MICREL MIC5237-3.3BT, MIC5237-3.3BU, MIC5237-5.0BT, MIC5237-2.5BU, MIC5237-5.0BU Datasheet

MIC5237 Micrel

MIC5237

500mA Low-Dropout Regulator

Preliminary Information

General Description

The MIC5237 is a general-purpose low-dropout regulator
capable of 500mA output current with better than 3% output
voltage accuracy. Using Micrel’s proprietary Super
ßeta PNP™ process with a PNP pass element, these regu­lators feature less than 300mV dropout voltage and typically
8mA ground current at full load.

Designed for applications that require moderate current over
a broad input voltage range, including hand-held and battery­powered devices, the MIC5237 is intended for applications
that can tolerate moderate voltage drop at higher current.

Key features include low ground current to help prolong
battery life, reversed-battery protection, current limiting, over­temperature shutdown, and thermally efficient packaging.
The MIC5237 is available in fixed output voltages only.

For space-critical applications and improved performance,
see the MIC5209 and MIC5219. For output current require­ments up to 750mA, see the MIC2937.

Ordering Information

Features

• Guaranteed 500mA output over the full operating
temperature range

• Low 300mV typical dropout voltage at full load

• Extremely tight load and line regulation

• Current and thermal limiting

• Reversed-battery protection

• TO-220 and TO-263 packages

• Low temperature coefficient

• No-load stability

• Low-noise output

Applications

• Portable and laptop computers

• Desktop computer

• Battery chargers

• SMPS post-regulator/dc-to-dc modules

• Consumer and personal electronics

Typical Application

Part Number Voltage Junct. Temp. Range Package

MIC5237-2.5BT 2.5V –40°C to +125°C TO-220
MIC5237-2.5BU 2.5V –40°C to +125°C TO-263
MIC5237-3.3BT 3.3V –40°C to +125°C TO-220
MIC5237-3.3BU 3.3V –40°C to +125°C TO-263
MIC5237-5.0BT 5.0V –40°C to +125°C TO-220
MIC5237-5.0BU 5.0V –40°C to +125°C TO-263

V

IN

≥5.6V

1.0µF

MIC5237-5.0

IN OUT

GND

V

OUT

5.0V ±3%

1.0µF
tantalum

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 [phone] • fax + 1 [phone] • http://www.micrel.com

January 2000 1 MIC5237

MIC5237 Micrel

Pin Configuration

3 OUT

TAB

MIC5237-x.xBT

TAB

(TO-220-3)

3 OUT
2 GND
1IN

2 GND
1IN

MIC5237-x.xBU

(TO-263-3)

Pin Description

Pin No. Pin Name Pin Function

1 IN Supply Input

2, TAB GND Ground: TO-220 and TO-263 pin 2 and TAB are internally connected.

3 OUT Regulator Output

Absolute Maximum Ratings

Input Voltage (VIN) ........................................ –20V to +20V

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

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

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

Operating Ratings

Input Voltage (VIN) ....................................... +2.5V to +16V

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

Package Thermal Resistance

TO-220 (θJA) .......................................................55°C/W

TO-220 (θJC) .........................................................3°C/W

TO-263 (θJC) .........................................................3°C/W

MIC5237 2 January 2000

MIC5237 Micrel

Electrical Characteristics

VIN = V

Symbol Parameter Conditions Min Typical Max Units

V

OUT

∆V

OUT

∆V

OUT/VOUT

∆V

OUT/VOUT

V

– V

IN

I

GND

PSRR Ripple Rejection f = 120Hz 75 dB
I

LIMIT

∆V

OUT

e

no

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

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. Parts are tested for load regulation in the load

Note 4: Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V

Note 5: Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of

Note 6: 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

+ 1.0V; C

OUT

Output Voltage Accuracy variation from nominal V

= 4.7µF, I

OUT

= 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted.

OUT

OUT

–3 3 %
–5 5 %

/∆T Output Voltage Note 2 40 ppm/°C

Temperature Coefficient
Line Regulation VIN = V

+ 1V to 16V 0.05 %/V

OUT

0.015 0.1 %/V

Load Regulation I

= 100µA to 500mA, Note 3 0.05 0.5 %

OUT

0.7 %

OUT

Dropout Voltage, Note 4 I

= 100µA1070mV

OUT

90 mV

I

= 50mA 115 190 mV

Ground Pin Current, Note 5 I

OUT

= 150mA 165 350 mV

I

OUT

= 500mA 300 600 mV

I

OUT

= 100µA80130µA

OUT

I

= 50mA 350 650 µA

OUT

280 mV

450 mV

700 mV

170 µA

900 µA

I

= 150mA 1.8 2.5 mA

OUT

3.0 mA

I

= 500mA 8 15 mA

OUT

20 mA

Current Limit V

= 0V 700 900 mA

OUT

1000

/∆P

Thermal Regulation Note 6 0.05 %/W

D

Output Noise V

operating the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction
temperature, T
dissipation at any ambient temperature is calculated using: P
tion will result in excessive die temperature, and the regulator will go into thermal shutdown. See the “Thermal Considerations” section for
details.

range from 100µA to 500mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.

differential.

the load current plus the ground pin current.

regulation effects. Specifications are for a 500mA load pulse at VIN = 16V for t = 10ms.

, the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable power

J(max)

C

OUT
OUT

= 5.0V, I
= 2.2µF

D(max)

= 50mA, 500

OUT

= (T

J(max)–TA

) ÷ θJA. Exceeding the maximum allowable power dissipa-

nV/ Hz

January 2000 3 MIC5237