LX7169CLD-TR [MICROSEMI]

Switching Controller, Voltage-mode, 3A, 3400kHz Switching Freq-Max, PDSO12;


型号：	LX7169CLD-TR
厂家：	Microsemi
描述：	Switching Controller, Voltage-mode, 3A, 3400kHz Switching Freq-Max, PDSO12 开关光电二极管
文件：	总9页 (文件大小：449K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

DESCRIPTION

KEY FEATURES

LX7169 is a step-down PWM Switching

regulator IC with integrated high side P-

Channel and low side N-Channel

Other features of the part are:

. 3A Step-down Regulator

. Operational Input Supply Voltage

Range: 3V-5.5V

. Integrated PMOS and NMOS

. Load Current from zero to 3A

. 3MHz Switching Frequency

. Input UVLO Protection

. Enable Pin

. Power Good

. Internal Soft-start

. Cycle-by-Cycle Over Current

Protection

. Hiccup Mode Operation Under

OCP

a) Cycle-by-cycle current limit

followed by HICCUP mode which

reduces the overall power dissipation of

the internal MOSFETs

MOSFETs. The IC operates using

hysteretic control topology with a full load

operating frequency of 3MHz. This

b) Thermal protection and internal

digital soft start.

switching frequency allows for small output

filter components while maintaining

excellent dynamic load response.

The LX7169 also provides a Power Good

function. The LX7169 is available in a 12L

3mm x 3.5mm DFN package.

The operational input voltage range of

LX7169 is from 3V to 5.5V. The SYNC

pin is tied low when not in use. A clock

signal to this pin will synchronize the

converter to an external source.

. RoHS Compliant for Pb Free

In the shutdown mode, the IC’s current

consumption is reduced to less than 1mA

and the output capacitor is discharged.

APPLICATIONS

. HDD

. Set-Top Box

. LCD TV’s

. Notebook/Netbook

. Routers

. Video Cards

. PC Peripherals

. PoE Powered Devices

IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com

PRODUCT HIGHLIGHT

VIN = 3V

to 5.5V

100k

PGOOD

PVIN

0.47µF

VOUT

0.01

µF

10µF

X5R

VCC

22µF

X5R

LX7169

1µF

VOUT

SYNC

Output Capacitor Range is

from 22µf to100µF

Output Inductor Range is

from 0.47µH to 1µH

GND

Power PAD

PACKAGE ORDER INFO

THERMAL DATA

12L DFN (3.0 x 3.5 mm)



_JA= 36C/W

T_A(C)

RoHS Compliant / Pb-free

THERMAL RESISTANCE-JUNCTION TO AMBIENT

Junction Temperature Calculation: T_J= T_A+ (P_Dx _JA).

The _JAnumbers are guidelines for the thermal performance of the

device/pc-board system. All of the above assume no ambient airflow.

-10 to +85

LX7169CLD

Note: Available in Tape & Reel. Append the letters “TR” to the part number.



_JAnumber above is with 4-layer PCB board.

(i.e. LX7169CLD-TR)

Microsemi

Analog Mixed Signal Group

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

Page 1

Rev. 1.1 2013-01-16

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

AABSOLUTE MAXIMUM RATINGS

PACKAGE PIN OUT

PVIN, VCC, EN, FB, PGOOD, VOUT, SYNC.................................................-0.3V to 7V

SW.....................................................................................................................-0.3V to 7V

SW (Shorter than 50ns) ....................................................................................... -2V to 7V

Maximum Operating Junction Temperature ................................................-10C to 150°C

Storage Temperature Range.........................................................................-65C to 150C

Peak Package Solder Reflow Temp. (40 seconds maximum exposure)......... 260°C (+0,-5)

SYNC

PGOOD

VOUT

GND

VCC

GND

PVIN

Notes: Exceeding these ratings could cause damage to the device. All voltages are with respect to GND.

Currents are positive into, negative out of specified terminal. These are stress ratings only and

functional operation of the device at these or any other conditions beyond those indicated under

“Recommended Operating Conditions” are not implied. Exposure to “Absolute Maximum Ratings”

for extended periods may affect device reliability.

PVIN

LD PACKAGE

(Top View)

Exposed Pad = GND

xxxx = Date/Lot Code

RoHS / Pb-free 100% Matte Tin Lead

Finish

ELECTRICAL CHARACTERISTICS

Unless otherwise specified, the following specifications apply over the operating ambient temperature of -10C

otherwise noted with the following test conditions: VCC = PVIN = 5V. Typical parameter refers to T_J=25°C



T_A



85C except where

Parameters

Symbol

Test Conditions/Comments

Min

Typ

Max

5.5

Units

Recommended Operating Range

VCC, PVIN

Operating Current

I_Q

Input Current

I_LOAD= 0

Input Current at Shut Down

I_IN

EN = GND

0.001

VCC Input UVLO

Under Voltage Lockout

UVLO Hysteresis

VCC

VCC rising

2.4

2.8

230

Feedback

V_REF

T_A= 25°C

0.792 0.800 0.808

Feedback Voltage Internal

Reference

Temperature range

0.788

0.812

FB Pin Input Current

Line Regulation

I_FB

V_INfrom 3V to 5.5V

0.30

-0.10

Load Regulation

I_LOAD= 0.5 to 3A

%/A

Vout Voltage Positioning

V_REG

Vout = 1.2V, Hysteretic Mode

Load from 0.1 to 1.5 amps, T_R=T_F= 100ns,

V_OUT= 1.2V C_OUT= 44µF

Transient Response

+/-40

FB UVLO

FB UVLO Threshold

V_FBULVO

70%

V_REF

Microsemi

Analog Mixed Signal Group

Page 2

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

ELECTRICAL CHARACTERISTICS

Unless otherwise specified, the following specifications apply over the operating ambient temperature of -10C

otherwise noted with the following test conditions: VCC = PVIN = 5V. Typical parameter refers to T_J=25°C



T_A



85C except where

Parameters

Symbol

Test Conditions/Comments

Min

Typ

Max

Units

OUTPUT DEVICE

R_DSONof High Side

R_DSONof Low Side

Current Limit

R_{DSON_H}

R_{DSON_L}

I_L

mΩ

^oC

3.75

4.5

150

5.5

Thermal Shut Down Threshold

Hysteresis

T_SH

T_H

PVIN OVP

Rising Threshold

OVP_R

OVP_F

6.5

6.3

Falling Threshold

5.5

2.6

OSCILLATOR FREQUENCY

Switching Frequency

In Constant Frequency Hysteretic Mode

3.4

MHz

SOFT START

Soft Start Time

Hiccup Time

T_SS

From EN high to PGOOD high.

FB = 0.2V

500

1.5

µs

T_HICCUP

SYNC

Input High

M_VIH

M_VIL

Input Low

0.4

EN INPUT

Input High

EN_VIH

EN_VIL

EN_H

Input Low

0.4

Hysteresis

0.1

Input Bias

EN_II

0.01

µA

POWER-GOOD

V_FBrising, In percentage of output voltage set-

point. During startup, the PGOOD will not go

high until the soft start cycle has finished.

Power-good Transition High

Threshold

V_PG

Hysteresis

V_PGHY

Either V_FBrising or falling

Power-good Internal FET

R_DSON

PG_RDSON

VCC=5V

100

300

ohm

PGOOD FET Leakage Current

Pgood Internal Glitch Filter

0.01

µA

µSec

Output Discharge

Internal Discharge Resistor

200

1400

ohm

Microsemi

Analog Mixed Signal Group

Page 3

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

FUNCTIONAL PIN DESCRIPTION

Name

Pin #

Description

Voltage feedback pin. Connect to the output terminal through a resistor divider network to

set the output voltage of the regulator to the desired value.

VOUT

GND

Attached to V_OUT.

3,4

Ground pin for the power stage.

Switch-node pin. Connect the output inductor between this pin and output capacitor. When

the chip is DISABLED, the internal discharge resistor will be enabled to discharge the

output capacitance. The current will flow into this pin.

5,6

7,8

Input voltage terminal of the regulator. A minimum of 10µF, X5R type ceramic capacitor

must be connected as close as possible from this pin to PGND plane to insure proper

operation.

PVIN

Analog input voltage terminal. Connect this pin to VIN with a 10ohm resistor and connect a

1µF ceramic capacitor from VCC to GND.

VCC

Pull this PIN higher than 1V will enable the CHIP. When pulled low, the IC will turn off and

the Internal discharge FETwill turn on to discharge the output capacitor through the SW pin.

Power-good pin. This is an open-drain output and should be connected to a voltage rail with

an external pull-up resistor. During the power on, this pin switches from Low to Hi state

when FB voltage reaches above the power good threshold and the internal soft start has

finished its operation. It will be pulled low when the FB falls below the power good

threshold minus the hysteresis.. It will turn back on when the pull FB rises above the

threshold.

PGOOD

SYNC

This pin should be tied to ground when not in use. When a clock is connected. The IC will

be in synchronous mode and switching frequency is synchronized to external CLOCK.

Ground pin for the power stage and analog circuit. For good thermal connection, this PAD

must be connected using VIAs to the GND plane and to the LAND pattern of the IC.

Power PAD

Microsemi

Analog Mixed Signal Group

Page 4

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

FUNCTIONAL BLOCK DIAGRAM

V_IN

V_OUT

V_FB

Hysteresis = XmV

ramp

Delay = Xns

Freq Correction

Hysteretic

Engine

Vref

Freq

Ref

Figure. 1. Functional Block Diagram.

Microsemi

Analog Mixed Signal Group

Page 5

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

OPERATION THEORY

Basic Operation

Over Current Protection

The operation of the controller consists of comparing The IC has the ability to protect against all types of

the V_fbvoltage to an internal reference. When the

V_fbvoltage is lower than the V_ref, the upper switch

turns on. When the V_fbvoltage is higher than V_ref,

short circuit protection. It has cycle by cycle short

protection that turns off the upper mosfet and ends

the cycle when the current exceeds the OCP

the upper switch turns off and the lower switch turns threshold, when this occurs, the off time is at least

on. An internal ramp is used to stabilize the 200ns before the upper fet is turned on again After

switching frequency and keep the V_fbimmune to the startup, if the FB pin drops below the Feedback

output capacitor, Co, value or parasitic components

(i.e. esr, esl). In addition, a frequency control loop

ensures the switching frequency is constant under

continuous conduction mode of operation.

UVLO threshold, the chip will go into a hiccup mode

of operation. This helps to protect against a crowbar

short circuit. The FB UVLO Alarm is not active

during startup.

Setting of the Output Voltage

Hiccup Mode of Operation

The values of R1 and R2 are chosen so according to Hiccup mode of operation will protect the IC during

the following equations:

a short of the output. After startup, it will be

triggered when the FB UVLO is exceeded





R₁

R₂





V_OUT



1 V_ref







Startup

The Reference is ramped up from zero voltage to

0.8V in 500µS. During this time, the PGOOD is

pulled low. When the reference reaches 0.8V,

signaling the end of the soft start cycle, the PGOOD

pin will go high within 5µS.

Microsemi

Analog Mixed Signal Group

Page 6

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

TYPICAL APPLICATION

VIN = 4.5V

to 5.5V

100k

PGOOD

0.47µF

PGOOD

PVIN

VOUT

0.01

µF

22µF

X5R

VCC

3.24k

2*22

µF

LX7169

1µF

X5R

6.49k

VOUT

SYNC

GND

Power PAD

Figure. 2: LX7169 Application

2A Dynamic response (0.47µH, 2x22µF)

Microsemi

Analog Mixed Signal Group

Page 7

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

Efficiency Vs Load: VIN=5V, VOUT=1.2V

100

25°C

-10°C

80°C

0.5

1.5

2.5

OUTPUT CURRENT - (A)

Figure 3. LX7169 Efficiency (Inductor part number: IHLP1616ABER47M01 )

Microsemi

Analog Mixed Signal Group

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

Page 8

Rev. 1.1 2013-01-16

LX7169

3A Step-Down Converter

PRODUCTION DATASHEET

PACKAGE DIMENSIONS

12 Pin Plastic DFN 3x3.5 mm Dual Exposed Pad

MILLIMETERS

MIN MAX

0.70 0.80

INCHES

Dim

MIN

0.027

MAX

0.031

0.002

0.05

0.20 REF

0.18 0.30

3.50 BSC

0.008 REF

Pin 1 ID

0.007

0.012

0.138 BSC

D2 2.45 2.70

0.096

0.106

0.50 BSC

3.00 BSC

0.019 BSC

0.118 BSC

1.45 1.70

0.35 0.55

0.20 0.30

0.057

0.014

0.008

0.067

0.022

0.012

Note:

1. Dimensions do not include mold flash or

protrusions; these shall not exceed 0.155mm(.006”)

on any side. Lead dimension shall not include

solder coverage.

2. Dimensions are in mm, inches are for reference

only.

PRODUCTION DATA – Information contained in this document is proprietary to

Microsemi and is current as of publication date. This document may not be modified in

any way without the express written consent of Microsemi. Product processing does not

necessarily include testing of all parameters. Microsemi reserves the right to change the

configuration and performance of the product and to discontinue product at any time.

Microsemi

Analog Mixed Signal Group

Page 9

Rev. 1.1 2013-01-16

One Enterprise Aliso Viejo, CA 92656 USA, 1-800-713-4113, 949-380-6100, fax 949-215-4996

LX7169CLD-TR [MICROSEMI]

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