MIC5253-1.8YC5TR - Micrel, Inc.

MIC5253 Micrel

MIC5253

100mA Low Noise µCap Teeny™ LDO

General Description

The MIC5253 is an efficient, CMOS voltage regulator opti-

mized for ultra-low-noise applications. It offers 1.5% initial

accuracy, extremely low dropout voltage (165mV at 100mA),

and low ground current (typically 95µA at full load). The

MIC5253 provides a very low noise output, ideal for RF

applications where a clean voltage source is required. A

noise bypass pin is also available for further reduction of

output noise.

Designed specifically for handheld and battery-powered de-

vices, the MIC5253 provides a TTL-logic-compatible enable

pin. When disabled, power consumption drops nearly to zero.

The MIC5253 also works with low-ESR ceramic capacitors,

reducing the amount of board space necessary for power

applications, critical in handheld wireless devices.

Available in the Teeny™ SC-70-5 package, the MIC5253

offers a wide range of output voltages. Key features include

current limit, thermal shutdown, faster transient response,

and an active clamp to speed up device turn-off.

Typical Application

OUT

= 1.0µF

Ceramic

BYP

= 0.01µF

Enable

Shutdown

OUT

MIC5253-x.xBC5

EN (pin 3) may be

connected directly

to IN (pin 1).

Ultra-Low-Noise Regulator Application

Features

•Input voltage range: 2.7V to 5.5V

•Teeny™ SC-70-5 package

•Ultra-low output noise: 30µV(rms)

•100mA continuous output current, 150mA peak current

•Stability with ceramic output capacitors

•Ultralow dropout: 165mV @ 100mA

•High output accuracy:

1.5% initial accuracy

3.0% over temperature

•Low ground current: 95µA

•TTL-Logic-controlled enable input

•“Zero” off-mode current

•Thermal shutdown and current limit protection

Applications

•Cellular phones and pagers

•Cellular accessories

•Battery-powered equipment

•Laptop, notebook, and palmtop computers

•Consumer/personal electronics

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

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MIC5253 Micrel

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Pin Configuration

GND

SC-70-5 (C5)

Pin Description

Pin Number Pin Name Pin Function

1 IN Supply Input.

2 GND Ground.

3 EN Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown.

Do not leave open.

4 BYP Reference Bypass: Connect external 0.01µF ≤ CBYP ≤ 1.0µF capacitor to GND to reduce output

noise. May be left open.

5 OUT Regulator Output.

Ordering Information

November 2005

Standard Marking Pb-Free Marking**

MIC5253-1.5BC5 715 MIC5253-1.5YC5 715 1.5V –40°C to +125°C SC-70-5

MIC5253-1.8BC5 718 MIC5253-1.8YC5 718 1.8V –40°C to +125°C SC-70-5

MIC5253-1.85BC5 71J MIC5253-1.85YC5 71J 1.85V –40°C to +125°C SC-70-5

MIC5253-2.5BC5 725 MIC5253-2.5YC5 725 2.5V –40°C to +125°C SC-70-5

MIC5253-2.6BC5 726 MIC5253-2.6YC5 726 2.6V –40°C to +125°C SC-70-5

MIC5253-2.7BC5 727 MIC5253-2.7YC5 727 2.7V –40°C to +125°C SC-70-5

MIC5253-2.8BC5 728 MIC5253-2.8YC5 728 2.8V –40°C to +125°C SC-70-5

MIC5253-2.9BC5 729 MIC5253-2.9YC5 729 2.9V –40°C to +125°C SC-70-5

MIC5253-3.0BC5 730 MIC5253-3.0YC5 730 3.0V –40°C to +125°C SC-70-5

MIC5253-3.1BC5 731 MIC5253-3.1YC5 731 3.1V –40°C to +125°C SC-70-5

MIC5253-3.2BC5 732 MIC5253-3.2YC5 732 3.2V –40°C to +125°C SC-70-5

MIC5253-3.3BC5 733 MIC5253-3.3YC5 733 3.3V –40°C to +125°C SC-70-5

* Other voltage options available. Contact Micrel Marketing for details.

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

Part Number Voltage* Junction

Temp. Range Package

OUTBYP

7xx

4 5

MIC5253 Micrel

Electrical Characteristics(5)

VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless otherwise noted.

Symbol Parameter Conditions Min Typical Max Units

VOOutput Voltage Accuracy IOUT = 100µA–1.5 1.5 %

–33%

∆VLNR Line Regulation VIN = VOUT + 1V to 6V 0.035 0.05 %/V

∆VLDR Load Regulation IOUT = 0.1mA to 100mA, Note 6 1.5 2.5 %

VIN – VOUT Dropout Voltage(7) IOUT = 50mA 80 150 mV

IOUT = 100mA 165 300 mV

IQQuiescent Current VEN ≤ 0.4V (shutdown) 0.2 1µA

IGND Ground Pin Current(8) IOUT = 0mA 75 100 µA

IOUT = 100mA 90 150 µA

PSRR Ripple Rejection f = 100Hz, COUT = 1.0µF, CBYP = 0.1µF66dB

f = 1kHz, VIN = VOUT +1, CBYP = 0.1µF70dB

f = 10kHz, VIN = VOUT +1, CBYP = 0.1µF65dB

tON Turn-On Time 30 150 µs

ILIM Current Limit VOUT = 0V 150 250 450 mA

enOutput Voltage Noise COUT = 1.0µF, CBYP = 0.01µF, 30

µV(rms)

f = 10Hz to 100kHz

Enable Input

VIL Enable Input Logic-Low Voltage VIN = 2.7V to 5.5V, regulator shutdown 0.4 V

VIH Enable Input Logic-High Voltage VIN = 2.7V to 5.5V, regulator enabled 1.6 V

IEN Enable Input Current VIL ≤ 0.4V, regulator shutdown 0.01 µA

VIH ≥ 1.6V, regulator enabled 0.01 µA

Thermal Protection

Thermal Shutdown Temperature 150 °C

Thermal Shutdown Hysteresis 10 °C

Notes:

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

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

3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max)–TA)/θJA. Exceeding the maximum allowable power

dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The θJA of the MIC5253-x.xBC5 (all versions) is

400°C/W on a PC board (see ”Thermal Considerations” section for further details).

4. Devices are ESD sensitive. Handling precautions recommended.

5. Specification for packaged product only.

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 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.

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.

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.

Absolute Maximum Ratings(1)

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

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

Power Dissipation (PD) ........................ Internally Limited(3)

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

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

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

ESD Rating(4) ................................................................................2kV

Operating Ratings(2)

Input Voltage (VIN) ...................................... +2.7V to +5.5V

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

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

Thermal Resistance

SC-70-5 (θJA) ....................................................400°C/W

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MIC5253 Micrel

Typical Characteristics

PSRR (dB)

FREQUENCY (Hz)

100µA

1mA

10mA

100mA

Power Supply Rejection Ratio

OUT

= 1.8V

= 2.8V

100 1k 10k 100k 1M

OUT

= 1µF

BYP

= 0.1µF

PSRR (dB)

FREQUENCY (Hz)

100µA

1mA

10mA

100mA

Power Supply Rejection Ratio

VOUT = 1.8V

VIN = 2.8V COUT = 1µF

CBYP = 0.01µF

100 1k 10k 100k 1M

0 25 50 75 100 125 150

GROUND CURRENT (µA)

OUTPUT CURRENT (mA)

Ground Pin Current

= V

OUT

+ 1V

OUT

=1.8V

-40 -20 0 20 40 60 80 100 120

GROUND CURRENT (µA)

TEMPERATURE (°C)

Ground Pin Current

LOAD

= 100µA

012345

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

Ground Pin Current

LOAD

= 100µA

012345

GROUND CURRENT (µA)

INPUT VOLTAGE (V)

Ground Pin Current

LOAD

= 100mA

0.2

0.4

0.6

0.8

1.2

1.4

1.6

1.8

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

OUTPUT VOLTAGE (mV)

INPUT VOLTAGE (V)

Dropout Characteristics

LOAD

= 100µA

LOAD

= 100mA

OUT

= 1.85V

100

150

200

250

-40 -20 0 20 40 60 80 100 120

DROPOUT VOLTAGE (mV)

TEMPERATURE (°C)

Dropout Voltage

= 3.6V

OUT

= 2.6V

LOAD

= 100mA

100

150

200

250

300

350

0 25 50 75 100 125 150

DROPOUT VOLTAGE (mV)

OUTPUT CURRENT (mA)

Dropout Voltage

125°C

25°C

–40°C

= 3.6V

OUT

= 2.6V

150

170

190

210

230

250

270

290

2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9

SHORT CIRCUIT CURRENT (mA)

INPUT VOLTAGE (V)

Short Circuit Current

2.5

2.55

2.6

2.65

2.7

-40 -20 0 20 40 60 80 100 120

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

Output Voltage

vs. Temperature

LOAD

= 100µA

OUT

= 2.6V

= 3.6V

-40 -20 0 20 40 60 80 100 120

GROUND CURRENT (µA)

TEMPERATURE (°C)

Ground Pin Current

ILOAD = 100mA

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MIC5253 Micrel

= 1µF Ceramic

OUT

= 1µF Ceramic

BYP

= 0.01µF

OUT

= 100µA

Line Transient Response

TIME (500µs/div)

Output Voltage

(50mV/div) Input Voltage

(1V/div)

CIN = 1µF Ceramic

COUT = 1µF Ceramic

CBYP = 0.01µF

VIN = 4V

100µA

100mA

Load Transient Response

TIME (5µs/div)

Output Current

(50mA/div) Output Voltage

(20mV/div)

CIN = 1µF Ceramic

COUT = 1µF Ceramic

CBYP = 0.01µF

VIN = 4V

Shutdown Delay

TIME (500µs/div)

Output Voltage

(500mV/div) Enable Voltage

(1V/div)

CIN = 1µF Ceramic

COUT = 1µF Ceramic

CBYP = 0.01µF

IOUT = 100µA

Enable Pin Delay

TIME (5µs/div)

Output Voltage

(500mV/div) Enable Voltage

(1V/div)

Functional Characteristics

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MIC5253 Micrel

Block Diagram

Reference

Voltage Startup/

Shutdown

Control

Quickstart/

Noise

Cancellation

Under-

voltage

Lockout

Thermal

Sensor

FAULT

Error

Amplifier Current

Amplifier

GND

BYP

OUT

ACTIVE SHUTDOWN

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MIC5253 Micrel

Applications Information

Enable/Shutdown

The MIC5253 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. This part is CMOS and the enable pin cannot

be left floating; a floating enable pin may cause an indetermi-

nate state on the output.

Input Capacitor

The MIC5253 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.

Output Capacitor

The MIC5253 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.

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

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 capaci-

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

X7R ceramic capacitor to ensure the same minimum capaci-

tance over the equivalent operating temperature range.

Bypass Capacitor

A capacitor can be placed from the noise bypass pin to

ground to reduce output voltage noise. The capacitor by-

passes the internal reference. A 0.01µF capacitor is recom-

mended for applications that require low-noise outputs. The

bypass capacitor can be increased, further reducing noise

and improving PSRR. Turn-on time increases slightly with

respect to bypass capacitance. A unique quick-start circuit

allows the MIC5253 to drive a large capacitor on the bypass

pin without significantly slowing turn-on time. Refer to the

“Typical Characteristics” section for performance with differ-

ent bypass capacitors.

Active Shutdown

The MIC5253 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

The MIC5253 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 MIC5253 is designed to provide 100mA of continuous

current in a very small package. Maximum ambient operating

temperature can be calculated based on the output current

and the voltage drop across the part. Given that the input

voltage is 5.0V, the output voltage is 2.9V, and the output

current = 100mA.

The actual power dissipation of the regulator circuit can be

determined using the equation:

PD = (VIN – VOUT) IOUT + VIN IGND

Because this device is CMOS and the ground current is

typically <100µA over the load range, the power dissipation

contributed by the ground current is < 1% and can be ignored

for this calculation.

PD = (5.0V – 2.9V) × 100mA

PD = 0.21W

To determine the maximum ambient operating temperature

of the package, use the junction-to-ambient thermal resis-

tance of the device and the following basic equation:

P (max) T (max) T

DJA

=−











TJ(max) = 125°C, the max. junction temperture of the die

θJA thermal resistance = 400°C/W

Table 1 shows junction-to-ambient thermal resistance for the

MIC5253 in the SC-70 package.

Package θθ

θθ

θJA Recommended θθ

θθ

θJA 1" Sq. θθ

θθ

θJC

Minimum Footprint Copper Clad

SC-70-5 (C5) 400°C/W 325°C 250°C/W

Table 1. Thermal Resistance

Substituting PD for PD(max) and solving for the ambient

operating temperature will give the maximum operating con-

ditions for the regulator circuit. The junction-to-ambient ther-

mal resistance for the minimum footprint is 400°C/W, from

Table 1. The maximum power dissipation must not be ex-

ceeded for proper operation.

For example, when operating the MIC5253-2.9BC5 at an

input voltage of 5.0V and 100mA load with a minimum

footprint layout, the maximum ambient operating tempera-

ture TA can be determined as follows:

0.21W 125 C T

C/W

=°−

=°

400

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MIC5253 Micrel

Therefore, a 2.9V application at 100mA of output current can

accept an ambient operating temperature of 41°C in a SC-70

package. For a full discussion of heat sinking and thermal

effects on voltage regulators, refer to the “Regulator Thermals”

section of

Micrel’s Designing with Low-Dropout Voltage Regu-

lators

handbook. This information can be found on Micrel's

website at:

http://www.micrel.com/_PDF/other/LDOBk_ds.pdf

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MIC5253 Micrel

Package Information

0.30 (0.012)

0.10 (0.004)

2.20 (0.087)

1.80 (0.071)

2.40 (0.094)

1.80 (0.071)

1.35 (0.053)

1.15 (0.045)

0.65 (0.0256) BSC

1.00 (0.039)

0.80 (0.032)

0.10 (0.004)

0.00 (0.000)

DIMENSIONS:

MM (INCH)

0.30 (0.012)

0.15 (0.006)

0.18 (0.007)

0.10 (0.004)

1.10 (0.043)

0.80 (0.032)

5-Pin SC-70-5 (C5)

MICREL, INC. 1849 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 at Purchaser’s own risk and Purchaser agrees to fully indemnify

Micrel for any damages resulting from such use or sale.

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