February 2005 1 MIC5233
MIC5233 Micrel, Inc.
MIC5233
High Input Voltage, Low IQ µCap LDO Regulator
General Description
The MIC5233 is a 100mA 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 MIC5233 ideal for multi-cell Li-Ion battery
systems.
A µCap LDO design, the MIC5233 is stable with either
ceramic or tantalum output capacitor. It only requires a 2.2µF
capacitor for stability.
Features of the MIC5233 include enable input, thermal shut-
down, current limit, reverse battery protection, and
reverse leakage protection.
Available in fixed and adjustable output voltage versions, the
MIC5233 is offered in the IttyBitty™ SOT-23-5 package with
a junction temperature range of –40°C to +125°C.
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
IttyBitty is a trademark of Micrel, Inc.
Features
•Wide input voltage range: 2.3V to 36V
•Ultra low ground current: 18µA
•Low dropout voltage of 270mV at 100mA
•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
•Keep-alive supply in notebook and portable computers
•USB power supply
•Logic supply for high-voltage batteries
•Automotive electronics
•Battery powered systems
•3-4 cell Li-Ion battery input range
Typical Application
15
2
34
C
OUT
=2.2µF
ceramic
I
GND
=18µA
C
IN
=1.0µF
EN
MIC5233BM5
V
IN
V
OUT
R
1
R
2
OFF
ON
Ultra-Low Current Adjustable Regulator Application
Ordering Information
Standard Pb-Free Junction
Part Number Marking Part Number Marking Voltage Temp Range Package
MIC5233-1.8BM5 L318 MIC5233-1.8YM5 L318 1.8V –40°C to +125°CSOT-23-5
MIC5233-2.5BM5 L325 MIC5233-2.5YM5 L325 2.5V –40°C to +125°CSOT-23-5
MIC5233-3.0BM5 L330 MIC5233-3.0YM5 L330 3.0V –40°C to +125°CSOT-23-5
MIC5233-3.3BM5 L333 MIC5233-3.3YM5 L333 3.3V –40°C to +125°CSOT-23-5
MIC5233-5.0BM5 L350 MIC5233-5.0YM5 L350 5.0V –40°C to +125°CSOT-23-5
MIC5233BM5 L3AA MIC5233YM5 L3AA ADJ. –40°C to +125°CSOT-23-5
10
15
20
25
30
35
40
481216 20 24 28 32 36 40
GROUND CURRENT (µA)
INPUT VOLTAGE (V)
I
OUT
= 10µA
I
OUT
= 1mA
I
OUT
= 100µA
Ground Current vs. Input Voltage
MIC5233 Micrel, Inc.
MIC5233 2 February 2005
Pin Configuration
IN
OUT
NC or
ADJ.
EN
L3xx
13
45
2
GND
SOT-23-5
Pin Description
SOT-23-5 Pin Name Pin Function
1INSupply Input.
2GND Ground.
3ENEnable (Input): Logic low = shutdown; logic high = enable
4NC (fixed) No Connect.
ADJ (ADJ.) Adjust (Input): Feedback input. Connect to resistive voltage-divider network.
5OUT Regulator Output.
February 2005 3 MIC5233
MIC5233 Micrel, Inc.
Electrical Characteristics (Note 4)
TA = 25°C with VIN = VOUT + 1V; IOUT = 100µA; VEN ≥ 2V; Bold values indicate –40°C<T
J< +125°C; unless otherwise specified.
Parameter Condition Min Typ Max Units
Output Voltage Accuracy Variation from nominal VOUT –1.0 +1.0 %
–2.0 +2.0 %
Line Regulation VIN = VOUT + 1V to 36V 0.04 0.5 %
Load Regulation IOUT = 100µA to 100mA 0.25 1 %
Dropout Voltage IOUT = 100µA50mV
IOUT = 50mA 230 300 mV
400 mV
IOUT = 100mA 270 400 mV
450 mV
Ground Current IOUT = 100µA1830µA
35 µA
IOUT = 50mA 0.35 0.70 mA
IOUT = 100mA 1 2 mA
Ground Current in Shutdown VEN ≤ 0.6V; VIN = 36V 0.1 1 µA
Short Circuit Current VOUT = 0V 190 350 mA
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
VEN = 2.0V; Regulator ON 0.1 1.0 µA
VEN = 36V; 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.
Note 4. Specification for packaged product only.
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
ESD Rating, Note 3
Operating Ratings (Note 2)
Input Supply Voltage ........................................ 2.3V to 36V
Enable Input Voltage ........................................... 0V to 36V
Junction Temperature (TJ) ....................... –40°C to +125°C
Package Thermal Resistance
SOT-23-5 (θJA) .................................................. 235°C/W
MIC5233 Micrel, Inc.
MIC5233 4 February 2005
Typical Characteristics
0
10
20
30
40
50
60
70
0.01 0.1 1 10 100 1000
PSRR (dB)
FREQUENCY (kHz)
Power Supply
Rejection Ratio
I
OUT
= 100mA
0
50
100
150
200
250
300
350
020406080100
DROPOUT VOLTAGE (mV)
OUTPUT CURRENT (mA)
Dropout Voltage
vs. Output Current
0
50
100
150
200
250
300
350
400
450
500
-40 -20 0 20 40 60 80 100 120
DROPOUT VOLTAGE (mV)
TEMPERATURE (°C)
Dropout Voltage
vs. Temperature
I
OUT
= 100mA
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
00.511.5 2 2.5 3 3.5 4
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Dropout
Characteristics
ILOAD = 100µA
ILOAD = 50mA
ILOAD = 100mA
0
100
200
300
400
500
600
700
800
900
1000
0102030405060708090100
GROUND CURRENT (µA)
OUTPUT CURRENT (mA)
Ground Pin Current
vs. Output Current
V
IN
= 4V
10
12
14
16
18
20
22
24
26
28
30
0100 200 300 400 500
GROUND CURRENT (µA)
OUTPUT CURRENT (µA)
Ground Pin Current
vs. Output Current
V
IN
= 24V
V
IN
= 12V V
IN
= 4V
V
IN
= 36V
40
45
50
55
60
65
70
75
80
-40 -20 0 20 40 60 80 100 120
GROUND CURRENT (µA)
TEMPERATURE
(
°C
)
Ground Pin Current
vs. Temperature
I
LOAD
= 10mA
200
220
240
260
280
300
320
340
360
380
400
-40 -20 0 20 40 60 80 100 120
GROUND CURRENT (µA)
TEMPERATURE
(
°C
)
Ground Pin Current
vs. Temperature
I
LOAD
= 50mA
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
-40 -20 0 20406080100120
GROUND CURRENT (mA)
TEMPERATURE (°C)
Ground Pin Current
vs. Temperature
I
LOAD
= 100mA
0
10
20
30
40
50
60
70
80
90
100
1.5 2 2.5 3 3.5 4
GROUND CURRENT (µA)
INPUT VOLTAGE (V)
Ground Pin Current
vs. Input Voltage
I
OUT
= 10µA
I
OUT
= 1mA I
OUT
= 100µA
I
OUT
= 10µA
200
300
400
500
600
700
800
900
1000
1100
1200
1.5 2 2.5 3 3.5 4
GROUND CURRENT (µA)
INPUT VOLTAGE (V)
Ground Pin Current
vs. Input Voltage
IOUT=100mA
IOUT = 50mA
10
15
20
25
30
35
40
481216 20 24 28 32 36 40
GROUND CURRENT (µA)
INPUT VOLTAGE (V)
Ground Pin Current
vs. Input Voltage
IOUT = 10µA
IOUT = 1mA
IOUT = 100µA
February 2005 5 MIC5233
MIC5233 Micrel, Inc.
0
20
40
60
80
100
120
-20 -10 0 10
INPUT CURRENT (mA)
SUPPLY VOLTAGE (V)
Input Current
vs. Supply Voltage
V
EN
= 5V
R
LOAD
= 30Ω
2.95
2.96
2.97
2.98
2.99
3.00
3.01
3.02
3.03
3.04
3.05
-40 -20 0 20 40 60 80 100 120
OUTPUT VOLTAGE (V)
TEMPERATURE
(
°C
)
Output Voltage
vs. Temperature
I
LOAD
= 100µA
0
50
100
150
200
250
300
-40 -20 0 20 40 60 80 100 120
SHORT CIRCUIT CURRENT (mA)
TEMPERATURE (°C)
Short Circuit Current
vs. Temperature
V
IN
= 4V
Load Transient Response
TIME (400µs/div.)
OUTPUT CURRENT
(100mA/div.)
OUTPUT VOLTAGE
(200mV/div.)
VIN = 4V
VOUT = 3V
COUT = 4.7µF ceramic
100mA
0mA
MIC5233 Micrel, Inc.
MIC5233 6 February 2005
Functional Diagrams
IN
EN
OUT
R1
R2
GND
ENABLE
V
REF
Block Diagram – Fixed Output Voltage
IN
EN
R1
R2
ADJ
OUT
GND
ENABLE
V
REF
Block Diagram – Adjustable Output Voltage
February 2005 7 MIC5233
MIC5233 Micrel, Inc.
Applications Information
Enable/Shutdown
The MIC5233 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 MIC5233 has high input voltage capability up to 36V. 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 capaci-
tors can be used for bypassing. A larger value may be
required if the source supply has high ripple.
Output Capacitor
The MIC5233 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 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.
No-Load Stability
The MIC5233 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 Consideration
The MIC5233 is designed to provide 100mA 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 ther-
mal resistance of the device and the following basic equation:
PTT
D(MAX)
J(MAX) A
JA
=−
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 MIC5233.
Package θθ
θθ
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 – VOUT)IOUT + VIN×IGND
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 MIC5233-3.0BM5 at 50°C with
a minimum footprint layout, the maximum input voltage for a
set output current can be determined as follows:
P125 C 50 C
235 C/W
D(MAX) =°−°
°
PD(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 MIC5233 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 – VOUT)IOUT + VIN x IGND
Due to the potential for input voltages up to 36V, 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 dissipa-
tion calculated for a 50°C ambient, 319mV.
PDMAX = (VIN – VOUT)IOUT + VIN x IGND
319mW = (VIN – 3V)100mA + VIN x 2.8mA
Ground pin current is estimated using the typical character-
istics of the device.
619mW = VIN (102.8mA)
VIN = 6.02V
For higher current outputs only a lower input voltage will work
for higher ambient temperatures.
Assuming a lower output current of 10mA, the maximum input
voltage can be recalculated:
319mW = (VIN – 3V)10mA + VIN x 0.1mA
349mW = VIN x 10.1mA
VIN = 34.9V
Maximum input voltage for a 10mA load current at 50°C
ambient temperature is 34.9V, utilizing virtually the entire
operating voltage range of the device.
MIC5233 Micrel, Inc.
MIC5233 8 February 2005
Adjustable Regulator Application
The MIC5233BM5 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 R
R
OUT REF 1
2
=+
1
Where VREF = 1.24V.
Feedback resistor R2 should be no larger than 300kΩ.
OUT
ADJ.
VIN
R1
R2
2.2µF
1.0µF
EN
IN
VOUT
GND
MIC5233BM5
Figure 1. Adjustable Voltage Application
February 2005 9 MIC5233
MIC5233 Micrel, Inc.
Package Information
0.20 (0.008)
0.09 (0.004)
0.60 (0.024)
0.10 (0.004)
3.02 (0.119)
2.80 (0.110) 10°
0°
3.00 (0.118)
2.60 (0.102)
1.75 (0.069)
1.50 (0.059)
0.95 (0.037) REF
1.30 (0.051)
0.90 (0.035)
0.15 (0.006)
0.00 (0.000)
DIMENSIONS:
MM (INCH)
0.50 (0.020)
0.35 (0.014)
1.90 (0.075) REF
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
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.
© 2003 Micrel, Incorporated.
