MIC5238-1.1BD5_技术文档

MIC5238

Micrel

MIC5238

Ultra-Low Quiescent Current, 150mA µCap LDO Regulator

General Description

Features

The MIC5238 is an ultra-low voltage output, 150mA LDO

regulator. Designed to operate in a single supply or dual

supply mode, the MIC5238 consumes only 23µA of bias

current, improving efficiency. When operating in the dual

supply mode, the efficiency greatly improves as the higher

voltage supply is only required to supply the 23µA bias

currentwhiletheoutputandbasedrivecomesoffofthemuch

lower input supply voltage.

• Ultra-low input voltage range: 1.5V to 6V

• Ultra-low output voltage: 1.1V minimum output voltage

• Low dropout voltage: 310mV at 150mA

• High output accuracy: ±2.0% over temperature

• µCap: stable with ceramic or tantalum capacitors

• Excellent line and load regulation specifications

• Zero shutdown current

• Reverse leakage protection

• Thermal shutdown and current limit protection

• IttyBitty™ SOT-23-5 package

As a µCap regulator, the MIC5238 operates with a 2.2µF

ceramic capacitor on the output, offering a smaller overall

solution. It also incorporates a logic-level enable pin that

allows the MIC5238 to be put into a zero off-current mode

when disabled.

Applications

• PDAs and pocket PCs

• Cellular phones

• Battery powered systems

• Low power microprocessor power supplies

The MIC5238 is fully protected with current limit and thermal

shutdown. It is offered in the IttyBitty™ SOT-23-5 package

with an operating junction temperature range of

–40°C to +125°C.

Ordering Information

Part Number

Marking Voltage* Junction Temp. Range

Package*

SOT-23-5

TSOT-23-5

MIC5238-1.1BM5

MIC5238-1.3BM5

MIC5238-1.1BD5

MIC5238-1.3BD5

L411

L413

N411

N413

1.1V

1.3V

1.1V

1.3V

–40°C to +125°C

* For other voltages and package option contact the factory

Typical Application

MIC5238-1.0BM5

1

5

V_IN=1.5V

1.0V

C_IN

2

3

C_OUT=2.2µF

ceramic

4

EN_OFF

ON

V_BIAS=2.5V

C_BIAS

Ultra-Low Voltage Application

IttyBitty is a trademark of Micrel, Inc.

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

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MIC5238

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Pin Configuration

EN GND IN

3

2

1

3

2

1

L4xx

N4xx

4

5

4

5

BIAS

OUT

SOT-23-5 (M5)

TSOT-23-5 (D5)

Pin Description

SOT-23-5

Pin Name

Pin Function

Supply Input

Ground

1

2

3

IN

GND

EN

Enable (Input): Logic low = shutdown; logic high = enable. Do no leave

open.

4

5

BIAS

OUT

BiasSupply Input

Regulator Output

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Absolute Maximum Ratings (Note 1)

Operating Ratings (Note 2)

Input Supply Voltage ........................................ –0.3V to 7V

BIAS Supply Voltage........................................ –0.3V to 7V

Enable Input Voltage........................................ –0.3V to 7V

Power Dissipation .................................... Internally Limited

Junction Temperature .............................. –40°C to +125°C

Storage Temperature ............................... –65°C to +150°C

ESD Rating, >1.5µA HBM, Note 3

Input Supply Voltage .......................................... 1.5V to 6V

BIAS Supply Voltage.......................................... 2.3V to 6V

Enable Input Voltage............................................. 0V to 6V

Junction Temperature (T ) ....................... –40°C to +125°C

J

Package Thermal Resistance

SOT-23-5 (θ ) ..................................................235°C/W

JA

Electrical Characteristics (Note 4)

T_A= 25°C with V_IN= V_OUT+ 1V; V_BIAS= 3.3V; I_OUT= 100µA; V_EN= 2V, Bold values indicate –40°C < T_J< +125°C; unless otherwise specified.

Parameter

Condition

Min.

Typ.

Max.

Units

Output Voltage Accuracy

Variation from nominal V_OUT

–1.5

–2

+1.5

+2

%

Line Regulation

V_BIAS= 2.3V to 6V, Note 5

V_IN= (V_OUT+ 1V) to 6V

Load = 100µA to 150mA

0.25

0.04

0.7

0.5

1

%

Input Line Regulation

Load Regulation

Dropout Voltage

I

_OUT= 100µA

50

230

mV

I_OUT= 50mA

I_OUT= 100mA

I_OUT= 150mA

300

400

270

310

450

500

BIAS Current, Note 6

Input Current, Pin 1

I_OUT= 100µA

23

µA

I

_OUT= 100µA

I_OUT= 50mA, Note 7

_OUT= 100mA

I_OUT= 150mA

7

0.35

1

20

µA

mA

I

2

2.5

Ground Current in Shutdown

V

_EN≤ 0.2V; V_IN= 6V; V_BIAS= 6V

1.5

0.5

350

5

µA

mA

µA

V_EN= 0V; V_IN= 6V; V_BIAS= 6V

V_OUT= 0V

Short Circuit Current

Reverse Leakage

Enable Input

500

0.2

V_IN= 0V; V_EN= 0V; V_OUT= nom V_OUT

Input Low Voltage

Input High Voltage

Enable Input Current

Regulator OFF

Regulator ON

V

2.0

V_EN= 0.2V; Regulator OFF

–1.0

0.01

0.1

1.0

µA

V_EN= 2.0V; Regulator ON

Note 1. Exceeding the absolute maximum rating may damage the device.

Note 2. The device is not guaranteed to function outside its operating rating.

Note 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.

Note 4. Specification for packaged product only.

Note 5. Line regulation measures a change in output voltage due to a change in the bias voltage.

Note 6. Current measured from bias input to ground.

Note 7. Current differential between output current and main input current at rated load current.

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Typical Characteristics

Output Voltage

PSRR

Output Voltage

vs. V

150mA Load

vs. V

BIAS

IN

1.15

1.1

80

1.2

1.1

1

100µA

150mA

100µA

150mA

70

60

50

40

30

1.05

1

0.9

0.8

0.7

0.6

0.5

0.4

0.95

0.9

C_OUT= 2.2µF ceramic

20

V_IN= 2.1V

0.85

0.8

10

V

_OUT= 1.1V

0

1.11.21.31.41.51.61.71.81.9 2 2.1

1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2

INPUT BIAS (V)

10 100 1k 10k 100k 1M 10M

FREQUENCY (Hz)

INPUT V (V)

IN

Ground Current (V

)

IN

Dropout Voltage

vs. Load

Ground Current (V

)

IN

vs. V Supply

IN

vs. Output Current

V_IN= V_OUT+ 1

400

1800

1600

1400

1200

1000

800

600

400

200

0

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

V_IN= V_OUT+ 1

1.1V

150mA

350

300

250

200

150

100

50

0

25 50 75 100 125 150

OUTPUT CURRENT (A)

0

25 50 75 100 125 150

OUTPUT CURRENT (mA)

0

0.5

V

1.0

SUPPLY (V)

1.5

2.0

IN

Ground Current (V

)

BIAS

Ground Current (V

)

BIAS

Shutdown Current of

vs. Output Current

V_IN= V_OUT+ 1

30

25

20

15

10

5

vs. Input Voltage

V

IN

30

25

20

15

10

5

7

6

5

4

3

2

1

0

I_LOAD= 150mA

No Load

0

25 50 75 100 125 150

OUTPUT CURRENT (mA)

0

0.5

1

1.5

2

2.5

3

0

0.5

1

1.5

2

INPUT VOLTAGE (V)

ENABLE (V)

Ground Current (V

vs Temperature

)

Shutdown Current

IN

Shutdown Current of V

V

+ V Tied

BIAS

IN

10

9

8

7

6

5

4

3

2

1

0

20

30

25

20

15

10

5

1.1V

100µA

No Load

18

16

14

12

10

8

6

4

2

-40 -20

0

20 40 60 80 100 120

0

0.5

1

1.5

2

0

0.5

1

1.5

2

TEMPERATURE (°C)

ENABLE (V)

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V

Ground Current

V

Ground Current

IN

V

Ground Current

BIAS

vs. Temperature

2

2.4

2.2

2

vs. Temperature

1.1V

75mA

1.1V

150mA

40

35

30

25

20

15

10

5

1.8

1.6

1.4

1.2

1

1.1V

100µA

1.8

1.6

1.4

1.2

1

0.8

0.6

0.4

0.2

0

0.8

0.6

0.4

-40 -20

0

20 40 60 80 100 120

TEMPERATURE (°C)

-40 -20

0

20 40 60 80 100 120

0

TEMPERATURE (°C)

-40 -20

0

20 40 60 80 100 120

TEMPERATURE (°C)

V

Ground Current

V

Ground Current

BIAS

Output Voltage

vs. Temperature

40

35

30

25

20

15

10

5

1.1025

1.1020

1.1015

1.1010

1.1005

1.1000

1.0995

1.0990

1.0985

1.0980

1.0975

1.1V

100µA

150mA

35

30

25

20

15

10

5

75mA

0

-40 -20

0

20 40 60 80 100 120

-40 -20

0

20 40 60 80 100 120

-40 -20

0

20 40 60 80 100 120

TEMPERATURE (°C)

Short Circuit Current

vs. Temperature

Dropout Voltage

vs. Temperature

500

450

400

350

300

250

200

150

100

50

500

Load = 150mA

450

400

350

300

250

200

150

100

50

0

-40 -20

0

20 40 60 80 100 120

-40 -20

0

20 40 60 80 100 120

TEMPERATURE (°C)

August 2003

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MIC5238

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Line Transient Response

Load Transient Response

3.1V

2.1V

1.1V output

C_OUT= 4.7µF ceramic

1.1V Output

C_OUT= 4.7 F ceramic

150mA

1mA

TIME (200 s/div.)

TIME (400 s/div.)

EN Turn-On Characteristic

Load Transient Response

150mA

0mA

V_IN= 4V

V_OUT= 3V

C_OUT= 4.7µF ceramic

TIME (40 s/div.)

TIME (400µs/div.)

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Functional Diagram

OUT

IN

BIAS

EN

ENABLE

V_REF

GND

Block Diagram – Fixed Output Voltage

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MIC5238

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Recommended

Applications Information

Package

θ

JA

Minimum Footprint

Enable/Shutdown

SOT-23-5

235°C/W

The MIC5238 comes with an active-high enable pin that

allowstheregulatortobedisabled.Forcingtheenablepinlow

disables the regulator and sends it into a “zero” off-mode-

current state. In this state, current consumed by the regulator

goes nearly to zero. Forcing the enable pin high enables the

output voltage.

Table 1. SOT-23-5 Thermal Resistance

The actual power dissipation of the regulator circuit can be

determined using the equation:

P = (V – V

)I

+ V I

D

IN

OUT OUT IN GND

Substituting P

for P and solving for the operating

D

Input Bias Capacitor

D(MAX)

conditions that are critical to the application will give the

maximum operating conditions for the regulator circuit. For

example, when operating the MIC5238-1.0BM5 at 50°C with

a minimum footprint layout, the maximum input voltage for a

set output current can be determined as follows:

The input capacitor must be rated to sustain voltages that

may be used on the input. An input capacitor may be required

when the device is not near the source power supply or when

supplied by a battery. Small, surface mount, ceramic capaci-

tors can be used for bypassing. Larger values may be

required if the source supply has high ripple.

125°C − 50°C

P

=

D(MAX)

Output Capacitor

235°C/W

The MIC5238 requires an output capacitor for stability. The

design requires 2.2µF or greater on the output to maintain

stability. The design is optimized for use with low-ESR

ceramic chip capacitors. High ESR capacitors may cause

high frequency oscillation. The maximum recommended

ESR is 3Ω. The output capacitor can be increased without

limit. Larger valued capacitors help to improve transient

response.

P

= 319mW

D(MAX)

The junction-to-ambient (θ ) thermal resistance for the

JA

minimum footprint is 235°C/W, from Table 1. It is important

that the maximum power dissipation not be exceeded to

ensure proper operation. With very high input-to-output volt-

age differentials, the output current is limited by the total

powerdissipation. Totalpowerdissipationiscalculatedusing

the following equation:

X7R/X5R dielectric-type ceramic capacitors are recom-

mended because of their temperature performance. X7R-

type capacitors change capacitance by 15% over their oper-

ating temperature range and are the most stable type of

ceramiccapacitors.Z5UandY5Vdielectriccapacitorschange

value by as much as 50% and 60% respectively over their

operatingtemperatureranges. Touseaceramicchipcapaci-

tor with Y5V dielectric, the value must be much higher than a

X7R ceramic capacitor to ensure the same minimum capaci-

tance over the equivalent operating temperature range.

P = (V – V

)I

+ V x I

+ V

x I

D

IN

OUT OUT

IN

GND

BIAS BIAS

Since the bias supply draws only 18µA, that contribution can

be ignored for this calculation.

If we know the maximum load current, we can solve for the

maximum input voltage using the maximum power dissipa-

tion calculated for a 50°C ambient, 319mV.

P

= (V – V

)I

+ V x I

DMAX

IN

OUT OUT IN GND

319mW = (V – 1V)150mA + V x 2.8mA

IN

Ground pin current is estimated using the typical character-

istics of the device.

No-Load Stability

TheMIC5238willremainstableandinregulationwithnoload

unlike many other voltage regulators. This is especially

important in CMOS RAM keep-alive applications.

469mW = V (152.8mA)

IN

V

= 3.07V

IN

Thermal Considerations

For higher current outputs only a lower input voltage will work

for higher ambient temperatures.

The MIC5238 is designed to provide 150mA of continuous

current in a very small package. Maximum power dissipation

canbecalculatedbasedontheoutputcurrentandthevoltage

drop across the part. To determine the maximum power

dissipation of the package, use the junction-to-ambient ther-

malresistanceofthedeviceandthefollowingbasicequation:

Assumingaloweroutputcurrentof20mA,themaximuminput

voltage can be recalculated:

319mW = (V – 1V)20mA + V x 0.2mA

IN

339mW = V x 20.2mA

IN

V

= 16.8V

IN

T

− T

A

J(MAX)

Maximum input voltage for a 20mA load current at 50°C

ambient temperature is 16.8V. Since the device has a 6V

rating, it will operate over the whole input range.

P

=

D(MAX)

θ

JA

T

is the maximum junction temperature of the die,

J(MAX)

Dual Suppy Mode Efficiency

125°C, and T is the ambient operating temperature. θ is

A

JA

By utilizing a bias supply the conversion efficiency can be

greatly enhanced. This can be realized as the higher bias

supplywillonlyconsumeafewµA’swhiletheinputsupplywill

require a few mA’s! This equates to higher efficiency saving

valuable power in the system. As an example, consider an

output voltage of 1V with an input supply of 2.5V at a load

layout dependent; Table 1 shows the junction-to-ambient

thermal resistance for the MIC5238.

MIC5238

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August 2003

MIC5238

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current of 150mA. The input ground current under these

conditions is 2mA, while the bias current is only 20µA. If we

calculate the conversion efficiency using the single supply

approach, it is as follows:

Input power = V × output current + V × V ground current

IN

+ V

x V

ground current

BIAS

Input power = 1.5 × 150mA + 1.5 × 0.002 + 2.5 × 0.0002 =

225mW

Input power = V × output current + V × (V

ground

Output power = 1V × 150mA = 150mW

Efficiency = 150/225 × 100 = 66.6 %

IN

BIAS

current + V ground current)

IN

Input power = 2.5V × 150mA + 2.5 × (0.0002+0.002) =

380.5mW

Therefore, by using the dual supply MIC5238 LDO the

efficiency is nearly doubled over the single supply version.

Output power = 1V × 0.15 = 150mW

Efficiency = 150/380.5 × 100 = 39.4%

This is a valuable asset in portable power management

applications equating to longer battery life and less heat

being generated in the application.

Now, using a lower input supply of 1.5V, and powering the

bias voltage only from the 2.5V input, the efficiency is as

follows:

This in turn will allow a smaller footprint design and an

extended operating life.

August 2003

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MIC5238

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Package Information

1.90 (0.075) REF

0.95 (0.037) REF

1.75 (0.069) 3.00 (0.118)

1.50 (0.059) 2.60 (0.102)

DIMENSIONS:

MM (INCH)

1.30 (0.051)

0.90 (0.035)

3.02 (0.119)

2.80 (0.110)

0.20 (0.008)

0.09 (0.004)

10°

0°

0.15 (0.006)

0.00 (0.000)

0.50 (0.020)

0.35 (0.014)

0.60 (0.024)

0.10 (0.004)

SOT-23-5 (M5)

1.90BSC

2.90BSC

1.90BSC

0.30

0.45

DIMENSIONS:

Millimeter

0.90

0.80

1.00

0.90

2.9BSC

1.60BSC

0.20

0.12

0.30

0.50

0.10

0.01

1.90BSC

TSOT-23-5 (D5)

MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com

The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.

Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can

reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into

the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s

use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify

Micrel for any damages resulting from such use or sale.

MIC5238

10

August 2003


型号：	MIC5238-1.1BD5
厂家：	MICREL SEMICONDUCTOR
描述：	Ultra-Low Quiescent Current, 150mA ?Cap LDO Regulator 超低静态电流， 150毫安？帽LDO稳压器稳压器
文件：	总10页 (文件大小：123K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

MIC5238-1.1BD5 [MICREL]

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