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MIC5268
Micrel
MIC5268
150mA Cap CMOS LDO Regulator w/Power Good Preliminary Information
General Description
The MIC5268 is an efficient, precise CMOS voltage regulator with power good output. The MIC5268 offers better than 3% initial accuracy, and constant ground current (typically 100A)over load . The MIC5268 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in hand-held wireless devices. Key features include current limit, thermal shutdown, a pushpull output for faster transient response, and an active clamp to speed up device turnoff. Available in the IttyBittyTM SOT-23-5 package, the MIC5268 is a fixed 1.2V regulator.
Features
* * * * * * * * * * Power Good indicator Load independent, ultralow ground current: 100A 150mA output current Current limiting Thermal shutdown Tight load and line regulation "Zero" off-mode current Stability with low-ESR capacitors Fast transient response TTL-Logic-controlled enable input
Applications
* Processor power-up sequencing * Laptop, notebook, and palmtop computers * PCMCIA VCC and VPP regulation/switching
Ordering Information
Part Number MIC5268-1.2BM5 Marking L512 Voltage 1.2 Junction Temp. Range* -40C to +125C Package SOT-23-5
Other voltages available. Contact Micrel for details.
Typical Application
47k VIN MIC5268-x.xBM5
1 2 Enable Shutdown 3 4 5
VOUT COUT PG
EN
EN (pin 3) may be connected directly to IN (pin 1).
1.2V Regulator with Power Good
IttyBitty is a trademark of Micrel, Inc. Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
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MIC5268
MIC5268
Micrel
Pin Configuration
EN GND IN
3 2 1
L512
4 5
PG
OUT
MIC5268-x.xBM5
Pin Description
Pin Number 1 2 3 4 5 Pin Name IN GND EN PG OUT Pin Function Supply Input Ground Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. Power Good Output Regulator Output
MIC5268
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Absolute Maximum Ratings (Note 1)
Supply Input Voltage (VIN) .................................. 0V to +7V Enable Input Voltage (VEN) .................................. 0V to VIN Flag Output Voltage (VPG) ................................... 0V to VIN Junction Temperature (TJ) ...................................... +150C Storage Temperature ............................... -65C to +150C Lead Temperature (soldering, 5 sec.) ....................... 260C ESD, Note 3
Operating Ratings (Note 2)
Input Voltage (VIN) ......................................... +2.7V to +6V Enable Input Voltage (VEN) .................................. 0V to VIN Flag Output Voltage (VPG) ................................... 0V to VIN Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance SOT-23(JA) ......................................................235C/W
Electrical Characteristics
VIN = 2.7V, VEN = VIN; IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Symbol VO VLNR VLDR IQ IGND PSRR ILIM Enable Input VIL VIH IEN Enable Input Logic-Low Voltage Enable Input Logic-High Voltage Enable Input Current VIN = 5.5V, regulator shutdown VIN = 5.5V, regulator enabled VIL 0.4V; VIN = 5.5V VIH 1.6V; VIN = 5.5V Thermal Protection Thermal Shutdown Temperature Thermal Shutdown Hysteresis Power Good , Note 6 VPG VOL IPG VPG Delay
Note 1. Note 2. Note 3. Note 4. Note 5. Note 6.
Parameter Output Voltage Accuracy Line Regulation Load Regulation Quiescent Current Ground Pin Current, Note 5
Conditions IOUT = 100A VIN = 2.7V to 6V IOUT = 0.1mA to 150mA, Note 4 VEN 0.4V (shutdown) PG = NC IOUT = 0mA; VIN = 6.0V IOUT = 150mA; VIN = 6.0V f = 120Hz, COUT = 4.7F, IOUT = 150mA VOUT = 0V
Min -3 -4 -0.3
Typical
Max 3 4 0.3
Units % % %/V % A A A dB mA
3 0.45 110 110 tbd 160 350
5 1 150 150
Power Supply Rejection Current Limit
0.4 1.6 0.01 0.01
V V A A C C
150 10
Low Threshold High Threshold PG Output Logic-Low Voltage Power Good Leakage Current Delay time to Power Good
% of VOUT (PG ON) % of VOUT (PG OFF) IL = 10mA power good off, VPG = 5.5V See Timing Diagram
88 97 250 0.01 1 5 500
% % mV A ms
Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground pin current. The power good is a function of the output voltage being 5% low and the detection of one of the following: overcurrent, overtemperature or dropout. See "Applications Information" section for additional information.
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MIC5268
MIC5268
Micrel
Block Diagrams
IN EN Reference Voltage Startup/ Shutdown Control Quickstart
PULL UP
Thermal Sensor
FAULT
Error Amplifier
Current Amplifier
PULL DOWN
OUT
Undervoltage Lockout
ACTIVE SHUTDOWN
Out of Regulation Detection PG Overcurrent Dropout Detection Delay
GND
Timing Diagram
VOUT
97% 88% 97%
Fault Condition VEN
Min - Max 1-5ms
1-5ms
VPG
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Typical Characteristics
Ground Current vs. Input Voltage
113
GROUND CURRENT (A) GROUND CURRENT (A)
Ground Current vs. Output Current
99.4 99.2 99 98.8 98.6 98.4 98.2 0 20 40 60 80 100 120 140 160 OUTPUT CURRENT (mA)
GROUND CURRENT (A)
Ground Current vs. Temperature
110
111 109 107 105 103 101 99 97
IOUT = 100A
VIN = 3.3V
105 100 95 90
IOUT = 100A
IOUT = 150mA
IOUT = 150mA
95 2.5 3 3.5 4 4.5 5 5.5 6 6.5 INPUT VOLTAGE (V)
85 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
Short Circuit Current vs. Input Voltage
SHORT CIRCUIT CURRENT (mA) SHORT CIRCUIT CURRENT (mA)
Short Circuit Current vs. Temperature
400 380 360 340 320 300 280 260 240 220 200 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C) POWER GOOD DELAY (ms) VIN = 3.3V 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2
Power Good Delay vs. Input Voltage
IOUT = 100A
360 350 340 330 320 310 300 290 280 270 260 2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1 INPUT VOLTAGE (V)
1.1 1 2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1 INPUT VOLTAGE (V)
Power Good Delay vs. Temperature
POWER GOOD DELAY (ms) 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C) 1.195 VIN = 3.3V OUTPUT VOLTAGE (V) 1.19 1.185 1.18 1.175
Output Voltage vs. Input Voltage
1.195 OUTPUT VOLTAGE (V) IOUT = 100A 1.19 1.185 1.18 1.175 1.17 1.165 1.16 0
Output Voltage vs. Output Current
IOUT = 150mA
1.17 2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1 INPUT VOLTAGE (V)
VIN = 3.3V 20 40 60 80 100 120 140 160 OUTPUT CURRENT (mA)
Output Voltage vs. Temperature
1.205 ENABLE VOLTAGE (V) OUTPUT VOLTAGE (V) 1.2 1.195 1.19 1.185 IOUT = 100A 1.18 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
Enable Voltage vs. Input Voltage
1.4 ENABLE VOLTAGE (V) 1.3 1.2 1.1 1 0.9 0.8 0.7 IOUT = 100A 0.6 2.6 3.1 3.6 4.1 4.6 5.1 5.6 6.1 INPUT VOLTAGE (V) 1.2 1.15 1.1 1.05 1 0.95 0.9 0.85
Enable Voltage vs. Temperature
VIN = 3.3V
0.8 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (C)
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MIC5268
Micrel
Transient Response The MIC5268 implements a unique output stage to dramatically improve transient response recovery time. The output is a totem-pole configuration with a P-channel MOSFET pass device and an N-channel MOSFET clamp. The N-channel clamp is a significantly smaller device that prevents the output voltage from overshooting when a heavy load is removed. This feature helps to speed up the transient response by significantly decreasing transient response recovery time during the transition from heavy load (100mA) to light load (100A). Active Shutdown The MIC5268 also features an active shutdown clamp, which is an N-channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. Thermal Considerations The MIC5268 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: TJ(max) - TA PD(max) = JA 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 junction-toambient thermal resistance for the MIC5268.
Package SOT-23-5 (M5) JA Recommended JA 1" Square Minimum Footprint Copper Clad 235C/W 185C/W JC 145C/W
Applications Information
Enable/Shutdown The MIC5268 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. This part is CMOS and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor An input capacitor is not required for stability. A 1F input capacitor is recommended when the bulk ac supply capacitance is more than 10 inches away from the device, or when the supply is a battery. Output Capacitor The MIC5268 requires an output capacitor for stability. The design requires 1F or greater on the output to maintain stability. The capacitor can be a low-ESR ceramic chip capacitor. The MIC5268 has been designed to work specifically with the low-cost, small chip capacitors. Tantalum capacitors can also be used for improved capacitance over temperature. The value of the capacitor can be increased without bound. X7R dielectric 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 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 or a tantalum capacitor to ensure the same minimum capacitance value over the operating temperature range. Tantalum capacitors have a very stable dielectric (10% over their operating temperature range) and can also be used with this device. Power Good The power good output is an open-drain output. It is designed essentially to work as a power-on reset generator once the regulated voltage was up and/or a fault condition. The output of the power good drives low when a fault condition AND an undervoltage detection occurs. The power good output comes back up once the output has reached 97% of its nominal value and a 1ms to 5ms delay has passed. See Timing Diagram. The MIC5268's internal circuit intelligently monitors overcurrent, overtemperature and dropout conditions and ORs thes outputs together ti indicate some fault condition. this output is fed into an on-board delay circuitry that drives the open drain transistor to indicate a fault.
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 MIC5268-1.2BM5 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) = 315mW The junction-to-ambient thermal resistance for the minimum footprint is 235C/W, from Table 1. The maximum power dissipation must not be exceeded for proper operation. Using the output voltage of 1.2V and an output current of 150mA, the maximum input voltage can be determined. Because this device is CMOS and the ground current is typically 100A over the load range, the power dissipation contributed by the 6 September 2002
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MIC5268
ground current is < 1% and can be ignored for this calculation. 315mW = (VIN - 1.2V) 150mA 315mW = VIN *150mA - 195mW 510mW = VIN *150mA VIN(max) = 3.4V Therefore, a 1.2V application at 150mA of output current can accept a maximum input voltage of 3.4V in a SOT-23-5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the Regulator Thermals section of Micrel's Designing with Low-Dropout Voltage Regulators handbook. Dual-Supply Operation When used in dual supply systems where the regulator load is returned to a negative supply, the output voltage must be diode clamped to ground.
Micrel
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MIC5268
MIC5268
Micrel
Package Information
1.90 (0.075) REF 0.95 (0.037) REF
1.75 (0.069) 1.50 (0.059)
3.00 (0.118) 2.60 (0.102)
DIMENSIONS: MM (INCH) 3.02 (0.119) 2.80 (0.110) 1.30 (0.051) 0.90 (0.035) 10 0 0.15 (0.006) 0.00 (0.000) 0.20 (0.008) 0.09 (0.004)
0.50 (0.020) 0.35 (0.014)
0.60 (0.024) 0.10 (0.004)
SOT-23-5 (M)
MIC5268
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MIC5268
Micrel
MICREL, INC. 1849 FORTUNE DRIVE
TEL
SAN JOSE, CA 95131
WEB
USA
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
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. (c) 2002 Micrel, Incorporated
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MIC5268

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