MIC5235-2.8YM5 TR - Micrel

MIC5235

Ultra-Low Quiescent Current, 150mA

µCap LDO Regulator

General Description

The MIC5235 is a 150mA highly accurate, low dropout

regulator with high input voltage and ultra-low ground

current. This combination of high voltage and low ground

current makes the MIC5235 ideal for USB and portable

electronics applications, using 1-cell, 2-cell or 3-cell Li-Ion

battery inputs.

A µCap LDO design, the MIC5235 is stable with either

ceramic or tantalum output capacitor. It only requires a

2.2µF capacitor for stability.

Features of the MIC5235 includes enable input, thermal

shutdown, current limit, reverse battery protection, and

reverse leakage protection.

Available in fixed and adjustable output voltage versions,

the MIC5235 is offered in the IttyBitty® SOT-23-5 package

with a junction temperature range of –40°C to +125°C.

Features

• Wide input voltage range: 2.3V to 24V

• Ultra low ground current: 18µA

• 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 battery protection

• Reverse leakage protection

• Thermal shutdown and current limit protection

• IttyBitty® SOT-23-5 package

• Adjustable output from 1.24V-20V

Applications

• USB power supply

• Cellular phones

• Keep-alive supply in notebook and portable computers

• Logic supply for high-voltage batteries

• Automotive electronics

• Battery powered systems

Typical Application

COUT=2.2µF

ceramic

IGND=18µA

CIN=1.0µF

MIC5235BM5

VIN VOUT=1.8V

49 14 19 24

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

IOUT =10µA

IOUT = 1mA

IOUT = 100µA

Ultra-Low Current Adjustable Regulator Application

Ground Current vs. Input Voltage

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

May 2008 M9999-051508

Micrel, Inc. MIC5235

May 2008 2 M9999-051508

Ordering Information

Part Number Marking Codes

Standard Pb-Free Standard Pb-Free*

Voltage**

Junction

Temp. Range

Package

MIC5235-1.5BM5 MIC5235-1.5YM5 L215 L215 1.5V –40° to +125°C 5-Pin SOT-23

MIC5235-1.8BM5 MIC5235-1.8YM5 L218 L218 1.8V –40° to +125°C 5-Pin SOT-23

MIC5235-2.5BM5 MIC5235-2.5YM5 L225 L225 2.5V –40° to +125°C 5-Pin SOT-23

MIC5235-2.7BM5 MIC5235-2.7YM5 L227 L227 2.7V –40° to +125°C 5-Pin SOT-23

MIC5235-3.0BM5 MIC5235-3.0YM5 L230 L230 3.0V –40° to +125°C 5-Pin SOT-23

MIC5235-3.3BM5 MIC5235-3.3YM5 L233 L233 3.3V –40° to +125°C 5-Pin SOT-23

MIC5235-5.0BM5 MIC5235-5.0YM5 L250 L250 5.0V –40° to +125°C 5-Pin SOT-23

MIC5235BM5 MIC5235YM5 L2AA L2AA Adj. –40° to +125°C 5-Pin SOT-23

* Under bar symbol (_) may not be to scale.

** Contact factory regarding availability for voltages not listed.

Pin Configuration

OUT

L2xx

GND

L2xx

OUT

ADJ

L2xx

GND

L2xx

SOT-23-5 (Fixed)

SOT-23-5 (Adjustable)

Pin Description

Pin Number Pin Name Pin Function

1 IN Supply Input.

2 GND Ground.

3 EN Enable (Input): Logic low = shutdown; logic high = enable.

NC (fixed) No Connect. 4

ADJ (adj.) Adjust (Input): Feedback input. Connect to resistive voltage-divider network.

5 OUT Regulator Output.

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Absolute Maximum Ratings(1)

Input Supply Voltage ........................................ –20V to 38V

Enable Input Voltage....................................... –0.3V to 38V

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

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

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

ESD Rating(3)

Operating Ratings(2)

Input Supply Voltage ......................................... 2.3V to 24V

Enable Input Voltage............................................ 0V to 24V

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

Package Thermal Resistance

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

Electrical Characteristics(4)

TA = 25°C with VIN = VOUT + 1V; IOUT = 100µA, Bold values indicate –40°C<TJ<+125°C; unless otherwise specified.

Parameter Condition Min Typ Max Units

Output Voltage Accuracy Variation from nominal VOUT –1.0

–2.0

+1.0

+2.0

Line Regulation VIN = VOUT + 1V to 24V 0.04 %

Load Regulation Load = 100µA to 150mA 0.25 1 %

Dropout Voltage IOUT = 100µA

IOUT = 50mA

IOUT = 100mA

IOUT = 150mA

230

270

310

300

400

450

500

Reference Voltage 1.22 1.24 1.25 V

Ground Current IOUT = 100µA

IOUT = 50mA

IOUT = 100mA

IOUT = 150mA

0.35

0.7

µA

Ground Current in Shutdown VEN ≤ 0.6V; VIN = 24V 0.1 1 µA

Short Circuit Current VOUT = 0V 350 500 mA

Output Leakage,

Reverse Polarity Input

Load = 500Ω; VIN = –15V –0.1 µA

Enable Input

Input Low Voltage Regulator OFF 0.6 V

Input High Voltage Regulator ON 2.0 V

Enable Input Current VEN = 0.6V; Regulator OFF

VEN = 2.0V; Regulator ON

VEN = 24V; Regulator ON

–1.0 0.01

0.1

0.5

1.0

2.5

µA

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. Human body model, 1.5k in series with 100pF.

4. Specification for packaged product only.

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May 2008 4 M9999-051508

Typical Characteristics

0.01 0.1 11 0 100 1000

PSRR (dB)

FREQUENCY (kHz)

Power Supply

Rejection Ratio

ILOAD = 150mA

100

150

200

250

300

350

02 04 06 08 0 100 120 140 160

DROPOUT VOLTAGE (mV)

OUTPUT CURRENT (mA)

Dropout Voltage

vs. Output Current

100

150

200

250

300

350

400

450

500

-40 -20 02 04 06 08 0 100 120

DROPOUT VOLTAGE (mV)

TEMPERATURE (°C)

Dropout Voltage

vs. Temperature

IOUT = 150mA

0.5

1.5

2.5

3.5

0 0.5 1 1.5 2 2.5 3 3.5 4

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout

Characteristics

ILOAD = 100µA

ILOAD = 75mA

ILOAD = 150mA

500

1000

1500

2000

2500

3000

02 04 06 08 0 100 120 140 160

GROUND CURRENT (µA)

OUTPUT CURRENT (mA)

Ground Pin Current

vs. Output Current

VIN =4V

0 100 200 300 400 500

GROUND CURRENT (µA)

OUTPUT CURRENT (µA)

Ground Pin Current

vs. Output Current

VIN = 24V

VIN = 12V

VIN =4V

-40 -20 02 04 06 08 0 100 120

GROUND CURRENT (µA)

TEMPERATURE (°C)

Ground Pin Current

vs. Temperature

ILOAD = 10mA

500

520

540

560

580

600

620

640

660

680

700

-40 -20 02 04 06 08 0 100 120

GROUND CURRENT (µA)

TEMPERATURE (°C)

Ground Pin Current

vs. Temperature

ILOAD = 75mA

1.5

1.6

1.7

1.8

1.9

2.1

2.2

2.3

2.4

2.5

-40 -20 02 04 06 08 0 100 120

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Pin Current

vs. Temperature

ILOAD = 150mA

100

1.5 2 2.5 3 3.5 4

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

Ground Pin Current

vs. Input Voltage

IOUT = 10mA

IOUT = 1mA IOUT = 100µA

IOUT =10µA

0.4

0.6

0.8

1.2

1.4

1.6

1.8

2.2

2.4

1.5 2 2.5 3 3.5 4

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

Ground Pin Current

vs. Input Voltage

IOUT =150mA

IOUT = 75mA

49 14 19 24

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

Ground Pin Current

vs. Input Voltage

IOUT =10µA

IOUT = 1mA

IOUT = 100µA

Micrel, Inc. MIC5235

May 2008 5 M9999-051508

Typical Characteristics (continued)

100

120

-20 -10 0 10

INPUT CURRENT (mA)

SUPPLY VOLTAGE (V)

Input Current

vs. Supply Voltage

VEN =5V

RLOAD =30

2.95

2.96

2.97

2.98

2.99

3.01

3.02

3.03

3.04

3.05

-40 -20 02 04 06 08 0 100 120

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

Output Voltage

vs. Temperature

ILOAD = 100 µA

100

150

200

250

300

350

400

-40 -20 02 04 06 08 0 100 120

SHORT CIRCUIT CURRENT (mA)

TEMPERATURE (°C)

Short Circuit Current

vs. Temperature

VIN =4V

VIN = 4V

150mA

0mA

VOUT = 3V

COUT = 4.7µF ceramic

Micrel, Inc. MIC5235

May 2008 6 M9999-051508

Functional Diagram

OUT

GND

ENABLE

VREF

1.24V

Block Diagram – Fixed Output Voltage

ADJ

OUT

GND

ENABLE

VREF

1.24V

Block Diagram – Adjustable Output Voltage

Micrel, Inc. MIC5235

May 2008 7 M9999-051508

Application Information

Enable/Shutdown

The MIC5235 comes with an active-high enable pin that

allows the regulator to be disabled. Forcing the enable

pin low 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.

Input Capacitor

The MIC5235 has high input voltage capability up to

24V. 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 capacitors can be used

for bypassing. Larger values may be required if the

source supply has high ripple.

Output Capacitor

The MIC5235 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.

X7R/X5R dielectric-type ceramic capacitors are

recommended because of their temperature

performance. X7R-type capacitors change capacitance

by 15% over their operating temperature range and are

the most stable type of ceramic capacitors. Z5U and

Y5V dielectric capacitors change value by as much as

50% and 60% respectively over their operating

temperature ranges. To use a ceramic chip capacitor

with Y5V dielectric, the value must be much higher than

a X7R ceramic capacitor to ensure the same minimum

capacitance over the equivalent operating temperature

range.

No-Load Stability

The MIC5235 will remain stable and in regulation with no

load unlike many other voltage regulators. This is

especially important in CMOS RAM keep-alive

applications.

Thermal Considerations

The MIC5235 is designed to provide 150mA of

continuous current in a very small package. Maximum

power dissipation can be calculated based on the output

current and the voltage drop across the part. To

determine the maximum power dissipation of the

package, use the junction-to-ambient thermal resistance

of the device and the following basic equation:

⎟

⎠

⎞

⎜

⎝

⎛−

AJ(MAX)

D(MAX) θ

TJ(MAX) is the maximum junction temperature of the die,

125°C, and TA is the ambient operating temperature. θJA

is layout dependent; Table 1 shows examples of the

junction-to-ambient thermal resistance for the MIC5235.

Package θJA Recommended

Minimum Footprint

SOT-23-5 235°C

Table 1. SOT-23-5 Thermal Resistance

The actual power dissipation of the regulator circuit can

be determined using the equation:

D = (VIN – VOUT)IOUT + VINIGND

Substituting PD(MAX) for PD and solving for the operating

conditions that are critical to the application will give the

maximum operating conditions for the regulator circuit.

For example, when operating the MIC5235-3.0BM5 at

50°C with a minimum footprint layout, the maximum

input voltage for a set output current can be determined

as follows:

⎟

⎠

⎞

⎜

⎝

⎛

°−°

=C/W235

C50C125

PD(MAX)

D(MAX) = 319mW

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

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

important that the maximum power dissipation not be

exceeded to ensure proper operation. Since the

MIC5235 was designed to operate with high input

voltages, careful consideration must be given so as not

to overheat the device. With very high input-to-output

voltage differentials, the output current is limited by the

total power dissipation. Total power dissipation is

calculated using the following equation:

D = (VIN – VOUT)IOUT + VIN × IGND

Due to the potential for input voltages up to 24V, ground

current must be taken into consideration. If we know the

maximum load current, we can solve for the maximum

input voltage using the maximum power dissipation

calculated for a 50°C ambient, 319mV.

D(MAX) = (VIN – VOUT)IOUT + VIN x IGND

319mW = (VIN – 3V)150mA + VIN x 2.8mA

Ground pin current is estimated using the typical

characteristics of the device.

769mW = VIN (152.8mA)

IN = 5.03V

For higher current outputs only a lower input voltage will

work for higher ambient temperatures.

Assuming a lower output current of 20mA, the maximum

input voltage can be recalculated:

Micrel, Inc. MIC5235

May 2008 8 M9999-051508

Where VREF = 1.24V.

319mW = (VIN – 3V)20mA + VIN x 0.2mA

Feedback resistor R2 should be no larger than 300kΩ.

379mW = VIN x 20.2mA

OUT

ADJ.

VIN

2.2µF

1.0µF EN

VOUT

GND

MIC5235BM5

VIN = 18.8V

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

ambient temperature is 18.8V, utilizing virtually the entire

operating voltage range of the device.

Adjustable Regulator Application

The MIC5235BM5 can be adjusted from 1.24V to 20V by

using two external resistors (Figure 1). The resistors set

the output voltage based on the following equation:

Figure 1. Adjustable Voltage Application

⎟

⎠

⎞

⎜

⎝

⎛

⎟

⎠

⎞

⎜

⎝

⎛

REFOUT R

1VV

Micrel, Inc. MIC5235

May 2008 9 M9999-051508

Package Information

SOT-23-5 (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

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

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.

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