MIC3730-1.8WR - Micrel, Inc.

November 2005 1 M9999-110305

MIC37300/37301/37302 Micrel, Inc.

MIC37300/37301/37302

3.0A, Low-Voltage µCap LDO Regulator

General Description

The Micrel MIC37300/01/02 is a 3.0A low-dropout linear volt-

age regulator that provides a low-voltage, high-current output

with a minimum number of external components. It offers

high precision, ultra-low-dropout (500mV overtemperature),

and low-ground current.

The MIC37300/01/02 operates from an input of 2.25V to

6.0V. It is designed to drive digital circuits requiring low-volt-

age at high currents (i.e., PLDs, DSP, microcontroller, etc.).

It is available in ﬁxed and adjustable output voltages. Fixed

voltages include 1.5V, 1.8V, 2.5V and 3.3V. The adjustable

version is capable of 1.24V to 5.5V.

Features of the MIC37300/01/02 LDO include thermal and

current-limit protection, and reverse-current protection.

Logic enable and error ﬂag pins are available on the 5-pin

version.

Junction temperature range of the MIC37300/01/02 is from

–40°C to 125°C.

For applications requiring input voltage greater than 6.0V,

see the MIC3910x, MIC3915x, MIC3930x, and MIC3950x

LDOs.

All data sheets and support documentation can be found on

Micrel’s web site at www.micrel.com.

Typical Application

VOUTVIN

GND

COUT

47µF, Ceramic

MIC37300

VIN = 3.0V VOUT = 2.5V

Fixed 2.5V Regulator

VOUTVIN

FLG

GND

VEN

COUT

47µF, Ceramic

100k

MIC37301

VIN = 3.0V VOUT = 2.5V

CIN

Fixed 2.5V Regulator with Error Flag

Features

• 3.0A minimum guaranteed output current

• 500mV maximum dropout-voltage overtemperature

Ideal for 3.0V to 2.5V conversion

Ideal for 2.5V to 1.8V, 1.65V, or 1.5V conversion

• Stable with ceramic or tantalum capacitor

• Wide input voltage range:

VIN: 2.25V to 6.0V

• +1.0% initial output tolerance

• Fixed and adjustable output voltages:

MIC37300 — 3-pin ﬁxed

MIC37301 — 5-pin ﬁxed with ﬂag

MIC37302 — 5-pin adjustable

• Excellent line and load regulation speciﬁcations

• Logic controlled shutdown

• Thermal shutdown and current-limit protection

• Reverse-leakage protection

• Low proﬁle S-Pak package

Applications

• LDO linear regulator for low-voltage digital IC

• PC add-in cards

• High-efﬁciency linear power supplies

• SMPS post regulator

• Battery charger

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

Super ßeta PNP is a registered trademark of Micrel, Inc.

VOUTVIN

ADJ

GND

VEN

COUT

47µF, Ceramic

1.3V

MIC37302

VIN

CIN

Adjustable Regulator

100

150

200

250

300

350

400

450

500

0 0.5 1 1.5 2 2.5 3

DROPOUT (mV)

OUTPUT CURRENT (A)

Dropout vs.

Output Current

2.5VOUT

3.3VOUT

MIC37300/37301/37302 Micrel, Inc.

M9999-110305 2 November 2005

Ordering Information

Part Number Output Current Voltage** Junction Temp.

Range Package

Standard RoHS Compliant*

MIC37300-1.5BR MIC37300-1.5WR 3.0A 1.5V –40ºC to +125ºC S-Pak-3

MIC37300-1.65BR MIC37300-1.65WR 3.0A 1.65V –40ºC to +125ºC S-Pak-3

MIC37300-1.8BR MIC37300-1.8WR 3.0A 1.8V –40ºC to +125ºC S-Pak-3

MIC37300-2.5BR MIC37300-2.5WR 3.0A 2.5V –40ºC to +125ºC S-Pak-3

MIC37300-3.3BR MIC37300-3.3WR 3.0A 3.3V –40ºC to +125ºC S-Pak-3

MIC37301-1.5BR MIC37301-1.5WR 3.0A 1.5V –40ºC to +125ºC S-Pak-5

MIC3730-1.8BR MIC3730-1.8WR 3.0A 1.8V –40ºC to +125ºC S-Pak-5

MIC37301-2.5BR MIC37301-2.5WR 3.0A 2.5V –40ºC to +125ºC S-Pak-5

MIC37301-3.3BR MIC37301-3.3WR 3.0A 3.3V –40ºC to +125ºC S-Pak-5

MIC37302BR MIC37302WR 3.0A ADJ –40ºC to +125ºC S-Pak-5

MIC37302BU MIC37302WU 3.0A ADJ –40ºC to +125ºC TO-263-5

*RoHS Compliant with 'high-melting solder' exemption.

**Other voltages available. Contact Micrel for details.

Pin Conﬁguration

5 FLG/ADJ

4 VOUT

3 GND

2 VIN

1 EN

S-PAK-5 (R)

TO-263-5 (U)

3 VOUT

2 GND

1 VIN

S-PAK-3 (R)

Pin Description

Pin Number Pin Number Pin Name Pin Function

TO-263-5 S-PAK-3

S-PAK-5

1 EN Enable (Input): CMOS compatible input. Logic high = enable, logic

low = shutdown.

2 1 VIN Input voltage which supplies current to the output power device.

3 2 GND Ground: TAB is connected to ground.

4 3 VOUT Regulator Output.

5 FLG Error Flag (Output): Open collector output. Active-low indicates an output

fault condition.

ADJ Adjustable Regulator Feedback Input: Connect to resistor voltage divider.

November 2005 3 M9999-110305

MIC37300/37301/37302 Micrel, Inc.

Electrical Characteristics(5)

TA = 25°C with VIN = VOUT + 1V; VEN = VIN; IL = 10mA; bold values indicate –40°C < TJ < +125°C; unless otherwise noted.

Parameter Condition Min Typ Max Units

Output Voltage Accuracy IL = 10mA –1 +1 %

10mA < IOUT < IL(max), VOUT + 1 ≤ VIN ≤ 6V –2 +2 %

Output Voltage Line Regulation VIN = VOUT +1.0V to 6.0V, IL = 10mA 0.02 0.5 %

Output Voltage Load Regulation IL = 10mA to 3A 0.2 1 %

VIN – VOUT; Dropout Voltage(6) IL = 1.5A 175 350 mV

IL = 3A 310 500 mV

Ground Pin Current(7) IL = 3A 27 40 mA

50 mA

Ground Pin Current in Shutdown VIL < 0.5V, VIN = VOUT + 1V 1.0 5 µA

Current Limit VOUT = 0 4.75 6.5 A

Start-up Time VEN = VIN, IOUT = 10mA, COUT = 47µF 170 500 µs

Enable Input

Enable Input Threshold Regulator enable 2.25 V

Regulator shutdown 0.8 V

Enable Pin Input Current VIL < 0.8V (Regulator shutdown) 2 µA

4 µA

VIH > 2.25V (Regulator enabled) 1 15 30 µA

75 µA

Flag Output

IFLG(LEAK) VOH = 6V 1 µA

2 µA

VFLG(LO) VIN = 2.25V, IOL = 250µA(8) 210 400 mV

500 mV

VFLG Low Threshold, % of VOUT below nominal 93 %

Hysteresis 2 %

High Threshold, % of VOUT below nominal 99.2 %

MIC37302 Only

Reference Voltage 1.228 1.240 1.252 V

1.215 1.265 V

Adjust Pin Bias Current 40 80 nA

120 nA

Notes:

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

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

3. PD(max) = (TJ(max) – TA) / θJA, where θJA, depends upon the printed circuit layout. See “Applications Information.”

4. Device is ESD sensitive. Handling precautions recommended.

5. Speciﬁcation for packaged product only.

6. VDO = VIN – VOUT when VOUT decreased to 98% of its nominal output voltage with VIN = VOUT +1V. For output voltages below 1.75V, dropout volt-

age speciﬁcation does not apply due to a minimum input operating voltage of 2.25V.

7. IGND is the quiescent current. IIN = IGND + IOUT.

8. For a 2.5V device, VIN = 2.250V (device is in dropout).

Absolute Maximum Rating(1)

Supply Voltage (VIN) ..................................................... 6.5V

Enable Input Voltage (VEN)(3) ....................................... 6.5V

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

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

Storage Temperature (TS) .................. –65°C ≤ TJ ≤ +150°C

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

ESD(4)

Operating Maximum Rating(2)

Supply Voltage (VIN) .......................................2.25V to 6.0V

Enable Input Voltage (VEN) .................................0V to 6.0V

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

Package Thermal Resistance

S-Pak (θJC) ....................................................... 2°C/W

TO-263-5 (θJC) .................................................. 2°C/W

MIC37300/37301/37302 Micrel, Inc.

M9999-110305 4 November 2005

Typical Characteristics

0.01 0.1 1 10 100 1000

FREQUENCY (kHz)

Power Supply

Rejection Ratio

IOUT = 3A

COUT = 47µF

CIN = 0

VIN = 2.5V

VOUT = 1.5V

0.01 0.1 1 10 100 1000

FREQUENCY (kHz)

Power Supply

Rejection Ratio

IOUT = 3A

COUT = 100µF

CIN = 0

VIN = 2.5V

VOUT = 1.5V

100

150

200

250

300

350

400

450

500

0 0.5 1 1.5 2 2.5 3

DROPOUT (mV)

OUTPUT CURRENT (A)

Dropout vs.

Output Current

2.5VOUT

3.3VOUT

100

150

200

250

300

350

400

450

-40 -20 0 20 40 60 80 100 120

DROPOUT (mV)

TEMPERATURE(°C)

Dropout vs.

Temperature

2.5VOUT

0.2

0.4

0.6

0.8

1.2

1.4

1.6

1.5 1.7 1.9 2.1 2.3 2.5

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(1.5V)

3A Load

10mA Load

0.5

1.5

2.5

1.5 2 2.5 3 3.5

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(2.5V)

3A Load

10mA Load

0.5

1.5

2.5

3.5

1.5 2 2.5 3 3.5 4

OUTPUT VOLTAGE (V)

INPUT VOLTAGE (V)

Dropout Characteristics

(3.3V)

3A Load

10mA Load

0 0.5 1 1.5 2 2.5 3

GROUND CURRENT (mA)

OUTPUT CURRENT (A)

Ground Current

vs. Output Current

0.0001

0.0002

0.0003

0.0004

0.0005

0.0006

012345

GROUND CURRENT (mA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage (1.5V)

100mA

10mA

012345

GROUND CURRENT (mA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage (1.5V)

012345

GROUND CURRENT (mA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage (2.5V)

0.2

0.4

0.6

0.8

1.2

1.4

012345

GROUND CURRENT (mA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage (2.5V)

100mA

10mA

November 2005 5 M9999-110305

MIC37300/37301/37302 Micrel, Inc.

0.2

0.4

0.6

0.8

1.2

1.4

012345

GROUND CURRENT (mA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage (3.3V)

100mA

10mA

012345

GROUND CURRENT (mA)

SUPPLY VOLTAGE (V)

Ground Current

vs. Supply Voltage (3.3V)

-40 -20 0 20 40 60 80 100 120

GROUND CURRENT (mA)

TEMPERATURE (°C)

Ground Current

vs. Temperature

IOUT=1.5A

2.5VOUT

-40 -20 0 20 40 60 80 100 120

GROUND CURRENT (mA)

TEMPERATURE(°C)

Ground Current

vs. Temperature

IOUT=3A

2.5VOUT

2.4

2.45

2.5

2.55

2.6

-40 -20 0 20 40 60 80 100 120

OUTPUT VOLTAGE (V)

TEMPERATURE (°C)

Output Voltage

vs. Temperature

2.5VOUT

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-40 -20 0 20 40 60 80 100 120

GROUND CURRENT (mA)

TEMPERATURE(°C)

Ground Current

vs. Temperature

IOUT=10mA

2.5VOUT

0.5

1.5

2.5

3.5

4.5

5.5

2.25 3 3.75 4.5 5.25 6

SHORT CIRCUIT CURRENT (A)

SUPPLY VOLTAGE (V)

Short-Circuit Current

vs. Suppl

Voltage

-40 -20 0 20 40 60 80 100 120

SHORT CIRCUIT CURRENT (A)

TEMPERATURE (°C)

Short-Circuit Current

vs. Temperature

2.5VIN

0.2

0.4

0.6

0.8

1.0

0 0.5 1 1.5 2 2.5 3 3.5 4

FLAG VOLTAGE (V)

FLAG CURRENT (mA)

Flag Voltage

vs. Flag Current

5VIN

3.3VIN

2.5VIN

100

150

200

250

300

350

400

-40 -20 0 20 40 60 80 100 120

FLAG VOLTAGE (mV)

TEMPERATURE (°C)

Flag Low Voltage

vs. Temperature

=250

Flag Current

0.01 0.1 1 10 100 1000 10000

FLAG VOLTAGE (V)

RESISTANCE (kΩ)

Error Flag Pull-Up Resistor

F lag L ow (FAULT)

F lag High (OK)

VIN = 5V

-40 -20 0 20 40 60 80 100 120

ENABLE CURRENT (µA)

TEMPERATURE (°C)

Enable Current

vs. Temperature

2.5VE N

MIC37300/37301/37302 Micrel, Inc.

M9999-110305 6 November 2005

Functional Characteristics

OUTPUT CURRENT

(3A/div.)

OUTPUT VOL

AGE

(50mV/div.)

VIN = 3.3V

VOUT = 2.5V

COUT = 47µF Ceramic

Load Transient Response

10mA

INPUT VOL

AGE

(2V/div.)

OUTPUT VOL

AGE

(50mV/div.)

COUT = 47µF Ceramic

Line Transient Response

3.3V

ENABLE VOL

AGE

(2V/div.)

OUTPUT VOL

AGE

(1V/div.)

IOUT = 3A

VIN = 3.3V

COUT = 47µF

Enable Transient Response

2.5V

November 2005 7 M9999-110305

MIC37300/37301/37302 Micrel, Inc.

Applications Information

The MIC37300/01/02 is a high-performance low-dropout volt-

age regulator suitable for moderate to high-current regulator

applications. Its 500mV dropout voltage at full load and over-

temperature makes it especially valuable in battery-powered

systems and as high-efﬁciency noise ﬁlters in post-regulator

applications. Unlike older NPN-pass transistor designs, there

the minimum dropout voltage is limited by the based-to-emit-

ter voltage drop and collector-to-emitter saturation voltage,

dropout performance of the PNP output of these devices is

limited only by the low VCE saturation voltage.

A trade-off for the low dropout voltage is a varying base drive

requirement. Micrel’s Super ßeta PNP process reduces this

drive requirement to only 2% to 5% of the load current.

The MIC37300/01/02 regulator is fully protected from dam-

age due to fault conditions. Current limiting is provided. This

limiting is linear; output current during overload conditions

is constant. Thermal shutdown disables the device when

the die temperature exceeds the maximum safe operating

temperature. The output structure of these regulators allows

voltages in excess of the desired output voltage to be applied

without reverse current ﬂow.

Thermal Design

Linear regulators are simple to use. The most complicated

design parameters to consider are thermal characteristics.

Thermal design requires the following application-speciﬁc

parameters:

• Maximum ambient temperature (TA)

• Output current (IOUT)

• Output voltage (VOUT)

• Input voltage (VIN)

• Ground current (IGND)

First, calculate the power dissipation of the regulator from these

numbers and the device parameters from this datasheet.

PD = (VIN – VOUT) IOUT + VIN IGND

where the ground current is approximated by using numbers

from the “Electrical Characteristics” or “Typical Characteris-

tics.” Then the heat sink thermal resistance is determined

with this formula:

θSA = ((TJ(max) – TA)/ PD) – (θJC + θCS)

Where TJ(max) < 125°C and θCS is between 0°C and 2°C/W.

The heat sink may be signiﬁcantly reduced in applications

where the minimum input voltage is known and is large com-

pared with the dropout voltage. Use a series input resistor

to drop excessive voltage and distribute the heat between

this resistor and the regulator. The low-dropout properties of

Micrel’s Super ßeta PNP regulators allow signiﬁcant reduc-

tions in regulator power dissipation and the associated heat

sink without compromising performance. When this technique

is employed, a capacitor of at least 1.0µF is needed directly

between the input and regulator ground.

Refer to “Application Note 9” for further details and examples

on thermal design and heat sink applications.

Output Capacitor

The MIC37300/01/02 requires an output capacitor for stable

operation. As a µCap LDO, the MIC37300/01/02 can operate

with ceramic output capacitors as long as the amount of ca-

pacitance is 47µF or greater. For values of output capacitance

lower than 47µF, the recommended ESR range is 200mΩ to

2Ω. The minimum value of output capacitance recommended

for the MIC37300 is 10µF.

For 47µF or greater, the ESR range recommended is less

than 1Ω. Ultra-low ESR, ceramic capacitors are recommended

for output capacitance of 47µF or greater to help improve

transient response and noise reduction at high frequency.

X7R/X5R dielectric-type ceramic capacitors are recom-

mended 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 operat-

ing temperature ranges. To use a ceramic chip capacitor with

Y5V dielectric, the value must be much higher than an X7R

ceramic capacitor to ensure the same minimum capacitance

over the equivalent operating temperature range.

Input Capacitor

An input capacitor of 1.0µF or greater is recommended when

the device is more than 4 inches away from the bulk supply

capacitance, or when the supply is a battery. Small, surface-

mount chip capacitors can be used for the bypassing. The

capacitor should be place within 1" of the device for optimal

performance. Larger values will help to improve ripple rejec-

tion by bypassing the input to the regulator, further improving

the integrity of the output voltage.

Transient Response and 3.3V to 2.5V, 2.5V to 1.8V or

1.65V, or 2.5V to 1.5V Conversions

The MIC37300/01/02 has excellent transient response to

variations in input voltage and load current. The device has

been designed to respond quickly to load current variations

and input voltage variations. Large output capacitors are not

required to obtain this performance. A standard 47µF output

capacitor, preferably tantalum, is all that is required. Larger

values help to improve performance even further.

By virtue of its low-dropout voltage, this device does not

saturate into dropout as readily as similar NPN-based

designs. When converting from 3.3V to 2.5V, 2.5V to 1.8V or

1.65V, or 2.5V to 1.5V, the NPN-based regulators are already

operating in dropout, with typical dropout requirements of

1.2V or greater. To convert down to 2.5V without operating in

dropout, NPN-based regulators require an input voltage of 3.7V

at the very least. The MIC37300/01/02 regulator will provide

excellent performance with an input as low as 3.0V or 2.25V,

respectively. This gives the PNP-based regulators a distinct

advantage over older, NPN-based linear regulators.

MIC37300/37301/37302 Micrel, Inc.

M9999-110305 8 November 2005

Minimum Load Current

The MIC37300/01/02 regulator is speciﬁed between ﬁnite

loads. If the output current is too small, leakage currents

dominate and the output voltage rises. A 10mA minimum

load current is necessary for proper operation.

Error Flag

The MIC37301 features an error ﬂag circuit that monitors

the output voltage and signals an error condition when the

voltage is 5% below the nominal output voltage. The error

ﬂag is an open-collector output that can sink 10mA during a

fault condition.

Low output voltage can be caused by a number of problems,

including an overcurrent fault (device in current limit) or low

input voltage. The ﬂag is inoperative during overtemperature

shutdown.

Enable Input

The MIC37301/37302 also features an enable input for

on/off control of the device. Its shutdown state draws “zero”

current (only microamperes of leakage). The enable input is

TTL/CMOS compatible for simple logic interface, but can be

connected up to VIN. When enabled, it draws approximately

15µA.

Adjustable Regulator Design

VOUT

VIN

COUT

OUT

ADJ

GND

MIC37302

ENABLE

SHUTDOWN

V 1.240V 1 R1

OUT = +











Figure 2. Adjustable Regulator with Resistors

The MIC37302 allows programming the output voltage any-

where between 1.24V and the 5.5V maximum operating rating

of the family. Two resistors are used. Resistors can be quite

large, up to 1MΩ, because of the very high input impedance

and low bias current of the sense comparator. The resistor

values are calculated by:

R1 R2 V

1.240 1

OUT

= −











Where VOUT is the desired output voltage. Figure 2 shows

component deﬁnition. Applications with widely varying load

currents may scale the resistors to draw the minimum load

current required for proper operation (see above).

November 2005 9 M9999-110305

MIC37300/37301/37302 Micrel, Inc.

Package Information

θ1

4θ

2θ

1θ

5-Pin TO-263-5 (U)

5-Pin S-PAK (R)

MIC37300/37301/37302 Micrel, Inc.

M9999-110305 10 November 2005

3-Pin S-PAK (R)

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

This 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.