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MIC5235
Ultra-Low Quiescent Current, 150mA Cap LDO Regulator
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 Cap LDO design, the MIC5235 is stable with either ceramic or tantalum output capacitor. It only requires a 2.2F capacitor for stability. Features of the MIC5235 includes enable input, thermal shutdown, current limit, reverse battery protection, and reverse leakage protection. Available in fixed and adjustable output voltage versions, (R) the MIC5235 is offered in the IttyBitty SOT-23-5 package with a junction temperature range of -40C to +125C.
Features
* * * * * * * * * * * * Wide input voltage range: 2.3V to 24V Ultra low ground current: 18A Low dropout voltage: 310mV at 150mA High output accuracy: 2.0% over temperature Cap: 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(R) SOT-23-5 package Adjustable output from 1.24V-20V
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
40 GROUND CURRENT (A)
VIN CIN=1.0F EN
MIC5235BM5
1 2 3 4 5
VOUT=1.8V R1 R2 COUT=2.2F ceramic IGND=18A
35 30 25 20 15 10 49 IOUT = 10A 14 19 INPUT VOLTAGE (V) 24 IOUT = 1mA
IOUT = 100A
Ultra-Low Current Adjustable Regulator Application
Ground Current vs. Input Voltage
IttyBitty is a registered trademark of Micrel, Inc 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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MIC5235
Ordering Information
Part Number Standard Pb-Free Marking Codes Standard Pb-Free* Voltage** Junction Temp. Range Package
MIC5235-1.5BM5 MIC5235-1.8BM5 MIC5235-2.5BM5 MIC5235-2.7BM5 MIC5235-3.0BM5 MIC5235-3.3BM5 MIC5235-5.0BM5 MIC5235BM5
MIC5235-1.5YM5 MIC5235-1.8YM5 MIC5235-2.5YM5 MIC5235-2.7YM5 MIC5235-3.0YM5 MIC5235-3.3YM5 MIC5235-5.0YM5 MIC5235YM5
L215 L218 L225 L227 L230 L233 L250 L2AA
L215 L218 L225 L227 L230 L233 L250 L2AA
1.5V 1.8V 2.5V 2.7V 3.0V 3.3V 5.0V Adj.
-40 to +125C -40 to +125C -40 to +125C -40 to +125C -40 to +125C -40 to +125C -40 to +125C -40 to +125C
5-Pin SOT-23 5-Pin SOT-23 5-Pin SOT-23 5-Pin SOT-23 5-Pin SOT-23 5-Pin SOT-23 5-Pin SOT-23 5-Pin SOT-23
* Under bar symbol (_) may not be to scale. ** Contact factory regarding availability for voltages not listed.
Pin Configuration
EN GND IN
3 2 1
EN GND IN
3 2 1
L2xx L2xx
4 5 4
L2xx L2xx
5
NC
OUT
ADJ
OUT
SOT-23-5 (Fixed)
SOT-23-5 (Adjustable)
Pin Description
Pin Number Pin Name Pin Function
1 2 3 4 5
IN GND EN NC (fixed) ADJ (adj.) OUT
Supply Input. Ground. Enable (Input): Logic low = shutdown; logic high = enable. No Connect. Adjust (Input): Feedback input. Connect to resistive voltage-divider network. Regulator Output.
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Absolute Maximum Ratings(1)
Input Supply Voltage ........................................ -20V to 38V Enable Input Voltage....................................... -0.3V to 38V Power Dissipation .....................................Internally Limited Junction Temperature ...............................-40C to +125C Storage Temperature ................................-65C to +150C ESD Rating(3)
Operating Ratings(2)
Input Supply Voltage ......................................... 2.3V to 24V Enable Input Voltage............................................ 0V to 24V Junction Thermal....................................... -40C to +125C Package Thermal Resistance SOT-23-5 (JA).................................................235C/W
Electrical Characteristics(4)
TA = 25C with VIN = VOUT + 1V; IOUT = 100A, Bold values indicate -40CParameter Condition Min Typ Max Units
Output Voltage Accuracy Line Regulation Load Regulation Dropout Voltage
Variation from nominal VOUT VIN = VOUT + 1V to 24V Load = 100A to 150mA IOUT = 100A IOUT = 50mA IOUT = 100mA IOUT = 150mA
-1.0 -2.0 0.04 0.25 50 230 270 310 1.22 1.24 18 0.35 1 2 0.1 350 -0.1
+1.0 +2.0 1 300 400 400 450 450 500 1.25 30 35 0.7 2 4 1
500
% % % % mV mV mV mV mV mV mV V A A mA mA mA A mA A
Reference Voltage Ground Current IOUT = 100A IOUT = 50mA IOUT = 100mA IOUT = 150mA Ground Current in Shutdown Short Circuit Current Output Leakage, Reverse Polarity Input
Enable Input
VEN 0.6V; VIN = 24V VOUT = 0V Load = 500; VIN = -15V
Input Low Voltage Input High Voltage Enable Input Current
Regulator OFF Regulator ON VEN = 0.6V; Regulator OFF VEN = 2.0V; Regulator ON VEN = 24V; Regulator ON
2.0
0.6
V V A A A
-1.0
0.01 0.1 0.5
1.0 1.0 2.5
Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 4. Specification for packaged product only.
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Typical Characteristics
Power Supply Rejection Ratio
70 60 50 PSRR (dB) 40 30 20 10 0 0.01 0.1 11 0 100 FREQUENCY (kHz) 1000 DROPOUT VOLTAGE (mV) ILOAD = 150mA 350 300 250 200 150 100 50 0 02 04 06 08 0 100 120 140 160 OUTPUT CURRENT (mA)
Dropout Voltage vs. Output Current
DROPOUT VOLTAGE (mV)
500 450 IOUT = 150mA 400 350 300 250 200 150
Dropout Voltage vs. Temperature
100 50 0 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (C)
3.5 OUTPUT VOLTAGE (V) 3
Dropout Characteristics
3000 GROUND CURRENT (A) 2500 2000 1500 1000 500 0 02 ILOAD = 100A
Ground Pin Current vs. Output Current
GROUND CURRENT (A)
VIN = 4V
30 28 26 24 22 20 18 16 14 12 10 0
Ground Pin Current vs. Output Current
2.5 ILOAD = 75mA 2 1.5 1 0.5 0 0 0.5 1 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE (V) ILOAD = 150mA
VIN = 12V
VIN = 24V
VIN = 4V
04 06 08 0 100 120 140 160 OUTPUT CURRENT (mA)
100 200 300 400 500 OUTPUT CURRENT (A)
80 GROUND CURRENT (A) 75 70 65 60 55 50 45 40
Ground Pin Current vs. Temperature
GROUND CURRENT (A) ILOAD = 10mA
660 640 620 600 580 560 540 520 500
-40 -20 02
GROUND CURRENT (mA)
700 680
Ground Pin Current vs. Temperature
ILOAD = 75mA
2.5 2.4 2.3 2.2 2.1 2 1.9 1.8 1.7
Ground Pin Current vs. Temperature
ILOAD = 150mA
-40 -20 02
04 06 08 0 100 120
04 06 08 0 100 120
TEMPERATURE (C)
TEMPERATURE (C)
1.6 1.5 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (C)
Ground Pin Current vs. Input Voltage
GROUND CURRENT (A) GROUND CURRENT (A) 100 90 80 70 60 50 IOUT = 1mA 40 30 20 10 0 1.5 IOUT = 10A 2 2.5 3 3.5 INPUT VOLTAGE (V) 4 IOUT = 100A IOUT = 10mA
GROUND CURRENT (A)
2.4 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 1.5
Ground Pin Current vs. Input Voltage
40
Ground Pin Current vs. Input Voltage
IOUT =150mA
35 30 25 20 15 10 49 IOUT = 10A 14 19 INPUT VOLTAGE (V) 24 IOUT = 1mA
IOUT = 100A
IOUT = 75mA
2 2.5 3 3.5 INPUT VOLTAGE (V)
4
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Typical Characteristics (continued)
SHORT CIRCUIT CURRENT (mA)
120 INPUT CURRENT (mA) 100 80 60 40 20 0 -20
Input Current vs. Supply Voltage
OUTPUT VOLTAGE (V)
3.05 3.04 3.03 3.02 3.01 3 2.99 2.98 2.97 2.96
Output Voltage vs. Temperature
ILOAD = 100 A
400 350 300 250 200 150 100 50
Short Circuit Current vs. Temperature
VEN = 5V RLOAD = 30 -10 0 SUPPLY VOLTAGE (V) 10
VIN = 4V
2.95 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (C)
0 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (C)
150mA 0mA VIN = 4V VOUT = 3V COUT = 4.7F ceramic
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Functional Diagram
IN EN ENABLE OUT
1.24V VREF
GND
Block Diagram - Fixed Output Voltage
IN EN ENABLE R1 1.24V
OUT
VREF
ADJ R2
GND
Block Diagram - Adjustable Output Voltage
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TJ(MAX) - TA PD(MAX) = JA
Application 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-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 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 2.2F 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 3. 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. 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 operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than a 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 applications. Thermal Considerations 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: May 2008 7
TJ(MAX) is the maximum junction temperature of the die, 125C, and TA is the ambient operating temperature. JA is layout dependent; Table 1 shows examples of the junction-to-ambient thermal resistance for the MIC5235. Package SOT-23-5 JA Recommended Minimum Footprint 235C
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 + VINIGND 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 MIC5235-3.0BM5 at 50C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows:
125C - 50C PD(MAX) = 235C/W
PD(MAX) = 319mW The junction-to-ambient (JA) thermal resistance for the minimum footprint is 235C/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 - VOUT)IOUT + VIN x IGND 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 50C ambient, 319mV. PD(MAX) = (VIN - VOUT)IOUT + VIN x IGND 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:
M9999-051508
Micrel, Inc. 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 50C ambient temperature is 18.8V, utilizing virtually the entire operating voltage range of the device. 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:
VOUT R = VREF 1 + 1 R 2
MIC5235 Where VREF = 1.24V. Feedback resistor R2 should be no larger than 300k.
VIN MIC5235BM5 IN EN OUT R1 1.0F GND ADJ. R2 2.2F VOUT
Figure 1. Adjustable Voltage Application
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Package Information
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
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 a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2003 Micrel, Incorporated.
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