MIC5254_技术文档

MIC5254

Micrel

MIC5254

Dual 150mA µCap LDO with Error Flag Outputs

General Description

Features

The MIC5254 is an efficient, precise, dual CMOS voltage

regulator. It offers better than 1% initial accuracy, extremely

low dropout voltage (typically 135mV at 150mA) and low

ground current (typically 90µA) over load. The MIC5254

features two independent LDOs with error flags that indicate

an output fault condition such as overcurrent, thermal shut-

down and dropout.

• Input voltage range: 2.7V to 6.0V

• Dual, independent 150mA LDOs

• Error flags indicate fault condition

• Stable with ceramic output capacitor

• Ultra-low dropout: 135mV @ 150mA

• High output accuracy:

1.0% initial accuracy

2.0% over temperature

Designed specifically for handheld and battery-powered de-

vices, the MIC5254 provides a TTL-logic-compatible enable

pin.Whendisabled,powerconsumptiondropsnearlytozero.

• Low quiescent current: 90µA each LDO

• Tight load and line regulation

• Thermal shutdown and current limit protection

• “Zero” off-mode current

• TTL logic-controlled enable input

• MSOP-10 package

The MIC5254 also works with low-ESR ceramic capacitors,

reducing the amount of board space necessary for power

applications, critical in handheld wireless devices.

Key features include current limit, thermal shutdown, faster

transient response, and an active clamp to speed up device

turnoff. The MIC5254 is available in the MSOP-10 package

and is rated over a –40°C to +125°C junction temperature

range.

Applications

• Cellular phones and pagers

• Cellular accessories

• Battery-powered equipment

• Laptop, notebook, and palmtop computers

• Consumer/personal electronics

Ordering Information

Part Number

VOUTA

VOUTB

Junction Temp. Range

Package

MIC5254-SJBMM

3.3V

2.5V

–40°C to +125°C

MSOP-10

Other voltages available. Contact Micrel Marketing for details.

Typical Application

Dual Output LDO with Error Flags

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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Pin Configuration

FLGA

ENA

1

2

3

4

5

10 OUTA

9

8

7

6

INA

GNDA

FLGB

ENB

OUTB

GNDB

INB

MSOP-10 (BMM)

Pin Description

Pin Number

Pin Name

Channel

Pin Function

1

FLGA

A

Error Flag (Output): Open-drain output. Active low indicates an output

undervoltage condition.

2

ENA

A

Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;

logic low = shutdown. Do not leave open.

3

9

GNDA

INA

A

B

Ground.

Supply Input.

Regulator Output.

10

4

OUTA

FLGB

Error Flag (Output): Open-drain output. Active low indicates an output

undervoltage condition.

5

ENB

B

Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;

logic low = shutdown. Do not leave open.

7

6

8

GNDB

INB

B

Ground.

Supply Input.

Regulator Output.

OUTB

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Absolute Maximum Ratings (Note 1)

Operating Ratings (Note 2)

Supply Input Voltage (V ) .................................. 0V to +7V

Input Voltage (V ) ......................................... +2.7V to +6V

IN

Enable Input Voltage (V ) .................................. 0V to V

Enable Input Voltage (V ) ................................. 0V to +7V

EN

IN

EN

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

J

Power Dissipation (P ) ............... Internally Limited, Note 3

D

Thermal Resistance

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

J

MSOP-10 (θ ) ..................................................200°C/W

JA

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

Lead Temperature (soldering, 5 sec.) ....................... 260°C

ESD, Note 4.................................................................. 2kV

Electrical Characteristics (Note 5)

V_IN= V_OUT+ 1V, V_EN= V_{IN; OUT}= 100µA; T_J= 25°C, bold values indicate –40°C ≤ T_J≤ +125°C; unless noted.

I

Symbol

Parameter

Conditions

Min Typical Max

Units

V_O

Output Voltage Accuracy

I_OUT= 100µA

–1

–2

+1

+2

%

∆V_LNR

Line Regulation

V_IN= V_OUT+ 1V to 6V

I_OUT= 0.1mA to 150mA, Note 6

I_OUT= 100µA

0.02

1.5

0.1

90

0.075

2.5

%/V

%

∆V_LDR

Load Regulation

V_IN– V_OUT

Dropout Voltage, Note 7

mV

I_OUT= 100mA

150

I

_OUT= 150mA

135

200

250

mV

I_Q

Quiescent Current

V

_EN≤ 0.4V (shutdown)

0.2

90

1

µA

I_GND

Ground Pin Current, Note 8

I_OUT= 0mA

150

I_OUT= 150mA

117

60

µA

PSRR

Power Supply Rejection

f = 10Hz, V_IN= V_OUT+ 1V; C_OUT= 1µF

f = 100Hz, V_IN= V_OUT+ 0.5V; C_OUT= 1µF

f = 10kHz, V_IN= V_OUT+ 0.5V

V_OUT= 0V

dB

60

dB

45

dB

I_LIM

Current Limit

160

425

30

mA

e_n

Output Voltage Noise

µV(rms)

Enable Input

V_IL

V_IH

I_EN

Enable Input Logic-Low Voltage

Enable Input Logic-High Voltage

Enable Input Current

V_IN= 2.7V to 5.5V, regulator shutdown

V_IN= 2.7V to 5.5V, regulator enabled

0.4

V

1.6

V

_IL≤ 0.4V, regulator shutdown

_IH≥ 1.6V, regulator enabled

0.01

500

µA

Ω

V

Shutdown Resistance Discharge

Error Flag

V_FLG

Low Threshold

High Threshold

% of V_OUT(Flag ON)

% of V_OUT(Flag OFF)

90

%

96

V_OL

I_FL

Output Logic-Low Voltage

Flag Leakage Current

I_L= 100µA, fault condition

0.02

0.01

0.1

V

Flag OFF, V_FLG= 6V

µA

Thermal Protection

Thermal Shutdown Temperature

Thermal Shutdown Hysteresis

150

10

°C

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. The maximum allowable power dissipation of any T (ambient temperature) is P

= (T

–T )/θ . Exceeding the maximum allowable

J(max) A JA

A

D(max)

power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The θ of the MIC5254-SJBMM is

JA

200°C/W on a PC board (see “Thermal Considerations” section for further details).

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Note 4. Devices are ESD sensitive. Handling precautions recommended.

Note 5. Specification for packaged product only.

Note 6. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load

range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.

Note 7. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V

differential. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum

input operating voltage is 2.7V.

Note 8. Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground

pin current.

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Typical Characteristics

For each LDO Channel.

Power Supply Rejection Ratio

PSRR vs. Voltage Drop

70

60

50

40

30

20

10

0

I_LOAD= 100µA

60

50

60

50

40

30

20

10

0

100µA*

50mA*

40

I_LOAD= 150mA

50mA*

30

100mA*

150mA*

20

*I_LOAD

C_OUT= 4.7µF Ceramic

10

C_OUT= 1.0µF Ceramic

C_OUT= 1µF

0

10

0

200 400 600 800 1000

VOLTAGE DROP (mV)

100

10k

10

100

1k

10k 100k 1M

1k

100k 1M

FREQUENCY (Hz)

Ground Pin Current

130

115

113

111

109

107

105

103

101

99

125

120

115

110

105

100

95

125

120

115

110

105

100

V_IN= V_OUT+ 1V

97

I_LOAD= 100µA

I_LOAD= 150mA

95

0.1

1

10

100

1000

-40 -20 0 20 40 60 80 100120140

OUTPUT CURRENT (mA)

TEMPERATURE (°C)

Dropout

Characteristics

Ground Pin Current

3.5

140

120

100

80

140

3

2.5

2

120

100

80

60

40

20

0

100µA

150mA

1.5

1

60

40

0.5

0

20

I_LOAD= 100µA

I_LOAD= 150mA

0

1

2

3

4

5

6

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

INPUT VOLTAGE (V)

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

INPUT VOLTAGE (V)

Dropout Voltage

0.14

180

160

140

120

100

80

T = –40°C

160

140

120

100

80

0.12

0.1

0.08

0.06

0.04

0.02

0

T = 25°C

T = 125°C

60

40

20

I_LOAD= 100µA

I_LOAD= 150mA

0

-40 -20

0

20 40 60 80 100120140

-40 -20 0 20 40 60 80 100120140

0

20 40 60 80 100 120 140 160

OUTPUT CURRENT (mA)

TEMPERATURE (°C)

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Typical Characteristics

For each LDO Channel.

Output Voltage vs.

Temperature

Short Circuit Current

3.40

3.38

3.36

3.34

3.32

3.30

3.28

3.26

3.24

3.22

3.20

600

500

490

480

470

460

450

440

430

420

410

400

V_IN= V_OUT+ 1V

500

400

300

200

100

0

I_LOAD= 100µA

-40 -20

0

20 40 60 80 100 120

3

3.5

4

4.5

5

5.5

6

-40 -20 0 20 40 60 80 100120140

TEMPERATURE (°C)

INPUT VOLTAGE (V)

TEMPERATURE (°C)

Enable Threshold

vs. Temperature

Error Flag Pull-Up Resistor

1.3

4.5

4

Power Good

1.25

1.2

3.5

3

1.15

1.1

2.5

2

1.05

1

V_IN= 4V

1.5

1

0.95

0.9

0.5

0

0.85

0.8

I_LOAD= 100µA

Power Fail

-40 -20

0

20 40 60 80 100120140

0.1

1

10

100 1000 10000

TEMPERATURE (°C)

RESISTANCE (kΩ)

Test Circuit

MIC5254

V_INA

V_OUTA

9

10

1

VINA OUTA

47kΩ

1µF

2

1µF

Ceramic

FLAGA

0.01µF

ENA FLGA

GNDA OUTB

V_OUTB

3

8

47kΩ

V_INB

6

4

7

VINB FLGB

ENB GNDB

1µF

Ceramic

FLAGB

5

1µF

0.01µF

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Functional Characteristics

For each LDO Channel

Load Transient Response

Line Transient Response

C_IN= 1µF Ceramic

C_OUT= 1µF Ceramic

I_OUT= 100µA

C_IN= 1µF Ceramic

C_OUT= 1µF Ceramic

V_IN= 4V

150mA

100µA

TIME (4µs/div)

TIME (400µs/div)

Enable Pin Delay

Shutdown Delay

C_IN= 1µF Ceramic

C_OUT= 1µF Ceramic

I_OUT= 150mA

C_IN= 1µF Ceramic

C_OUT= 1µF Ceramic

I_OUT= 150mA

TIME (10µs/div)

Error Flag Start-up*

Error Flag Shutdown*

TIME (400µs/div)

* See Test Circuit

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Functional Diagram

INA

ENA

Startup/

Shutdown

Control

Reference

Voltage

Quickstart

Thermal

Sensor

FAULT

Error

Amplifier

Current

Amplifier

OUTA

Under-

voltage

Lockout

ACTIVE SHUTDOWN

Out of

Regulation

Detection

FLGA

Overcurrent

Dropout

Detection

GNDA

INB

ENB

Startup/

Shutdown

Control

Reference

Voltage

Quickstart

Thermal

Sensor

FAULT

Error

Amplifier

Current

Amplifier

OUTB

Under-

voltage

Lockout

ACTIVE SHUTDOWN

Out of

Regulation

Detection

FLGB

Overcurrent

Dropout

Detection

GNDB

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input without using a pull-down capacitor, there can be a

glitch on the error flag upon start up of the device. This is due

to the response time of the error flag circuit as the device

starts up. When the device comes out of the “zero” off mode

current state, all the various nodes of the circuit power up

before the device begins supplying full current to the output

capacitor. The error flag drives low immediately and then

releases after a few microseconds. The intelligent circuit that

triggers an error detects the output going into current limit

ANDtheoutputbeinglowwhilechargingtheoutputcapacitor.

The error output then pulls low for the duration of the turn-on

time. Acapacitorfromtheerrorflagtogroundwillfilteroutthis

glitch. The glitch does not occur if the error flag pulled up to

the output.

Applications Information

Enable/Shutdown

The MIC5254 comes with an active-high enable pin for each

regulator that allows the regulator to be disabled. Forcing the

enablepinlowdisablestheregulatorandsendsitintoa“zero”

off-mode-currentstate. Inthisstate, currentconsumedbythe

regulator goes nearly to zero. Forcing the enable pin high

enablestheoutputvoltage. ThispartisCMOSandtheenable

pin cannot be left floating; a floating enable pin may cause an

indeterminate state on the output.

Input Capacitor

The MIC5254 is a high performance, high bandwidth device.

Therefore, it requires a well-bypassed input supply for opti-

mal performance. A 1µF capacitor is required from the input

to ground to provide stability. Low ESR ceramic capacitors

provide optimal performance at a minimum of space. Addi-

tional high-frequency capacitors, such as small-valued NPO

dielectric type capacitors, help filter out high frequency noise

and are good practice in any RF based circuit.

Active Shutdown

The MIC5254 also features an active shutdown clamp, which

is an N-Channel MOSFET that turns on when the device is

disabled. This allows the output capacitor and load to dis-

charge, de-energizing the load.

No Load Stability

Output capacitor

TheMIC5254willremainstableandinregulationwithnoload

unlike many other voltage regulators. This is especially

important in CMOS RAM keep-alive applications.

The MIC5254 requires an output capacitor for stability. The

design requires 1µF 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 300mΩ. The output capacitor can be increased, but

performance has been optimized for a 1µF ceramic output

capacitor and does not improve significantly with larger

capacitance.

Thermal Considerations

The MIC5254 is a dual LDO voltage regulator designed to

provide two output voltages from one package. Both regula-

tor outputs are capable of sourcing 150mA of output current.

Proper thermal evaluation needs to be done to ensure that

the junction temperature does not exceed it’s maximum

value, 125°C. Maximum power dissipation can be calculated

basedontheoutputcurrentandthevoltagedropacrosseach

regulator. The sum of the power dissipation of each regulator

determines the total power dissipation. The maximum power

dissipation that this package is capable of handling can be

determined using thermal resistance, junction to ambient,

and the following basic 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-

torwithY5Vdielectric, thevaluemustbemuchhigherthanan

X7R ceramic capacitor to ensure the same minimum capaci-

tance over the equivalent operating temperature range.

T

− T

A





J(max)

P

=

D(max)





θ





JA

Error Flag

T

is the maximum junction temperature of the die,

J(max)

125°CandT istheambientoperatingtemperatureofthedie.

The error flag output is an active-low, open-drain output that

drives low when a fault condition AND an undervoltage

detection occurs. Internal circuitry intelligently monitors

overcurrent, overtemperature and dropout conditions and

ORs these outputs together to indicate some fault condition.

The output of that OR gate is ANDed with an output voltage

monitor that detects an undervoltage condition. That output

drives the open-drain transistor to indicate a fault. This

prevents chattering or inadvertent triggering of the error flag.

The error flag must be pulled-up using a resistor from the flag

pin to either the input or the output.

A

θ

is layout dependent. Table 1 shows the typical thermal

JA

resistance for a minimum footprint layout for the MIC5254.

Package

θ_JAat Recommended Minimum Footprint

200°C/W

MSOP-10

Table 1. Thermal Resistance

The actual power dissipation of each regulator output can be

calculated using the following simple equation:

P = (V – V

)I

+ V × I

D

IN

OUT OUT IN GND

Each regulator contributes power dissipation to the overall

power dissipation of the package.

The error flag circuit was designed essentially to work with a

capacitor to ground to act as a power-on reset generator,

signaling a power-good situation once the regulated voltage

was up and/or out of a fault condition. This capacitor delays

the error signal from pulling high, allowing the downstream

circuitstimetostabilize.Whentheerrorflagispulled-uptothe

P

= P

+ P

D(reg1) D(reg2)

D(total)

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Each output is rated for 150mA of output current, but the

application may limit the amount of output current based on

the total power dissipation and the ambient temperature. A

typical application may call for one 3.3V output and one 2.5V

output from a single Li-Ion battery input. This input can be as

high as 4.2V.

P

= 135.5mW

D(reg1)

Since the total power dissipation allowable is 325mW, the

maximumpowerdissipationofthesecondregulatorislimited

to:

P

= P

+ P

D(max)

D(reg1) D(reg2)

325mW = 135.5mW + P

D(reg2)

When operating at high ambient temperatures, the output

current may be limited. When operating at an ambient of

60°C, the maximum power dissipation of the package is

calculated as follows:

P

= 189.5mW

D(reg2)

The maximum output current of the second regulator can be

calculated using the same equations but solving for the

output current (ground current is constant over load and

simplifies the equation):





125°C − 60°C

200°C/W

P

=





D(max)





P

= (V – V

)I

+ V × I

D(reg2)

IN

OUT OUT IN GND

189.5mW = (4.2V – 2.5V)I

+ 4.2V × 100µA

P = 325mW

OUT

D

I

= 111.2mA

Fortheapplicationmentionedabove,ifregulator1issourcing

150mA, it contributes the following to the overall power

dissipation:

OUT

The second output is limited to 110mA due to the total power

dissipation of the system when operating at 60°C ambient

temperature.

P

= (V – V

)I

+ V × I

D(reg2)

IN

OUT OUT IN GND

= (4.2V – 3.3V)150mA + 4.2V × 100µA

D(reg1)

MIC5254

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MIC5254

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Package Information

3.15 (0.122)

2.85 (0.114)

DIMENSIONS:

MM (INCH)

4.90 BSC (0.193)

3.10 (0.122)

2.90 (0.114)

1.10 (0.043)

0.94 (0.037)

0.26 (0.010)

0.10 (0.004)

0.30 (0.012)

0.15 (0.006)

0.05 (0.002)

6° MAX

0° MIN

0.70 (0.028)

0.40 (0.016)

0.50 BSC (0.020)

10-Pin MSOP (BMM)

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.

September 2003

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MIC5254


型号：	MIC5254
厂家：	MICREL SEMICONDUCTOR
描述：	DUAL 150MA UCAP LDO WITH ERROR FLAG OUTPUTS 双150MA UCAP LDO提供错误标志产出输出元件
文件：	总11页 (文件大小：161K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

MIC5254 [MICREL]

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