MICREL MIC5235 Datasheet

MIC5235 Micrel

40

MIC5235

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 3.0V and adjustable output voltage verisons, the
MIC5235 is offered in the IttyBitty™ SOT-23-5 package with
a junction temperature range of –40°C to +125°C.

Ultra-Low Quiescent Current, 150 mA

µ

Cap LDO Regulator

Final Information

Features

• Wide input voltage range: 2.3V to 24V

• Ultra low ground current: 18µA

• Low dropout voltage of 310mV at 150mA

• High output accuracy of ±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

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

C

=1.0µF

IN

Ultra-Low Current Adjustable Regulator Application

OFF

Ordering Information

Part Number Marking Voltage Junction Temp. Range* Package

MIC5235-3.0BM5 L230 3.0V –40°C to +125°C SOT-23-5
MIC5235BM5 L2AA ADJ. –40°C to +125°C SOT-23-5

35

30

I

= 1mA

OUT

25

20

15

I

GROUND CURRENT (µA)

OUT

10

4 9 14 19 24

INPUT VOLTAGE (V)

= 10µA

I

OUT

= 100µA

Ground Current vs. Input Voltage

IN

ON

MIC5235BM5

15

2
34

EN

V

=1.8V

OUT

C

R

1

R

2

=2.2µF

OUT

ceramic

I

=18µA

GND

V

IttyBitty is a trademark of Micrel, Inc.

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

January 2002 1 MIC5235

MIC5235 Micrel

Pin Configuration

GND

2

IN

13

EN

L2xx

45

NC or
ADJ.

OUT

SOT-23-5

Pin Description

SOT-23-5 Pin Name Pin Function

1 IN Supply Input
2 GND Ground
3 EN Enable (Input): Logic low = shutdown; logic high = enable
4 NC (fixed) No Connect

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

5 OUT Regulator Output

MIC5235 2 January 2002

MIC5235 Micrel

Absolute Maximum Ratings (Note 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

Operating Ratings (Note 2)

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

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

Junction Temperature (T
Package Thermal Resistance

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

) ....................... –40°C to +125°C

J

ESD Rating, Note 3

Electrical Characteristics

TA = 25°C with VIN = V

Parameter Condition Min Typ Max Units

Output Voltage Accuracy Variation from nominal V

Line Regulation VIN = V
Load Regulation Load = 100µA to 150mA 0.25 1 %
Dropout Voltage I

Ground Current I

Ground Current in Shutdown VEN ≤ 0.6V; VIN = 24V 0.1 1 µA
Short Circuit Current V
Output Leakage, Load = 500Ω; VIN = –15V –0.1 µA

Reverse Polarity Input

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 –1.0 0.01 1.0 µA

OUT

+ 1V; I

= 100µA , Bold values indicate –40°C<TJ< +125°C; unless otherwise specified.

OUT

OUT

+ 1V to 24V 0.04 %

OUT

= 100µA50mV

OUT

= 50mA 230 300 mV

I

OUT

I

= 100mA 270 400 mV

OUT

–1.0 +1.0 %

–2.0 +2.0 %

400 mV
450 mV

= 150mA 310 450 mV

I

OUT

= 100µA1830µA

OUT

I

= 50mA 0.35 0.7 mA

OUT

= 100mA 1 2 mA

I

OUT

I

= 150mA 2 4 mA

OUT

= 0V 350 500 mA

OUT

500 mV

35 µA

VEN = 2.0V; Regulator ON 0.1 1.0 µA
VEN = 24V; Regulator ON 0.5 2.5 µA

Note 1. Exceeding the absolute maximum rating may damage the device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.

January 2002 3 MIC5235

MIC5235 Micrel

)

)

)

)

)

)

Typical Characteristics (MIC5235-3.0BM5)

Power Supply

Rejection Ratio

70
60
50
40
30

PSRR (dB)

20
10

0

0.01 0.1 1 10 100 1000

I

= 150mA

LOAD

FREQUENCY (Hz

Dropout

3.5

2.5

1.5

OUTPUT VOLTAGE (V)

0.5

Characteristics

I

3

2

1

0

0 0.5 1 1.5 2 2.5 3 3.5 4

= 100µA

LOAD

I

= 75mA

LOAD

I

LOAD

INPUT VOLTAGE (V)

= 150mA

Dropout Voltage

vs. Output Current

350
300
250
200
150
100

50

DROPOUT VOLTAGE (mV)

0

0 20 40 60 80 100 120 140160

OUTPUT CURRENT (mA

Ground Pin Current

vs. Output Current

3000

2500

2000

1500

1000

500

GROUND CURRENT (µA)

0

0 20 40 60 80 100 120 140160

OUTPUT CURRENT (mA)

VIN = 4V

Dropout Voltage
vs. Temperature

500
450

I

= 150mA

OUT

400
350
300
250
200
150
100

DROPOUT VOLTAGE (mV)

50

0

-40 -20 0 20 40 60 80 100120

TEMPERATURE (°C)

Ground Pin Current

vs. Output Current

30
28
26
24

VIN = 12V

22
20
18
16
14

GROUND CURRENT (µA)

12
10

VIN = 4V

0 100 200 300 400 500

OUTPUT CURRENT (µA)

VIN = 24V

Ground Pin Current

vs. Temperature

80

I

75
70
65
60
55
50

GROUND CURRENT (µA)

45
40

-40 -20 0 20 40 60 80 100 120

TEMPERATURE (°C

LOAD

= 10mA

Ground Pin Current

vs. Input Voltage

100

I

90
80
70
60
50
40
30
20

GROUND CURRENT (µA)

10

= 10mA

OUT

I

= 1mA

OUT

0

1.5 2 2.5 3 3.5 4

INPUT VOLTAGE (V

I

OUT

I

= 100µA

OUT

= 10µA

Ground Pin Current

700
680
660
640
620
600
580
560
540

GROUND CURRENT (µA)

520
500

vs. Temperature

I

= 75mA

LOAD

-40 -20 0 20 40 60 80 100 120

TEMPERATURE (°C

Ground Pin Current

vs. Input Voltage

2.4

2.2

I

=150mA

OUT

2

1.8

1.6

1.4

1.2
1

I

= 75mA

OUT

0.8

GROUND CURRENT (µA)

0.6

0.4

1.5 2 2.5 3 3.5 4

INPUT VOLTAGE (V)

Ground Pin Current

vs. Temperature

2.5

2.4

2.3

2.2

2.1
2

1.9

1.8

1.7

GROUND CURRENT (mA)

1.6

1.5

-40 -20 0 20 40 60 80 100120

I

= 150mA

LOAD

TEMPERATURE (°C

Ground Pin Current

vs. Input Voltage

40

35

30

I

= 1mA

OUT

25

20

15

I

GROUND CURRENT (µA)

OUT

10

4 9 14 19 24

INPUT VOLTAGE (V)

= 10µA

I

OUT

= 100µA

MIC5235 4 January 2002

MIC5235 Micrel

)

)

0

50

100

150

200

250

300

350

400

-40 -20 0 20 40 60 80 100120

SHORT CIRCUIT CURRENT (mA)

TEMPERATURE (°C)

Short Circuit Current

vs. Temperature

VIN = 4V

Input Current

vs. Supply Voltage

120

100

80

60

40

VEN = 5V

= 30Ω

R

LOAD

INPUT CURRENT (mA)

20

0

-20 -10 0 10

SUPPLY VOLTAGE (V

Output Voltage

3.05

3.04

3.03

3.02

3.01

2.99

2.98

2.97

OUTPUT VOLTAGE (V)

2.96

2.95

vs. Temperature

I

= 100µA

LOAD

3

-40 -20 0 20 40 60 80 100120

TEMPERATURE (°C

Load Transient Response

January 2002 5 MIC5235

(200mV/div.)

OUTPUT VOL TA GE

(100mA/div.)

OUTPUT CURRENT

TIME (400µs/div.)

150mA

VIN = 4V

= 3V

V

OUT

= 4.7µF ceramic

C

OUT

0mA

MIC5235 Micrel

Functional Diagram

EN

IN

EN

IN

ENABLE

V

REF

GND

OUT

Block Diagram – Fixed Output Voltage

OUT

ENABLE

R1

V

REF

GND

Block Diagram – Adjustable Output Voltage

ADJ

R2

MIC5235 6 January 2002

MIC5235 Micrel

P

125 C 50 C

235 C/W

D(MAX)

=

°− °

°











Applications 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-mode­current 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. X7R­type 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 an
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 application.

Thermal Consideration

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:

TT



J(MAX) A

=





T

J(MAX)

P

D(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 junction­to-ambient thermal resistance for the MIC5235.

−



θ

JA





Package θJA Recommended

Minimum Footprint

SOT-23-5 235°C/W

Table 1. SOT-23-5 Thermal Resistance

The actual power dissipation of the regulator circuit can be
determined using the equation:

PD = (VIN – V

Substituting P

OUT)IOUT

for PD and solving for the operating

D(MAX)

+ VINI

GND

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:

P

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:

PD = (VIN – V

OUT)IOUT

+ VIN x I

GND

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

P

DMAX

= (VIN – V

OUT)IOUT

+ VIN x I

GND

319mW = (VIN – 3V)150mA + VIN x 2.8mA

Ground pin current is estimated using the typical character­istics of the device.

769mW = VIN (152.8mA)
VIN = 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:

319mW = (VIN – 3V)20mA + VIN x 0.2mA
379mW = VIN x 20.2mA
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.

January 2002 7 MIC5235

MIC5235 Micrel

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:

VV

OUT

Where V

=+

= 1.24V.

REF

REF

1












R

1







R







2

Feedback resistor R2 should be no larger than 300kΩ.

V

1.0µF

IN

MIC5235BM5

IN

EN

GND

OUT

ADJ.

V

OUT

R

1

2.2µF

R

2

Figure 1. Adjustable Voltage Application

MIC5235 8 January 2002

MIC5235 Micrel

Package Information

1.90 (0.075) REF

0.95 (0.037) REF

3.02 (0.119)

2.80 (0.110)

0.50 (0.020)

0.35 (0.014)

1.75 (0.069)

1.50 (0.059)

1.30 (0.051)

0.90 (0.035)

0.15 (0.006)

0.00 (0.000)

SOT-23-5 (M5)

3.00 (0.118)

2.60 (0.102)

10°

0°

DIMENSIONS:

MM (INCH)

0.20 (0.008)

0.09 (0.004)

0.60 (0.024)

0.10 (0.004)

MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 [phone] FAX + 1 [phone] WEB http://www.micrel.com

This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or

other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.

© 2002 Micrel Incorporated

January 2002 9 MIC5235