SC573 [SEMTECH]

300mA Low-Noise LDO Regulator;


型号：	SC573
厂家：	SEMTECH CORPORATION
描述：	300mA Low-Noise LDO Regulator
文件：	总17页 (文件大小：1113K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

SC573

300mA Low-Noise LDO Regulator

POWER MANAGEMENT

Features

Description

SC573 is a low dropout linear voltage regulator designed

for use in applications with space constraints and low

power requirements. SC573 provides fixed output

voltages, delivering up to 300mA of load current. Fixed

output voltage eliminates the need for external feedback

resistors.



Input voltage range — 2.3V to 5.5V

Single 300mA (maximum) output

Dropout at 300mA load — 180mV (Typ)

Quiescent supply current — 50μA

Shutdown current — 100nA



Output noise — 100μVRMS /V

Over-temperature protection

Short-circuit protection

Under-voltage lockout

Internal 100Ω output discharge

SC70-5 Package

The device has an input, output and enable pin. Using the

lowest possible input voltage for the output voltage

reduces the power loss and improves overall package

thermal performance and efficiency.



The device has fast turn-on and turn-off voltage slew rate

for fast system start up and reset response. Low quiescent

current extends battery life.

Applications



LoRa® sensors, nodes and gateways

IoT low power radio applications

Consumer electronics

Wearable & Portable electronics

GPS devices

Set top boxes/HDTVs

Communication electronics

Industrial electronics

SC573 provides protection circuitry such as short-circuit

protection, under-voltage lockout, and thermal

protection to prevent device failures. Stability is

maintained by using 1µF capacitors on the output pins.

SC70-5 package and small ceramic bypass capacitors

minimize the required PCB area.

Typical Application Circuit

SC573

VOUT

VIN

VOUT

C_OUT

C_IN

1µF

GND

1µF

Final Rev 2.1

SC573

Pin Configuration

Ordering Information

Device

Marking

SC5H

Ordering Info

Output Voltage³

SC573V33RTRC

SC573V18RTRC

SC573EVB

3.3V

1.8V

SC5L

Evaluation Board

(1) Available in tape and reel only. A reel contains 3,000

devices.

(2) Pb-free, halogen hree, RohS / WEEE compliant

(3) Voltage Options: for additional fixed output voltage

options, contact Semtech marketing

Marking Information

SC573V18RTRC

SC573V33RTRC

Final Rev 2.1

SC573

Absolute Maximum Ratings

Recommended Operating Conditions

VIN (V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0 Ambient Temperature Range (°C) . . . . . . . . . -40 < T_A< +85

EN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0 V_IN(V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 to 5.5

All Other Pins (V) . . . . . . . . . . . . . . . . . . .. -0.3 to (V_VIN+ 0.3) EN to GND(V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to VIN

ESD⁽¹⁾PROTECTION LEVEL(kV). ............. ...................4

Thermal Information

Thermal Resistance, Junction to Ambient(2) (°C/W ) .. 262

Maximum Junction Temperature (°C) . . . . . . . . . . . . . . +125

Storage Temperature Range (°C). . . . . . . . . . . . -65 to +150

Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260

Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters

specified in the Electrical Characteristics section is not recommended.

NOTES:

(1) Tested according to JEDEC standard JESD22-A114-B.

(2) Calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.

Electrical Characteristics

Unless otherwise noted V_VIN= Max[V_OUT+ 1.0V or 2.3V], C_IN= 1μF, C_OUT= 1μF, V_EN= V_VIN, -40 °C < T_j< 125°C. Typical values are at T_A=

25°C. All specifications apply to both LDOs unless otherwise noted.

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Input Supply Voltage Range

2.3

5.5

_OUT=1mA,

Output Voltage Accuracy

Maximum Output Current

ΔV

-3

+/- 2

V_IN≥ Max(V_OUT+ 1.0V or 2.3V).

300

I_OUT= 300mA, V_IN= 3.0V to 3.6V

180

300

450

400

540

490

1.2

I_OUT= 300mA, V_IN= 3.0V to 3.6V,

-40°C < T_A< 85°C

Dropout Voltage

I_OUT= 300mA, V_IN= 2.3V to 3.0V

_OUT= 300mA, V_IN= 2.3V to 3.0V

-40°C < T_A< 85°C

Shutdown Current

Quiescent Current

EN=0,

0.1

μA

µA

I_OUT= 0mA, V_EN= V_IN

Load Regulation

Line Regulation

ΔV

I_OUT= 1mA to I_MAX,-40 °C≤T_A≤85°C

I_OUT= 1mA, -40 °C ≤ T_A≤85°C

0.02

0.1

%/V

Final Rev 2.1

SC573

Electrical Characteristics (continued)

Parameter

Symbol

Conditions

Min

Typ

Max

Units

Current Limit

I_LIM

350

550

750

R_load

= 50Ω

Noise⁽³⁾

e_N

100

μV_RMS/V

10Hz < f < 100kHz

Power Supply Rejection

Ratio⁽³⁾

PSRR

I_OUT= 5mA, f = 1kHz,

Under Voltage Lockout

UVLO Hysteresis

V_UVL

V_INRising

1.95

2.1

2.25

V_UVLO-HYS

100

Over Temperature Protection

Threshold⁽⁴⁾

T_OT

Temperature Rising

150

°C

Over Temperature Threshold

Hysteresis

V_OT-HYS

Digital Inputs

Logic Input High Threshold

Logic Input Low Threshold

Logic Input High Current

Logic Input Low Current

Notes:

V_IH

V_IL

I_IH

V_IN= 5.5V

V_IN= 2.5V

V_IN= 5.5V

1.2

0.4

1.6

μA

I_IL

(1) 50mV per LSB accuracy; when V_OUTsetting is lower than approximately 1.8V, accuracy specification percentage increases accordingly

(2) Dropout voltage is defined as V_IN- V_OUT, when V_OUTis 100mV below the value of V_OUTat V_IN≥ Max(V_OUT+ 1.0V or 2.3V).

(3) Not tested in production, typical performance characteristic based on bench characterization

(4) Thermal shutdown does not latch LDO off. Recovery begins if the temperature drops by the hysteresis level.

Final Rev 2.1

SC573

Pin Configurations and Descriptions

SC573

Pin Name Pin Function

VIN

GND

Input supply for LDO – Bypass with a 1μF capacitor

Ground

Enable for LDO, Internal 5MΩ pull-down resistor

Ground

GND

VOUT

LDO Output -- Bypass with a 1μF capacitor

Final Rev 2.1

SC573

Block Diagram

SC573

VREF

VOUT

VIN 1

UVLO

O/T

Current

Limit

Power-

2,4

GND

Logic

Final Rev 2.1

SC573

Typical Characteristics

Load Regulation (V_IN=5.0V, V_OUT=3.3V)

Load Regulation (V_IN=3.6V, V_OUT=3.3V)

Load Regulation (V_IN=4.2V, V_OUT=1.8V)

Load Regulation (V_IN=3.6V, V_OUT=1.8V)

Line Regulation (V_OUT=3.3V, I_OUT=300mA)

Line Regulation (V_OUT=3.3V, I_OUT=150mA)

Final Rev 2.1

SC573

Typical Characteristics

Line Regulation (V_OUT=1.8V, I_OUT=150mA)

Line Regulation (V_OUT=1.8V, I_OUT=250mA)

Dropout Voltage (V_OUT=3.3V, I_OUT=50mA)

Dropout Voltage (V_OUT=3.3V, I_OUT=150mA)

Dropout vs Load Current (V_OUT=3.3V)

Dropout Voltage (V_OUT=3.3V, I_OUT=300mA)

Final Rev 2.1

SC573

Typical Characteristics

Start Up (Enable) (V_OUT=3.3V)

Start Up Via V_IN(V_OUT=3.3V)

V_IN

2V/div

V_IN

2V/div

V_OUT

2V/div

V_OUT

1V/div

2V/div

I_OUT

100mA/div

150mA/div

V_IN= 5V

_OUT= 300mA

100us/div

V_IN= 5V

I_OUT= 300mA

1ms/div

Start Up (Enable) (V_OUT=1.8V)

Start Up Via V_IN(V_OUT=1.8V)

V_IN

2V/div

V_IN

2V/div

V_OUT

2V/div

V_OUT

1V/div

2V/div

I_OUT

100mA/div

150mA/div

V_IN= 5V

I_OUT= 300mA

100us/div

V_IN= 5V

I_OUT= 300mA

1ms/div

Shutdown (V_OUT=3.3V)

Shutdown (V_OUT=1.8V)

V_IN

2V/div

V_IN

2V/div

V_OUT

1V/div

V_OUT

1V/div

I_OUT

100mA/div

I_OUT

100mA/div

V_IN= 5V

I_OUT= 300mA

V_IN= 5V

I_OUT= 300mA

2ms/div

Final Rev 2.1

SC573

Typical Waveforms

V_OUT=3.3V, 0 to 300mA Load Transient

V_OUT

20mV/div

I_OUT

100mA/div

200us/div

V = 3.6V

I_OU^IN_T= 0A to 300mA

V_OUT=3.3V, 0 to 300mA Load Transient

V_OUT

20mV/div

I_OUT

100mA/div

V_IN= 4.2V

I_OUT= 0A to 300mA

200us/div

V_OUT=3.3V, 0 to 300mA Load Transient

V_OUT

20mV/div

I_OUT

100mA/div

V_IN= 5V

I_OUT= 0A to 300mA

200us/div

Final Rev2.1

SC573

Typical Waveforms

V_OUT=3.3V Noise Spectral Density

V_IN= 5.4V, V_OUT= 3.3V, Load 50 Ohms

V_OUT=1.8V, PSRR, Iout=30mA

Final Rev2.1

SC573

Applications Information

General Description

SC573 is a linear regulator with low dropout voltage,

low supply current, and low output noise. The device

provides a simple, low cost solution with minimal PCB

area. It has a miniature package size and needs two 1µF

0402 size external capacitors for its input and output.

The LDO provides up to 300mA output current.

Figure 1: Timing Diagram

The Output Noise

LDO noise generally is characterized through noise

spectral density (NSD) and total RMS value in the

frequency band between 10Hz to 100kHz. The noise

spectral density can be measured using a network

analyzer with active probes. The RMS noise value is

obtained from the noise spectral density curve by taking

the square root of the area within the frequency range

from 10Hz to 100kHz.

Power On and Off Control and Turn-on Dela

SC573 device has an enable pin (EN) that controls the

LDO output. Pulling the enable pin high will enable the

device when V_INis above its UVLO level at about 2.4V.

Pulling this pin low causes the device to shutdown

where it typically draws 100nA from the input supply.

When the enable pin is connected to the input voltage

supply, the device turn-on and turn-off has two voltage

thresholds to overcome. At the turn-on event, the enable

pin voltage needs to be greater than the enable threshold

and the V_INvoltage needs to be higher than the UVLO.

The higher of the two voltages, which is the UVLO,

determines the turn on time. At turn- off, the first

condition of either enable threshold low or the V_INUVLO

will determine the turn-off event.

The normalized output noise for SC573 is at a typical

value of 100µV_RMS/V. The generalized output voltage

noise can be approximated by: V_RMS=V_OUT*100 µV.

Protection Features

After the enable goes high, the IC has a delay time before

the output voltage ramps up. The delay is typically

between 120µs to 510µs. The 510µs is related to the lower

V_INcondition.

SC573 provides protection features to ensure that no

damage is incurred in the event of a fault condition. These

functions include:

•

Under-Voltage Lockout

With

1μF output capacitor (capacitor part

Over-Temperature Protection

number: GRM155R61A105kE15) at no load conditions,

the output voltage ramp time is typically at 15µs. The

device has an internal discharge MOSFET to discharge

the output voltage when the enable pin is asserted low;

the typical discharge time is at 2ms. The enable and

disable waveforms are illustrated in Figure 1, and the

Oscilloscope waveform is shown in the Typical

Characteristics.

Short-Circuit Protection with peak and fold-

back current limit

Final Rev2.1

SC573

Thermal Considerations

Applications Information (continued)

Although SC573 can provide 300mA of output current,

the maximum power dissipation in the device is restricted

by the miniature package size. The graph in Figure 2 can

be used as a first-order guideline to determine whether

the input voltage, output voltage, output current, and

ambient temperature of the system result in power

dissipation within operating limits.

Under-Voltage Lockout

The Under-Voltage Lockout (UVLO) circuit protects the

device from operating in an unknown state if the input

voltage supply is too low.

When either V^INdrops below the UVLO threshold, as

defined in the Electrical Characteristics section, the LDO

is disabled. The LDO is re-enabled when V_INis increased

above the hysteresis level. When powering up with V^IN

below the UVLO threshold, the LDO remains disabled.

Over-Temperature Protection

An internal Over-Temperature (OT) protection circuit

monitors the internal junction temperature. When the

temperature exceeds the OT threshold as defined in the

Electrical Characteristics section, the OT protection dis-

ables the corresponding LDO output. When the

temperature drops below its hysteresis value, the LDO

output will resume.

Short-Circuit Protection

The output has short-circuit protection with peak current

limit and fold back current limit. If the output current

exceeds the peak current limit, the output voltage will

drop and the output current will be limited to its fold

back current limit value. See the waveforms in the typical

operation section. If the short circuit is removed or the

load current reduces to below the fold back current limit,

the LDO output will rise back into regulation.

Figure 2: Maximum P_Dvs. T_A

The following procedure can be followed to determine if

the thermal design of the system is adequate. The junc-

tion temperature of the SC573 can be determined in

known operating conditions using the following

equation:

Component Selection

SC573 is designed to minimize the PCB solution area.

The recommended input and output capacitors are 1μF

with 0402 package, part number GRM155R61A105kE15.

T_J= T_A+(P_Dx θ_JA)

Although there is no maximum value of output capacitor

specified, very large values may increase the rise time of

the output voltages without affecting stability. It is

recommended that the value of output capacitance be

restricted to a maximum of 10μF. Ceramic capacitors of

type X5R or X7R should be used because of their low ESR

and stable temperature coefficients. Tantalum capacitors

and Y5V capacitors are not recommended.

where

T_J= Junction Temperature (°C)

T_A= Ambient Temperature (°C)

θ_JA= Thermal Resistance Junction to Ambient (°C/W)

P_D= Power Dissipation (W)

Final Rev2.1

SC573

Applications Information (continued)

Layout Considerations

The diagram in Figure 3 below illustrates proper layout of

a circuit. The layout considerations are listed below:

Example

A SC573LH is used to provide an output voltage of 3.3V

at 150mA. The input voltage is 4.2V, and the ambient

temperature of the system is 60°C.

• Attach pin 2 (GND) of the device to a copper pad

with vias connected to the GND plane. This

enables better heat transfer from the device to

the PCB.

P_D= 0.15 X (4.2 – 3.3)

• Place the input and output capacitors close to

the device for optimal transient response and

device behavior. Extra copper trace length

between the device input and output to the

capacitor soldering pad introduces parasitic

inductance.

= 0.135W

and

T_J= 60°C + (0.135W x 262°C/W*) = 95.4°C

• Connect all ground connections of the input and

output capacitors directly to the ground plane

whenever possible to minimize ground potential

differences on the PCB. Shown in the evaluation

board layout below, the SC573 ground pins,

input and output capacitors are all connected to

the ground plane through vias.

This calculation shows that the junction temperature is

about 95°C and is well below the allowed maximum

junction temperature of 125°C for this power dissipation.

Figure 3 — SC573 Layout Example

Final Rev2.1

SC573

Outline Drawing — SC70-5

Final Rev2.1

SC573

Land Pattern — SC70-5

DIMENSIONS

DIM

INCHES

MILLIMETERS

(.073)

.039

.026

.016

.033

.106

(1.85)

1.00

0.65

0.40

0.85

2.70

(C)

NOTES:

CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).

THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.

CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR

COMPANY'S MANUFACTURING GUIDELINES ARE MET.

Final Rev2.1

SC573

owner. The information presented in this document does not form part of any quotation or contract, is believed to be

accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any

consequence of its use. Publication thereof does not convey nor imply any license under patent or other industrial or

intellectual property rights. Semtech assumes no responsibility or liability whatsoever for any failure or unexpected

operation resulting from misuse, neglect improper installation, repair or improper handling or unusual physical or

electrical stress including, but not limited to, exposure to parameters beyond the specified maximum ratings or

operation outside the specified range.

SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED ORWARRANTEDTO BE SUITABLE FOR USE IN LIFE-

SUPPORT APPLICATIONS, DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF SEMTECH

PRODUCTS IN SUCH AP- PLICATIONS IS UNDERSTOOD TO BE UNDERTAkEN SOLELY AT THE CUSTOMER’S OWN RISk.

Should a customer purchase or use Semtech products for any such unauthorized application, the customer shall

indemnify and hold Semtech and its officers, em- ployees, subsidiaries, affiliates, and distributors harmless against all

claims, costs damages and attorney fees which could arise.

Contact Information

Semtech Corporation

Power Management Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805) 498-2111 Fax: (805) 498-3804

www.semtech.com

Final Rev2.1

SC573 [SEMTECH]

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