MIC5231-2.85BM5 - Micrel - Datasheet.Live

MIC5231

Micropower µCap LDO Regulator

IttyBitty is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

November 2008 M9999-110408-B

General Description

The MIC5231 µCap low dropout voltage regulator is

intended for low output current biasing applications. It

features extremely low ground current, not greater than

4µA under all load and temperature conditions, making it

efficient and ideal for keep-alive applications in devices

such as notebook computers.

The MIC5231 offers better than 2% initial accuracy and

low dropout (typically 150mV at 10mA output current). An

output capacitor is not required for stable operation,

decreasing cost and board space. Tiny ceramic chip

capacitors may be used to improve transient response.

The MIC5231 also features a control pin which allows the

regulator to be shut down when not required. Its shutdown-

state draws zero current, benefiting battery-powered appli-

cations.

The MIC5231 is available in fixed output voltages of 2.75V,

3.0V, 3.3V and 5V in the small SOT-23-5 IttyBitty®

package. Contact Micrel for other voltage options.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• Extremely low quiescent current—only 0.65µA

• No output capacitor requirement

• Stable with ceramic or tantalum capacitors

• IttyBitty® SOT-23-5 surface-mount package

• 10mA output drive

• Low 150mV at 10mA dropout voltage

• Tight load and line regulation

• Low temperature coefficient

• Logic-level enable input

Applications

• Real-time clocks

• SRAM backup

• Cellular telephones

• Laptop, notebook and palmtop computers

• Battery-powered equipment

• Bar code scanners

• SMPS post-regulator and DC-to-DC modules

_________________________________________________________________________________________________________

Typical Application

OUT

MIC5231-5.0YM5

GND

VIN

6V VOUT

5V Linear Regulator Application

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Ordering Information(1)

Part Number Marking Voltage Temperature Range Package Lead

Finish

MIC5231-2.75BM5 LM2H 2.75V –40°C to +125°C 5-Pin SOT-23 Standard

MIC5231-2.75YM5 LM2H(2) 2.75V –40°C to +125°C 5-Pin SOT-23(3) Pb-Free

MIC5231-3.0BM5 LM30 3.0V –40°C to +125°C 5-Pin SOT-23 Standard

MIC5231-3.0YM5 LM30(2) 3.0V –40°C to +125°C 5-Pin SOT-23(3) Pb-Free

MIC5231-3.3BM5 LM33 3.3V –40°C to +125°C 5-Pin SOT-23 Standard

MIC5231-3.3YM5 LM33(2) 3.3V –40°C to +125°C 5-Pin SOT-23(3) Pb-Free

MIC5231-5.0BM5 LM50 5.0V –40°C to +125°C 5-Pin SOT-23 Standard

MIC5231-5.0YM5 LM50(2) 5.0V –40°C to +125°C 5-Pin SOT-23(3) Pb-Free

Notes:

1. Other voltages available. Contact factory for details.

2. Under bar ( ) symbol used to identify Pb-Free device may not be to scale.

3. SOT-23-5 is a RoHS-compliant package. Lead finish is a NiPdAu. Mold compound is Halogen free.

Pin Configur ation

MIC5231-5.0BM5 (M5)

MIC5231-5.0YM5 (M5)

Pin Description

Pin Number Pin Name Pin Function

1 EN Enable (Input): Active high. Logic high = enable; logic low = shutdown. Do not float.

2 GND Ground.

3 IN Supply Input.

4 OUT Regulated Output.

5 NC Not internally connected.

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Absolute Maximum Ratings(1)

Supply Voltage (VIN)...................................... –0.6V to +14V

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

Storage Temperature (Ts) .........................–60°C to +150°C

ESD Rating(3).................................................................. 2kV

Operating Ratings(2)

Supply Voltage (VIN)........................................3.5VV to 12V

Ambient Temperature (TA) .......................... –40°C to +85°C

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

Thermal Resistance(4)

Electrical Characteristics

VIN = VOUT + 1V; IL = 100µA; CL = 0.47µF; TJ = 25°C, bold values indicate –40°C≤ TJ ≤ +125°C, unless noted.

Symbol Parameter Condition Min Typ Max Units

VOUT Output Voltage Accuracy variation from nominal VOUT –2

–3

∆VOUT/∆T Output Voltage

Temperature Coefficient

Note 5 250 ppm/°C

Line Regulation VIN = 6V to 12V 0.2 0.25 % ∆VOUT/VOUT

Load Regulation IL = 10µA to 10mA, Note 6 0.2 1 %

IL = 1mA 15 mV VDO Dropout Voltage, Note 7

IL = 10mA 150 300 mV

VIN = 6V, IL = 10mA 0.65 3 µA IQ Ground Pin Current

VIN = 12V, IL = 10mA 1.1 4 µA

PSRR Ripple Rejection f = 100Hz, IL = 100µA 50 dB

Enable Input

VEN = logic low (regulator off) 0.4 0.18 V VENL Enable Input Voltage

VEN = logic high (regulator on) 1.4 V

IENL Enable Input Current VENL ≤ 0.18V (regulator off) 1 nA

IENH Enable Input Current VENH ≥ 1.4V (regulator on) 1 nA

Notes:

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

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

3. Devices are ESD sensitive. Handling precautions recommended.

4. The maximum allowable power dissipation at any TA (ambient temperature) is PD(max) = (TJ(max) – TA) ÷ θJA. The θJC of the MIC5231 is 130°C/W.

Mounted to a standard PC board, the θJA is approximately 235°C/W.

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

6. Regulation is measured at constant junction temperature using low duty cycle pulse testing.

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

For outputs below 3.5V, dropout voltage is the input-to-output differential with the minimum input voltage 3.5V. Minimum input operating voltage is

3.5V.

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Typical Characteristics

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Block Diagram

IN OUT

GND

MIC5231

Bandgap

Reference

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Application Information

Input Capacitor

A 0.1µF (or larger) capacitor should be placed from the

IN (supply input) to GND (ground) if there is more than

20cm of wire between IN and the ac filter capacitor or if

supplied from a battery.

Output Capacitors

The MIC5231 does not require an output capacitor for

stability. A 1µF or larger capacitor is recommended

between OUT (output) and GND to improve the

regulator’s transient response. A 0.1µF capacitor can be

used to reduce overshoot recovery time at the expense

of overshoot amplitude. The ESR (effective series

resistance) of this capacitor has no effect on regulator

stability, but low-ESR capacitors improve high frequency

transient response. The value of this capacitor may be

increased without limit, but values larger than 10µF tend

to increase the settling time after a step change in input

voltage or output current.

The MIC5231 has no minimum load current; it will

remain stable and in regulation with no load (other than

the internal voltage divider). This is especially important

in real-time clock and CMOS RAM keep-alive

applications.

Minimum Load Current

The MIC5231 does not require a minimum load for

proper operation. This allows the device to operate in

applications where very light output currents are required

for keep-alive purposes. This is important for powering

SRAM or Flash memory in low-power modes for

handheld devices.

Safe Operating Conditions

The MIC5231 does not incorporate current limit or

thermal shutdown in the design. The output pass

element is approximately 15Ω, therefore, when a short

occurs from the output to ground, the current is self-

limited. The pass element has a positive temperature

coefficient, such that when the device gets hot, the

output impedance goes up, limiting the current even

further. The maximum junction temperature for the

device is +125°C, and it is important that this is not

exceeded for any length of time.

Thermal Considerations

The MIC5231 is not intended for sourcing currents that

would cause a large power loss in the device, but since it

is not current limited, it is possible to source more than

the rated 10mA. At this point, it is important to ensure

that the die temperature does not exceed +125°C.

Power dissipation in the regulator is calculated as

follows:

(

)

GNDINOUTOUTIND IVI VVP ⋅+

−

The MIC5231 consumes only 0.65µA over load and

does not need to consider that contribution in the power

dissipation equation, therefore the equation is simplified.

(

)

OUTOUTIND I VVP

−

The MIC5231, in the IttyBitty SOT-23-5 package, has a

thermal resistance, junction-to-ambient, of 235°C/W.

Using this number, the power dissipation capability of

that package, without exceeding a +125°C junction

temperature rating, can easily be calculated.

AJ(MAX)

D(MAX) θ

P−

C/W235

TC125

D(MAX) °

−°

If the device is being operated at +85°C, the maximum

power dissipation allowed can easily be determined.

C/W235

C85C125

PD(MAX) °

°−°

170mWPD(MAX)

Therefore, the device can only dissipate 170mW

maximum. If the MIC5231 is powered off of a 12V

source and the output voltage is 3.3V, the maximum

output current can be calculated.

(

)

OUTOUTIND(MAX) I VVP

−

(

)

OUT

I 3.3V12V170mW −

8.7V

170mW

IOUT =

19.5mAIOUT

Therefore, the device can source almost 20mA at an

ambient of +85°C before the die temperature exceeds

+125°C.

Micrel, Inc. MIC5231

November 2008 7 M9999-110408-B

Package Information

5-Pin SOT-23 (M5)

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com

The information furnished by Micrel in this data sheet 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 a Purchaser’s own risk and Purchaser agrees to fully

indemnify Micrel for any damages resulting from such use or sale.