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产品型号MIC2940A-5.0BU的概述

MIC2940A-5.0BU的概述 MIC2940A-5.0BU是一款高性能、低压差（LDO）稳压器，广泛应用于各种电子设备中，能够提供稳定的5V输出电压。此芯片因其稳健性和高效性，受到许多工程师和设计师的青睐，特别是在要求较低噪声和高电流输出的应用场合。MIC2940A的最大输出电流可达到1A，适合为微处理器、数字电路和其他电源敏感型设备供电。芯片的详细参数 MIC2940A-5.0BU在技术参数上表现优良，主要参数如下： - 输出电压: 5.0V - 最大输出电流: 1A - 输入电压范围: 6V至30V - 压差电压: 0.5V（当输出电流为1A时） - 静态电流: 500µA - 工作温度范围: -40℃至+125℃ - 过温保护: 内置 - 电源抑制比（PSRR）: 65dB（工频） - 负载响应时间: 快速，约200µs - 封装形式: TO-220、TO-263、SOT...

产品型号MIC2940A-5.0BU的Datasheet PDF文件预览

MIC2940A/2941A

Micrel

MIC2940A/2941A

1.25A Low-Dropout Voltage Regulator

Preliminary Information

General Description

Features

•

High output voltage accuracy

Guaranteed 1.25A output

The MIC2940A and MIC2941A are “bulletproof” efficient

voltage regulators with very low dropout voltage (typically

40mV at light loads and 350mV at 1A), and low quiescent

current(240µAtypical).ThequiescentcurrentoftheMIC2940A

increases only slightly in dropout, thus prolonging battery life.

Key MIC2940A features include protection against reversed

battery,fold-backcurrentlimiting,andautomotive“loaddump”

protection (60V positive transient).

Low quiescent current

Low dropout voltage

Extremely tight load and line regulation

Very low temperature coefficient

Current and thermal limiting

Input can withstand –20V reverse battery and +60V

positive transients

The MIC2940 is available in both fixed voltage (3.3V, 5V, and

12V) and adjustable voltage configurations. The MIC2940A-

xx devices are three pin fixed voltage regulators. A logic-

compatible shutdown input is provided on the adjustable

MIC2941A,whichenablestheregulatortobeswitchedonand

off.

•

Logic-controlled electronic shutdown

Output programmable from 1.24V to 26V(MIC2941A)

Available in TO-220, TO-263, TO-220-5, and TO-263-5

packages.

Applications

•

Battery Powered Equipment

Cellular Telephones

Laptop, Notebook, and Palmtop Computers

PCMCIA V_CCand V_PPRegulation/Switching

Bar Code Scanners

Automotive Electronics

SMPS Post-Regulator/ DC to DC Modules

Voltage Reference

High Efficiency Linear Power Supplies

Pin Configuration

2 3 4 5

INPUT GROUND OUTPUT

TO-263 Package

TO-263-5 Package

(MIC2941ABU)

(MIC2940A-xxBU)

MIC2941A Pinout

1) Adjust

2) Shutdown

3) Ground

4) Input

2 3 4 5

Front View

OUTPUT

INPUT GROUND

TO-220 Package

(MIC2940A-xxBT)

5) Output

TO-220-5 Package

(MIC2941ABT)

The Tab is Ground on TO-220 and TO-263 packages

June 1999

MIC2940A/2941A

Micrel

Absolute Maximum Ratings

If Military/Aerospace specified devices

are required, contact your local Micrel

representative/distributor for availability

and specifications.

Ordering Information

Part Number

Voltage Temperature Range*

Package

TO-220

TO-263

TO-220

TO-263

TO-220

TO-263

TO-220-5

TO-263-5

Power Dissipation (Note 1) ............... Internally Limited

MIC2940A-3.3BT

MIC2940A-3.3BU

MIC2940A-5.0BT

MIC2940A-5.0BU

MIC2940A-12BT

MIC2940A-12BU

MIC2941ABT

3.3

5.0

–40°C to +125°C

Lead Temperature (Soldering, 5 seconds) ........ 260°C

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

Operating Junction Temperature Range

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

TO-220 θ_JC........................................................ 2 °C/W

TO-263 θ_JC........................................................ 2 °C/W

Input Supply Voltage ...............................–20V to +60V

Operating Input Supply Voltage .................. 2V^†to 26V

Adjust Input Voltage (Notes 9 and 10)

......................................................–1.5V to +26V

Shutdown Input Voltage .........................–0.3V to +30V

Error Comparator Output Voltage .......... –0.3V to +30V

Adj

MIC2941ABU

†

Across the full operating temperature, the minimum

* Junction temperatures

input voltage range for full output current is 4.3V to 26V.

Output will remain in-regulation at lower output voltages

and low current loads down to an input of 2V at 25°C.

Schematic Diagram

FEEDBACK

R18

20kΩ

Q15A

Q15B

Q24

Q26

Q25

OUT

R11

SENSE

kΩ

R27

R17

12 kΩ

Q14

R11

20.6

kΩ

Q17

Q16

V TAP

R28

Q20

20 kΩ

Q22

R10

150

kΩ

Q42

31.4 kΩ

Q21

Q23

40 pF

50 kΩ

R15

100 kΩ

180

kΩ

140

kΩ

27.8 kΩ

R12

110

kΩ

R14

350

kΩ

R13

100

kΩ

R16

30 kΩ

Q40

Q13

Q12

R17

Q41

Q11

10 Ω

Q29

R30

Q18

Q19

Q28

kΩ

50 kΩ

13 kΩ

R21 8 Ω

50 kΩ

10 kΩ

Q30 Q31

SHDN

R23 60 kΩ

Q37

Q36

R22

150 kΩ

R24

50 kΩ

ERROR

Q38

Q34

R26

60 kΩ

DENOTES CONNECTION ON FIXED

VOLTAGE VERSIONS ONLY

R25

2.8 kΩ

GND

Q39

MIC2940A/2941A

June 1999

MIC2940A/2941A

Micrel

Electrical Characteristics

Limits in standard typeface are for T_J= 25°C and limits in boldface apply over the full operating temperature range.

Unless otherwise specified, V_IN= V_OUT+ 1V, I_L= 1000mA, C_L= 10µF. The MIC2941A is programmed to output 5V and has

_SHUTDOWN≤ 0.6V.

Symbol

Parameter

Conditions

Min

–1

Typical

Max

Units

V_O

Output Voltage

Accuracy

–2

5 mA ≤ I_L≤ 1A

–2.5

2.5

100

∆V_O

∆T

Output Voltage

Temperature Coef.

Line Regulation

(Note 2)

ppm/°C

∆V_O

V_O

V_IN= V_OUT+ 1V to 26V

0.03

0.04

0.10

0.40

0.16

0.20

∆V_O

V_O

Load Regulation

I_L= 5mA to 1.25A

I_L= 5mA to 1A

(Note 3)

V_IN– V_O

Dropout Voltage

(Note 4)

I_L= 5mA

200

350

400

240

150

180

250

320

450

600

I_L= 250mA

I_L= 1000mA

I_L= 1250mA

I_GND

Ground Pin Current I_L= 5mA

(Note 5)

350

500

4.5

µA

I_L= 250mA

I_L= 1000mA

I_L= 1250mA

I_GNDDO

Ground Pin

V_IN= 0.5V less than designed V_OUT

330

600

µA

Current at Dropout (V_OUT≥ 3.3V)

(Note 5)

I_L= 5mA

V_OUT= 0V

(Note 6)

I_LIMIT

Current Limit

1.6

0.05

400

260

2.4

∆V_O

∆P_D

e_n

Thermal Regulation (Note 7)

0.2

%/W

Output Noise

Voltage

C_L= 10µF

C_L= 33µF

µV RMS

(10Hz to 100kHz)

I_L= 100mA

June 1999

MIC2940A/2941A

Micrel

Electrical Characteristics (MIC2941A Only)

Parameter

Conditions

Min

Typical

Max

Units

Reference Voltage

1.223

1.235

1.247

1.210

1.260

V max

Reference Voltage

(Note 8)

1.204

1.266

Adjust Pin

Bias Current

Reference Voltage

Temperature

Coefficient

ppm/°C

nA/°C

Adjust Pin Bias

Current Temperature

Coefficient

0.1

Shutdown Input

Input Logic Voltage

1.3

Low (ON)

High (OFF)

0.7

2.0

Shutdown Pin

Input Current

V_SHUTDOWN= 2.4V

100

µA

V_SHUTDOWN= 26V

450

600

750

µA

Regulator Output

(Note 10)

Current in Shutdown

Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not

apply when operating the device outside of its rated operating conditions. The maximum allowable power dissipation is a function of the

maximum junction temperature, T_{J (MAX)}, the junction-to-ambient thermal resistance, θ_JA, and the ambient temperature, T_A. The maximum

allowable power dissipation at any ambient temperature is calculated using: P_(MAX)= (T_J(MAX)– T_A)/ θ_JA.Exceeding the maximum allowable

power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.

Note 2: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.

Note 3: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Changes in output voltage due to

heating effects are covered by the thermal regulation specification.

Note 4: Dropout Voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value

measured at 1V differential. At low values of programmed output voltage, the minimum input supply voltage of 4.3V over temperature must

be taken into account.

Note 5: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus

the ground pin current.

Note 6: The MIC2940A features fold-back current limiting. The short circuit (V_OUT= 0V) current limit is less than the maximum current with

normal output voltage.

Note 7: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding

load or line regulation effects. Specifications are for a 200mA load pulse at V_IN= 20V (a 4W pulse) for T = 10ms.

Note 8:

V_REF≤ V_OUT≤ (V_IN– 1 V), 4.3V ≤ V_IN≤ 26V, 5mA < I_L≤ 1.25A, T_J≤ T_{J MAX.}

Note 9: Circuit of Figure 3 with R1 ≥ 150kΩ. V_SHUTDOWN≥ 2 V and V_IN≤ 26 V,V_OUT= 0.

Note 10: When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode

clamped to ground.

Note 11: Maximum positive supply voltage of 60 V must be of limited duration (< 100 ms) and duty cycle ( ≤ 1%). The maximum continuous

supply voltage is 26V.

MIC2940A/2941A

June 1999

MIC2940A/2941A

Micrel

Typical Characteristics

Dropout Voltage

vs. Temperature

Dropout Voltage

vs. Output Current

Dropout

Characteristics

1000

800

600

400

200

500

400

300

200

100

I_LOAD= 5mA

I_LOAD= 1.25A

-60 -30

30 60 90 120 150

0.00 0.25 0.50 0.75 1.00 1.25

TEMPERATURE (°C)

OUTPUT CURRENT (A)

INPUT VOLTAGE (V)

Ground Current

vs. Output Current

Ground Current

vs. Supply Voltage

Ground Current

vs. Supply Voltage

400

300

200

100

FIXED 5V

I_LOAD= 5mA

FIXED 3.3V DEVICE

I_LOAD= 1.25A

0.1

100

1000 11000A00

OUTPUT CURRENT (mA)

SUPPLY VOLTAGE (V)

INPUT VOLTAGE (V)

Ground Current

vs. Temperature

Ground Current

vs. Temperature

Ground Current

vs. Temperature

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

0.40

0.30

0.20

0.10

0.00

I_LOAD= 1.25A

I_LOAD= 100mA

I_LOAD= 5mA

-60 -30

30 60 90 120 150

-60 -30

30 60 90 120 150

-60 -30

30 60 90 120 150

TEMPERATURE (°C)

Fixed 3.3V Output Voltage

vs. Temperature

Short Circuit and Maximum

Current vs. Temperature

Ground Current

vs. Input Voltage

3.40

3.38

3.36

3.34

3.32

3.30

3.28

3.26

3.24

3.22

3.20

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

1000

V_OUT= V_NOMINAL– 0.5V

R_LOAD= 100Ω

800

600

400

200

V_OUT= 0V

FIXED 3.3V

VERSION

3 SAMPLES

-200

-60 -30

30 60 90 120 150

-60 -30

30 60 90 120 150

-30 -20 -10

10 20 30

TEMPERATURE (°C)

INPUT VOLTAGE (V)

June 1999

MIC2940A/2941A

Micrel

MIC29401/2 Shutdown Current

vs. Temperaure

Load Transient

125

100

750

500

250

200

100

C_OUT= 100 µF

C_OUT= 10 µF

V_EN= 5V

-100

-250

-520.0

1.5

-220.0

1.5

V_EN= 2V

1.0

5mA

0.5

0.0

-0.5

-60 -30

30 60 90 120 150

-5

TEMPERATURE (°C)

TIME (ms)

MIC29402/3 Adjust Pin

Current vs. Temperature

Line Transient

C_OUT= 10 µF

C_OUT= 100 µF

-20

-140

-10

I_LOAD= 5mA

-60 -30

30 60 90 120 150

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

TIME (ms)

-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

TIME (ms)

TEMPERATURE (°C)

Output Impedance

vs. Frequency

0.1

I_LOAD= 10mA

0.01

FREQUENCY (Hz)

MIC2940A/2941A

June 1999

MIC2940A/2941A

Micrel

Reducing Output Noise

Applications Information

External Capacitors

In reference applications it may be advantageous to reduce

the AC noise present at the output. One method is to reduce

A 10µF (or greater) capacitor is required between the the regulator bandwidth by increasing the size of the output

MIC2940A output and ground to prevent oscillations due to capacitor. This is relatively inefficient, as increasing the

instability. Most types of tantalum or aluminum electrolytics capacitor from 1 µF to 220 µF only decreases the noise from

will be adequate; film types will work, but are costly and 430µV to 160µV_RMSfor a 100kHz bandwidth at 5V output.

therefore not recommended. Many aluminum electrolytics Noise can be reduced by a factor of four with the MIC2941A

haveelectrolytesthatfreezeatabout–30°C,sosolidtantalums by adding a bypass capacitor across R₁, since it reduces the

are recommended for operation below –25°C. The important high frequency gain from 4 to unity. Pick

parameters of the capacitor are an effective series resistance

of about 5Ω or less and a resonant frequency above 500kHz.

The value of this capacitor may be increased without limit.

C_BYPASS

R • 200 Hz

At lower values of output current, less output capacitance is

required for output stability. The capacitor can be reduced to

3.3µF for current below 100mA or 2.2µF for currents below 10

mA. Adjusting the MIC2941A to voltages below 5V runs the

error amplifier at lower gains so that more output capacitance

is needed. For the worst-case situation of a 1.25A load at

1.23V output (Output shorted to Adjust) a 22µF (or greater)

capacitor should be used.

or about 0.01 µF. When doing this, the output capacitor must

be increased to 22 µF to maintain stability. These changes

reduce the output noise from 430 µV to 100 µV rms for a 100

kHzbandwidthat5Voutput.Withthebypasscapacitoradded,

noisenolongerscaleswithoutputvoltagesothatimprovements

are more dramatic at higher output voltages.

Automotive Applications

TheMIC2940Aisideallysuitedforautomotiveapplicationsfor

a variety of reasons. It will operate over a wide range of input

voltages with very low dropout voltages (40mV at light loads),

andverylowquiescentcurrents(240µAtypical).Thesefeatures

are necessary for use in battery powered systems, such as

automobiles. It is a “bulletproof” device with the ability to

survive both reverse battery (negative transients up to 20V

below ground), and load dump (positive transients up to 60V)

conditions. A wide operating temperature range with low

temperature coefficients is yet another reason to use these

versatile regulators in automotive designs.

The MIC2940A will remain stable and in regulation with load

currents ranging from 5mA on up to the full 1.25A rating. The

external resistors of the MIC2941A version may be scaled to

draw this minimum load current.

A 0.22µF capacitor should be placed from the MIC2940A

input to ground if there is more than 10 inches of wire between

the input and the AC filter capacitor or if a battery is used as

the input.

Programming the Output Voltage (MIC2941A)

The MIC2941A may be programmed for any output voltage

betweenits1.235Vreferenceandits26Vmaximumrating.An

external pair of resistors is required, as shown in Figure 3.

The complete equation for the output voltage is

V_OUT= V_REFx { 1 + R₁/R₂} – |I_FB| R₁

4.75V

OUTPUT

where V_REFis the nominal 1.235 reference voltage and I_FBis

the Adjust pin bias current, nominally 20nA. The minimum

recommended load current of 1 µA forces an upper limit of

1.2MΩ on the value of R₂, if the regulator must work with no

load (a condition often found in CMOS in standby), I_FBwill

produce a –2% typical error in V_OUTwhich may be eliminated

at room temperature by trimming R₁. For better accuracy,

choosing R₂= 100kΩ reduces this error to 0.17% while

increasing the resistor program current to 12 µA. Since the

MIC2941Atypicallydraws100µAatnoloadwithSHUTDOWN

open-circuited, this is a negligible addition.

VOLTAGE

NOT

ERROR

VALID

INPUT

VOLTAGE

1.3V

* SEE APPLICATIONS INFORMATION

Figure 1. ERROR Output Timing

June 1999

MIC2940A/2941A

Micrel

Typical Applications

OUT

1.2V

26V

OUT

≈5V

OUT

V_OUT= 5V

SHUTDOWN

INPUT

SHUTDOWN

22µF

100

OFF

10µF

GND ADJUST

1.23V

GND

REF

= V

REF

x (1 +

)

OUT

Figure 2. MIC2940A-5.0 Fixed +5V Regulator

Figure 3. MIC2941A Adjustable Regulator

+5V to +7V

OUT

≈ V

OUT

SHUTDOWN

INPUT

OUT

SHUTDOWN

OFF

10µF

300kΩ

100pF

GND

ADJUST

GND ADJUST

220kΩ

180kΩ

470 kΩ

3.3V

2N2222

Input Output

3.3V

5.0V

*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV TO 400mV,

DEPENDING ON LOAD CURRENT.

ADJUST PIN LOW= ENABLE OUTPUT. Q1 ON = 3.3V, Q1 OFF = 5.0V.

Figure 4. MIC2941A Wide Input Voltage Range Current Limiter

Figure 5. MIC2941A 5.0V or 3.3V Selectable Regulator with

Shutdown.

MIC2940A/2941A

June 1999

MIC2940A-5.0BU相关文章

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MIC2940A-5.0BU产品参数

型号:	MIC2940A-5.0BU
是否无铅：	含铅
是否Rohs认证：	不符合
生命周期：	Active
零件包装代码：	D2PAK
包装说明：	TO-263, 3 PIN
针数：	4
Reach Compliance Code：	unknown
风险等级：	5.71
Is Samacsys：	N
最大回动电压 1：	0.6 V
最大输入电压：	26 V
最小输入电压：	2 V
JESD-30 代码：	R-PSSO-G3
JESD-609代码：	e0
长度：	10.363 mm
湿度敏感等级：	3
功能数量：	1
端子数量：	3
工作温度TJ-Max：	125 °C
工作温度TJ-Min：	-40 °C
最大输出电流 1：	1.25 A
最大输出电压 1：	5.125 V
最小输出电压 1：	4.875 V
标称输出电压 1：	5 V
封装主体材料：	PLASTIC/EPOXY
封装代码：	TO-263
封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE
峰值回流温度（摄氏度）：	240
调节器类型：	FIXED POSITIVE SINGLE OUTPUT LDO REGULATOR
座面最大高度：	4.902 mm
表面贴装：	YES
技术：	BIPOLAR
端子面层：	TIN LEAD
端子形式：	GULL WING
端子节距：	2.54 mm
端子位置：	SINGLE
处于峰值回流温度下的最长时间：	30
宽度：	8.7755 mm
Base Number Matches：	1

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