PRECISION 2.5V REFERENCE (±2% max.)

(150ns typ.)

COMPENSATION

CHARACTERISTICS

HYSTERESIS

(±1Amp peak)

ECONOMY OFF-LINE FLYBACK OR

FORWARD CONVERTERS

DC-DC BUCK OR BOOST CONVERTERS

LOW COST DC MOTOR CONTROL

LX1552/3/4/5

K E Y F E A T U R E S

A P P L I C A T I O N S

, C

Start-Up Hysteresis Max. Duty

A T A

Voltage

8.4V

16V

URRENT

P T I O N S P E R

L I N D

-M

LX155xCPW

TSSOP

20-pin

H E E T

0.8V

ODE

O C

—

PWM

# : 1552

<100%

<50%

Cycle

A R T

Related parts for LX1553

LX1553 Summary of contents

Page 1

... FORWARD CONVERTERS DC-DC BUCK OR BOOST CONVERTERS LOW COST DC MOTOR CONTROL Part # Start-Up Hysteresis Max. Duty 250µA Voltage LX1552 16V 6V 248K LX1553 8.4V 0.8V 0.56W LX1554 16V 6V LX1555 8.4V 0.8V using the Ceramic DIP TSSOP Y PW 8-pin 20-pin — ...

Page 2

LX1552/3/4 ...

Page 3

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for LX155xC with 0°C ...

Page 4

... COMP 4. Gain defined as ISENSE 5. Adjust V above the start threshold before setting at 15V Output frequency equals oscillator frequency for the LX1552 and LX1553. Output frequency is one half oscillator frequency for the LX1554 and LX1555 34V GROUND** 16V (1552/1554) 8.4V (1553/1555) ...

Page 5

GRAPH / CURVE INDEX Characteristic Curves FIGURE # 1. OSCILLATOR FREQUENCY vs. TIMING RESISTOR 2. ...

Page 6

LX1552/3/4/5 FIGURE 1. — OSCILLATOR FREQUENCY vs. TIMING RESISTOR 1000 100 C = 6.8nF T 10 ...

Page 7

... FIGURE 5. — OUTPUT INITIAL ACCURACY vs. TEMPERATURE 65.0 LX1552 and LX1553 only 63.5 62.0 60.5 59.0 57.5 56.0 54.5 53.0 51.5 50.0 -75 -50 - Ambient Temperature - (°C) A FIGURE 7. — REFERENCE VOLTAGE vs. TEMPERATURE 5.03 5.02 5.01 5.00 4.99 4.98 4.97 4.96 4.95 -75 -50 - Ambient Temperature - (°C) A Copyright © 1994 Rev ...

Page 8

... FIGURE 12. — START-UP CURRENT vs. SUPPLY VOLTAGE PWM ODE 250 225 200 LX1552/LX1554 175 150 125 100 LX1553/LX1555 -75 -50 - Ambient Temperature - (°C) A 250 LX1552/LX1554 225 T = 25°C A 200 175 150 ...

Page 9

... FIGURE 16. — START-UP THRESHOLD vs. TEMPERATURE 8.8 8 125°C A 8.6 8.5 8.4 8 -55°C A 8.2 8.1 8.0 7.9 7.8 3.0 3.5 4.0 4.5 5.0 LX1552/3/4/5 -M PWM ODE TEMPERATURE V = 15V PIN3 C = 1nF L -75 -50 - Ambient Temperature - (°C) A LX1553 LX1555 -75 -50 - Ambient Temperature - (°C) A 100 125 100 125 9 ...

Page 10

... FIGURE 18. — MINIMUM OPERATING VOLTAGE vs. 11.0 LX1552 10.8 LX1554 10.6 10.4 10.2 10 100 125 FIGURE 20. — LOW LEVEL OUTPUT SATURATION VOLTAGE 1.20 LX1553 1.08 LX1555 0.96 0.84 0.72 0.60 0.48 0.36 0.24 0.12 0. 100 125 -M PWM ODE S ...

Page 11

FIGURE 21. — OUTPUT SATURATION VOLTAGE vs. OUTPUT CURRENT and TEMPERATURE 6 ...

Page 12

... Start-up Voltage Hysterises Voltage PART # ( LX1552 16V 8.4V LX1553 LX1554 16V 8.4V LX1555 UNDERVOLTAGE LOCKOUT The LX155x undervoltage lock-out is designed to maintain an ultra low quiescent current of less than 250µA, while guarantee- ing the IC is fully functional before the output stage is activated. Comparing this to the SG384x series reduction in start-up current is achieved resulting in 75% less power dissipation in the start-up resistor ...

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LX1553 MICROSEMI [Microsemi Corporation], LX1553 Datasheet

LX1553

Available stocks

Related parts for LX1553

LX1553 Summary of contents

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